J_)// 73 UNITED STATES DEPARTMENT OF THE INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. CONTENTS Page Abstract 1 Introduction 2 Historical background 2 Purpose and scope of report 3 Orthography of geographic names 4 Acknowledgments 4 Annotated bibliography 5 Geology 10 Stratigraphy 10 Outline of stratigraphy 10 Cretaceous(?) system 13 Eocene series 13 Gatuncillo formation 13 Eocene or Oligocene series 22 Marine member of Bohio(?) formation 22 Oligocene series 24 Bohio formation 24 Caimito formation, exclusive of Madden basin and Pacific coastal area 28 Tuffaceous strata in Chorrera area 31 Bas Obispo formation and Las Cascadas agglomerate 31 Oligocene and Miocene series 32 Caimito formation of Madden basin and Pacific coastal area 32 Miocene series 34 Culebra formation, including Emperador limestone member 34 Cucaracha formation 39 Panamd, formation, including La Boca marine member and Pedro Miguel ag- glomerate member 39 Gatun formation 42 Pliocene series 47 Chagres sandstone, including Toro lime- stone member 47 Pleistocene series 50 Correlation of Tertiary formations in different areas 50 Page Geology — Continued Igneous rocks 52 Cretaceous(?) volcanic and intrusive rocks 52 Tertiary volcanic and intrusive rocks 53 Granular intrusive rocks 53 Dike rocks 54 Volcanic rocks and tuff 54 Chemical composition 55 Age 56 Structure 57 Structural history 57 Structural features 58 Mineral resources 58 Metallic mineral deposits 58 Nonmetallic mineral deposits 59 Oil possibilities 60 Description of Tertiary mollusks 62 Gastropods 62 Family Trochidae 62 Family Turbinidae 64 Family Phasianellidae 65 Family Phasianellidae? 66 Family Neritidae 66 Family Thiaridae? 68 Family Littorinidae 68 Family Vitrinellidae 69 Family Rissoidae 76 Family Rissoinidae 77 Family Xenophoridae 77 Family Hipponicidae 78 Family Hipponicidae? 78 Family Crepidulidae 79 Family Calyptraeidae 79 Family Naticidae 84 Family Turritellidae 97 Localities at which fossils were collected 112 References cited 131 Index 137 ILLUSTRATIONS [Plates 1, 2 in pocket, plates 3-23 follow p. 145] Plate 1. Geologic map of Canal Zone and adjoining parts of Panama In pocket. 2. Geologic map of Gaillard Cut area, Canal Zone In pocket 3. Foraminiferal limestone from Gatuncillo formation of Madden basin, Panama. 4. Echinoid-bearing limestone from Gatuncillo formation of Madden basin, Panamd. 5. Boulder conglomerate of Bohio formation at Salud Point, Barro Colorado Island, Canal Zone. 6. Poorly sorted conglomerate of Bohio formation on Transisthmian Highway near Las Cumbres, just south of continental divide, Panama. 7. Alhajuela sandstone member of Caimito formation at north abutment of Madden Dam, Canal Zone. ni IV CONTENTS Plate 8. Emperador limestone member of Culebra formation on west bank of Panama Canal at canal station 1619, Canal Zone. 9. Coralliferous limestone at base of La Boca marine member of Panama formation on Rio Masambi 200 meters up- stream from east bank of Panama Canal, Canal Zone. 10. Strata in middle part of Gatun formation on east side of Gatun Third Locks excavation, Canal Zone. 11. Toro limestone member of Chagres sandstone resting on marly siltstone in middle part of Gatun formation in road cut 3 kilometers southwest of Gatun, Canal Zone. 12. Toro limestone member of Chagres sandstone in road cut 3 kilometers north-northwest of Gatun, Canal Zone. 13. Chagres sandstone in road cut 3 kilometers south of Lagarto, Panama. 14. Middle and late Eocene mollusks from Gatuncillo formation. 15. Late Eocene or early Oligocene mollusks from marine member of Bohio(?) formation and late Oligocene mollusks from middle member of Caimito formation in Gatun Lake area. 16. Early Miocene mollusks from Culebra formation and La Boca marine member of Panama formation. 17. Middle and late Miocene mollusks from Gatun formation. 18. Middle and late Miocene mollusks from Gatun formation and early Pliocene mollusk from Chagres sandstone. 19, 20. Middle Miocene mollusks from Gatun formation. 21, 22. Middle and late Miocene mollusks from Gatun formation. 23. Middle Miocene mollusks from Gatun formation. Page Figure 1. Map of Panama showing principal areas of Tertiary marine sedimentary formations and area covered by plate 1__ 11 2. Ungulate metapodial from transition zone between Culebra and Cucaracha formations 38 3. Reconnaissance geologic map of Caribbean coastal part of Panama immediately west of Canal Zone 45 4. Correlation of Tertiary formations in different areas 51 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE AND ADJOINING PARTS OF PANAMA GEOLOGY, AND DESCRIPTION OF TERTIARY MOLLUSKS (GASTROPODS: TROCHIDAE TO TURRITELLIDAE) By W. P. Woodring ABSTRACT Most of the area covered by the present report lies in the central Panama area of Tertiary marine sedimentary rocks, which extends obliquely across the trend of the isthmus. The central Panama area contains a sequence of Tertiary deposits, for the most part marine, ranging in age from middle Eocene to early Pliocene. In the southwestern part of the Canal Zone and farther west a thick sequence of volcanic rocks borders the marine area. In the Gaillard Cut area, along the Panama Canal, the marine and volcanic rocks interfinger. The oldest rocks, forming the basement on which the Tertiary formations rest, are more or less altered basaltic and andesitic lavas. Altered tuffs containing microscopic marine fossils are interbedded with the lavas. These basement rocks are of Cretaceous (?) age. Sometime during Late Cretaceous, Paleo- cene, or early Eocene time they were strongly deformed and perhaps at about the same time were intruded by dioritic and dacitic rocks. This is the strongest regional deformation in the known geologic history of this part of Panamd. The middle and upper Eocene Gatuncillo formation rests with marked unconformity on the basement rocks. The Gatuncillo is widely transgressive and is essentially uniform lithologically, consisting principally of fine-grained detrital rocks. There is no indication of nearby volcanism during middle and late Eocene time. Volcanism reached a climax during Oligocene and early Miocene time. The volcanic centers, which presumably are now concealed by later volcanic rocks, evidently were located in southern Panama not far west of the Canal Zone. A tongue of Oligocene (?) volcanic rocks, interpreted to have accumulated at the periphery of a volcanic pile, extends eastward across the canal in the northern part of the Gaillard Cut area. These volcanic rocks, consisting of agglomerate, tuff, and thin ande- sitic flows and flow breccias, constitute the Bas Obispo formation and Las Cascadas agglomerate. They are considered of Oligo- cene (?) age because of their inferred relation to Oligocene deposits in the adjoining marine area. The Oligocene deposits in the marine area are heterogenous and contain much volcanic debris. The earliest of these deposits are basaltic boulder conglomerate and basaltic graywacke forming the Bohio formation. This coarse debris, directly overlying the fine-grained rocks of the Gatuncillo formation, indicates movements in the source areas. As a result of these movements the Bohio formation overlaps the Gatuncillo forma- tion in the Pacific coastal area east of the Canal Zone. The Bas Obispo formation is thought to grade northward into the Bohio. Though the Bohio represents for the most part an extension of nonmarine deposits into the marine area, it includes marine deposits. Marine upper Eocene or lower Oligocene strata in the western part of the Gatun Lake area are interpreted as a marine member in the lower part of the Bohio (?) ; the basal part of the Bohio in the Quebrancha syncline includes lower Oligocene marine siltstone; and the upper part of the formation on Barro Colorado Island and in the Pacific coastal area contains thin upper Oligocene marine deposits. Late Oligocene time also witnessed the deposition in the marine area of heterogenous strata overlying the Bohio formation. These strata are almost entirely marine and are grouped as the Caimito formation. The Caimito overlaps the Bohio in the northern part of Madden basin and apparently also northeast of Gatun Lake, where it evidently rests directly on the basement. The overlap indicates continuation of the minor movements that affected the distribution of the Bohio formation. The Caimito formation is made up chiefly of tuffaceous sandstone, tuffaceous siltstone, conglomerate, tuff, agglomerate, and limestone. In the Quebrancha syncline it includes the eco- nomically important Quebrancha limestone member, which is quarried for the manufacture of cement. The lower member in the Gatun Lake area (or perhaps the entire formation) is thought to grade southward into the Las Cascadas agglomerate of the Gaillard Cut area. Alternating marine and volcanic deposits were laid down in the Gaillard Cut area in early Miocene time. These deposits make up, in ascending order, the Culebra formation, including the Emperador limestone member, the Cucaracha formation, and the Panama formation, including the La Boca marine member and the Pedro Miguel agglomerate member. Though the Culebra formation contains much tuffaceous material, it consists of dark thin-bedded shale, mudstone, and siltstone; calcareous sand- stone, and limestone — all laid down during a minor marine transgression. The Cucaracha formation consists almost entirely of nonmarine tuff, altered to bentonitic clay. Tuff and rela- tively fine grained agglomerate are the chief constituents of the Panama formation proper; silty mudstone, sandstone, limestone, and tuff make up the La Boca marine member; coarse-grained agglomerate the Pedro Miguel agglomerate member. The La Boca marine member represents a reinvasion of the sea that transgressed across the Cucaracha and Culebra formations onto the Bas Obispo formation. Two of these lower Miocene forma- tions, the Culebra and Cucaracha, are readily eroded. They form topographic basins between hills of agglomerate and basalt, and these topographic basins determined the course of the canal. The Panama formation is the youngest Tertiary formation in the Gaillard Cut area and in the Pacific coastal area east of the Canal Zone. Tuffaceous sandstone and limestone deposited in Madden basin during early Miocene time are grouped with the underlying strata of late Oligocene age in that area as the Caimito formation. Though the lower Miocene part of the Caimito formation of Madden basin is thought to include the equivalent of the lower Miocene formations of the Gaillard Cut area, there is no satis- factory faunal or lithologic correlation from one area to the other. The lower Miocene formations of the Gaillard Cut area and the deposits in Madden basin considered to be their equivalent represent the early half of the early Miocene, which corresponds to the late Oligocene of some paleontologists. The youngest deposits in Madden basin (the Alhajuela sandstone member of the Caimito formation), however, are younger than the disputed Oligocene or Miocene. Madden basin is the only area where GEOLOGY AND PALEONTOLOGY OF CANAL ZONE late lower Miocene marine deposits have been found. They are almost exactly in the center of the present isthmus. The Oligocene and lower Miocene volcanic rocks include widespread remnants of basalt flows in the Gaillard Cut and adjoining areas. The climax of volcanism during Oligocene and early Miocene time was accompanied by marked intrusive activity. Stocks of quartz diorite, diorite, and dacitic and andesitic rocks, dikes of andesite, and dikes and irregular bodies of basalt represent that interval of intrusive activity and are not known to be younger. The Gatun formation was deposited during a middle and late Miocene marine transgression. The Gatun of the area covered by plate 1 is assigned to the middle Miocene. The upper part at the west end of the outcrop area is considered late Miocene. The relations between the Gatun formation and the Caimito formation — the next older formation in the Gatun Lake and Caribbean coastal areas — are unknown. The apparent absence of lower Miocene deposits in those areas indicates discontinuity, and transgressive overlap of the Caimito is shown by relations at the east end of the outcrop area of the Gatun, where it directly overlies the basement rocks. At least minor movements (and perhaps regional deformation) took place before the Gatun was deposited. How far inland beyond its present outcrop area the Gatun formation extended is not known. If it extended far inland, presumably it extended through Madden basin. The only tuff in the Gatun formation is very fine-grained and evidently was derived from a distant source. The Chagres sandstone, including the Toro limestone member, represents a minor early Pliocene transgression. The Chagres crops out in a narrow belt along the Caribbean coast. The Toro limestone member consists of thin basal calcareous strata de- posited in shallow water. These shallow-water deposits suggest that the formation did not extend much beyond its present inland border. The Chagres contains little tuffaceous material. The moderately strong deformation of the pre-Gatun Tertiary formations is of regional extent, the results of the second regional deformation, but is not well dated. It may have taken place during early Miocene time or during Pliocene time after deposi- tion of the Chagres sandstone. The Gatun formation and Chagres sandstone are only mildly deformed, but mild deforma- tion in the Caribbean coastal area may have taken place at the same time as stronger deformation elsewhere. Pleistocene deposits, characterized by much black organic material, are found in valleys that were cut in the Chagres standstone and older formations and later filled during sub- mergence. Near the coast the Pleistocene strata include fossilif- erous marine deposits. Seventy-eight species and subspecies of Tertiary mollusks, representing 15 families of gastropods, are described and 13 others are recorded. Fifty of the 91 forms are from the Gatun formation. These 91 forms are estimated to represent about a seventh of the total available molluscan fauna in the marine Tertiary formations. INTRODUCTION HISTORICAL BACKGROUND Marked advances in knowledge of the geology of the present Canal Zone coincide with three periods of active investigations bearing on construction of the canal or on proposed changes affecting it: French operations (1881-89 and 1895-99), American construction (1905- 13), and Third Locks and Sea-level Conversion Route studies (1938-48). With one exception, accounts of the geology that were published before French operations started are of historical interest only (Garella, 1845, 1849, pp. 519- 524; Wagner, 1861; Maack, 1874, pp. 164-167; Wyse, Reclus, and Sosa, 1879, pp. 153-163; Boutan, 1880). The exception is Boutan's account. His scientifically and historically important paper, published in 1880, a few years after the earliest description of the microscopic petrology of American rocks, was based on a micro- scopic examination at the Ecole de Mines of rocks he collected along the Panama Railroad just before French operations got under way. He also had a better idea of the age of the sedimentary rock formations than his predecessors. Chaper's report (1890), written during liquidation of the first French company, does not add much to Boutan's. During the operations of the first French company collections of fossils were sent to the French paleontolo- gist Henri Douville. His age assignments (Douville, 1891), published after liquidation of the first company, placed the geology on a firmer footing. The most important publication during the period of French operations was prepared by the French geologist Marcel Bertrand in collaboration with a Swiss engineer who had worked on the canal, Philippe Zurcher (Bertrand and Zurcher, 1899). It was based on the work done by the French companies and on a new set of age assignments by Douville (1898). The account by Bertrand and Zurcher emphasized the fol- lowing major features of the geology along the canal: the pyroclastic rocks and associated lavas southeast of the big bend in Rio Chagres at the present site of Gamboa are the oldest rocks; the strata overlying them are in general progressively younger toward both the Caribbean Sea and the Pacific Ocean; the fossiliferous strata are of Oligocene and Miocene age. The vol- canic rocks are now thought to be of the same age as the oldest sedimentary formations along the shores of Gatun Lake. Otherwise Bertrand and Ziircher's con- clusions have been confirmed by later investigations and are accepted at the present time. In the meantime R. T. Hill visited Panama in 1895, before the second French company resumed operations. He evidently did not have access to most of the sub- surface records and there is no indication that he was aware of Douville's 1891 note. His report (1898) was supported by paleontologic work by Dall. Hill thought the oldest strata, probably pre-Tertiary, to be on the Pacific coast. Through some misfortune, one of his collections of fossils was mislabelled before it reached D all's hands. As a result of the mislabelling, Dall referred part of the Gatun formation to the Eocene, an error that affected American geologic literature for many years. INTRODUCTION Soon after American operations were started, Ernest Howe was employed by the Isthmian Canal Commission to study the geology. Though he was in the Canal Zone only five months during 1906 and 1907, his reports clearly set forth the essential features and went a long way toward systematizing the stratigraphic nomenclature (Howe, 1907, 1907a, 1908). Appoint- ment of D. F. MacDonald, formerly of the U. S. Geological Survey, as resident geologist during the last two years of the construction period (1911-13) led to further advances and to the gathering of much infor- mation (MacDonald, 1913, 1913a, 1915, 1919). Only the first of the four publications by MacDonald just cited is generally cited on the following pages in the discussion of the stratigraphy. The others contain practically identical descriptions, aside from new names. Many of the fossils described in the present report were collected by MacDonald or by MacDonald and Vaughan, when Vaughan collaborated with him in the latter part of 1911. The stratigraphy, as worked out by MacDonald and Vaughan, was described in Bulletin 103 of the U. S. National Museum (Vaughan, 1919). Though Bulletin 103 was issued in 1919, many of its parts were published separately in 1918, and Jackson's part on the echinoids was issued separately in 1917 and again in 1918. In the preparation of Bulletin 103 Vaughan enlisted the services of a group of paleontolo- gists, who described practically all the Canal Zone fossils then available in the National Museum collec- tions, except the mollusks. Not all the fossils described in Bulletin 103 are mentioned in the summaries on the following pages. Calcareous algae (M. A. Howe, 1918), land plants (Berry, 1918), Bryozoa (Canu and Bassler, 1918), decapod crustaceans (Rathbun, 1918), and barnacles (Pilsbry, 1918) are omitted. The third period of marked advances resulted from investigations, including the study of some 2,000 cores, of the Geological Section of the Special Engineering Division of the Panama Canal, carried out under the direction of T. F. Thompson. The surface and sub- surface studies undertaken by this staff of geologists were for the most part directly related to the Third Locks and Sea-level Conversion Route projects. The published reports prepared by the Geological Section include summaries of the geology and more detailed descriptions of particular areas (Thompson, 1943, 1943a, 1944, 1947, 1947a). The oldest rocks, older than any along the canal, were found to consist of a basement of unknown age overlain by deposits of Eocene age. Agglomerate along the southeastern part of the canal, formerly correlated with agglomerate underlying the Culebra formation, overlies the Culebra. Marine deposits in the same region formerly identified as the Culebra formation, also are younger than that formation. PURPOSE AND SCOPE OF REPORT The National Museum's collection of fossil mollusks from the Canal Zone represent a collecting span of a century. Not many collections, however, were received prior to 1911, when the fossils collected by MacDonald began to arrive. It was expected that the mollusks would be studied by W. H. Dall, the dean of American Tertiary invertebrate paleontologists. For the most part he got no further than generic identification of MacDonald 's early collections. Therefore the mol- lusks — the most abundant fossils then available — were omitted when Bulletin 103 was assembled. A considerable number of mollusks from the richly fos- siliferous Gatun formation, collected while the canal was being constructed, were described by Toula (1909, 1911) and by Brown and Pilsbry (1911, 1913) before the publication of Bulletin 103. Other Gatun species have been recorded in scattered publications, and also a few from other formations (Culebra formation and its Emperador limestone member, Toro limestone member of Chagres sandstone). Nevertheless the National Museum collections represent much valuable information, which is not in useable form until the fossils are adequately studied. The present report is designed to meet that need. The collections obtained before and during con- struction of the canal are especially valuable, for very few of them can be duplicated. Some of them, par- ticularly in Gaillard Cut, represent excavated prisms of rock; many other localities are now submerged; still others are inaccessible through the rapid dis- integration of rock and the rapid growth of a thick cover of vegetation. To take advantage of the store of information gathered by the Geological Section of the Special Engineering Division, field work in the Canal Zone was undertaken during the dry season early in 1947. By that time it was evident that work in the fairly com- plete succession of lower and middle Tertiary marine formations in Panama east of the Canal Zone was needed to interpret the less complete partly marine succession of the same age in the Zone. Further field work was carried out early in 1949 and early in 1954. The work in 1954 was limited to Barro Colorado Island and nearby parts of the Gatun Lake area. The geology of Barro Colorado is to be described in a separate publication. The field work was designed as a stratigraphic and paleontologic project — not as a mapping project, which would have been very time-consuming. Some kind of map, however, was needed to show the localities GEOLOGY AND PALEONTOLOGY OF CANAL ZONE at which fossils were collected. A decision was reached to compile a geologic map, based on the material in the publications and files of the Geological Section of the Special Engineering Division, supplemented by scattered personal observations. The resulting map on the scale of 1:75,000, issued as a separate publication in 1955, is reproduced with minor alterations as plate 1 of the present report. The quality of the map is very uneven. Parts of it show the geology in con- siderable detail; other parts are greatly generalized and represent rapid reconnaissance. Despite its de- fects, however, it shows the geologic setting of the Canal Zone and adjoining parts of Panama. The only comparable map was published by MacDonald (1915, pi. 4; 1919, pi. 153) on a scale of about 1:260,000. The base used for the 1955 map does not show the recent suburban expansion of the city of Panama. At first the present report was planned to consist of a discussion of the stratigraphy, summaries of the occur- rence of fossils other than mollusks, and description of the Tertiary mollusks. While the work was in progress, an incomplete carbon copy of a manuscript by Mac- Donald on the geology of Panama was found among Dall's effects at the U. S. National Museum. This report, prepared soon after MacDonald's tour of duty as resident geologist in the Canal Zone, was mentioned by MacDonald (1913, p. 579) and Vaughan (1919, p. v). It was not finished because Dall's work on the fossils was not completed. One of MacDonald's duties as resident geologist was to recommend rock for use as concrete aggregate, as armoring for breakwaters and earth dams, and for other construction purposes. In carrying out this assignment he examined outcrops of igneous rocks, studied thin sections of them, and ar- ranged for chemical analyses of some of the rocks to be made in the chemical laboratory of the U. S. Geological Survey. His description of the rocks, which is more complete than his published notes, and the chemical analyses are included in his manuscript. They have been incorporated in the present report, although the analyses have already been published. Though the present report includes more than stra- tigraphy and paleontology, the title — chosen for brev- ity — is too comprehensive. Many aspects of the geology are omitted or are only briefly considered. This report is, in fact, a progress report so far as the geology is concerned. Much of the area covered by plate 1 has not yet been studied and it may bo a long time before the entire region is adequately studied. The systematic paleontology deals with the mollusks in about 260 collections from all the fossiliferous Terti- ary formations, which range in age from middle and late Eocene to early Pliocene. In chapter A, 78 species and subspecies of gastropods are described and 13 others are recorded. These 91 forms are estimated to repre- sent about a seventh of the total available molluscan fauna to be described. Fifty of the 91 are from the Gatun formation, an indication of the size of the Gatun fauna. Fuller discussion of the age and correlation of the formations is planned for the final part of the report. That part also is to contain a discussion of the broader aspects of the succession of faunas, including their bear- ing on the history of the Panama land bridge and the light they shed on paleoecology. ORTHOGRAPHY OF GEOGRAPHIC NAMES Spanish orthography, including accent marks, is used for geographic names in Panama. In the Canal Zone, however, many names of Spanish origin are anglicized and for such names accent marks are omitted. The major streams cross the boundary, and therefore "rio" or "quebrada" is used for all the streams that are named, regardless of location. The plan just outlined results in "Panama" for the name of the country, the capital city, and a geologic formation, but "Panama Railroad" and "Panama Canal" for two features in the Canal Zone. ACKNOWLEDGMENTS Brig. General J. H. Stratton, (retired, then Col.), Supervising Engineer in charge of the Special Engineer- ing Division, and T. F. Thompson, Chief of the Geo- logical Section of the Division, placed every facility at my disposal during the field work in 1947, and Mr. Thompson again in 1949, when the Division had prac- tically completed its work and its staff was greatly reduced. Mr. Thompson has a wide familiarity with the geology of the Canal Zone and Panama^ which he freely shared, and he guided me to many localities where fossils are available. Other geologists of the Geological Section were very helpful. Special acknowledgment should be made to S. K. Bartholomew, L. H. Hender- son, S. M. Jones, J. M. Matthews, T. G. Moran, J. R. Schultz, R. H. Stewart, J. A. Tavelli, and L. C. Woolfe. The general geologic map (pi. 1) is based for the most part on material gathered by geologists of the Geo- logical Section: principally a published map of the Gatun Lake area by S. M. Jones (1950, pi. 2); a map of the Quebrancha syncline by T. F. Thompson, a small part of which was published (Thompson, 1944); a map of an area east of Gamboa, between Rio Chagres and Madden Highway, by L. C. Woolfe; strip maps along the proposed sea-level canal (Thompson, 1947a, figs. 29-32) ; strip maps of the Chorerra route by J. R. Schultz. Mr. Thompson and Mr. Stewart offered valuable suggestions for filling in gaps. I, however, must assume responsibility for the map's shortcomings, INTRODUCTION which will become apparent as additional work is done. G. E. Lewis, of the U. S. Geological Survey, and J. G. Marks, of Creole Petroleum Corporation, assisted in preparation of the Spanish explanation. The sea- level canal strip maps already mentioned were used for the more detailed map of the Gaillard Cut area (pi. 2). The field photographs, from the files of the Special Engineering Division, are available through the kind- ness of Mr. Thompson. Large faunas of smaller Foraminifera from the Gatun- cillo and Bohio formations, collected in 1947 and 1949, were identified by H. H. Renz and P. J. Bermiidez, both of Caracas, Venezuela. Larger Foraminifera collected at the same time were identified by W. S. Cole, of Cornell University and the U. S. Geological Survey (Cole, 1952 (1953)); corals by J. W. Wells, of Cornell University and the U. S. Geological Survey; echinoids by C. W. Cooke, of the U. S. Geological Survey (Cooke, 1948). M. N. Bramlette, of the Scripps Institution of Oceanography and the U. S. Geological Survey, furnished notes on smaller Forami- nifera found in the Caimito and Culebra formations and in the La Boca marine member of the Panama for- mation. R. A. Stirton, of the University of California, kindly furnished drawings of a mammal bone and com- ments concerning that interesting fossil. Samples of lava and tuff from the basement complex were examined by W. S. Burbank, of the U. S. Geological Survey, who also kindly read the part of the report dealing with the igneous rocks. Extensive collections of mollusks from the Gatun formation, deposited at Stanford University by Mr. Thompson, were generously loaned by Miss A. Myra Keen. For permission to examine types and other specimens I am indebted to H. A. Pilsbry, A. A. Olsson, and Miss Anne Harbison, of the Academy of Natural Sciences of Philadelphia; W. S. Cole, of Cornell University; the late G. D. Harris, of the Paleontological Research Institution; J. W. Durham, of the University of California; and L. G. Hertlein, of the California Academy of Sciences. For much advice I am indebted to H. A. Rehder, of the U. S. National Museum, and R. T. Abbott, formerly of that institution, where this work was carried out. ANNOTATED BIBLIOGRAPHY The following briefly annotated bibliography lists publications on the geology and paleontology of the Canal Zone and adjoining parts of Panama. It includes publications containing information on those subjects, though the publications are primarily devoted to other areas. With three exceptions, it does not include publications on engineering aspects of construction, of the canal — notably on the canal slides — despite men- tion or discussion of geologic features. The three ex- ceptions are MacDonald's U. S. Bureau of Mines Bulletin 86, issued in 1915, the National Academy of Sciences 1924 report on slides, and MacDonald's 1947 posthumous publication on the same subject. No attempt has been made to glean incidental geologic observations from early literature. A great number of travelers crossed the isthmus during the California gold rush, first by boat up Rio Chagres to Las Cruces (a short distance above the present site of Gamboa) and thence by muleback, and later by the Panama Railroad, which was completed in 1855. Some of the travelers who wrote about their journey in books or nongeologic periodicals may have recorded observa- tions on the geology. 1845. Garella, Napoleon, Projet d'un canal de jonction de l'Ocean Pacifique et de l'Ocean Atlantique a travers l'isthme de Panama, 233 p., maps, profiles, Paris. Chapter 4 (p. 35-46), "Apercu geologique sur la constitution des terrains de l'isthme", is generalized and of little interest. The 1:200,000 hachured topographic map, prepared in 1844, is an important historical document. 1849. Garella, Napoleon, Project of a canal to connect the Atlantic and Pacific oceans across the Isthmus of Panama: U. S. 30th Cong., 2nd sess., House Rept. 145, p. 506-590, maps, profiles. Translation of preceding publication. 1853. Moore, J. C, Notes on the fossil Mollusca and fish from San Domingo: Geol. Soc. London Quart. Jour., v. 9, p. 129-132. A note at the end of this paper (p. 132) is the first record in a scientific journal of the discovery of Miocene fossils in the present Canal Zone. The fossils were found "about 2}i miles from the shores of Navy Bay [Limon Bay] * * * in a cutting of the Panama Railway" [near Mindi]. 1855. Deck, Isiah, Notes on the geological features of the Panama Railroad: Mining Mag., v. 4, p. 240-245, New York. Fossils were observed at Monkey Hill [Mount Hope] but not at Gatun. 1855. Conrad, T. A., Report on the fossil shells collected in California by Wm. P. Blake, geologist of the expe- dition under the command of Lieutenant R. S. Williamson, United States Topographical Engineers; appendix to the preliminary geological report of William P. Blake: U. S. Pacific R. R. Expl., U. S. 33rd Cong., 1st sess., House Ex. Doc. 129, p. 5-20. Includes three species of mollusks collected by Blake. The type of one species (Gratelupiaf mac- tropsis) is in the National Museum. 1857. Blake, W. P., Geological report [Williamson's reconnais- sance in California]: U. S. Pacific R. R. Expl., v. 5, pt. 2, 370 p., 11 pis., maps, sections. Observations on trip across Panama are recorded (p. 1-2). A few fossils were collected "at Gatun, or Monkey Hill?." The species indicate they were collected at Gatun. 413788—57- 6 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE 1857. Conrad, T. A., Descriptions of the fossil shells [William- son's reconnaissance in California]: Idem, app., art. 2, p. 317-329, pis. 2-9. Conrad's 1855 descriptions are repeated and poor illustrations are added. 1857. Conrad, T. A., Description of the Tertiary fossils collected on the survey [Williamson's survey in California and Oregon]: Idem, v. 6, pt. 2, p. 69-73, pis. 2-5. Includes five species of mollusks collected by Newberry at Gatun. 1861. Wagner, Moritz, Beitrage zu einer physisch-geographis- chen Skizze des Isthmus von Panama: Petermanns Mitt., Erganzungsheft 5, 25 p., map. Geologic observations are incidental and unim- portant. Reddish conglomerate and fragmental rocks at city of Panama are assigned to Permian. 1874. Maack, G. A., Report on the geology and natural history of the isthmuses of Choco, of Darien, and of Panama, in Self ridge, T. O., Reports of explorations and surveys to ascertain the practicability of a ship-canal between the Atlantic and Pacific Oceans by the way of the Isthmus of Darien, p. 155-175, Washington. Geologic observations along Panama Railroad (p. 164-167) are inconsequential. Maack, like Wagner, suggested a Permian age for red conglom- erate at Panama. 1879. Wyse, L. N. B., Reclus, Armand, and Sosa, P., Rapports sur les etudes de la commission internationale d'exploration de l'isthme americain, 294 p., 2 maps, Paris. Account of geology along route of proposed canal, like earlier accounts, is of historical interest only. List of rocks collected (p. 279-280) was prepared by Daubree. 1880. Boutan, E., Note sur la constitution geologique de l'isthme de Panama: Annales de Mines, 7th ser., t. 18, p. 5-58, 2 pis. (map and profiles). Interesting account of geology along route of proposed canal, based on microscopic examination, at Ecole des Mines, of rocks collected along Panama Railroad. 1881. Gabb, W. M., Descriptions of Caribbean Miocene fossils: Acad. Nat. Sci. Philadelphia Jour., 2d ser., v. 8, p. 337-348, pis. 44, 45. Includes eight species of mollusks collected by Newberry at Gatun. 1886. Wyse, L. N. B., Le canal de Panama, 399 pp., maps, woodcuts, Paris. Discussion of geology (pp. 12-20) is drawn from earlier accounts. Fossils at scattered localities are mentioned. Shaded relief map of canal route is on scale of 1:100,000. 1890. [Chaper, ], Description geologique des terrains traversees par le canal: Commission d'6tudes in- stitute par le liquidateur de la compagnie universelle, Rapport 6, 30 p., Paris. According to Douville (1898, p. 589, footnote), Chaper, an engineer of the first French company, wrote this account. It does not add much to Boutan's. Black fossiliferous limestone at Vamos Vamos, however, is mentioned. 1890- Dall, W. H., Contributions to the Tertiary fauna of 1903. Florida: Wagner Free Inst. Sci. Trans., v. 3, 6 pts., 1,654 p., 60 pis. Includes mollusks from Vamos Vamos, Gatun, and Monkey Hill [Mount Hope]. 1891. Douville, Henri, Sur l'age des couches traversees par le canal de Panama: Acad. Sci. Paris Compte Rendu, t. 112, p. 497-499. First modern age assignments. The fossiliferous strata are assigned to Oligocene and Miocene. 1896. Guppy, R. J. L., and Dall, W. H., Descriptions of Tertiary fossils from the Antillean region: U. S. Natl. Mus. Proc, v. 19, p. 303-331, pis. 27-30. Includes two species of mollusks from Gatun and Monkey Hill [Mount Hope]. 1898. Hill, R. T., The geological history of the Isthmus of Panama and portions of Costa Rica: Mus. Comp. Zool. Harvard College Bull., v. 28, p. 151-285, 19 pis., 24 figs. Geology of Panama Railroad and French canal. 1898. Douville, Henri, Sur l'age des couches traversees par le canal de Panama: Soc. Geol. France Bull., 3me ser., t. 26, p. 587-600. Some of Douville's 1891 age assignments are changed; others are reinforced by additional data. 1899. Bertrand, Marcel, and Zurcher, Philippe, Etude geolo- gique sur l'isthme de Panama: Compagnie Nouvelle du Canal de Panama, Rapport de la Commission, app. 1, p. 83-106, map, structure sections, Paris. Most satisfactory of earlier accounts of geology of canal route. The map (scale 1:100,000), which has 10-meter (or several tens of meters) contours along route of canal and up Rio Chagres to Alhajuela, is the last and the best of the French maps. Bouvier, E. L., Calappa zurcheri, crabe nouveau des terrains miocenes de Panama: Mus. Hist. Nat. Paris Bull., t. 5, p. 189-192, 1 fig. Locality where this fossil was found is not specified. Hershey, O. H., The geology of the central portion of the Isthmus of Panama: Calif. Univ., Dept. Geol., Bull., v. 2, p. 231-267, map. Panama formation at and near Panama is briefly mentioned (p. 245-246) . Hershey's age assignments are much too old. 1904. Cushman, J. A., Pleistocene foraminifera from Panama: Am. Geologist, v. 33, p. 265-266. List of 14 species from a locality near Mindi. 1904. Lemoine, P., and Douville, R., Sur le genre Lepidocyclina Giimbel: Soc. Geol. France Mem. 32 (t. 12), p. 1-42, pis. 1-3. Includes Lepidocyclina chaperi and L. canellei,, both named for engineers of first French company. 1907. Howe, Ernest, Report on the geology of the Canal Zone: Isthmian Canal Comm., Ann. Rept., 1907, app. E, p. 108-138, pi. 147. Principal features of Canal Zone geology. 1907. Howe, Ernest, Isthmian geology and the Panama Canal: Econ. Geology, v. 2, p. 639-658, pi. 8. Economic aspects of geology are emphasized. 1908. Howe, Ernest, The geology of the Isthmus of Panama: Am. Jour. Sci., 4th ser., v. 26, p. 212-237. Stratigraphy and paleontology are emphasized. 1909. Toula, Franz, Eine jungtertiare Fauna von Gatun am Panama-Kanal: K. k. Geol. Reichsanstalt Jahrb., Band 59, p. 673-760, pis. 25-28, 15 figs. Mollusks, otoliths, and a few other fossils from Gatun formation, mostly from Gatun Locks site and spillway of Gatun Dam. 1899. 1901. INTRODUCTION 1911. Brown, A. P., and Pilsbry, H. A., Fauna of the Gatun formation, Isthmus of Panama: Acad. Nat. Sci. Phila. Proc, v. 63, p. 336-373, pis. 22-29. Mollusks from Gatun Locks site, one of which also occurs at Monkey Hill [Mount Hope]. 1911. Toula, Franz, Die jungtertiare Fauna von Gatun am Panama-Kanal; 2. Teil: K. k. Geol. Reichsanstalt Jahrb., Band 61, p. 487-530, pis. 30, 31. Mollusks and a few coral, echinoid, and crab remains. 1912. Dall, W. H., New species of fossil shells from Panama and Costa Rica: Smithsonian Misc. Coll., v. 59, no. 2, 10 p., March, 1912. Includes 11 species of Pleistocene mollusks collected near Mount Hope and 1 species and variety collected at Toro Point [Toro limestone member of Chagres sandstone]. 1912. de Boury, E., in Cossmann, M., Essais de paleoconch- ologie comparee t. 9, 215 p., 10 pis., August, 1912. The fossil from Toro Point described by Dall five months earlier as Epitonium (Sthenorytis) toroense is described by de Boury as Stenorhytis chaperi (p. 177). 1913. de Boury, E., Catalogue raisonne de la collection de Scalaria vivants et fossiles du Museum de Paris: Mus. Hist. Nat. Paris Nouv. Arch., 5me ser., t. 4, p. 209-266, pis. 12-16. Includes another description of Stenorhytis chaperi (p. 252). 1913. Brown, A. P., and Pilsbry, H. A., Fauna of the Gatun formation, Isthmus of Panama; pt. 2: Acad. Nat. Sci. Phila. Proc, v. 64, p. 500-519, pis. 22-26, 5 figs., 1912 (1913). Mollusks from Gatun formation, from "the Pecten bed at tower N, Las Cascadas" [Emperador lime- stone member of Cuelbra formation], and mollusks and a crab from "the lignitic layers near tower N, Las Cascadas" [Culebra formation proper]. 1913. Brown, A. P., and Pilsbry, H. A., Two collections of Pleistocene fossils from the Isthmus of Panama: Idem, v. 65, p. 493-500, 3 figs. Numerous Pleistocene mollusks and a barnacle collected near Mount Hope and at north end of Gatun Locks are listed, and 6 species and subspecies of mollusks are described. 1913. MacDonald, D. F., Geology of the Isthmus: Canal Record, v. 6, no. 27, p. 213-215, Feb. 26, 1913. A preliminary account. Stratigraphic nomen- clature is same as in next item, but it would be in- appropriate to cite a weekly periodical of limited distribution for new stratigraphic names. 1913. MacDonald, D. F., Isthmian Geology: Isthmian Canal Comm., Ann. Rept., 1913, app. S, p. 564-582, pis. 65-77. With exception of names published later, this pub- lication is cited in present report for MacDonald's stratigraphic geology. Published in latter part of 1913; transmittal of volume is dated Sept. 15. 1913. MacDonald, D. F., Geologic section of the Panama Canal Zone (abstract): Geol. Soc. America Bull., v. 24, p. 707-710. Aside from omission of first two paragraphs, this is a republication of the earlier "Canal Record" account. 1913. 1915. 1915. 1917. 1917. 1918. 1918. 1918. 1918. 1918. Cossmann, M., Etude comparative de fossiles mioceniques recueillis a la Martinique et a l'isthme de Panama: Jour. Conchyliologie, t. 61, pp. 1-64, pis. 1-5. Includes mollusks from Gatun formation at Mindi and Monkey Hili [Mount Hope]. Douville, Henri, Les couches a orbitoldes de l'isthme de Panama: Soc. Geol. France Compte Rendu Som., 1915, no. 16, p. 129-131. Oligocene age of limestone on upper Chagres [Gatun cillo formation] is reiterated, despite presence of a discocyclinid. Strata at Pena Blanca [Caimito formation] and Pedro Miguel [probably Culebra formation] are considered to be of Aquitanian age. MacDonald, D. F., Some engineering problems of the Panama Canal in their relation to geology and topog- raphy: U. S. Bur. Mines Bull. 86, 88 p., 29 pis., 9 figs. The name "Toro limestone" is proposed. De- scription of some formations is more detailed than in MacDonald's earlier publications. Sheldon, P. G., Atlantic slope Areas: Palaeontographica Americana, v. 1, no. 1, p. 1-101, pis. 1-16. A new name, Area balboai (p. 69), is proposed for a species from Culebra formation. Jackson, R. T., Fossil echini of the Panama Canal Zone and Costa Rica: U. S. Natl. Mus. Proc, v. 53, p. 489-501, pis. 62-68, 4 figs. Echinoids from Emperador limestone [member of Culebra formation] and Gatun formation. Howe, M. A., On some fossil and Recent Lithothamnieae of the Panama Canal Zone: U. S. Natl. Mus. Bull. 103, p. 1-13, pis. 1-11. Calcareous algae from Caimito formation [mis- identified as Culebra formation and Emperador limestone member] and Pleistocene deposits. Reis- sued in complete volume, 1919. Berry, E. W., The fossil higher plants from the Canal Zone: Idem, p. 15-44, pis. 12-18. Plants from Bohio, Culebra, Cucaracha, and Gatun formations. Reissued in complete volume, 1919. Cushman, J. A., The smaller fossil Foraminifera of the Panama Canal Zone: Idem, p. 45-87, pis. 19-33. Foraminifera from Caimito [misidentified as Culebra] and Culebra formations, Emperador lime- stone member of Culebra formation, La Boco marine member of Panama formation [misidentified as Culebra formation], Gatun formation, and Pleisto- cene strata. Reissued in complete volume, 1919. Cushman, J. A., The larger fossil Foraminifera of the Panama Canal Zone: Idem, p. 89-102, pis. 34-45. Foraminifera from Caimito formation [misidenti- fied as Culebra formation and Emperador limestone member], Culebra formation and Emperador lime- stone member, and La Boca marine member of Panama formation [misidentified as Culebra forma- tion]. Reissued in complete volume, 1919. Jackson, R. T., Fossil echini of the Panama Canal Zone and Costa Rica: Idem, p. 103-116, pis. 46-52, figs. 1-3. Reissue, with slight changes, of 1917 publication having same title. Reissued in complete volume, 1919. 8 1918. GEOLOGY AND PALEONTOLOGY OF CANAL ZONE 1918. 1918. 1919. 1919. 1919. 1919. 1919. 1921. 1921. 1924. 1924. Canu, Ferdinand, and Bassler, R. S., Bryozoa of the 1922. Canal Zone and related areas: Idem, p. 117-122, pi. 53. Two species from Emperador limestone [member of Culebra formation]. Reissued in complete volume, 1919. 1923. Rathbun, M. J., Decapod crustaceans from the Panama region: Idem, p. 123-184, pis. 54-66. Species from Caimito [misidentified as Culebra], Culebra, and Gatun formations, and Pleistocene strata. Reissued in complete volume, 1919. Pilsbry, H. A., Cirripedia from the Panama Canal Zone: Idem, p. 185-188, pi. 67. Five species from so-cllled Pliocene [Alhajuela sandstone member of Caimito formation], Gatun formation, and Pleistocene strata. Reissued in complete volume, 1919. Vaughan, T. W., Contributions to the geology and pale- ontology of the Canal Zone, Panama, and geologi- cally related areas in Central America and the West Indies: U. S. Natl. Mus. Bull. 103, 612 p., 154 pis., 27 figs. Separate parts of this volume are listed in present bibliography as 1918 or 1919 items. Vaughan, T. W., Fossil corals from Central America, Cuba, and Porto Rico, with an account of the Ameri- 1924. can Tertiary, Pleistocene, and Recent coral reefs: Idem, p. 189-524, pis. 68-152, figs. 4-25. Species from Caimito formation [misidentified as Culebra formation and Emperador limestone mem- ber], Culebra formation and Emperador limestone member, and La Boca marine member of Panama 1924- formation [misidentified as Emperador limestone 1925. member of Culebra formation] are described, and species from Pleistocene strata are listed. MacDonald, D. F., The sedimentary formations of the Panama Canal Zone, with special reference to the stratigraphic relations of the fossiliferous beds: Idem, p. 525-545, pis. 153, 154, figs. 26, 27. 1925. The name "Chagres sandstone" is proposed. Aside from that new name and slight changes in some age assignments, discussion of stratigraphy is essentially similar to that in MacDonald's 1915 ac- count. Includes measured stratigraphic sections. Vaughan, T. W., The biologic character and geologic cor- relation of the sedimentary formations of Panama 1925. in their relation to the geologic history of Central America and the West Indies: Idem, p. 547-612. Paleontology, age, and correlation of formations in Canal Zone. Sears, J. D., Deposits of manganese ore near Boqueron River, Panama: U. S. Geol. Survey Bull. 710, p. 1926. 85-91, figs. 1-3. Manganese prospects near Rio Boquer6n. South- ernmost prospect is shown on plate 1 of present 1926. report. Berry, E. W., A palm nut from the Miocene of the Canal Zone: U. S. Natl. Mus. Proc, v. 59, p. 21-22, 3 figs. Found in Gatun formation. Cooke, C. W., Orthaulax, a Tertiary guide fossil: U. S. Geol. Survey Prof. Paper 129, p. 23-37, pis. 2-5. 1926. Orthaulax gabbi is recorded from Caimito forma- tion [not so specified] and Culebra formation. Olsson, A. A., The Miocene of northern Costa Rica: Bull. Am. Paleontology, v. 9, no. 39, 309 p., 32 pis. Includes mollusks from Gatun formation of Canal Zone and one species from Toro limestone member of Chagres sandstone (Pecten macdonaldi) . Vaughan, T. W., Studies of the larger Tertiary forami- nifera from tropical and subtropical America: Natl. Acad. Sci. Proc, v. 9, p. 253-257. Includes Lepidocyclina miraflorensis from a lo- cality, apparently now submerged, evidently repre- senting La Boca marine member of Panama formation. Hanna, G. D., Rectifications of nomenclature: Calif. Acad. Sci. Proc, 4th ser., v. 13, p. 151-186. Three new names are proposed for Canal Zone fossil mollusks. National Academy of Sciences, Report of the Committee of the National Academy of Sciences on Panama Canal Slides: Natl. Acad. Sci. Mem., v. 18, 84 p., 51 pis., 19 figs. Appendix B on geology, by MacDonald, includes structure sections of part of Gaillard Cut. Appen- dix C is a discussion of chemical and physical prop- erties of Cucaracha formation. Vaughan, T. W., American and European Tertiary larger Foraminifera: Geol. Soc America Bull., v. 35, p. 785-822, pis. 30-36, 6 figs. Includes Miogypsina cushmani, from Culebra for- mation, and M. panamensis from strata now referred to Caimito formation. Douvilh?, Henri, Revision des Lepidocyclines: Soc. G6ol. France Mem., new ser., Mem. 2 (t. 2), 115 p., 7 pis., 83 figs. Includes Lepidocyclina canellei and L. chaperi, and a new species from upper valley of Rio Chagres, L. decorata, which has not been recognized in later collections (see Cole, 1952, [1953], p. 3). Dall, W. H., Illustrations of unfigured types of shells in the collections of the United States National Mu- seum: U. S. Natl. Mus. Proc, v. 66, art. 17, 41 p., 36 pis. Includes a Pliocene species (Sthenorytis loroense) and two Pleistocene species (Corbula macdonaldi and Yoldia perprotracta) described by Dall in 1912. Maury, C. J., A further contribution to the paleontology of Trinidad (Miocene horizons): Bull. Am. Paleon- tology, v. 10, no. 42, 250 p., 43 pis. Includes a species from Culebra formation (Sca- pharca balboai) and two from Gatun formation (Scapharca dariensis and dementia dariena). Hodson, Floyd, Venezuelan and Caribbean Turritellas: Idem, v. 11, no. 45, 50 p., 30 pis. Turritella altilira is illustrated. Vaughan, T. W., The stratigraphic horizon of the beds containing Lepidocyclina chaperi on Haut Chagres, Panama: Natl. Acad. Sci. Proc, v. 12, p. 519-522. At type locality, San Juan de Pequenf in upper Chagres valley (locality 3 of present report), Lepidocyclina chaperi is associated with upper Eocene species. Woodring, W. P., American Tertiary mollusks of the genus Clemenlia: U. S. Geol. Survey Prof. Paper 147, p. 25-47, pis. 14-17, 1 fig. INTRODUCTION 1927. 1927. 1927. 1929. 1930. 1930. 1930. 1931. 1931. 1932. 1933. 1934. Includes dementia dariena, which occurs in Gatun formation and is doubtfully recorded from Culebra formation. Vaughan, T. W., Larger Foraminifera of the genus Lepidocyclina related to Lepidocyclina mantelli: U. S. Natl. Mus. Proc, v. 71, art. 8, 5 p., 4 pis. Includes Lepidocyclina mirajlorensis. Palmer, K. V. W., The Veneridae of eastern America, Cenozoic and Recent: Palaeontographica Ameri- cana, v. 1, no. 5, 428 p., 45 pis. Includes described fossil species from the Canal Zone. Hodson, Floyd, Hodson, H. K., and Harris, G. D., Some Venezuelan and Caribbean mollusks: Bull. Am. Paleontology, v. 13, no. 49, 160 p., 40 pis. Includes species from Gatun formation. Anderson, F. M., Marine Miocene and related deposits of north Colombia: Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 73-213, pis. 8-23. Includes mollusks collected from Gatun formation at spillway of Gatun Dam. Li, Chih Chang, The Miocene and Recent Mollusca of Panama Bay: Geol. Soc. China Bull., v. 9, p. 249- 279, 8 pis., map. Includes species characteristic of Gatun forma- tion, stated to have been dredged at Pacific entrance to canal. Rutsch, R., Einige interessante Gastropoden aus dem Tertiar der Staaten Falcon und Lara (Venezuela): Eclogae Geol. Helvetiae, Band 23, p. 604-614, pi. 17. Type of Distorsio gatunensis is discussed and illustrated. Reeves, Frank, and Ross, C. P., A geologic study of the Madden Dam project, Alhajuela, Canal Zone: U. S. Geol. Survey Bull. 821, p. 11-49, pis. 4-13, figs. 1-5. Geology of Madden Dam site and area to be flooded by Madden Lake. Pilsbry, H. A., The Miocene and Recent Mollusca of Panama Bay: Acad. Nat. Sci. Phila. Proc, v. 83, p. 427-440, pi. 41, 3 figs. Eight of the species described by Li in 1930 are Miocene fossils. One (dementia dariena) is labelled "Gatun Locks and Spillway" and all have matrix characteristic of Gatun formation at and near Gatun. Hodson, Floyd, and Hodson, H. K., Some Venezuelan mollusks: Bull. Am. Paleontology, v. 16, no. 59, 94 p., 24 pis. Includes Macoma gatunensis. Vaughan, T. W., and Cole, W. S., A new species of Lepidocyclina from the Panama Canal Zone: Wash- ington Acad. Sci. Jour., v. 22, p. 510-514, 9 figs. Lepidocyclina pancanalis is described. The type locality, which is also the type locality of Miogypsina panamensis and Nummulites panamensis, represents Caimito formation, but is not so specified [locality 56 of present report]. Vaughan, T. W., Studies of American species of Foram- inifera of the genus Lepidocyclina: Smithsonian Misc. Coll., v. 89, no. 10, 53 p., 32 pis. Includes Lepidocyclina canellei and L. vaughani, Collins, R. L., A monograph of the American Tertiary pteropod mollusks: Johns Hopkins Univ., Studies in Geology, no. 11, p. 137-234, pis. 7-14. Includes a species from Gatun formation, Vagi- nella caribbeana. 1936. Tucker, H. I., The Atlantic and Gulf coast Tertiary Pectinidae of the United States: Am. Midland Naturalist, v. 17, p. 471-490, 4 pis. Includes Pecten macdonaldi, from Toro limestone member of Chagres sandstone. 1937. Coryell, H. N., and Embich, J. R., The Tranquilla shale (upper Eocene) of Panama and its foraminiferal fauna: Jour. Paleontology, v. 11, p. 289-305, pis. 41-43, 1 fig. Foraminifera from a locality on Rio Chagres, now flooded by Madden Dam. 1937. Coryell, H. N., and Fields, Suzanne, A Gatun ostracode fauna from Cativa, Panama: Am. Mus. Novitates 956, 18 p., 47 figs. Ostracodes from lower part of Gatun formation. 1941. Vaughan, T. W., and Cole, W. S., Preliminary report on the Cretaceous and Tertiary larger Foraminifera of Trinidad, British West Indies: Geol. Soc. America Special Paper 30, 137 p., 46 pis., 2 figs. Includes Operculinoides panamensis. 1941. Merriam, C. W., Fossil Turritellas from the Pacific coast region of North America: Calif. Univ., Dept. Geol. Sci., Bull., v. 26, no. 1, p. 1-214, pis. 1-41, 19 figs. Turritella altilira is illustrated. 1942. Olsson, A. A., Tertiary deposits of northwestern South America and Panamd: Eighth Am. Sci. Cong. Proc, v. 4, p. 231-287. Tertiary formations of Panamd,. 1943. [Thompson, T. F.], Geology: Panama Canal, Dept. Oper- ation and Maintenance, Special Eng. Div., Third Locks Project, pt. 2, chap. 3, 33 p., 21 figs. General discussion of geology of Canal Zone. 1943. [Thompson, T. F.], Foundations and slopes: Idem, pt. 2, chap. 5, 138 p., 6 pis., 136 figs. Detailed geology of Third Locks sites. 1944. Thompson, T. F., Geological explorations in the vicinity of Rio Quebrancha for the Panama Cement Com- pany: Panama Canal, Dept. Operation and Main- tenance, Special Eng. Div., 34 p., 10 pis., 4 figs. Geology of part of Quebrancha syncline, east of Canal Zone. 1945. Nicol, David, Restudy of some Miocene species of Glycymeris from Central America and Colombia: Jour. Paleontology, v. 19, p. 622-624, pi. 85. Includes Glycymeris canalis. 1946. Vaughan, T. W., Initiation of geological investigations in the Panama Canal Zone: Science, v. 104, no. 2696, p. 209. Geologic investigations during construction period after 1910 are attributed to a suggestion from Lord Bryce to President Taft. 1946. Keen, A. M., and Thompson, T. F., Notes on the Gatun formation (Miocene), Panama Canal Zone (abstract): Geol. Soc. America Bull., v. 57, p. 1,260. Three faunal zones are recognized. 1947. Nicol, David, Tropical American species of Glycymeris from the Tertiary of Colombia, and a new species from Panama: Jour. Paleontology, v. 21, p. 346-350, pi. 50. Includes Glycymeris schencki from Gatun forma- tion. 1947. MacDonald, D. F., Panama Canal slides: Panama Canal, Dept. Operation and Maintenance, Special Eng. Div., Third Locks Project, 73 p., 52 pis., 5 figs. 10 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE A posthumous publication. Discussion of geology includes some modification of MacDonald's earlier views. Geology of slide area in Gaillard Cut is shown on detailed map (scale, 1 inch=465 feet). 1947. [Thompson, T. F.J, Geology: Panama Canal, Rept. Governor under Public Law 280, 79th Cong., 1st Sess., Annex 3, 30 p., 8 figs. Geology of proposed sea-level canal is summarized. 1947. [Thompson, T. F.], Geology: Idem, App. 8, 84 p., 38 figs. Geology of proposed sea-level canal. Areal geology is shown on strip maps, scale 1:40,000 and 1:20,000. 1948. Cooke, C. W., Eocene echinoids from Panama: Jour. Paleontology, v. 22, p. 91-93, pi. 22. Eocene echinoids collected in Madden basin during field work for present report. 1949. Woodring, W. P., and Thompson, T. F., Tertiary forma- tions of Panama Canal Zone and adjoining parts of Panama: Am. Assoc. Petroleum Geologists Bull., v. 33, p. 223-247, 2 figs. Summary of stratigraphy and paleontology of Tertiary formations. 1949. Cole, W. S., Upper Eocene larger Foraminifera from the Panama Canal Zone: Jour. Paleontology, v. 23, p. 267-275, pis. 52-55. First published record of Eocene deposits in Canal Zone. The fossils were collected at locality 29 of present report. 1949. Bermudez, P. J., Pavoninoides, a new genus of the Milio- lidae from Panama: Cushman Lab. Foram. Research Contr., v. 25, pt. 3, p. 58, 1 fig. Pavoninoides panamensis, from "marly limestone of the Oligocene (probably middle), Madden Lake." Though the locality is indefinite, the limestone pre- sumably is in Gatuncillo formation. 1949. Rubio, Angel, Notas sobre geologfa de Panama: Panama, Ministerio de Educaci6n, Depto. de Cultura y Pub- licaciones, 183 p., 32 figs. Compilation of data on geology of Panama. 1950. Pilsbry, H. A., and Olsson, A. A., Review of Anticlimax, with new Tertiary species (Gastropoda, Vitrinelli- dae): Bull. Am. Paleontology, v. 33, no. 135, 22 p., 4 pis. Includes Anticlimax gatunensis and A. teleospira, from lower part of Gatun formation. 1950. Jones, S. M., Geology of Gatun Lake and vicinity, Panama: Geol. Soc. America Bull., v. 61, p. 893-922 2 pis., 2 figs. Geology of Gatun Lake area. Includes a geo- logic map, scale 1:125,000. 1952. Drooger, C. W., Study of American Miogypsinidae, 80 p., 3 pis., 14 figs., Zeist, Netherlands. Includes species from Caimito formation and Culebra formation, including Empcrador limestone member. 1952. Thompson, T. F., Ring dikes of the continental divide region, Panama Canal Zone (abstract): Geol. Soc. America Bull., v. 63, p. 1346, 1952. Ring-shaped and cup-shaped dikes surrounding hills of agglomerate in Gaillard Cut area. 1953. Cole, W. S., Eocene and Oligocene larger Foraminifera from the Panama Canal Zone and vicinity: U. S. Geol. Survey Prof. Paper 244, 41 p., 28 pis., 2 figs., 1952 [1953]. Eocene and Oligocene larger Foraminifera col- lected during field work for present report. 1953. Cole, W. S., Some late Oligocene larger Foraminifera from Panama: Jour. Paleontology, v. 27, p. 332-337, pis. 43, 44. Species in MacDonald's collections from Culebra formation, including Emperador limestone member, and La Boca marine member of Panama formation. 1954. Bramlette, M. N., and Riedel, W. R., Stratigraphic value of discoasters and some other microfossils related to Recent coccolithophores: Jour. Paleontology, v. 28, p. 385-403, pis. 38-39, 3 figs. Includes records of discoasters from Gatuncillo and Culebra formations. 1955. Woodring, W. P., Geologic map of Canal Zone and ad- joining parts of Panama: U. S. Geol. Survey, Misc. Geol. Invest., Map 1-1, scale 1:75,000. Reproduced with minor alterations as plate 1 of present report. 1956. Terry, R. A., A geological reconnaissance of Panama: Calif. Acad. Sci. Occasional Paper 23, 91 p., 3 pis., 8 figs. A general account of the geology of Panama, including Canal Zone. Published after present report was prepared. 1957. Cole, W. S., Late Oligocene larger Foraminifera from Barro Colorado Island, Panama Canal Zone: Bull. Am. Paleontology, v. 37, no. 163, p. 309-338, pis. 24-30. Description of species from Bohio and Caimito formations of Barro Colorado Island. GEOLOGY STRATIGRAPHY OUTLINE OF STRATIGRAPHY The region covered by plate 1 embraces all except the extreme western part of a Tertiary marine sedimentary area which may be designated the central Panama area (fig. 1). The boundaries of the areas shown in figure 1 represent the approximate known extent of Tertiary marine formations, not the outlines of deposi- tional basins. In the central Panama area, Tertiary marine formations extend across the continental divide. The stratigraphy in the region covered by plate 1 is notably different from place to place. For the purpose of description six main regions are recognized: Quebrancha syncline, Madden basin, Gatun Lake area, Caribbean coastal area, Gaillard Cut area, Pacific coastal region in Panama east of the Canal Zone. Quebrancha syncline and Madden basin are structural features east of the Canal Zone. Gaillard Cut, desig- nated Culebra Cut during the construction period, is the part of the canal excavation beginning opposite the south end of the Panama Railroad bridge across Rio Chagres at Gamboa and extending southeastward, across the continental divide, to the north end of Pedro Miguel Locks. The correlation of the formations in different areas is shown in figure 4. The basement on which the Tertiary formations rest consists principally of altered and strongly deformed volcanic rocks, including tuffs that contain marine GEOLOGY 11 S^—m— ^S 3 / X —V-^^ „ ^ Z J r\ ) / s » i y ,' \y *■ ^ h <*./ ^ ^y^^ — '\ ^1 V i--^~' y^^ \ 4 j s^ s ^ >^^ Punta S. iLVLr / 'C^- 5 ^ — TF] \ S 4 \f * , ° => c / \ i 5 J aj a 63 S / V fl? o - s ) V k J < I: _S„,~ x g K 1 « 1 9 o o s- O Q- I - ^ \< — < < vB. u 03 ^X 8 — e^w^ ^Sa v V S \ \ 03 \ ^1 ?Si,\\\\NN\VS( 1 \ ^ l \ -J / / c \ \ *" 1 / ° / ,T V z 1 / c / / rx^—i? / -- \ / « ?-_ / ; y •^"^ > i j / ^ \ ^i ) o ) c. / T 1 l /,§ t / ji£x H I ac \ — — ' — "3 J / > / / j \ f \ 1° c r \ ^ ° h ) / l " - = \ -S \ fJ \ \ %*. ° \ \ 1 % ,7 Q S * U s 1 \ /^ "V Ts° - o o 1 ' v — 3 S c coo -o s > . / ( ^b / ^ r : »^ i 3»*© J j S y : fi (■ *") ^S— /^*^ / \ X t= a £ / E / -^ F.qp ^' * V / / - ^9 1^U / # ^! o ra*Tt£ / \ L~.\p a *Mr\s> * ^ , V S = 1 'S W V .1 //*_ (\jl >-* — "-^ >° 5 S ~ \ it / 5 / ° |« WrVV \ / £ A * V / x / \ « ^ -, / «° f / i VO 1 a ^--yvx s o o\ •'>«# ? So '. < O ,_, 18" w t° PS a.- P 12 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE fossils. The volcanic rocks are intruded by dioritic rocks. This basal complex is probably of Cretaceous age, but so far all that is known about its age, in the region covered by pla^e 1, is that it is older than middle Eocene. It is much older than MacDoaald's (1913, pi. 4) igneous complex — a map term he used for vol- canic and intrusive rocks of Oligocene and early Miocene age. The middle and upper Eocene Gatuncillo formation rests with marked unconformity on the basement rocks. It has been identified east of the Canal Zone and in the eastern part of the Zone. Lithologically it is more uniform than the Oligocene and lower Miocene formations. Formations of known or inferred Oligocene age are of wide extent and very heterogeneous. They are marine and nonmarine, volcanic and nonvolcanic, at least nonvolcanic aside from tuffaceous debris. They represent all of Oligocene tune and for the most part are conformable to each other and to the Gatuncillo formation. In the Pacific coastal area, however, the Bohio formation overlaps the Gatuncillo formation and in the northern part of Madden basin the Caimito formation overlaps the Bohio. Except in the Gaillard Cut area, the Oligocene formations are marine or partly marine: the Bohio and Caimito formations. Though the Bohio formation (the older of the two) appears to be for the most part nonmarine, marine strata are found in it at different horizons. Isolated outcrops in the Gatun Lake area, inferred to represent a tongue of marine strata in the lower part of the Bohio formation, contain mollusks considered of eady Oligocene age and larger Foraminifera assigned to the late Eocene. Smaller Foraminifera of early Oligocene age are found in the basal part of the Bohio in the Quebrancha syncline. In both the Gatun Lake and Pacific coastal areas thin marine deposits in the upper part of the Bohio contain late Oligocene fossils. The Caimito formation overlies the Bohio and is for the most part marine. Late Oligocene fossils, particularly larger Foraminifera, are widespread in the Caimito. In Madden basin, however, the lower part of the formation is late Oligocene and the upper part is early Miocene. In the Gaillard Cut area the place of the Bohio and Caimito formations apparently is taken by the wholly nonmarine and volcanic Bas Obispo formation and Las Cascadas agglomerate. They are considered Oligo- cene (?) on the basis of their inferred relations to the Bohio and Caimito formations. The Bas Obispo forma- tion — the older of the two — seems to grade north- westward into the Bohio formation. The Las Cascadas agglomerate is thought to be the equivalent of the lower part, or perhaps all, of the Caimito formation of the Gatun Lake area. The upper part of the Caimito formation of Madden basin, including the formally named Chilibrillo lime- stone and Alhajuela sandstone members, consists of marine deposits of early Miocene age. Nonmarine and marine lower Miocene deposits in the Gaillard Cut area are subdivided into relatively thin formations : in ascend- ing order, the Culebra formation (including the Em- perador limestone member), the Cucaracha formation, and the Panama formation (including the La Boca marine member and Pedro Miguel agglomerate mem- ber). These three formations contain more volcanic material than supposedly equivalent deposits in Madden basin. The marine Culebra formation transgresses northward across the Las Cascadas agglomerate. According to present interpretations, the La Boca marine member of the Panama formation interfingers with the upper part of the Cucaracha, or overlaps the Cucaracha and Culebra formations and rests on the Bas Obispo. All three formations and some of the lower Miocene of Madden basin are assigned to the upper Oligocene by some paleontologists. The two Tertiary formations younger than those of early Miocene age are found only in the Gatun Lake and Caribbean coastal areas. These youngest forma- tions are marine and, like the Eocene Gatuncillo forma- tion, are more uniform lithologically than those of Oligocene and early Miocene age. The middle and upper Miocene Gatun formation is famous for its well- preserved fossils. Though the field relations between the Gatun and Caimito formations are unknown, the two formations evidently are separated by a discon- tinuity and perhaps by slight discordance. East of the Canal Zone the Gatun overlaps onto the Cretaceous(?) basement. The Gatun of the region covered by plate 1 is considered to be middle Miocene. The Gatun at the west end of the outcrop area, about 50 kilometers southwest of Colon, in the western part of the region shown in figure 3, is assigned to the late Miocene. The lower Pliocene Chagres sandstone is the youngest of the Tertiary formations. It overlies and partly overlaps the Gatun formation. The thin Toro lime- stone member lies at the base of the Chagres in the eastern part of the outcrop area. All the Tertiary formations are somewhat tuffaceous but the oldest and youngest contain the least tuffaceous debris, the Oligocene and lower Miocene the most. Moreover, the Oligocene and lower Miocene formations show a progressive southwest ward increase in volcanic and intrusive rocks, until in the southwestern part of the region covered by plate 1 there is nothing but volcanic and intrusive rocks. The change is strikingly shown on plate 1 ; in fact, more so than would be the case if the map were equally detailed throughout. The volcanic rocks themselves and also the intrusive rocks GEOLOGY 13 are undifferentiated in the southwestern part of the map area. These undifferentiated rocks, however, adjoin a strip along the canal where greater detail is shown than elsewhere on the map. CRETACEOUS(?) SYSTEM The oldest rocks in the Canal Zone and nearby, much older than any seen along the canal, are chiefly altered lavas and dioritic rocks. These extrusive and intrusive rocks are briefly described or mentioned under the heading "Igneous rocks." Altered tuffs and other altered sedimentary rocks are associated with the lavas. None of these rocks, sedimentary or igneous, was studied during the field work and they were observed only casually. They crop out in the eastern part of the Zone and extensively in Panama east of the Zone, making up the basement on which the Tertiary forma- tions rest. This basement on the borders of Madden basin was designated the volcanic complex by Reeves and Ross (1930, p. 18). Everywhere the basement forms high, rugged forested uplands and mountains. The composition, structure, and age of these rocks are important aspects of Pana- manian geology that remain to be studied. Contrary to the expectation of geologists not familiar with the tropics, the high-gradient streams in the rugged terrain characteristic of the basement offer a wealth of rock outcrops. Moreover, the streams are so numerous that a closely spaced network of outcrops is available. Strongly deformed altered tuffs were seen at a few localities. Three samples of different grain size, rang- ing fiom very fine-grained to very coarse and agglomer- ate, were collected on the Transisthmian Highway 2 kilometers east-southeast of the bridge across Rio Gatiin. They were examined by W. S. Burbank, who found them to be moderately to strongly chloritized and carbonatized. The coarse-grained rock contains andesitic and latitic fragments and some devitrified glass. The two samples of finer grain contain angular frag- ments of feldspar, pyroxene, iron oxides, and quartz. These rocks of finer grain are sheared and fractured, and cut by veinlets of calcite and a colorless mineral, probably a zeolite. Sedimentary and pyi-o clastic rocks of the basement complex at the Hyatt manganese prospects near Rio Boqueron, the southernmost of which is shown at the north edge of the general geologic map (pi. 1), consist of siliceous limestone, quartzite, sheared agglomerate, and fine-gram ed tuff(?) altered to schist (Simons, in Roberts and Irving, 1957, p. 121, 124). Thougn the age of the basement rocks is unkown — other than that they are older than the unconformably overlying middle and late Eocene deposits — they probably are Cretaceous, like widespread volcanic and associated rocks throughout the Caribbean region (Woodring, 1954, p. 722-725). Late Cretaceous Foram- inifera (Globotruncana and Gumbelina) are reportedjto have been found in northwestern Panama, near the Costa Rican border, in siliceous limestone that pre- sumably represents the same major unit as the base- ment rocks of plate 1. The basement, however, may include rocks older and younger than Cretaceous. The altered tuffs sampled near Rio Gatiin are not the kinds of rocks that would be chosen as being likely to contain fossils. Yet thin sections of the three types sampled show indeterminable Foraminifera and Radiolaria. If further work on the basement rocks is undertaken, it doubtless is only a matter of time until identifiable fossils are found. The siliceous limestones are partic- ularly promising for microscopic fossils. EOCENE SERIES GATUNCILLO FORMATION Formations of Paleocene and early Eocene age are unknown in the central Panama area. They may, however, be represented in the basement complex or by overlapped deposits in the structurally deeper parts of the area. The oldest known Tertiary formation is the Gatuncillo formation, which lies directly on the Cre- taceous (?) basement. The Gatuncillo formation was named by Thompson (1944, p. 12-13) as the Gatuncillo shale. The type region is in the valley of Rio Gatuncillo on the east limb of the Quebrancha syncline. The name Tran- quilla shale has priority, but that name was defined inadequately, principally on the basis of foraminifera! samples from a locality in Madden basin later flooded by Madden Dam (Coryell and Embich, 1937, p. 289; for location of Tranquilla see Reeves and Ross, 1930, pi. 5). The Gatuncillo crops out in the eastern part of the Canal Zone and east of the Zone. It forms rolling lowlands, which stand in contrast to the rugged up- lands characteristic of the basement complex. The thickness of the Gatuncillo is estimated to range from 150 to 800 meters. The formation unconformably overlies the Cretaceous(?) basement. In the type region and in other areas wherever the succession is complete, the Gatuncillo is conformably overlain by the Bohio formation. In Madden basin, however, the Bohio is overlapped by the Caimito formation. In the Pacific coastal area the Gatuncillo does not appear between the basement and the Bohio formation, being overlapped by the Bohio. Collections of larger Foraminifera sent to T. W. Vaughan many years ago by A. A. Olsson and R. A. Terry indicate that Eocene deposits reappear farther east in the Pacific coastal area in the valley of Rio Bayano, 45 kilometers east- 14 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE northeast of the eastern edge of the area shown on plate 1 (Terry, 1956, p. 32). Though the Gatuncillo consists chiefly of mudstone and siltstone, it includes bentonitic mudstone, sand- stone, and limestone, and at the base conglomerate of variable thickness. STRATIGRAPHY AND LITHOLOGY Rio Agua Sucia area. — The Rio Agua Sucia area lies west of the Quebrancha syncline, between the Azota Caballo and the Agua Sucia faults. Before it was realized that the deposits in the Rio Agua Sucia area are of Eocene age, the name Rio Duque shale was proposed for them (Thompson, 1944, p. 21-23). The area is crossed by the Trans- isthmian Highway. Cuts along the highway ex- pose mudstone, siltstone, and sandstone of the Gatuncillo formation. Mudstone and siltstone are more prevalent in the southeastern part of the area, sandstone in the northwestern part. The mudstone is more silty than in the Quebrancha syncline; sandstone is more prevalent than in other areas; and northwest- ward, which also is stratigraphically upward, the sand- stone is of coarser grain than in other areas. Sand- stone at locality 27 1 is medium-grained, poorly sorted, and contains much carbonaceous debris. The strata at locality 28 consist of poorly sorted gritty sandstone. The northwestward increase in grain size suggests that the depositional margin of the central Panama area was not far to the north. So far as observed, limestone is not common. Algal- foraminiferal limestone, about 15 meters thick, forms a little hill at locality 25, and foraminiferal limestone crops out at locality 23a. Quebrancha syncline. — In the type region, on the east flank of the Quebrancha syncline, the maximum thickness of the Gatuncillo formation is estimated to be 800 meters, apparently greater than in other areas. An earlier estimate of 3,C0G feet (900 meters) probably is excessive (Woodring and Thompson, 1949, p. 227). Fine-grained rocks — mudstone and siltstone — make up the bulk of the formation. limestone, bentonic mud- stone, sandstone, and conglomerate are minor con- stituents. Typical fine-grained rocks are readily acces- sible on Rio Quebrancha about 100 meters upstream from the Transisthmian Highway bridge (locality 21). The limestones are algal and foraminiferal and most of them have a thickness of less than a meter, such as i The localities at which fossils were collected are listed on pages 112-130 and, un- less otherwise specified in the list, are plotted on the general geologic map (pi. 1). those off the north side of the Transisthmian Highway 50 meters east of the bridge across Rio Gatuncillo (locality 20) and along the road leading southward from the Transisthmian Highway to Nuevo San Juan (localities 22, 23). On Quebrada Fea (the stream on the east side of Rio Gatuncillo valley 4 kilometers northeast of the Transisthmian Highway bridge across Rio Gatuncillo), however, algal-foraminiferal limestone has a thickness of at least 10 meters. Conglomerate and sandstone at the base of the formation are exposed on the Transisthmian Highway. The conglomerate, resting on Cretaceous(?) altered volcanic rocks, has a thickness of 30 to 90 centimeters and is made up of pebbles and cobbles of altered volcanic rock. It is overlain by soft medium- to fine-grained sandstone grading upward into soft silty fine-grained sandstone. The thickness of the sandstone is 6^ meters. Madden basin. — The largest outcrop area of the Gatuncillo formation is in the northern and north- eastern parts of Madden basin. Much of the outcrop area, however, is flooded by Madden Lake. The Eocene deposits of Madden basin were included in the Bohio formation by Reeves and Ross (1930, p. 17-18), although they are strikingly unlike those of the Bohio. The thickness of the formation is difficult to estimate, but probably is not more than 300 meters. Limestones are more extensive and individual units of limestone are thicker than in other areas. As else- where, algal or algal-foraminiferal limestone is most common, but other kinds of limestone are repre- sented. Algal and algal-foraminiferal limestone in the upper part of the Gatuncillo at locality 14 is fully 30 meters thick. It is separated by sandy strata from an overlying algal limestone that reaches a thickness of about 15 meters. Similar algal limestone, also about 15 meters thick, forms the natural bridge (puente natural) on Rio Puente. A cliff on the north side of Rio Puente, 800 meters in a direct line upstream from the natural bridge, exposes almost the same thickness of limestone. Silty somewhat fissile echinoid- bearing limestone (plate 4), soft yellowish marly lime- stone, moderately soft coralliferous limestone, and hard algal limestone, all representing a thickness of 10 meters, are exposed in a partly demolished hill at locality 11. There are numerous other exposures of limestone in Madden basin; in fact, all the fossils from that area were found in limestone. That lime- stone may occur at the base of the formation is shown by the following section measured on the south side of Rio Pequeni: GEOLOGY 1 5 Section of basal part of Gatuncillo formation on south side of Rio basin of Rio Frijol and the smaller area farther east. Pequeni near head of Madden Lake (locality 1) ^he thickness of the formation along Rio Frijol is Gatuncillo formation: Meters estimated to be between 300 and 400 meters. The Limestone, thin-bedded nodular-weathering; low- lithologic types are similar to those elsewhere: mild- est 1 meter more granular and somewhat sandy. ston6) s il t stone, sandstone, and thin beds of limestone. Scattered angular pieces and few pebbles of base- D „„ » ,i i, , ■ , j r ■ , /j- x r i i. o x- \ borne ol the sandstone contains carbonaceous debris, ment rocks (diameter of largest 8 centimeters) . -n ,. • throughout lower half, more numerous in some For a discussion of the Gatuncillo formation in the layers. Lepidocyclina abundant; many Yaberinella Gatun Lake area seaward from the Rio Frijol area in one layer. Collection (locality la) 3 to 4.5 see page 61. meters above base 10.6 Gamboa area. — A narrow band of Gatuncillo rocks Unexposed (possibly sandy or silty strata) 1. 5 ,- • ai i i j t i e ±\ i ■ i, • i >\ c \ rZ. . ', ..,,.,, j .. lies in the lowland north oi the high ridge north of Limestone, thin-bedded, in thicker beds than over- ° ° lying limestone. Contains Lepidocyclina and Gamboa. The strata dip northeastward and appear to Yaberinella. Collection (locality 1) 0.5 meter be overlain in normal succession by the Bohio forma- above base 1.5 tion. If the high ridge is underlain by basement rocks, Unexposed (possibly sandy or silty strata) 1.5 as ghown Qn plftte ^ and if the Gatuncillo is not Limestone, few boulders of altered volcanics at base_. .5 , 1,1 , 1, ,-, , x ,-• ,, ,-.. , t, . ' , , . , bounded by faults to the south or north, the thickness Basement of altered volcanic rock. ••,-, mi of the Gatuncillo is not more than 150 meters. The Thickness of section 15. 6 only outcrop of the Gatuncillo seen in this area consists of calcareous mudstone containing a thin layer of Fine-grained and sandy rocks presumably make up limestone (locality 37). the bulk of the formation. Fine-grained rocks are not jh Casaya area.— Outcrops of fossiliferous rocks of readily accessible, but they doubtless could be found t he Gatuncillo formation were found by R. H. Stewart by traversing streams. Sandy strata form a treeless a i ong Q ue brada de Oro, a northwestward-flowing area surrounding locality 11 and sandy strata in the tributary of Rio Casaya about 4 kilometers southeast upper part of the formation near locality 13 include f Gamboa (locality 38). The stream may be practically pure quartz sand. recognized by mine-machinery debris and caved adits. Rio Agwa Salud area— The Rio Agua Salud area is Limestone, sandstone, and siltstone of the Gatuncillo the long, narrow strip of the Gatuncillo formation on formation are intruded by dacite porphyry. These the upthrown side of the Chinilla fault, in the eastern sedimentary rocks are partly silicified. They probably part of the Canal Zone. Coring along the alinement are faulted against the Caimito formation, although no for a diversion channel for Rio Chagres — part of the fault is shown on plate 1. Sea-level Canal project— showed the presence of the No outcrop areas of the Gatuncillo formation are Gatuncillo formation in this area, the first record of known southwest of the Rio Casaya area. Though Eocene deposits in the Canal Zone. R. H. Stewart the formation seems to be thinning southwestward, it and T. F. Thompson recognized larger Foraminifera may extend farther in that direction beneath the of the Gatuncillo formation in cores from core hole Oligocene and lower Miocene strata penetrated by the SL84 (locality 29), drilled in 1947, and in float limestone cana l and the undifferentiated volcanic rocks farther at the core-hole locality. Their age identification was southwest, confirmed by W. S. Cole, who described the Foramini- fera (Cole/ 1949). The three localities in the Rio fossils and age Agua Salud area are core holes (localities 29-31), Smaller Foraminifera. — -In most of the areas smaller which started and bottomed in the Gatuncillo forma- Foraminifera are abundant in mudstone and siltstone. tion. The strata penetrated consist of mudstone, silt- Coryell and Embich described species collected at stone, silty sandstone, calcareous siltstone, silty lime- Tranquilla, a village on Rio Chagres flooded by stone, and limestone. The depth of penetration ranged Madden Lake, and assigned the fauna to the upper from 30.7 to 54.1 meters. Eocene (Coryell and Embich, 1937). H. H. Renz and Rio Frijol area. — The Rio Frijol area includes the P. J. Bermiidez kindly identified the following species outcrop area of the Gatuncillo formation in the drainage in five samples: 16 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Smaller Foraminijera from Gatuncillo formation [Identifications by H. H. Renz and P. J. Bermudez] Alabamina sp Allomorphina trigona Reuss Angulogerina sanjuanensis Coryell and Embich sp Anomalina pacoraensis Coryell and Embich cf. A. alazanensis Nuttall sp A nomalinoides sp Astacolus sp Bathy siphon eocenica Cushman and Hanna Bolivina alazanensis Cushman byramensis Cushman gracilis Cushman and Applin cf. B. gracilis Cushman and Ap- plin jacksonensis Cushman and Applin. cf. B. jacksonensis Cushman and Applin maculala Cushman and Stone cf. B. maculala Cushman and Stone malkinae Coryell and Embich cf. B. ventricosa Galloway and Heminway sp Bulimina alazanensis Cushman consanguinea Parker and Ber- mudez cf. B. cooperensis Cushman guayabalensis Cole cf. B. impendens Parker and Ber- mudez jacksonensis Cushman cf. B. jacksonensis var. cuneata Cushman palmcrae Parker and Bermudez,. cf. B. palmerae Parker and Ber- mudez pupoides d'Orbigny cf. B. pyrula d'Orbigny tuxpamensis Cole sp.. Localities a < x ■: x X X ■■ ■ X X X X •■: X X X X 3 £ t£c3 X X X X ■ > X X c « 35 X X X X :■: < X Smaller Foraminifera from Gatuncillo formation — Continued [Identifications by H. H. Renz and P. J. Bermudez] Bulim inella sp Cassidulina crassa d'Orbigny havanensis Cushman and miidez subglobosa Brady sp Ber- Cassidulinoides sp Ceratobulimina alazanensis Cushman and Harris Chilostomella mexicana Nuttall cf. C. ovoidea Reuss sp Chilostomelloides oviformis (Sherborn and Chapman) Chrysalogonium cf. C. asperum Cush- man and Stainforth elongatum Cushman and Jarvis sp Cibicides cocoaensis (Cushman) cf . C. concenlricus (Cushman) cf. C. cookei Cushman and Gar- rett leoni (Bermudez) mexicanus Nuttall perlucidus Nuttall cf. C. perlucidus Nuttall cf. C. pseudoungerianus (Cush- man) sp n. spp Clavulinoides cubensis Cushman and Bermudez havanensis Cushman and Ber- mudez sp Cornuspira olygogyra Hantken of Cushman Cyclammina cf. C. pacifica Beck sp Dentalina cf. D. communis d'Orbigny. cf. D. cooperensis Cushman cf. D. mucronata Neugeboren semilaevis Hantken sp spp Discorbis sp Localities O" :■: x v -: x x X X X :■ x 3 CO 3 £ - 24 X X X X 3£ ti.a < o 5 X X X X X X X >: x x x x • X X X X 35 X X X ? X X X GEOLOGY 17 Smaller Forarninifera from Gatuncillo formation — Continued [Identifications by H. H. Renz and P. J. Bermudez] Dorothia cylindrica (Nuttall). cf. D. nuttalli Cushman. sp. Ellipsoglandulina labiata (Schwager)-. multicostata (Galloway and Mor- rey) Eniosolenia cf. E. laevigata (Reuss)_. cf. E. marginata (Walker and Boys) orbignyana (Seguenza) sp Eponides jaeksonensis Cushman cf. E. rutteni Cushman and Ber- mudez umbonatus (Reuss) var. mullisepta Koch Frondicularia tenuissima Hantken Gaudryina (Pseudogaudryina) cf. G. jaeksonensis Cushman Glandulina sp Globigerina ciperoensis Bolli ouachitaensis Howe and Wallace. sp Globigerinoides mexicanus (Cushman) _ . sp Globobidimina hannai Cushman and Ellisor cf . G. hannai Cushman and Ellisor. sp Globorotalia centralis Cushman and Bermudez Globulina cf. G. gibba d'Orbigny rolundata (Bornemann) sp Giimbelina cubensis Palmer martini (Pjipers) Guttulina irregularis (d'Orbigny) Gyroidinoides girardana (Reuss) guayabalensis (Cole) soldanii var. octocamerala (Cush- man and Hanna) sp Localities X :■: x X X ■: x X X X • X X X X X X X X X • X X X X 3 CO =° £ 3 £ a X X X X X X X X X X X X X X X X ^- , teas X X X X X X X X X X X X X X X 35 X X X X X X X X X Smaller Forarninifera from Gatuncillo formation — Continued [Identifications by H. H. Renz and P. J. Bermudez] Hantkenina alabamensis Cushman suprasuturalis Bronnimann Haplophragmoides cf. H. dibollensis Cushman and Applin Hasligerinella eocanica Nuttall sp Hoglundina elegans (d'Orbigny) Karreriella arenasensis Cushman and Bermudez chilostoma (Reuss) mexicana (Nuttall) cf. K. mexicana (Nuttall) sp Lagena acuticostala Reuss cf. L. hexagona (Williamson) sp Lagenoglandulina subovala var. cha- gresensis Coryell and Embich Lagenonodosaria cf. L. sigmoidea Cory- ell and Rivero sp Loxostoma dalli (Cushman) Marginulina cf. M. abbreviate Neu- geboren cf. M. attenuate/, Neugeboren cf. M. eximia Neugeboren hantkeni (Bandy) cf. M. subcrassa Schwager cf. M. triangularis var. panamen- sis Coryell and Embich sp Marginulinopsis cocoaensis (Cushman). sp Matanzia? sp Nodogenerina heterosculpta Bermudez.. sp Nodosaria chirana Cushman Stone longiscata d'Orbigny multilineata (Bornemann).. soluta (Reuss) sp and Localities X < X X X X X X X X X X X X X X X X X X < X X X 24 X X X X X X X X X X < ••■ X X < X X X X :■: X X X 18 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Smaller Foraminifera from Galuncillo formation — Continued [Identifications by H. H. Renz and P. J. Bermudez] Nonion danvillense Howe and Wallace. pompilioides (Fichtel and Moll)... cf. N. pompilioides (Fichtel and Moll) sp Orthomorphina cf. 0. rohri (Cushman and Stainforth) Osangularia mexicana (Cole) sp Planularia sp Planulina marialana Hadley suturata Cushman and Bermudez. Plectina nuttalli Cushman and Stain- forth Plectofrondicularia cookei Cushman morreyae Cushman vaughani Cushman sp Pleurostomella alternans Schwager cf. P. palmerae Bermudez cf. P. praegerontica Cushman and Stainforth sp Pseudoglandulina laevigata (d'Or- bigny) cf . P. laevigata (d'Orbigny) ovata (Cushman and Applin) radicula (Linne) cf. P. radicula (Linne) sp Pullenia cf. P. bulloides (d'Orbigny)... sp Pyrgo pseudoinornala Cushman and Stainforth sp Quinqueloculina sp Iiobulus cf. R. dicampylus (Franzenau) terryi Coryell and Embich spp Rolaliatina mexicana Cushman Localities a cy X X X X X X X X X X X X X '■: X X X X a S3 3 £ 24 X X X X X X X X X X ■ X 3 Z ex ca 31 X :•: :•: ;•: X X X X X X X X 35 X X X X X Smaller Foraminifera from Galuncillo formation — Continued [Identifications by H. H. Renz and P. J. Bermudez] Saracenaria acutauricularis (Fichtel and Moll) cf. S. hantkeni (Cushman cf . S. latifrons (Brady) cf. S. schencki Cushman and Hob- Schenckiella cf. S. petrosa (Cushman and Bermudez) sp Sigmoilina tenuis (Czjzek).. Sigmomorphina sp Siphogenerina sp Siphonina advena Cushman. tenuicarinata Cushman. Siphonodosaria cf . S. annulifera (Cush- man and Bermudez) aff. S. curvatura (Cushman) cf. S. dentaliniformis (Cushman ard Jarvis) cf. S. nuttalli (Cushman and Jarvis) paucistriata (Galloway and Mor- rey) puntensis Coryell and Embich recta (Palmer and Bermudez) aff. S. subspinosa (Cushman) verneuili (d' Orbigny) var. emaciata (Palmer and Bermudez) sp Siphotextularia sp Spirolocidina cf. S. texana Cushman and Ellisor sp Spiroplectammina planulis (Coryell and Embich) Textularia hockleyensis var. malkinae Coryell and Embich cf. T. recta Cushman Textula ria? sp Localities X X X X X X X X X X 24 X X X X X CfJ $ X X X X GEOLOGY 19 Smaller Foraminif era from Gatuncillo formation — Continued [Identifications by H. H. Renz and P. J. Bermudez] Localities 33 C 03 _ > 3 & 3 CO *o 3 GO 03 S 3 £ ama sheet of American Geographical Society's map of Hispanic America 10 F=r-FrT=r Scale 1:1.000,0 X X > X X X X X X ? X ■ X X X X ? ... X X X ... X X X ... Polinices canalizonalis (Brown and Pilsbry). X stanislas-meunieri Maury Neverita (Olossaulax) reclusiana xena Wood- X X X X X X X X X X ■ ... ... " - ? ? > X X cf. -- X X X X X X X X X X X X X '• > :• X altilira praecellens Pilsbry and Brown... - — x X • ? ? ? X X X X X :■: >. X X sp. .... X ■ — X X ... — X X X X X ... ? X tifastigata Nelson - X X ... - - ■ - - .... ... - - - .... ... - - ... -_: GEOLOGY 49 (Trochidae to Turritellidae) [For explanation of symbols see p. 46] Localities Middle part Upper part Eastern area Western area Eastern area Western area S u5 u va X X CO o 00 as a o s to o to SJ CS O CO CO iC CO CO ■W ^ CN ce CO CO - 33 CO — 1 - C3 [ - M ■^ t- c* CO t - CO — 1— a i - O i - i - 1 - 1 - s r - 3 r — X Ex X X X X sp X X X X X Y X Y X X X X — X X X 'sp ... X X X X X X X sp. cf. X > X - X ■ '• X X X Y X X .-. X X ... X X X X X — X X ... X X — X X X X X ■ X ■ X — X X X X .'sp. ■ X X > X X • ... X ■ X ■ X X X X X X ■ X ... Y ? X - X X Y Y X ? X X X X X X X X X X X X - X X X X X 1 X • X X X X ? — — — - ... ... - > X :• X X X > X "~ X X sp. X X X X X ... ? X - X X > X - X - X ... X -- ... — - X X - — — ... X X X X X ... X X >: X < X X X — .... - - — X .... — ... - - — - .... — — - - X X ... X -- X X X X X X X X X — - X X X X X 1 - - ? X X X X ... X X — X X Y - ... ... 50 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE pally of lime-cemented coquina made up of small frag- ments of barnacles, shells, echinoid spines, and corals (pis. 11, 12). Barnacle fragments predominate at many localities and cross-bedding is common. Lenses of medium- to coarse-grained sandstone occur in the coquina. Descriptions of outcrops of the Toro have been published by MacDonald (1919, p. 544-545) and Olsson (1942, p. 246). The Chagres sandstone proper is made up of massive generally fine-grained sandstone and some siltstone (pi. 13). Unlike the Gatun formation, the Chagres is not known to include conglomerate or tuff, and the sandstone itself contains less volcanic material than sandstone of the Gatun. FOSSILS AND AGE Mollusks. — A few molds of mollusks from Olsson's Anomia zone are included in the families covered by chapter A of the present report: Calliostoma? sp. and Turritella gatunensisf from locality 194; Turritella altilira s. 1. from locality 195; Turbo aff. T. castaneus, Turritella gatunensisf, and Turritella mi metes? from locality 195. Olsson's Anomia zone (Olsson, 1942, p. 246-247) appears to be part of the shallow-water calcareous deposits forming the overlapping Toro limestone member of the Chagres sandstone rather than part of the Gatun formation. A new species of Calliostoma, C. metalium (localities 206, 206a), an unidentified mold of Crucibulum (locality 201), and Stigmaulax guppiana (locality 208) occur in the Chagres sandstone proper. The mollusks of the Chagres sandstone proper, unlike those of the Toro limestone member, indicate deposition in water of moderate depth. Echinoid. — A large species of Clypeaster, found in the Toro limestone member at locality 196 (Olsson's Anomia zone), is identified by C. W. Cooke as C. aff. <'. hi, in rsi. ('. lioinrsi occurs in the [mperial formation of the Colorado Desert, of disputed Miocene or Pliocene age (probably late Miocene). Age. — -The Chagres sandstone is close to the border between Miocene and Pliocene; it has been assigned to both series. Preliminary examination of the mollusks suggests early Pliocene, despite the presence of a few Gatun species, such as Stigmaulax guppiana, and of other species that have Gatun aflinities. PLEISTOCENE SERIES STRATIGRAPHY AND LITHOLOGY Pleistocene marine deposits occur at altitudes of a few feet above sea level and in the seaward part of buried valleys are interbedded with swamp and stream deposits. Swamp and stream deposits filling buried valleys extend as far inland as Gamboa on the Caribbean side of the Canal Zone and as far as Miraflores Locks on the Pacific side (Thompson, 1947a, p. 22). Black organic muck is the most widely distributed type of deposit. In fact, the geologists of the Geological Sec- tion of the Special Engineering Division used the in- formal designations Atlantic muck and Pacific muck for the Pleistocene deposits (Thompson, 1947a, p. 22). According to Thompson's description, much of the black muck represents swamp deposits and is a mixture of silt, very fine-grained organic debris, and partly carbonized wood, stems, and leaves. Layers of marine fossils are found in black organic silt and calcareous mud containing plant matter. They were encountered at the north end of the excavation for the Gatun Locks and in ditches in swamps north and east of Mount Hope (Brown and Pilsbry, 1913, p. 493-494; Mac- Donald, 1919, p. 544). Brown and Pilsbry casually used the name Mount Hope formation, which they attributed to W. B. Scott, for Pleistocene strata near Mount Hope (Brown and Pilsbry, 1913a, p. 493). FOSSILS AND AGE Corals. — Corals in collections from localities near Mt. Hope have been listed by Brown and Pilsbry (1913a, p. 497) and Vaughan (1919b, p. 563). They evidently represent reef-flat species. Mollusks.- — A few new species of mollusks were described by Dall (1912, p. 1-6) and Brown and Pilsbry (1913a). Brown and Pilsbry listed the species in the two collections they studied. The few species in then- collection from the north end of the Gatun Locks excavation indicate brackish water and the deposits themselves point to deposition in a swamp. The depositional environment of the large number of marine species in their collection from a locality near Mount Hope, and in MacDonald's collections from tin 1 same region, is uncertain on the basis of published data. Contrary to Dall's statement (1912, p. 1), Mac- Donald's collections from the Caribbean side do not contain any species now living along the Pacific side. The Pleistocene mollusks are not described in the systematic part of the present report . Age. — -With the exception of the new species of mol- lusks, the identified fossils from the Pleistocene marine deposits on the Caribbean side of the Canal Zone are known to be living in the Caribbean Sea. Dall, and Brown and Pilsbry realized that their new species may be found to be living when the fauna along the Carib- bean coast of Panama is better known. The Pleistocene deposits — -at least the marine deposits — probably are of late Pleistocene age, but may be too old for radio- carbon dating. CORRELATION OF TERTIARY FORMATIONS IN DIFFERENT AREAS Correlation of the Tertiary formations in different areas and age assignments, as adopted in the present GEOLOGY 51 A E t- = -. CJ Fl o> -- > V / ^ g \ ^ a uorjeuijoj 01IU1IEO 3N300rtd 3N330IW 3N3300HO 3N3003 (iisnoaovisao 3N3D031Vd 52 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE report, are shown in figure 4. Some features cannot be shown properly in figure 4: the age assignment for the Bas Obispo formation and Las Cascadas agglom- erate is 01igocene(?), despite the seemingly definite position on the chart; the age assignment for the marine member of the Bohio(?) formation of the Gatun Lake area is late Eocene or early Oligocene, not late Eocene and early Oligocene as the chart suggests. The correlations differ only in some minor details from those of Woodring and Thompson in 1949 (fig. 2). The following changes have been made in age assign- ments: Gatuncillo formation, middle and late Eocene instead of late Eocene; Bohio formation of all five areas, early and late Oligocene instead of only early Oligocene (except in Pacific coastal area, which was not shown in the 1949 chart); Culebra formation, including Emperador limestone member, early Miocene instead of late 01igocene(?) and early Miocene; upper part of Gatun formation in western area (not shown in figure 4), late Miocene, instead of middle or late Miocene; Chagres sandstone, early Pliocene instead of late Miocene or early Pliocene. Though the Bas Obispo and Las Cascadas formations are still considered Oligocene (?), they are given a greater probable time range in the Oligocene. Some of the proposed correlations are unsatisfactory. There is no satisfactory faunal or lithologic correlation between Madden basin and the Gaillard Cut area. On the contrary, at least parts of the Caimito formation of the Quebrancha syncline, the Gatun Lake area and the Pacific coastal area can be correlated with the lower part of the Caimito of Madden basin on fairly satis- factory faunal grounds. Plate 1 shows at a glance that Gaillard Cut and the Pacific part of the canal are close to the eastern border of a pile of volcanic rocks. Mad- den basin, the Quebrancha syncline, and the Gatun Lake area are farther seaward in the marine basin. The coarse pyroclastic rocks and flows of the Bas Obispo formation and Las Cascadas agglomerate, and the coarse pyroclastic rocks in the Panama formation represent seaward extensions of volcanic rocks from the volcanic pile. In Madden basin and the Que- brancha syncline such rocks are much thinner and are found only in the volcanic member of the Bohio formation and the pyro clastic-clay member of the Caimito formation. Pyroclastic deposits in the Gatun Lake area are of much finer grain than in Gaillard Cut. Tuffaceous debris is present in the Tertiary formations of all the area, but is more dominant in the Gaillard Cut area and the Pacific part of the canal than in Madden basin, the Quebrancha syncline, or the Gatun Lake area. The Cucaracha formation, for example, consists almost entirely of altered volcanic ash. The lack of studies of the pyroclastic rocks and the tuffaceous constituents of other rocks is the most serious deficiency in present knowledge of the geology of the Canal Zone and adjoining parts of Panama. Such studies are likely to yield clues to correlations of the formations that may be more convincing than the faunal correlations. IGNEOUS ROCKS The following brief account of the igneous rocks is based principally on MacDonald's manuscript on the geology of Panama mentioned on page 4. Much of the original manuscript, including some pages of the part dealing with the igneous rocks, is not preserved and his rock specimens and thin sections are no longer available. MacDonald's 1915 publication (p. 27-30) contains more data on the igneous rocks than his other publications. The igneous rocks may be divided into two age groups: Cretaceous(?) and Tertiary. That classifica- tion embodies the chief addition to MacDonald's treatment. CRETACEOUS (?) VOLCANIC AND INTRUSIVE ROCKS Altered basaltic and andesitic lavas are the most common rocks in the basement complex, at least along the Transisthmian Highway and the pipe-line road in the eastern part of the Canal Zone. Two samples from the eastern part of the Canal Zone were examined by W. S. Burbank, who reports that the rocks are similar in texture and composition to the basalt- andesite rocks of the Southern Peninsula of Haiti (Woodring, Brown, and Burbank, 1924, p. 320-330). Chlorite, calcite, and a little epidote are the principal alteration products in the two samples. Basalt containing unaltered olivine is exposed on Quebrada Lopez (between Sabanita and Rio Agua Clara) at the Transisthmian Highway bridge. Accord- ing to R. H. Stewart, similar olivine-rich basalt crops out in an extensive area northeast of the highway. Andesite at Porto Bello — the colonial settlement 35 kilometers northeast of Colon — is presumed to be part of the basement complex. As described by MacDonald, the rock is dark. Under the microscope it is markedly porphyritic and the phenocrysts are andesine, labridorite, bronzite, and some augite. The groundmass is largely glassy, but contains some minute crystals of plagioclase. This rock was used for con- crete in the construction of Gatun Locks and great slabs were quarried for armoring the Limon Bay breakwaters. The Cretaceous (?) lavas are intruded by dioritic rocks and dacitic porphyry. Though no debris from these intrusive rocks was noticed at the few localities where conglomerate of the Gatuncillo formation was observed, they probably antedate the Gatuncillo GEOLOGY 53 formation and probably are of late Cretaceous, Pale- ocene, or early Eocene age. Cobbles of granodiorite, found by MacDonald in the gravels of Rio Cbagres and in conglomerate of the Bohio formation, pre- sumably represent a group related to the Cretaceous (?) dioritic rocks. TERTIARY VOLCANIC AND INTRUSIVE ROCKS Though Tertiary lavas are found east of the canal and are widespread west of the canal, most of the Ter- tiary igneous rocks described by MacDonald and se- lected by him for chemical analysis were obtained from intrusive bodies. GRANULAR INTRUSIVE ROCKS Quartz diorite. — Cocovi Island, a small island in Panama Bay west of the entrance to the canal, was found by MacDonald to be made up of quartz diorite porphyry. The rock is light gray but weathers almost white. It is markedly porphyritic, the phenocrysts, up to 6 millimeters in diameter, consisting of andesine, andesine-labradorite, some quartz, and a little ortho- clase. Some of the feldspars are partly saussuritized. The ferromagnesian minerals are highly altered and for the most part unidentifiable; a few outlines of horn- blende crystals were recognized. Though the finely crystalline groundmass is somewhat cloudy and altered, it seems to consist of plagioclase and shreds of ferro- magnesian minerals. Magnetite, apatite, and chlorite are found in the rock. A chemical analysis of the por- phyry is included in the table on page 55 (analysis 1). Augite quartz diorite forms Point Farfan, on the west side of the Pacific approach to the canal at the ferry terminus opposite La Boca. At Point Farfan, like on Cocovi Island, MacDonald obtained, by blasting, rock that proved to be considerably altered, although of fresh appearance. The quartz diorite at Point Farfan is gray and weathers light gray. In hand specimens it is slightly porphyritic and the groundmass is granular and almost medium grained. In thin sections andesine and somewhat altered augite are conspicuous. Quartz is present in small irregular masses, some of which appear to be secondary. Many small shreds of highly altered indeterminable ferromagnesian minerals were observed. Magnetite and apatite are accessory min- erals and chlorite is the chief secondary mineral. The rock was analyzed and the results of the analysis are presented in the table on page 55 (analysis 2). Dacite. — The rock forming the Ancon Hill stock (be- tween An con and Balboa), as well as Naos Island and Culebra Island in Panama Bay, was described as rhyo- lite by Howe (1908, p. 230-231) and MacDonald (1915, p. 28-29). In his manuscript MacDonald points out that although the rock has the appearance of rhyolite and some thin sections show as much quartz as shown by many rhyolitcs, the chemical analysis and additional microscopic examination show that it is dacite. The dacite at Ancon Hill is light gray and weathers to a light creamy color. As described by MacDonald, it has a fine-grained texture and some lathlike pheno- crysts of plagioclase, the largest of which have faces measuring about 1 by 5 millimeters. In thin section the rock shows flow structure, particularly around the phenocrysts, which consist principally of andesine and some albite. Quartz in irregular grains, some augite, and a few small greatly altered needles of hornblende are present. The phenocrysts are widely scattered and grade in size into the coarser particles of the ground- mass. Though the groundmass is somewhat cloudy and altered, it consists principally of perthitic aggregates of orthoclase and plagioclase and some quartz and feld- spar intergrowths. Accessory minerals, in order of de- creasing abundance, are magnetite, ilmcnite, and apa- tite. A considerable amount of chlorite is present and scattered patches of an unidentified light yellowish sec- ondary mineral show in the groundmass. (See analysis 3, p. 55.) W. S. Burbank suggests that MacDonald's description and the chemical analysis indicate that the rock is considerably altered, principally by processes allied to albitization. During the construction of the canal a quarry on the west face of Ancon Hill, at a local- ity now known as Quarry Heights, furnished great quan- tities of this dacite for use in concrete in the construction of Miraflores and Pedro Miguel Locks. The stocks of porphyry between the canal and Mad- den basin, northeast of Gaillard Cut, include dacite porphyry, according to geologists of the Geological Sec- tion of the Special Engineering Division. The porphyry intruding the Gatuncillo formation in the Rio Casaya area (locality 38), for example, is dacite porphyry. The borders of this stock and the intruded rocks are slightly mineralized and some mining operations were carried on many years ago, as described on p. 59. MacDonald thought some of the rock in this area probably is grano- diorite, but he found nothing suitable for microscopic examination. Diorite.— A minor facies of the quartz diorite at Point Farfan is described by MacDonald as quartz-bearing gabbro. W. S. Burbank, however, points out that MacDonald's description of the mineralogical composi- tion and the chemical analysis indicate a classification near diorite. The rock is dark gray, medium-grained, and equigranular. The principal minerals, arranged in approximate order of relative abundance, are andesine, augite, and oligoclase. Quartz in small irregular patches is a minor constituent, which W. S. Burbank suggests may be secondary. Accessory magnetite, apatite, and ilmenite are present. Chlorite is found in the rock and some of the feldspars show slight saus- 54 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE suritization. W. S. Burbank points out that the soda content of the analysis of this rock on page 55 (analysis 4) is slightly high for normal diorite and suggests that the alteration recorded by MacDonald may indicate weak albitization. Andesite. — Andesite porphyry forms some of the stocks in the area between the canal and Madden basin. A small stock of hornblende andesite, characterized by conspicuous needles of hornblende, is being quarried along the road between Miraflores Lake and the Trans- isthmian Highway. DIKE ROCKS Andesite. — Andesitic dike rocks that cut the Las Cascadas agglomerate are mentioned by MacDonald. Basalt.— Dikes and small irregular intrusive bodies of almost black rocks, all grouped as basalt, are widely distributed southwestward from the southeastern part of the Gatun Lake area and the southern part of Mad- den basin. The irregular intrusive bodies form hills; in fact, most of the high hills in the southeastern part of the Canal Zone are formed by intrusive or extrusive basalt. Basalt obtained from dikes at 10 localities, for the most part in Gaillard Cut, was examined by Mac- Donald. These rocks are very dark and fine-grained. Labradorite, andesine, and augite are the principal constituents among the larger crystals. Some of the rocks also contain enstatite and a little biotite. The groundmass is made up of laths of plagioclase and grains of augite, but generally includes a little glassy material. Magnetite and ilmenite are the chief accessory minerals. Some chlorite and a few patches of serpentine — possibly an alteration product of olivine — are present. Basalt from a dike on the Panama Railroad 3 kilo- meters northwest of Monte Lirio was selected for chemi- cal analysis. (See table, p. 55, analysis 5.) As described by MacDonald, the rock is of coarser texture than the usual basalt in the Canal Zone and its feld- spars are more calcic. Hand specimens show crystal faces of pyroxene that shine with a resinous luster and have a maximum diameter of 4 millimeters. Under the microscope the largest phenocrysts are seen to be augite. The feldspar crystals, slightly in excess of the ferro- magnesian minerals, are for the most part labradorite and some of them are zoned. A little andesine is present. Augite occurs in granular aggregates as well as in phenocrysts. Magnetite, apatite, some ilmenite, and a few small grains of zircon are present. Secondary minerals consist of numerous patches of iron oxide(?), some serpentine that may be an alteration product of olivine, and a few small patches of chlorite. Some of the feldspar crystals are partly saussuritized and in zoned crystals the alteration is zonally selective. This rock was quarried for use in facing the water-level part of Gatun Dam. VOLCANIC ROCKS AND TUFF Dacite. — Dacitic glassy lava from the Las Cascadas agglomerate is included in the rocks selected for chemi- cal analysis (see analysis 6, p. 55). According to MacDonald's description, the glassy lava forms the matrix of thin flow breccia. The brecciated fragments enclosed in the glassy matrix consist chiefly of pyro- clastic rocks of the Las Cascadas. Some of the glassy lava contains elongated gas cavities drawn out in the direction of flow. The hard dacitic tuff in the Cucaracha formation, mentioned in the description of that formation, was also analyzed (analysis 7, p. 55). Thin sections of the tuff were examined by W. S. Burbank and R. L. Smith, who found it to be a welded tuff. The glassy base con- sists of compressed glass shards, for the most part partly or entirely altered to clay. Some of the plagio- clase (andesine-labradorite) crystals are euhedral; others are fragmental. Decomposition products of a few un- identifiable ferromagnesian minerals are recognizable and the rock has a few veinlets of calcite. Fragments of finely crystalline lavas of varying composition are scattered through the tuff. The dark little lentils, con- spicuous in hand specimens, consist of saponite (a clay mineral of the montmorillonite group), evidently an alteration product of compressed pumice lapillae. Andesite. — MacDonald mentioned andesitic flow breccias and dark coarse-grained andesitic flows in the Las Cascadas agglomerate. Basalt. — Some of the basalt in the southern part of the Canal Zone consists of remnants of flows and the undifferentiated volcanic rocks in the southwestern part of the map area include much basaltic lava. A flow remnant capping Gold Hill, which forms the continental divide on the east side of Gaillard Cut, is described by MacDonald as dark fine-grained basalt. The larger crystals consist of feldspar, mostly labra- dorite, and augite. Augite also occurs as grains and irregular aggregates. The groundmass is distinctly crystalline, though very fine-grained. It has about the same composition as the larger crystals. Small grains and irregular aggregates of magnetite, some apatite, and a little ilmenite are scattered through the rock. Epidote in light and dark yellow irregular patches fills cracks in broken feldspars and occurs as cloudy masses in the interior of some feldspar ciystals. The thin sections show no olivine, but a light yellow secondary mineral may represent altered remnants of olivine. A chemical analysis (No. 8) of this rock is included in the table on page 55. GEOLOGY 55 CHEMICAL COMPOSITION The chemical analyses of some of the rocks described in the preceding paragraphs are included in Mac- Donald's manuscript. As noted in the explanatory matter following the table of analyses, they have already been published in the Geological Survey's Bulletin 591. Missing pages of the manuscript may contain descrip- tions of the "andesitic rock near Empire" and the "lava near Las Cascadas", analyses of which were published in Bulletin 591. The norms of the analyzed rocks were calculated by MacDonald. Some abnormalities in mineralogical composition re- sulting from various degrees of albitization probably account for the high soda and low lime content of some of the rocks, particularly the dacites (analyses 3, 6). The low potash content is typical of many similar rocks in the Caribbean region. Analyses of igneous rocks and tuff from Canal Zone [Analysts: 1, 2, 6, 7, R. C. Wells; 3, 8, George Steiger; 4, 5, W. C. Wheeler] Granular intrusive rocks Dike rock Volcanic rocks and tuff 1 1 22 3 4 5 6 7 8 Si0 2 63. 51 18. 07 2.01 2. 18 2. 19 5. 14 4.08 .88 1. 07 . 60 . 33 None . 19 57. 39 15. 84 2.38 5.96 2. 41 5. 24 5. 23 .84 1. 09 1. 74 1. 35 Trace . 68 69.20 15. 00 1. 57 1. 83 . 69 1. 88 5.87 1. 81 .90 . 67 .52 None . 10 51. 72 15. 38 3.35 7.91 4. 38 7. 84 4.37 .47 .56 2.00 1. 67 None . 49 . 03 . 12 48.23 14. 69 4. 49 5. 85 6. 73 12. 12 2.55 1. 49 1. 50 . 98 1.00 Trace . 46 . 05 .09 62. 23 14.95 2. 04 1. 52 . 75 3. 10 5.08 1.26 I 8.94 .59 Trace . 04 65. 17 15. 22 2.08 3.98 1. 19 3. 79 3. 71 1. 52 2.57 . 96 .32 51. 04 A1,0 3 17. 34 Feo0 3 - -- 2. 88 FeO 7. 33 MgO 5. 50 CaO 9. 79 Xa 2 2. 88 K 2 . 53 H 2 0- f . 96 H,0+ 1 -2 Ti0 2 1. 32 C0 2 None P 2 5 . 25 S0 3 CI . 01 . 01 .05 . 01 s Cr 2 3 None . 16 .06 . 17 MnO .06 . 03 . 18 .02 . 15 . 06 . 13 BaO Total.. .... 100. 36 100. 41 100. 19 100. 45 100. 46 100. 50 100. 57 100. 67 1 Shows a trace of V 2 3 . J Shows traces of Zr0 2 , F, and V2O3. 1. Quartz diorite porphyry, Cocovi Island, Panama Bay. Clarke, F. W., Analyses of rocks and minerals from the laboratory of the U. S. Geol. Survey: U. S. Geol. Survey Bull. 591, p. 214, 1915, analysis O. 2. Augite quartz diorite, Point Farfan. Bull. 591, p. 214, analysis N. 3. Dacatie, Ancon Hill. Bull. 591, p. 213, analysis A. 4. Diorite, Point Farfan. Bull. 591, p. 214, analysis P. 5. Basalt, Panama Railroad, 3 km northwest of Monte Lino. Bull. 591, p. 214, analysis Q. 6. Dacitic glassy lava in Las Cascadas agglomerate, Gaillard Cut. Bull. 591, p. 213, analysis E. 7. Dacitic tuff in Cucaracha formation, Gaillard Cut. Bull. 591, p. 213, analysis B. 8. Basalt capping Gold Hill, Gaillard Cut. Bull. 591, p. 213, analysis G. 56 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Norms [Cross— Iddings — Pirsson — Washington classification] 1 2 3 4 5 6 8 Quartz - __________ 22. 26 5. 00 34. 58 24. 74 1. 22 8. 22 5. 00 44. 01 20. 01 22. 74 10. 56 49. 25 9. 45 2. 40 2. 78 35. 63 21. 68 20. 16 7.78 42. 97 14. 18 3. 06 Orthoclase _ _ _ 8. 34 20. 96 24. 74 2 78 Albite. __ 24 10 Anorthite __ _ 33 08 Corundum. _ _ _ Diopside . 81 12. 63 3. 15 11. 19 14. 63 26. 26 3. 09 4. 75 6. 50 1. 82 .93 .99 1. 63 11 12 1 I VplTSt Ill-lie .. _ Olivine _ ___. 6.06 17. 40 Magnetite . Ilmenite Apatite 2. 78 . 60 . 31 3. 48 2.58 1. 55 2. 32 . 91 1. 57 4. 87 3. 19 1. 24 3.02 1. 22 4. 17 2. 43 . 62 Symbols: (1) 1.4.3.5, amadorose; (2) II. 5.3. 5, beerbachose; (3) 1.4.2.4, lassenose; (4) II. 5. 3. 5, beerbachose; (5) III. 5.3. 4, camp- tonose; (6) 1.4.3.4, yellowstonose; (8) II. 5.4.4-5, hessose. AGE The Bobio formation of the Que bran cha syneline, which is of Oligocene age, includes a thin flow of basalt. Flow breccias and minor flows are found in the Oligocene (?) Bas Obispo formation aDd Las Cascadas agglomerate. Coarse-grained fragmental vol- canic rocks, in the form of agglomerates, make up the bulk of the Bas Obispo formation and Las Cascadas agglomerate and occur in other formations of Oligocene and early Miocene age, particularly tbe Caimito forma- tion of the Gatun Lake area (Oligocene), the Oligocene part of the Caimito formation of Madden basin, and the Panama formation (early Miocene). Altered tuff is the chief constituent of the early Miocene Cucaracha formation, wbich underlies the Panama formation. The Gatuncillo formation (middle and late Eocene) and Chagres sandstone (early Pliocene) contain very little tuft'aceous material, and tuff in the middle Miocene Gatun formation is very fine-grained. The distribution outlined in the preceding paragraph indicates that the well-dated Tertiary volcanic rocks, including the fragmental volcajics derived from a nearby source, are of Oligocene and early Miocene age. The volcanic centers presumably were in the area of undifferentiated volcanic rocks in the southwestern part of the area covered by plate 1 or farther west. Ma ay remnants of basaltic flows in the southeastern part of the Canal Zone which are not dated, except insofar as they lie on rocks of Oligocene or early Miocene age, probably are of the same age as the better dated volcanic rocks. The fine-grained tuffaceous material in formations of earlier and younger age than Oligocene and early Miocene evidently was erupted at distant localities, probably west of the map area, where a thick succession of volcanic rocks is known to be present. The thick succession of that area doubtless includes flows and intrusives younger than those of the map area. The intrusive Tertiary rocks are intruded into forma- tions ranging in age from middle and late Eocene to early Miocene. In the Gatun Lake area the Oligocene Caimito formation is intruded by basalt, but no intru- sive rocks have been found in the next yoimger forma- tion — the middle Miocene Gatun formation — or in the still younger Chagres sandstone. In the Gaillard Cut area and still farther southeast, the formations of early Miocene age (Culebra, Cucaracha, and Panama for- mations) are widely intruded by dikes, sills, and stocks. In that area, however, no Tertiary deposits younger than those just mentioned are recognized and they represent the early half of the early Miocene. If the upper limit of intrusive activity in the Gatun Lake area is applicable in the Gaillard Cut area and farther southeast, none of the intrusive rocks is younger than early Miocene. Some of them, however, may be older. The intrusive rocks, like the volcanic rocks, probably represent the period of time from Oligocene to early Miocene. The youngest intrusive rocks include the basalt forming dikes that extend around small hills of agglom- erate in the Gaillard Cut area (Thompson, 1947a, p. 27; 1952). The agglomerate, which represents part of the Pedro Miguel agglomerate member of the Panama formation, is faulted into the underlying Cucaracha formation along a more or less circular minor fault dipping steeply toward the agglomerate. Movement along the fault may have resulted principally from plastic deformation of the bentonitic clay of the Cucaracha formation. The basalt dike is intruded GEOLOGY 57 along the fault. Drilling through the agglomerate, however, shows that some of the dikes are cup-shaped rather than ring-shaped (Thompson, 1952). STRUCTURE STRUCTURAL, HISTORY Late Cretaceous or early Tertiary deformation. — The strongest deformation in the known geologic history of the Canal Zone and adjoining parts of Panama took place after eruption of the Cretaceous(?) lavas and deposition of the interbedded sedimentary rocks and before the laying down of the basal part of the Gatun- cillo formation in middle Eocene time. At the present time this deformation is poorly dated and the structural pattern it produced will not be known until the base- ment rocks are studied and mapped. Almost vertical altered tuffs on the Transisthmian Highway between Kio Gatun and Rio Agua Sucia strike northward. The basement rocks elsewhere in the eastern part of the Canal Zone and nearby show a north-south grain (Jones, 1950, pi. 2). The intrusion of the dioritic and dacitic rocks that metamorphosed the lavas and tuffs probably accompanied the deformation. Movements during late Eocene{?) to early Miocene time. — Minor and local movements during middle Tertiary time are indicated by coarse detritus and over- laps. The earliest of these movements, late Eocene or early Oligocene, is suggested by the coarse detritus of the Bohio formation and the overlap of the Bohio on the basement complex in the Pacific coastal area east of the Canal Zone. The source of the coarse detritus may have been beyond the limits of the region covered by plate 1, both to the southwest and northeast. Minor movement during the middle or late Oligocene is indicated by overlap of the Caimito formation on the Gatuncillo formation in the northern part of Madden basin and by the presumed overlap of the Caimito on the basement northeast of Gatun Lake. Overlap of the Culebra formation on the Las Cascadas agglomerate points to late Oligocene movement. The overlap of the La Boca marine member of the Panama formation on the Bas Obispo formation sug- gests comparable minor movement during early Mio- cene time. Miocene or Pliocene deformation. — Regional deforma- tion, the second period of regional deformation now recognized, took place during Miocene or Pliocene time. The present structural features of the central Panama area were then formed. The dating is uncertain not only because basic data are still incomplete, but also because the Gatun formation and the Chagres sand- stone do not have an extensive distribution. The Gatun formation, which is of middle Miocene age in the region covered by plate 1, is not known to overlie early Miocene deposits at outcrop localities anywhere in the central Panama area. The structural relations be- tween the Gatun formation and the Caimito forma- tion — the next older formation in the Gatun Luke and Caribbean coastal areas — are at present unknown. The overlap of the Gatun on the basement, however, indicates at least minor movement presumably at the end of early Miocene time and the regional deformation probably took place at that time. The Gatun forma- tion and also the early Pliocene Chagres sandstone dip gently seaward in the relatively narrow coastal strip where those formations are preserved. The distribu- tion of the Caimito formation and the marine member of the Bohio (?) formation in the western part of the Gatun Lake area indicates a pronounced unconformity between the Gatun and those older formations or that the Gatun is separated from them by a fault. A fault is suggested on plate 1. Minor movement, evidently of late Miocene age, is indicated by the partial overlap of the Chagres sandstone on the Gatun formation. The regional deformation may have taken place in middle or late Pliocene time after deposition of the Chagres sand- stone, but that appears to be unlikely. How far southward the Chagres sandstone and Gatun formation extended is not known. The Chagres sand- stone, however, apparently did not extend far. The Toro limestone member, at the base of the Chagres in the northeastern part of its outcrop area, and the A/ioraia-bearing strata at the base farther southwest are shallow-water deposits. The conglomerate and other deposits at the base of the Gatun formation be- tween Sabanitas and Maria Chiquita also represent a shallow-water facies. That area, however, is at the east end of the basin. To the southwest, in the Gatun Lake area, the Gatun may have extended considerably be- yond its present inland border. The base of the forma- tion east of Zorra Island, however, has not yet been examined and farther southwest the inland border of the formation is under Gatun Lake, and was concealed by extensive swamps before the flooding of the lake. In the area where the inland border of the Gatun is con- cealed, the middle part of the formation may overlap the lower part, just as farther west, in the region covered by figure 3, the upper part seems to overlap both lower and middle parts. If the formation extended far beyond its present inland border, the submerged area probably passed through Madden basin. Fossils char- acteristic of the Gatun formation are supposed to have been dredged in Panama Bay off La Boca during the construction of the canal (Li, 1930). Pilsbry, (1931, p. 427-428), who examined the types and figured speci- mens described by Li, found that the few Miocene fossils, among the Recent species actually dredged in Panama Bay, are indeed characteristic of the Gatun. 58 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE One of them, however, is labeled "Gatun Locks and Spillway" and all have a matrix typical of the Gatun formation at and near Gatun. The record of Gatun fossils in Panama Bay is spurious. STRUCTURAL FILATURES During the period when geological work was prac- tically limited to a narrow strip along the canal, the canal appeared to cross a major anticlinal crest which is located immediately southeast of Gamboa, about half- way across the isthmus, and is essentially parallel to the trend of the isthmus. When two sets of volcanic rocks (Cretaceous (?) and Oligocene to early Miocene) were differentiated, however, it was evident that the anti- clinal crest along the canal is a minor feature in a belt of Tertiary rocks extending obliquely across the isthmus. Plate 1 shows a marked contrast between the Gaillard Cut area and the region to the north and east. Though the numerous minor faults and folds of the Gaillard Cut area reflect the detailed work that has been carried out there, its location with reference to the trough of the Tertiary marine basin may have a bearing on its struc- tural features. The Gaillard Cut area is in the transi- tion zone between a volcanic sequence and a marine sequence, and the cover of sedimentary strata in the transition zone is thin. The largest well-defined folds — Madden basin and Quebrancha syncline — lie east of the Canal Zone in the trough of the Tertiary marine basin. Madden basin has the greater structural relief. It is the only area where late early Miocene marine deposits have been found and they are almost exactly at the middle of the isthmus. Madden basin is a broad gentle fold trending north-northeastward. Toward the south it flares out in an area where the geology is not well known. As shown by Reeves and Ross (1930, pi. 6), a narrow belt of relatively steeply dipping rocks (20° to 45°) extends northward from Rio Cbagres on the west side of the basin. The floor of the basin may be irregular through overlap of the Bohio formation by the Caimito formation. Quebrancha syncline also trends north-northeast- ward, but is more sharply folded than Madden basin. The southward-plunging anticline between Quebrancha syncline and Madden basin is greatly modified by the Limon fault. The northeastward trending anticline in Bohio Peninsula, in the Canal Zone, appears to be well defined. The interpretation that it extends farther south westward, and there reaches its greatest structural relief, is adopted to account for the upper Eocene or lower Oligocene strata of the marine member of the Bohio (?) formation in the northern part of the peninsula ending in Palcnquilla Point and on Trinidad Island. Evidence for a major eastward-trending fault, just north of Trinidad Island and just south of the Brujas Islands, is presented on page 61. So far as known the faidts are steeply dipping normal faults and many of them probably have strike-slip displacement (Jones, 1950, p. 906). Most of the major faults have a general northward trend, but the trend of that group of faults ranges from about N. 30° W. to about N. 30° E. A few major faults, such as the Rio Gatun fault and a fault along the lower course of Rio Frijol northwest of Gamboa, trend more to the east, about N. 70° E. The Chinilla fault, one of the group of major faults having a general northward trend, lies close to the Panama Railroad south of the embayment of Gatun Lake formed by Rio Agua Salud and Rio Frijolito. When MacDonald and Vaughan examined the fresh cuts and collected fossils from the Caimito formation along the railroad in 1911, they had no way of knowing that strata older than any along the canal or railroad (strata of the Gatuncillo formation) crop out only 200 meters east of the railroad. Jones' geologic map of the Gatun Lake area (1950, pi. 2) shows many faults and fractures not shown on plate 1 of the present report. The structure of the volcanic rocks west of Gaillard Cut is practically unknown. Detailed field work east of the Gaillard Cut area should show whether there is any correlation between the thin sedimentary cover and the structure of the Gaillard Cut area. Two characteristic formations of the thin sedimentary cover do not extend far east; the Culebra and Cucaracha formations. The distribution of those two formations in the complexly faulted Gadlard Cut area determined the course of the canal. Both are readily eroded and form topographic basins between irregularly arranged hills of basalt and agglomerate. MINERAL RESOURCES METALLIC MINERAL DEPOSITS Gold. — Gold ore has been mined in two districts: in the basement rocks southeast of Sabanita and at a stock of dacite porphyry southeast of Gamboa. I am indebted to R. H. Stewart for guiding me to the area southeast of Sabanita. Evidence of three periods of mining activity may be seen along streams immedi- ately north and northeast of Cerro Santa Rita (at the summit of which is located the 268-meter triangulation station plotted on plate 1): remnants of large stone mortars pointing to aboriginal operations; caved and also almost imperceptible adits associated with a French boiler still standing upright; and modern adits. The aboriginal operations suggest the origin of the name for Bahia de las Minas, the bay into which the streams drain. When Mr. Stewart first visited this GEOLOGY 59 region in 1947, the boiler fire-box door (now missing) bore the name of a French manufacturer and the date 1883. The country rock is olivine-rich basalt, a typical exposure of which is readily accessible at the Trans- isthmian Highway bridge across Quebrada Lopez, a small stream 1 % kilometers in a direct line northwest of the junction with the road to Nueva Providencia. The ore occurs in sulphide-bearing small quartz veins. No data are available on the mineralogy and tenor of the ore or on the tonnage that has been mined. Gold-mining operations at a stock of dacite porphyry southeast of Gamboa were carried on near the head of Quebrada de Oro, a small northwestward-flowing trib- utary of Rio Casaya. Locality 38 is located on Que- brada de Oro downstream from the adits (pi. 1). Rem- nants of mine and mill machinery and stretches of tram track are strewn along the stream. Mr. Adrian Bouche, of Pedro Miguel, the present owner of the property, orally reported that an English Company installed the mine and mill in the late 1870's or early 1880's, but that there is no evidence any gold was produced. The adits are located in a narrow aureole of mildly contact- metamorphosed sedimentary rocks of the Gatuncillo formation at the border of the porphyry stock. No attempt was made to enter the caved adits. Other adits and pits are located in the same stock of dacite porphyry, across the divide and 700 meters south of locality 38, near the head of a tributary of Rio Sardanilla, which flows southward and westward toward the Panama Canal. Boutan (1880, p. 31-32) mentioned a road built to haul machinery to a gold mine on Rio Sardanilla. The last French map, in the report of a Commission of the second French canal company that includes an account of the geology by Bertrand and Zurcher (1899), shows near Rio Sardanilla a "mine de quartz aurifere en exploitation." In his unpublished manuscript, written about 1918 and mentioned on page 4 of the introduction of the present report, MacDonald reported that none of some 40 samples from the most promising veinlets, "about 2% miles east of the canal opposite Las Cascadas," showed gold values of more than $1.00 to the ton. That statement evidently refers to the Quebrada de Oro area. He also reported on samples collected "a mile more or less in a southeasterly direction from these [those of preceding two sentences] old workings"; that is, in the Rio Sardanilla area. The gold value of his samples is as follows: Gold value (as of about 1912) of samples collected in Rio Sardanilla area [Extracted from manuscript by D. F. MacDonaldJ Value of gold Sample per ton Float from quartz vein $6. 80 End of open cut 1. 04 Open cut . 41 Outcrop, top of ridge . 20 Lower part of cut Trace Manganese.- — Plate 1 was extended far enough to the north to show the location of the southern of two man- ganese prospects near Rio Boquer6n. An abandoned tram line extends from the prospects to the coast near Nombre de Di6s. The country rock consists of strongly deformed, low-grade metamorphic rocks — quartzite, siliceous limestone, micaceous schist (probably meta- morphosed tuff), and greenstone (highly altered al- glomerate) — all representing the Cretaceous(?) base- ment complex. The ore deposits are manganese oxides associated with red jasper. Boulder-like masses of ore form great trains down the slopes and streams. These deposits were described briefly by Sears (1919) and are described in greater detail by Simons hi a recent pub- lication (Roberts, R. J., and Irving, E. M., 1957, p. 119- 128), from which the preceding sentences were abstracted. In the publication just cited Simons mentions a minor manganese prospect in Madden basin, south of Rio Chilibrillo and about 2 kilometers south of Casa Larga. According to a written communication from T. F. Thompson, shallow pits and trenches scattered over an area of about a hectare show aggregations of manganif- erous concretions and lenses in the Bohio formation. NONMETALLIC MINERAL DEPOSITS Limestone for cement.— Limestone in the Quebrancha limestone member of the Caimito formation is at present the most important nonmetallic mineral de- posit. The limestone is quarried by the Cia. Cemento Panama, S.A., immediately east of the Transisthmian Highway on the east limb of the Quebrancha syncline (locality 62, pi. 1) and is processed as an ingredient for cement in the company's adjoining plant. The thick- ness and properties of three grades of limestone and one of calcareous siltstone are described in Thompson's (1944) detailed report. The reserves are enormous. Other limestones in the Caimito formation of Madden basin and the Gatun Lake area, the Emperador limestone member of the Culebra formation, and at the base of the La Boca marine member of the Panama formation 60 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE may be suitable for cement. According to an oral communication from Thompson, the widespread lime- stones of the Gatuncillo formation are too high in magnesia. Rock for construction. — MacDonald (1915, p. 35-38) adequately covered construction material used in the building of the canal. The great quarry in dacite on the west face of Ancon Hill, the quarry in basalt at Sosa Hill adjoining the Balboa docks, and the quarry in basalt on the west side of the Panama Railroad 3 kilometers northwest of Monte Lirio, are reminders of the construction period. Since MacDonald wrote his account, a quarry has been opened in hornblende andesite on the Chiva Chiva Road 6)3 kilometers northeast of Pedro Miguel. OIL POSSIBILITIES Though the central Panama area of Tertiary marine sedimentary formations is small and the total thick- ness of marine strata is moderate, the oil possibilities deserve consideration, especially since the discovery in 1956 of oil in the Costa Rican part of the Bocas del Toro area. The southeastern end of the Costa Rican part of the Bocas del Toro area is shown in figure 1. At the time of writing (Sept., 1956) the discovery well, Union Oil Co. No. 2 Cocoles, located lji kilometers north of the international boundary, had just been completed and stratigraphic data had not been released. In many respects the stratigraphic succession in the southeastern part of the Bocas del Toro area is similar to that in the central Panama area, which includes the Canal Zone. On the islands of Bocas del Toro Archi- pelago a thin section of carbonate and other rocks of Pliocene age crops out. They are underlain in the archipelago and on the mainland by Miocene strata, designated by Olsson the Gatun stage or formation (Olsson, 1922, p. 10-16). The upper part of Olsson's Gatun consists of carbonate and fine-grained, calcareous detrital rocks of late Miocene age, correlated with the upper part of the Gatun formation in the western area of the present report. The lower part of Olsson's Gatun corresponds to the late middle Miocene middle part of the Gatun in the Canal Zone and also to the late middle Miocene upper part in the eastern area, although the depth-facies in the Bocas del Toro basin is shallower than that of the upper part in the Canal Zone. The equivalent of the early middle Miocene lower part of the Gatun in the Canal Zone is missing at the outcrop in the Bocas del Toro area or is partly represented by nonmarine conglomerate, rocks of finer grain containing land plants, and lignite. Olsson's Gatun rests unconformably on the Uscari formation (or better Uscari shale) , which consists almost entirely of moderately deep-water fine-grained rocks (Olsson, 1922, p. 10). Light oil issues from fractures in strongly deformed strata of the Uscari in the type region along Uscari Creek. The Uscari is of late Oligocene and early Miocene age and corresponds in age to the Caimito formation of Madden basin. The oldest outcropping Tertiary strata in the southeastern part of the Bocas del Toro area are limestones, probably of both Oligocene and Eocene age. The presence of subsurface marine strata of Eocene age is a reasonable expectation. There are two important differences between the two areas. No oil seeps have been found in the central Panama area and nothing in the Oligocene and lower Miocene outcrop section closely resembles the almost uniformly fine-grained rocks of the Uscari shale. Three districts in the part of the central Panama area covered by plate 1 are promising for testing oil possibilities: the Gatun Lake district, Madden basin, and the Pacific coastal district east of Panama City. Gatun Lake district. — Estimates of outcrop and prob- able maximum subsurface thickness in the Gatun Lake district are as follows. Estimated outcrop and probable maximum subsurface thickness of sedimentary rock formations in Gatun Lake district Maximum subsurface Outcrop thickness thickness in Formation in meters meters Chagres sandstone 250 250 Deposits of late Miocene age Overlapped 100 Gatun formation 250 500 Deposits of early Miocene age Overlapped 300 Caimito formation 300 400 Bohio formation 300 300 Marine member of Bohio (?) forma- tion 100 250 Gatuncillo formation 25+ 300 Total 1,225+ 2,400 The outcropping formations in the Gatun Lake district are marine, with the exception of the Bohio formation, which is nonmarine throughout most of the area. On Barro Colorado Island, however, the upper part of the Bohio includes thin marine tongues of some- what calcareous, medium-grained subgraywacke, sug- gesting that the nonmarine coarse-grained rocks are replaced seaward by marine rocks of finer grain. The upper part of the Gatun formation consists of more or less calcareous, sandy and silty rocks containing GEOLOGY 61 a clay-like matrix. The fauna, which includes pelagic Foraminifera, a few pteropods, and a rich assortment of benthonic foraminifera and mollusks, indicates a mod- erate-depth environment (50 to 100 fathoms; outer neritic zone of forthcoming "Treatise on paleoecology" to be published by the Geological Society of America). The late Miocene upper part of the Gatun in the western area, west of the Canal Zone (fig. 3), is overlapped by the Chagres sandstone, but is presumed to be present in the subsurface section. Deposits of early Miocene age are unknown in the Gatun Lake district. That they were deposited there is indicated by the Caribbean faunal affinities of the early Miocene part of the Caimito formation in Madden basin. As it is unlikely that they were removed before deposition of the Gatun formation, it is concluded that they are overlapped by the Gatun, which, along the northeast border of the central Panama area, overlaps the Caimito formation and rests on the Cretaceous (?) basement. Except on Barro Colorado Island, the Caimito forma- tion consists of moderately coarse, shallow-water, highly tuffaceous rocks and thin algal-foraminiferal limestone. Though the lower part of the Caimito on Barro Colorado includes thin algal-foraminiferal lime- stone, it is made up chiefly of medium- to very fine- grained, somewhat tuffaceous sandstone. These fine- grained rocks contain a moderate-depth fauna. At one locality (54n) silty, very fine-grained sandstone con- tains numerous discoasters and other pelagic cocco- lithophores and numerous pelagic Foraminifera. The outcrop section of the Caimito on Barro Colorado, like that of the Bohio formation, points to progressively deeper water and finer grain size in a seaward direction. By the same line of reasoning outlined for deposits of early Miocene age, the Gatuncillo formation is expect- able in the subsurface section of the Gatun Lake district. That expectation recently was realized, when the Gatuncillo was indentified at a depth much shallower than expected. In 1955 Pi. H. Stewart, of the Panama Canal Company's Meteorological and Hydrographic Branch, examined the cores obtained in Core Hole CH-5, drilled in 1946 at a locality in Gatun Lake 325 meters south of Guava Island, a small island of the Brujas Islands group. (The core-hole locality is 1.3 kilometers east of locality 55a of plate 1.) The cores include a considerable thickness of fossiliferous lime- stone, logged as part the Caimito (?) formation when the core hole was drilled. Mr. Stewart, however, thought it probably is a limestone of the Gatuncillo formation and his suspicion was confirmed when W. S. Cole identified Heterostegina ocalana, Lepidocyclina macdonaldi, L. chaperi, and Asterocyclina georgiana in 413788—57 5 a sample of readily disintegrated limestone from the core. A synopsis of the core is as follows: Log of Core Hole CH-5, drilled in Gatun Lake Thickness (meters) Lake sediments 0. 9 Caimito(?) formation: Bentonitic tuff grading downward into sandy siltstone in basal 3 m 11. 2 Gatuncillo formation: Hard fossiliferous limestone grading downward into soft marly limestone in lower 1.9 m 11. 5 Sandy siltstone and thin beds of tuff and limestone^ . 14. 4 Total thickness 38. The presence of the Gatuncillo formation 11.2 meters below the bottom of the lake sediments can hardly be accounted for without an assumption of a major fault trending a little north of east and lying just north of Trinidad Island and just south of the Brujas Islands group. The Caimito formation is not known to overlap the Bohio formation anywhere in the central part of the Gatun Lake area, although in the northeastern part of the area, north of Nueva Providencia, it evidently overlaps both Bohio and Gatuncillo. The strata in the core hole overlying the Gatuncillo formation do not suggest overlapping deposits. Nevertheless the silt- stone strongly suggests the tuffaceous siltstone of the Caimito exposed on the south coast of Pato Horqueto Island (locality 55a, pi. 1), the island in the Brujas group west of the core-hole site. If these suggestions are correct, the core hole passed through a fault at a depth of 29.7 meters below the surface of the lake — a fault having a stratigraphic displacement of about 300 meters. No evidence indicating a fault, however, was recorded by the geologist who prepared the log. As a matter of fact, a fault of that character and of the trend just specified accounts for the marine member of the Bohio (?) formation on Trinidad Island much more satisfactorily than plate 1. The Gatuncillo formation, consisting chiefly of moderate-depth siltstone and mudstone, is a likely source for oil throughout the central Panama area and its limestones are suitable reservoirs. Madden basin. — -The following table shows estimates of outcrop and probable maximum subsurface thickness in Madden basin. Estimated outcrop and probable maximum subsurface thickness of sedimentary rock formations in Madden basin Maximum Outcrop subsurface thickness thickness Formation (meters) (meters) Caimito formation 450 450 Bohio formation 0-200 300 Gatuncillo formation 300 500 Total 750-950 1,250 62 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE As in the Gatun Lake district, the hulk of the Bohio formation consists of nonmarine boulder conglomerate. At the continental divide the upper part of the forma- tion includes thin lenses of algal-foraminiferal lime- stone. In the Quebrancha syncline, northwest of Madden basin, the Bohio is made up of gray wacke grit, the basal part of which includes marine siltstone. In the northern part of Madden basin the Caimito forma- tion overlaps the Bohio. The Gatuncillo formation evidently rests on an uneven surface of the basement complex. Reeves and Ross (1930, p. 18, pi. 5) mentioned and mapped a small outcrop of dioritic rock near the head of Rio Azote Caballo, just south of the present south shore of Madden Lake. This outcrop evidently is the top of a basement hill or ridge, on the sides of which the Gatuncillo is overlapped by the Caimito. Practically pure quartz sandstone in the upper part of the Gatuncillo is exposed along the road from Casa Larga to Laguna, near locality 13 — the only locality where such sandstone was observed in the area covered by plate 1. Pacific coastal district east of Panamd City. — In the Pacific coastal district east of Panama City, the Gatuncillo formation is overlapped by the Bohio forma- tion. The Gatuncillo reappears farther east in the valley of Rio Bayano, 45 kilometers east-northeast of the eastern border of plate 1 (Terry, 1956, p. 32). DESCRIPTION OF TERTIARY MOLLUSKS The formal description of species is held to a mini- mum. Lengthy descriptions almost invariably include matter at the generic level which is of no value in the discrimination of species. The following terms are used for type material of species : Type: A specimen selected by the describer as the name- bearer of a species. Also known as holotype. Paratype: A specimen showing a feature, or features, not shown by type. Also used by others for any specimen, other than type, on which the description of a species is based. Syntype: A specimen in a lot of two or more on which a species is based, but none of which was selected by the describer as the name-bearer. Also known as cotype. Lectotype: A syntype subsequently selected as the name- bearer. Neotype: A specimen, from the same locality and horizon, selected as the name-bearer to take the place of destroyed or lost type material. Tiipniypr: A specimen from the same locality and horizon as the name-bearer. Terms used for types of genera are as follows: Orthotype: Type by original designation. Monotype: Type by monotypy. Also known as haplotype. Tautotype: Type by tautonymy. Logotype: Type by subsequent designation. Adoption of the preceding terms for the types of genera, which have the advantage of brevity, was prompted by Iredale's (1939, p. 223) usage in his Great Barrier Reef report. Monotype, however, has been substituted for haplotype. Iredale's usage was based on Jordan's, who in turn picked up terms from Cooke, but also added one of his own. Those interested in the origin and varying usage of the terms in the preceding two lists will find definitions and citations in Frizzell's useful "Terminology of types" (1933). It is entirely appropriate to use the term "type" for a species and a genus. There can be no confusion : the type of a species is a specimen, whereas the type of a genus is a species. The following new subgeneric names are proposed: Aepystoma, subgenus of Teinosioma, Vitrineilidae. Type: Teinostoma (Aepystoma) andrium Woodring, n. sp., Gatun formation, Miocene, p. 70. Gender neuter. Diaerecallus, subgenus of Teinostoma, Vitrineilidae. Type: Teinostoma (Diaerecallus) sychnum Woodring, n. sp., Gatun formation, Miocene, p. 71. Gender mascu- line. Hapalorbis, subgenus of Solaiiorbis, Vitrineilidae. Type: Circulus liriope Bartsch, Recent, Gulf of Cali- fornia, p. 75. Gender masculine. Hypterita, subgenus of Neverita, Naticidae, Polinicinae. Type: Natica helicoides Gray, Recent, Baja California to Peril, p. 92. Gender feminine. GASTROPODS Family TROCHIDAE Trochids are rare in the Tertiary formations of the Canal Zone and adjoining parts of Panama. Each of the two species of Calliostoma herewith described is represented by two specimens. In addition three other trochids are recognized: a minute "Margarites" from the middle part of the Gatun formation; an exfoliated apical fragment sculptured with nodose spirals, evi- dently a calliostome, also found in the middle part of the Gatun formation; and an incomplete impression, probably a calliostome sculptured with weakly noded spirals, from the Toro limestone member of the Chagres sandstone. Each of these three trochids is represented by only one specimen. Subfamily MARGARITINAE Genus? "Margarites" species Minute, very thin-shelled, outline naticid, whorls rapidly enlarging. Protoconch consisting of a smooth naticoid whorl. End of protoconch marked by fine closely spaced axial and spiral threads. Both sets of threads gradually become more widely spaced and on later part of penult they disappear, the early part of the penult bearing a sutural thread, a thread on the shoulder, and widely spaced retractive axial threads gastropods: trochidae to turritellidae 63 between them. Body whorl smooth. Outer lip broken far back. Columella!- lip incomplete. Umbilicus evi- dently very narrow, umbilical border broadly rounded. Height 2.4 mm, diameter 2.2 mm. This curiously sculptured species represents an un- known genus of the Margaritinae. The outline and thin shell suggest "Solariella" iridea Dall (1889, p. 382), dredged by the Blake off Cape Florida at a depth of 193 fathoms. "Solariella" iridea, however, has more inflated whorls, no axial sculpture, a faintly undulated spiral near the suture, a wider umblicus, and elongate nodes on the umbilical border. Though "Solariella" iridea was described as a variety of "Solariella" lubrica Dall, it is not closely related to that species, which is the type of the genus Suavotrochus (Dall, 1924, p. 90), described as a section of Solariella. Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, locality 155c. Subfamily CALLIOSTOMATINAE Genus Calliostoma Swainson Swainson, A treatise on malacology, p. 351, 1840. Type (logotype, Herrmannsen, Indicis generuni malacozoorum, v. 1, p. 154, 1846): Trochus conulus Linne (cited by Swainson as "conula Mart."), Recent, Mediterranean Sea. Subgenus Calliostoma s. s. Calliostoma (Calliostoma) metalium Woodring, n. sp. Plate 18, figures 12-14 An imperforate very weakly sculptured, nonnoded, carinate callistome of medium size. Whorls rapidly enlarging, outline of spire concave. Whorls, except body whorl of mature shells near outer lip, very strongly carinated by a peripheral spiral, which is visible on spire whorls adjoining anterior suture. Three weak spirals visible on earliest preserved whorl, which is somewhat exfoliated. A few very faint spirals visible on anterior part of other spire whorls. Body whorl between suture and periphery bearing weak spirals. Base bearing faint spirals adjoining periphery and wider faint spirals adjoining columellar lip. Columellar lip everted, molded against base of shell except n3ar base of lip. Height (almost complete, but crushed) 19.5 mm, diameter (incomplete) 24 mm (type). Type: USNM 561430. Type locality: 206a (Stanford Univ. locality 2699, Caribbean coast near mouth of Rio Pifia, road cut on west side of river about 90 m. west of road fork, Panama; same locality as USGS 16937), Chagres sandstone. Though the type is somewhat crushed and evidently is immature, the characters of this weakly sculptured, nonnoded, carinate species are well defined. Much of the type is more or less exfoliated, but even unex- foliated patches are very weakly sculptured, aside from the strong peripheral spiral. That the type is not mature and that the peripheral spiral is reduced near the outer lip of mature shells are shown by an exfoliated body whorl fragment from the type locality — the only specimen other than that illustrated. This fragment indicates a body-whorl diameter of at least 30 millimeters. In outline of spire, strongly carinate periphery, and almost smooth base, Calliostoma metalium is allied to C. aurora Dall (1889, p. 366, pi. 37, fig. 2), dredged at a depth of 140 fathoms off Barbados. (Dall also recorded a fragment from a depth of 576 fathoms.) C. metalium, however, lacks the noded spirals of C. aurora and the basal spirals of the fossil are even weaker. Occurrence: Chagres sandstone (early Pliocene), localities 206, 206a. Subgenus Leiotrochus Conrad Conrad, Acad. Nat. Sci. Philadelphia Proc, p. 288, 1862. Type (monotype): Leiotrochus distans Conrad, Miocene, Maryland. Assignment of Calliostoma eremum to Leiotrochus has the advantage of indicating that this species has an umbilicus. It is doubtful, however, whether the strongly sculptured C. eremum and its allies are closely related to the faintly sculptured C. distans. For the characters of C. distans, reliance is placed on specimens in the U. S. National Museum from Yorktown, Virginia, labelled C. briani Conrad. According to Dall (1890- 1903, pt. 2, p. 402, 1892), who handled specimens identified by Conrad, C. briani is C. distans. The C. distans of the Maryland Geological Survey Miocene volume (Martin, 1904, p. 258, pi. 61, fig. 6) is imper- forate and has moderately strong sculpture. Evidently it is not C. distans, as it does not agree with Conrad's description. As suggested by Gardner (1926-47, p. 619-620, 1947), a more natural grouping of perforate and im- perforate species of Calliostoma may possibly be gained through a study of the development of the sculpture. Calliostoma (Leiotrochus) eremum Woodring, n. sp. Plate 22, figures 3,5 A perforate calliostome of medium size. Whorls of spire slightly inflated, body whorl strongly inflated. Sculpture of spire whorls and of body whorl between periphery and suture consisting of strongly noded primary spirals (3 on earliest preserved whorl, 5 to 6 on penult, and 9 to 12 on body whorl). A weakly noded secondary spiral in some interspaces. On late whorls some secondary spirals are transformed into primaries by becoming wider and more strongly noded. Base sculptured with 10 or 11 primary spirals. A 64 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE secondary spiral present or absent in interspaces on base. Nodes on basal spirals long, low, and not well defined. Edge of umbilicus not sharply angulated and therefore junction of basal and columellar lips not angulated. Interspaces on base and umbilical wall adjoining innermost basal spiral roughened by axial wrinkles. Remainder of umbilical wall smooth, aside from subdued growth lines. Height (incomplete) 17.5 mm, diameter 19 mm (type). Height (almost complete) 18.7 mm, diameter 19 mm (para type). Type: USNM 561311; paratype, Stanford Univ. Type locality: 155c (USGS 16915, Gatun Third Locks excavation, east side of excavation, 1 mile (1.6 km) north of Gatun Lake, Canal Zone), middle part of Gatun formation. This species is represented by two specimens, both collected at the Gatun Third Locks. It has a less angulated umbilical border than Calliostoma grabaui Maury (1917, p. 155, pi. 24, fig. 19), from the middle Miocene Gurabo formation of the Dominican Republic, and also has weaker nodes on the spirals of the body whorl, particularly on the base. C. mancinella Olsson (1922, p. 164, pi. 15, figs. 9, 10), from the middle Miocene of Costa Rica, has a lower spire, less inflated spire whorls, and more widely spaced basal nodes. The more inflated spire whorls and less angulated umbilical border of C. eremum differentiate it from the living C. sayanum. Dall (1889, p. 370, pi. 33, figs. 10, 11), which furthermore is twice as large. The two specimens of C. sayanum mentioned by Dall in 1889 still are the only representatives of that species in the collections of the U. S. National Museum: the type dredged at a depth of 120 fathoms 20 miles southeast of Cape Hatteras and a body-whorl fragment from a depth of 107 fathoms 36 miles south of Cape Hatteras. Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 155, 155c. Family TURBINIDAE Genus Turbo Linne Linne, Systema naturae, ed. 10, p. 761, 1758. Type (logotype, Montfort, Conchologie systematique, v. 2, j>. 203, 1810): Turbo petholalus (Turbo petholatus Linn6), Recent, tropical western Pacific and Indian Oceans. Subgenus Marmarostoma Swainson Swainson, Zoological illustrations, 2d ser., v. 1, text accompany- ing pi. 1 1 (unnumbered), 1829. Type (orthotype) : Turbo chrysostomus Linnd, Recent, tropical western Pacific. When Swainson proposed the generic name Marma- rostoma, he designated Turbo chrysostomus as the type. The only species of Marmarostoma, however, described by him at that time, M. undulata (correctly M. un- dulatum), evidently is the Panamic species named Turbo saxosus by Wood (1828, p. 20, pi. 6, fig. 45) a year earlier; that is, it is a species of the subgenus Callopoma Gray (Gray, M. E., 1850, p. 87; type (logo- type, Cossmann, 1895-1924, pt, 11, p. 116, 1918): Turbo fiuctuosus Wood, cited by Cossmann as Turbo fluctuatus Gray), Recent, tropical eastern Pacific), characterized by a deep central pit and granular ribs on the operculum. Many years ago Iredale (1915, p. 444) discussed Swainson's type designation, but, apparently on the tacit assumption that Turbo marmoratus Linne is the type of Turbo, he considered Marmarostoma to be a synonym of Turbo. Thiele in his Handbuch der sys- tematischen Weichtierkunde and Wenz in his treatise on fossil gastropods have called attention to the avail- ability of Marmarostoma in place of the better known Senectus Swainson (1840, p. 348; type (logotype), Herrmannsen, 1846-52, v. 2, p. 438, 1848: Turbo chrys- ostomus Linne, (cited by Swainson as "chrysostomus Mart."), which is an objective synonym. Caribbean fossil and Recent species that are referred to Marmarostoma are not typical of that subgenus. The operculum of Turbo chrysostomus and its close allies has marginal oblique nairow grooves separating minutely granular bands, whereas the operculum of the Caribbean species has a more or less distinct shallow marginal ledge and is faintly granulai or smooth. Turbo (Marmarostoma) aff. T. castaneus Gmelin Plate 20, figure 10 Of medium size, sculpture nonlamellar. Early whorls bearing a conspicuous practically smooth basal spiral. Later whorls weakly shouldered, sculptured with noded spirals. Somewhat worn operculum assumed to represent this species is smooth, bearing a poorly defined shallow marginal ledge. Height (not quite complete) 20.5 mm, diameter (incomplete) 18 mm (figured specimen). An incomplete apparently immature shell and asso- ciated operculum from the middle part of the Gatun formation and a mold of a few whorls from the Toro limestone member of the Chagres sandstone are identi- fied as Turbo aff. T. castaneus. They may, in fact, represent the Recent Caribbean T. castaneus. The operculum fitted into a shell considerably larger than the only shell collected at the same locality. The typical form of T. castaneus, as long accepted, is sculptured with nonlamellar noded spirals. Recent Caribbean shells that have noded spirals but also have thin lamellae forming vaulted scales on the primary spiral at the shoulder, or on that spiral and others, have been referred to T. crenulatus, also named b} r Gmelin. T. crenulatus has the same geographic range gastropods: trochidae to turritellidae 65 as T. castaneus (North Carolina to the West Indies), but is said to be more common at slightly shallower depths (Dall, 1890-1903, pt. 2, p. 382, 1892). It has been considered a synonym of T. castaneus, a variety of castaneus, or a valid species. The collections of the U. S. National Museum indicate that the two forms intergrade. They are considered forms of a variable species, at least until more is known about their habitat and habits. The fossils from Panama are nonlamellar. They are not as strongly shouldered as most Recent shells — that is, the spiral at the shoulder is not as strong — and the nodes on the sutural spiral, particularly on the specimen from the Gatun formation, are not as coarse as those of most Recent shells. In both features, however, a few Recent shells closely approach the fossils. Other fossils suggest that Turbo castaneus was living in the Miocene Caribbean Sea. A small incomplete strongly shouldered lamellar specimen from the middle Miocene Bowden formation of Jamaica is recorded as Turbo (Senectus) species (Woodring, 1928, p. 411). A strongly shouldered nonlamellar form, Turbo (Senectus) cf. castaneus (Rutsch, 1934, p. 40, pi. 1, figs. 1, 2) occurs in the late Miocene Punta Gavildn formation of Vene- zuela. Turbo crenulatoides Maury (1917, p. 153, pi. 24, fig. 14), from the middle Miocene Cercado and Gurabo formations of the Dominican Republic, is sculptured with strong lamellae that extend from suture to base on the body whorl. It is doubtful, however, whether it can be differentiated from strongly lamellar Recent shells. Late Miocene deposits in western Florida yielded a strongly shouldered Turbo bearing a few lamellae on spirals below the shoidder on the later part of the body whorl. It was recorded as Turbo castaneus var. crenu- latus (Mansfield, 1930, p. 127, pi. 19, fig. 5). T. casta- neus and T. castaneus var. crenulatus are recorded from the Pliocene Caloosahatchie formation of Florida. Occurrence : Middle part of Gatun formation (middle Miocene), eastern area, locality 155b. Toro limestone member of Chagres sandstone, (early Pliocene), locality 196. Family PHASIANELLIDAE When the family name Tricoliidae was used in 1928 (Woodring, 1928, p. 418), it was not intended as a new name. It was used under the impression that the name had been proposed or suggested: evidenth T the result of an erroneous interpretation, perhaps of Iredlae's (1924, p. 232) statement. At all events the name is to be suppressed, for Tricolia appears to be properly re- ferred to the family Phasianellidae. Genus Tricolia Risso Risso, Histoire naturelle des principales productions de I'Europe meridionale, v. 4, p. 122, 1826. Type (logotype, Gray, Zool. Soc. London Proc, p. 144, 1847): Turbo pullus (Turbo pullus Linn6), Recent, Mediterranean. (Gray cited the generic name as Tricolea.) Before the generic name Tricolia can be used it is necessary to dispose of Lamarck's name Phasianella (1804, p. 295). Though that name appeared in a pub- lication on fossils from the vicinity of Paris and two Eocene species are the only ones that were described, Lamarck stated that he was naming the genus for a Recent shell, "faisan (phasianus)" . Despite Lamarck's clear intention and although there is no doubt about the identification of the shell he mentioned and partly described, he cited no references that could be used in fixing its Latin name. Therefore the view that faisan (=Buccinum australis Gmelin) is the type by original designation (Woodring, 1928, p. 418, 419, footnote) is hardly admissible. I am indebted to H. A. Rehcler for pointing out that the deficiency in Lamarck's treatment was rectified within the next year by Roissy (1805 or 1806, p. 330), when he wrote "Le type de ce nouveau genre, que Ton doit encore a M. de Lamarck, est une jolie coquille appelee/awan, * *." He stated that this species is from New Holland and on the next page described it as Phasianella variegata, citing Buccinum tritonis Chemnitz in synonymy. This is an unequivocal type designation and it is irrelevant that Lamarck used only a vernacular name for the type species. The type of Phasianella therefore is P. variegata Roissy (= Buc- cinum australis Gmelin). Roissy 's action fortunately saves the traditional usage of Phasianella. Tricolia calypta Woodring, n. sp. Plate 15, figures 1, 2 Of medium size, moderately inflated, spire high. Columellar lip and parietal callus thin. Umbilical groove narrow. Type showing curved strongly retrac- tive bands on later part of body whorl, bands standing out in slight relief on the somewhat altered and cor- roded shell, but may originally have been color bands. Operculum unknown. Height 4.8 mm, diameter 3.1 mm (type). Type: USNM 561327. Type locality: 40a (USGS 2683, Vamos Vamos, off Palenquilla Point, Canal Zone, now submerged), marine member of Bohio(?) formation. The type and an additional specimen are in one of Hill's collections from Vamos Vamos, and two others are in MacDonald and Vaughan's collection from the same locality. The type is the only specimen that shows the retractive bands. The whorls of Tricolia calypta are less constricted at the suture than those of T. precursor (Dall) (1915, p. 94, pi. 12, fig. 5), and the species from Panama has a 66 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE narrower umbilical groove. T. precursor occurs in the early Miocene Tampa limestone of Florida. In Europe Tricolia is recognized in strata as old as Paleocene, but T. calypta is the earliest American species so far described. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), Gatun Lake area, localities 40a, 40d. Family PHASIANELLIDAE? Tricolia? syntoma Woodring, n. sp. Plate 17, figure 47 Small, strongly inflated, spire low, outline like that of a minute naticid. Columellar lip wide, its outer edge bearing a faint low narrow rim. Parietal callus thick, continuous with the columellar lip, its edge sharply defined. Umbilical groove very narrow, almost closed. Operculum unknown. Height 2.2 mm, diameter 2.2 mm (type). Type: USNM 561328. Type locality: 170a (USGS 8411, headwaters of Quebrada Cafia (Rio Cano Quebrado), Panama, middle part of Gatun formation. The family and generic assignment of this minute species, represented by one specimen from the middle part of the Gatun formation, are doubtful. Some features suggest a low-spired Tricolia, but no species of Tricolia examined has a wide-rimmed columellar lip. The type and only specimen of "Eucosmia" lurida Dall (1897, p. 15, pi. 1, fig. 11) in the collection of the U. S. National Museum (a Recent shell from British Colum- bia) has a wide distinctly rimmed columellar lip, which is not shown on the poorly drawn aperture of Dall's illustration. This species, however, is probably a Homalopoma related to H. subobsoletum (Willett) (1937, p. 63, pi. 25). Most species of Tricolia have a thin parietal callus that fades out on the parietal wall. Nevertheless some species have a moderately thick callus that joins the columellar lip. Despite its rela- tively narrow aperture, Tricolia? syntoma may repre- sent an undescribed turbinid genus remotely related to Homalopoma. In outline Tricolia? syntoma suggests the Miocene Jamaican species Tricolia (Eulithidium) hadra Wood- ring (1928, p. 420, pi. 34, figs. 10, 11) and a minute Recent Cuban Tricolia described by Dall (1889, p. 351, 1>1. 19, fig. 10b) as "Phasianella (Eucosmia)" brevis d'Orbigny. Both species, however, have Tricolia-Yike apertural features. Occurrence: Middle part of Gatun formation (mid- dle Miocene), western area, locality 170a. Family NERITIDAE Subfamily NERITINAE Genus Velates Montfort Montfort, Conchyliologie systematique, v. 2, p. 355, 1810. Type (orthotype): Velates conoideus (Nerita conoidea Lamarck«= Nerita perversa Gmelin), Eocene, Paris Basin. Velates perversus (Gmelin), subspecies? Plate 14, figures 5-8 Reaching a large size, ovid in ventral plan, apex moderately eccentric. Columellar lip bearing seven or eight teeth. Callus deeply indented adjoining lower end of columellar lip and extending along inner border of outer lip, forming a wide rim. Approximate height 60 mm, restored diameter 100 mm (largest specimen). Height 22.5 mm, diameter 43.7 mm (larger figured specimen). Though Velates was found in limestone of the Gatun- cillo formation at five localities, the only specimens showing the aperture are from locality 38 in the Rio Casaya area. The shell of medium size shown on plate 14, figures 5, 7 is the largest of 18 collected at that locality. Twelve of the 18 have complete col- umellar lips, and on 9 the outer lip is preserved. The shells from locality 38, and the incomplete specimens from the other localities so far as they are preserved, closely resemble Lutetian Paris Basin specimens of Velates perversus (for citations and synonymy see Eames, 1952, p. 12). The fossils from Panama that show the outer lip, however, have a wide rim along the inner border of the lip, whereas the rim is absent on 10 Paris Basin shells ranging in diameter from three to 70 millimeters. Katherine V. W. Palmer has kindly called my atten- tion to the illustrations of V. balkanicus Bontscheff (1896 [1897], p. 380, pi. 6, figs. 1-5), based on specimens from the Eocene of Bulgaria. The illustrations show a rim on the outer lip like that on the specimens from Panama. Bontscheff (1896 [1897], p. 380, pi. 6, fig. 6) also described a variety (V. balkanicus marginatus) for specimens on which the thin edge of the outer lip extends around the entire aperture, bordering the callus. The teeth of the Bulgarian fossils are heavier than those of specimens from Panama. It is doubtful whether the rim on the outer lip is an indication of close relation- ship Velates has a range of Late Cretaceous to late Eocene. V. perversus is widely distributed in Eocene deposits from India to the Mediterranean region and the Paris Basin, reaching its acme in the middle Eocene. The genus is relatively rare in the American Eocene. Under the name V. schmideliana, V. perversus is recorded from gastropods: trochidae to turritellidae 67 the Yellow Limestone of Jamaica (Trechmann, 1923, p. 347, pi. 15, figs. 1-3). A similar, if not identical, form (Trechmann, 1929, p. 490, pi. 18, figs. 19a, b) and an unidentified species (Trechmann, 1924, p. 10, pi. 1, fig. 7) have been found in other Eocene strata of that island. Fossils from California have been referred to V. perversus (Vokes, 1935, p. 382, pi. 25, figs. 1, 3, 5, pi. 26, fig. 1) and to a species of doubtful validity, V. californicus Vokes (1935, p. 384, pi. 26, figs. 3-8. A Florida locality yielded a large Velates, possibly a large form of V. perversus, described as V. floridanus Richards (1946; Richards and Palmer, 1953, p. 13, pi. 1, figs. 6-9). V. vokesi Cooke (1946; 1919, p. 126, pi. 5, figs. 7, 8), from the middle Eocene of the island of St. Bartholomew, is represented by poorly preserved specimens, none of which shows the aperture. The apex of V. vokesi is almost marginal, like that of V. noetlingi Cossmann and Pissarro (Cox, 1931, p. 37). The groove on the large specimen of V. vokesi figured by Cooke and also on the small figured specimen, which is the type, evidently marks the boundary be- tween the area where growth takes place by addition to the outer lip and the area where growth is the result of resorption of the callus. The boundary between these two areas on the opposite side of the shell is not apparent. A species of Velates, similar in outline to V. vokesi, is found in limestone of middle(?) Eocene age in the Sierra de Bahoruco of the Dominican Republic, and in deposits of probable middle Eocene age in Chiriqui Province, Panama and Baja California. The remarkable architecture of Velates was described many years ago by Woodward (1892). Occurrence: Gatuncillo formation (middle and late Eocene), Madden basin, localities 6, 7, 9, 15; Rio Casaya area, locality 38. Genus Neritina Lamarck Lamarck, Encyclopedie methodique, Histoire naturelle des vers, v. 3, pi. 455; Liste, p. 11, 1816. Type (logotype, Children, Lamarck's Genera of shells, p. Ill, 1823): Neritina pulligera (Nerita pulligera Linne), Recent, rivers of India and Melanesia. Opinion 119 of the International Commission on Zoological Nomenclature, issued in 1931, placed Neritina Lamarck, with N. pulligera as the type, in the Official List of Generic Names. Subgenus Vitta Morch Morch, Catalogus conchyliorum * * * Comes de Yoldi, pt. 1, p. 166, 1852. Type (logotype, Baker, Acad. Nat. Sci. Phila. Proc, v. 75, p. 137, 1923): Nerita virginea Linn6, Recent, southern Florida to northern South America, mainly estuarine. The convex callus and color pattern suggest that the following two species may be allied to Neritina virginea. They therefore are doubtfully assigned to the subgenus Vitta. According to Baker, in the publication just cited, Vitta is estuarine to fresh-water and is found in eastern America and western Africa. Neritina (Vitta?) species Small, spire worn. Callus thick, moderately convex. Columellar lip finely and weakly denticulate. Color pattern poorly preserved, consisting of dark wavy axial lines. Height (practically complete) 7 mm, diameter (in- complete) 6 mm. Height (practically complete) 5 mm, diameter (practically complete) 5 mm. This unidentified Neritina is represented by four incomplete specimens from the Culebra formation at locality 108c. The columellar lip is exposed on only one of them. The smallest has traces of dark axial lines and another shows such lines on a remnant of the outer calcite shell layer adjoining the edge of the callus. This Culebra species, like the following Gatun species, may be allied to the Recent Caribbean Neritina virginea (Linne). It has a thicker callus than small specimens of that Recent species. Occurrence: Culebra formation (early Miocene). Gaillard Cut, locality 108c. Neritina (Vitta?) cf. N. virginea (Linne) Plate 21, figures 1, 2 Small, spire corroded. Callus moderately thick, strongly convex. Columellar lip finely and weakly denticulate. Color pattern consisting of closely spaced minutely zigzag dark axial lines, wider at forward apex of V's (apex toward outer lip). Near outer lip and also near callus the widened apices disintegrate into isolated triangles. On later half of body whorl a solid relatively wide dark spiral band adjoins suture. Height (incomplete, spue corroded) 3.6 mm, diameter 3.6 mm (figured specimen). Two small shells, collected from the middle part of the Gatun formation at two localities in the western area, are referred to Neritina cf. N. virginea (Linne). The color pattern is well preserved on the figured specimen. On the other, slightly larger, specimen only small patches of the outer calcite layer, and therefore of the color lines, remain. The lines evidently are not as closely spaced as on the figured specimen. The convex callus and color pattern suggest relation- ship to the Caribbean Recent N. virginea, which reaches a much larger size. The most common color pattern of N. virginea consists of wavy dark lines interrupted by dark-bordered ovoid or triangular light- colored eyes. The eyes are absent on some specimens and in some subspecies, but on Recent shells that lack eyes the lines are not as strongly zigzagged as on the figured fossil from Panama. A specimen collected at (is GEOLOGY AND PALEONTOLOGY OF CANAL ZONE the type locality of Neritina (Puperita) jigulopicta Maury (1917, p. 152, pi. 24, fig. 10; Cercado formation, Dominican Republic), presumably conspecific with N. Jigulopicta, has the callus and the prevailing color pattern of N. virginea and evidently belongs to that species. The fossils from the Gatun formation, and also those from the Culebra formation referred to Neritina sp., may be immature shells of species as large as N. virginea, or may be mature shells of small species. As shown by numerous specimens, A 7 ", chipolana Dall (1890-1903, pt, 2, p. 422, pi. 23, fig. 19, 1892), from the Chipola formation of Florida, is a small species (height 5 millimeters) comparable in size to the fossils from Panama. It has a color pattern of widely spaced, irregularly curved or zigzag, axial lines, or widely spaced groups of two to five such lines. The callus is thinner than that of the fossils from Panama and is indented by a ledge adjoining the base of the columellar lip. Occurrence : Middle part of Gatun formation (middle Miocene), western area, localities 161c, 170a. Family THIARIDAE? Genus Hannatoma Olsson? Olsson, Bull. Am. Paleontology, v. 17, no. 63, p. 80, 1931. Type (orthotype): Melanatria? gesteri Hanna and Israelsky, Oligocene, Peril. Hannatoma? cf. H. emendorferi Olsson Plate 14, figure 3 Of small size for genus Hannatoma, Mesalia-Yike in outline. Preserved spire whorls preceding penult sculp- tured with two strong flangelike spirals, the posterior spiral adjoining the suture, the anterior spiral lying a little in front of middle of whorl. Penult bearing also a narrower spiral emerging from anterior suture. Body whorl broken; aperture and growth line unknown. Height (incomplete) 35.5 mm, diameter (incomplete) 15 mm (figured specimen). An incomplete silicified fossil from the Gatuncillo formation in the Rio Casaya area is doubtfully identi- fied as a species of Hannatoma comparable to H. emendorferi, which occurs in the Eocene of Peru, in strata thai were thought to be of Oligocene age when the species was described (Olsson, 1931, p. 82, pi. 15, figs. 3, 8). Unfortunately the aperture is not preserved and the growth line is not discernable. The spirals are more flangelike than those of //. emendorferi and of a closely allied, or identical, form found in strata of late Koeene age in eastern Colombia and western Venezuela. Some species of Mesalia, including forms of the widely distributed Eocene M. fasciata (Lamarck) (Cox, 1930, j). 157, pi. 18, figs. 2, 3) have two flangelike spirals on spire whorls. The spirals, however, are narrow and the posterior one does not adjoin the suture. Occurrence: Gatuncillo formation (middle Eocene), Rio Casaya area, locality 38. Family LITTORINIDAE Genus Littorina Ferussac Ferussac, Tableaux systematiques des arimaux mollusques, p. XI (vernacular name "littorine" for "paludines marines", five species of which are listed or p. ix-x with the designation "Paludina, marine"), p. XXXIV ["Littorine, Littorina" as subgenus of "Paludine, Paludina, Feruss. (fiuv. et marin)", no species mentioned], 1822. Type (logotype, de Blainviile, Dictionnaire des sciences naturelles, v. 56, p. 98 ("le genre Littorine, ayant pour type le T. littoreus") , 1828: Turbo littoreus Linn6, Recent, western Europe. Ferussac gave no definition of the name Littorina and cited no species under it. On other pages, however, he listed five species as marine species of Paludina and on still another page he stated that he was forming a sub- genus under the name littorine for marine paludines, which constituted the genus Trochus of Adanson. These vernacular names are the same as those used on page XXXIV with the corresponding formal names. This is a roundabout method, involving vernacular names, of determining what species Ferussac included under Littorina. Littorina aff. I. angulifera (Lamarck) Plate 16, figures 1, 2 Of medium size, high-spired. Periphery of body whorl sharply angulated at beginning of whorl, obtusely angulated toward outer lip. Narrow spiral grooves visible on preserved parts of outer shell. Columellar lip excavated. Height (practically complete) 12 mm, diameter 8.5 mm (figured specimen). An imperfect specimen of the genus Littorina w*as found in the uppermost part of the Culebra formation in an association of brackish-water and marine species. Much of the shell is not preserved, including the edge of the basal and outer lips. The sculpture, however, remains on two patches of outer shell. It shows to best advantage on the base of the bod}* whorl adjoining the thin wash of parietal callus. Imperfecl as this fossil is, it is of exceptional interest, as it is the first Tertiary Littorina to be recorded from the Caribbean region and it extends back to the early Miocene the lineage of a living Caribbean species, L,. unijii/ifi in (Lamarck) (Bequaert, 1943, p. 23, pi. 7). The fossil so closely resembles small angulated speci- mens of L,. angulifera that unequivocal assignment to that species may be justified. The columellar lip is wider than on most small shells of L,. angulifera ex- gastropods: trochidae to turritellidae 69 amined, but on some small shells of the Recent species it is as wide or wider. According to Bequaert (1943, p. 24), in his recent monograph of the western Atlantic species of the genus, L. angulijera is found, generally on mangroves in brackish inlets, from Florida to Brazil, on the west coast of Africa, and has reached the Pacific coast of Panama by transportation through the Panama Canal. This species is recorded from Pleistocene deposits on the Caribbean side of the Canal Zone near Mount Hope (Brown and Pilsbry 1913a, p. 495). It is represented in three of MacDonald's Pleistocene collections from that area (USGS 5849, 5850, 5868) and also in two lots of Pleistocene fossils he collected at and near the north end of Gatun Locks (USGS 5867, 6038). After this report was in proof a small imperfect specimen that seems to be L. angulijera was found in a collection from strata of middle Miocene age on Rio Banana in southeastern Costa Rica (USGS 5882f) and a large specimen, unequivocally identified as that species, was found in a collection of late Miocene fossils from Swan Cay, in the Bocas del Toro Archi- pelago, northwestern Panama (USGS 8305). Bequaert (1943, p. 3) assigned L. angulifera to the subgenus Littoraria. Occurrence: Uppermost part of Culebra formation (early Miocene), Gaillard Cut, locality 110. Family VITRINELIIDAE Studies of Recent vitrinellids have not yet progressed far enough to sort the genera of probably diverse affin- ities that are currently placed in this family. The Gatun formation yielded all the vitrinellids described in the present report. Genus Teinostoma H. and A. Adams H. and A. Adams, Genera of Recent Mollusca, v. 1, p. 122, August, 1853. Type (virtual monotype and logotype, A. Adams, Thesaurus conchyliorum, pt. 22, p. 259, 1863): Teinostoma politum A. Adams, Recent, Santa Elena (presumably Ecuador). Pilsbry and McGinty (1945-50, pt. 1, p. 1, 1945) have pointed out that Teinostoma was virtually mono- typic, as T. anomalum C. B. Adams, the only species mentioned other than T. politum, was a nude name. No known Caribbean fossil species has the characters of the subgenus Teinostoma s.s. : greatly depressed shell and spoutlike extension of the peristome. Subgenus Idioraphe Pilsbry Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 73, p. 398, 1922. Type (orthotype): Teinostoma angulatum (Gabb) (Cyclops angulatus Gabb), Miocene, Dominican Republic. It has been claimed that the spire of Teinostoma s.s. is concealed by overlap of the body whorl (Woodring, 1928, p. 444) and that it is not concealed (Pilsbry and 413788—57 6 Olsson, 1941, p. 47). As a matter of fact, it has become evident that both statements are justified (Pilsbry and Olsson, 1945-52, p. 38, 1952). The typical form of the type species, known only from Arthur Adams' descriptions and illustrations, reproduced by Pilsbry and Olsson (1945-52, p. 251, pi. 22, fig. 6, 1945; p. 38, pi. 2, figs. 1, la, lb, 1952), has an exposed spire. A form from the Gulf of California, so similar in essen- tial features to T. politum that it was described as T. politum ultimum (Pilsbry and Olsson, 1945-52, p. 252, pi. 22, figs. 1, la, lb, 1945), has a concealed spire. In other words, the subgenus Idioraphe, which has a con- cealed spire, is not as sharply set off as it was once thought to be. Idioraphe also resembles Teinostoma s.s. in having a thick shell, thick callus, and thick enamel. Nevertheless Idioraphe is a useful name for small teinostomes that have a concealed spire, are not strongly depressed, and lack the spoutlike extension of the peristome characteristic of T. politum. Teinostoma (Idioraphe) spermatia Woodring, n. sp. Plate 17, figures 19-24, 31-33, 37-39 ^Teinostoma cf. carinatum d'Orb., Toula, K. k. Geol. Reichsan- stalt Jahrb., BaDd 61, p. 497, pi. 31, fig. 10, 1911 (Miocene, Canal Zone). Small, thick-shelled, depressed but somewhat dome- shaped. Periphery bluntly angular on early part of body whorl, narrowly rounded on later part. Tip of spire exposed, remainder concealed by overlap of body whorl. Entire spire concealed by enamel on very large specimens. Umbilical and parietal callus thick and completely coalesced. Height 0.7 mm, diameter 1.8 mm (type); height 1.1 mm, diameter 2.6 mm (large form, figured). Type: USNM 561312; paratypes, Stanford Univ. Type locality: 147b (USGS 6033c, Panama Railroad, about 3,500 feet (1,065 m) southeast of Gatun railroad station, Canal Zone), middle part of Gatun formation. Teinostoma spermatia is the most widespread teino- stome in the middle part of the Gatun formation and is particularly abundant at the type locality, where several hundred specimens were collected. It is rep- resented, however, by only one specimen from the upper part of the formation, and none was found in the lower part. Immature shells (pi. 17, figs. 22-24) are more nearly circular than mature shells. Furthermore the outer lip of immature shells ascends almost to the tip of the spire and therefore has a different outline from that of mature shells. Three specimens from the type locality, one of which is illustrated (pi. 17, figs. 19-21), show faint to fairly strong microscopically punctate spiral striae. This sculpture is doubtless a normal character, but is ordinarily concealed by enamel. The three 70 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE specimens that show it have thin enamel, except on the later part of the body whorl, where the sculpture grad- ually disappears under the thicker coat of enamel. Fourteen specimens from the type locality that are assigned to T. spermatid are exceptionally large as com- pared with scores of apparently mature specimens, like the type. As shown on plate 17, figure 31, the tip of the spire of this relatively large form is covered with a thin glaze of enamel. These 14 large specimens, which do not intergrade with the much more abundant smaller apparently also mature form, may represent a different species. If so, however, immature shells of the large and the small species have not been distin- guished and apparently are indistinguishable. Species more or less closely resembling Teinostoma spermatid have been living in American waters since Eocene time. The very similar T. tectispira (Pilsbry, in Olsson and Harbison, 1953, p. 417, pi. 50, figs. 6-6c), a Pliocene species from Florida, has no trace of spiral sculpture. T. spermdtid is more depressed and more elongate in dorsal outline than T. angulatum (Gabb) (Pilsbry, 1922, p. 398, pi. 37, figs. 1, la, lb), and even the large form of T. spermatia is a little smaller. T. angulatum, which is found in the Cercado formation of the Dominican Republic, has very faint closely spaced spiral striae. Species similar to T. spermatia are living in both western Atlantic and eastern Pacific waters. T. cryptospira (Verrill) (Bush, 1897, p. 118, figs. 1, 2) ranging from Cape Hatteras to Florida, is more circular in dorsal outline. T. cecinella Dall (1919, p. 369), a species from Lower California, is more elongate in dorsal outline, larger, and has a thicker shell. Toula's Teinostoma cf. T. carinatum may be T. spermatia, though his illustrations show an exposed spire and a peripheral carina. Pilsbry (in Olsson and Harbison, 1953, p. 415), however, thought it is very similar to the Recent T. carinatum (d'Orbigny). Occurrence: Middle and upper parts of Gatun forma- tion (middle Miocene). Middle part, eastern area, localities 146, 147b, 147f, 147g, 147h, 147i (identifica- tion doubtful), 153a. Upper part, eastern area, locality 177. Teinostoma (Idioraphe) angulatum trochalum Woodring, n. subsp. Plate 17, figures 4-6 Small, moderately depressed, dome-shaped. Periph- ery moderately angular on early part of body whorl, rounded on later part. Spire partly concealed by over- lap of body whorl and glaze of enamel. Umbilical and parietal callus thick and coalescing. Height 1 mm, diameter (incomplete) 1.7 mm (type). Type: USNM 561431; paratypes, Stanford Univ. Type locality: 137 (USGS 16911, Transisthmian Highway, 1.7 km northwest of Sabanita, Panama), lower part of Gatun formation. This teinostome, found in the lower part of the Gatun formation, is considered a small race of T. angulatum (Gabb), the type of Idioraphe, from the Miocene of the Dominican Republic (Pilsbry, 1922, p. 398, pi. 37, figs. 1, la, lb). Gabb's specimens were collected at an un- known locality in the Dominican Republic. Specimens from the Cercado formation — Maury's T. sandomingense (Maury, 1917, p. 156, pi. 24, fig. 24)— evidently are conspecific, although the early part of the body whorl of the type has a more sharply angulated periphery. T. angulatum trochalum is smaller and lacks spiral sculpture. T. umbilicatum (Lea) (Mansfield, 1930, p. 134, pi. 20, figs. 1-3) and other Tertiary species from southeastern United States, as well as the Recent T. cryptospira (Verrill), have a less angular periphery. Occurrence: Lower part of Gatun formation (middle Miocene), localities 136a, 137, 138a. Subgenus Aepystoma Woodring, n. subgen. Type: Teinostoma {Aepystoma) andrium Woodring, n. sp., Mio- cene, Gatun formation, Panama and Canal Zone. Of medium size, thick-shelled, spire moderately de- pressed, exposed. Smooth or sculptured with punctate fine spiral striae. Umbilical and parietal callus thick, more or less coalesced. Callus filling umbilicus on mature shells. The subgeneric name Aepystoma is proposed for a group of thick-shelled teinostomes that have an ex- posed spire and callus-filled umbilicus. Fossil and Recent Panamic species allied to Teinostoma andrium have been assigned to the subgenus Pseudorotella by Pilsbry and Olsson. Pseudorotella, however, has a smaller and thinner shell and less depressed spire. Teinostoma (Aepystoma) andrium Woodring, n. sp. Plate 17, figures 40-42; plate 18, figures 9-11 Of medium size, thick-shelled, dorsal surface slightly domed. Periphery rounded on later part of body whorl, faintly and bluntly angular on early part. Sculpture of microscopically punctate faint spiral striae, for most part concealed on body whorl of mature specimens by glaze of enamel. Umbilical and parietal callus thick and coalescing. Height 2 mm, diameter 4.7 mm (type). Type: USNM 561315; paratype, Stanford, Univ. Type locality: 137 (USGS 16911, Transisthmian Highway, 1.7 km northwest of Sabanita, Panama), lower part of Gatun formation. Teinostoma andrium is by far the largest of the Gatun teinostomes. The sculpture is distinct only on early gastropods: trochidae to turritellidae 71 whorls. The umbilicus of immature shells is not com- pletely filled with callus (pi. 17, fig. 41). T. andrium is closely related to T. caroniense Maury (1925, p. 249, pi. 43, figs. 3, 4), a late Miocene species from Trinidad, but has a flatter columellar lip and flatter umbilical callus. The recent Ecuadorean T. millepunctatum Pilsbry and Olsson (1945-52, p. 253, pi. 23, figs. 1, la, lb, 1945) has more coarsely punctate spirals, and is smaller and thinner. The Recent west- ern Panamic T. imperfectum Pilsbry and Olsson (1945- 52, p. 254, pi. 22, figs. 2, 2a, 2b, 1945) also is smaller and thinner, and has a thin, narrow umbilical callus. Occurrence: Lower and middle parts of Gatun forma- tion (middle Miocene). Lower part, locality 137. Middle part, eastern area, locality 147i. Subgenus Pseudorotella Fischer Fischer, Jour. Conchyliologie, t. 6, p. 52, 1857. Type (monotype): Pseudorotella semistriata (d'Orbigny) (Rotella semistriata d'Orbigny), Recent, Cuba. Pseudorotella is used in the present report for small, smooth or spirally sculptured teinostomes that have a moderately thick shell, exposed relatively high spire, wide umbilical callus filling — or not quite filling— the umbilicus, and narrow parietal callus. This usage may be found to be inappropriate when specimens of the type species are available. The type species has fine spiral striae above the periphery, according to d'Or- bigny's illustrations. As suggested by Pilsbry and McGinty (1945-50, pt. 1, p. 2, 1945), subgeneric rank is preferable to the generic rank that has been assigned to Pseudorotella (Woodring, 1928, p. 445). The Miocene Jamaican "Pseudorotella" homala Woodring (1928, p. 447, pi. 38, figs. 13-15) represents a minor group of teinostomes, more closely related to Aepy stoma than to Pseudorotella, characterized by a bicarinate truncated periphery and relatively strong spiral sculpture. Teinostoma (Pseudorotella) pycnum (Woodring) Plate 17, figures 25-27 Pseudorotella pycna Woodring, Carnegie Inst. Washington Pub. 385, p. 446, pi. 38, figs. 10-12, 1928 (Miocene, Jamaica). Small, moderately thick-shelled, periphery rounded. Body whorl pinched against suture, producing a sug- gestion of a sutural collar, corresponding to faint gutter between outer lip and parietal callus. Umbilical callus thick, filling umbilicus. Parietal callus narrow, its edge sharply defined. Height 0.8 mm, diameter 1.3 mm (figured specimen). Type: USNM 135502. Type locality: Bowden, Jamaica, Bowden formation (middle Miocene). The faint sutural collar and narrow parietal callus are characteristic features of Teinostoma pycnum. The few specimens from the Gatun formation are slightly smaller than the t}-pe. T. vitreum (Gabb) (Pilsbry, 1922, p. 399, pi. 37, figs. 3, 3a, 3b), from the Cercado formation of the Dominican Republic, lacks the faint sutural collar. T. parvicallum Pilsbry and McGinty (1945-50, pt. 1, p. 4, pi. 2, fig. 2, 1945), a Recent teinostome from Florida, is slightly larger and has a higher spire. Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, locality 138. Middle part, eastern area, locality 147b. Bowden formation (middle Miocene), Jamaica. Teinostoma (Pseudorotella) stemonium Woodring, n. sp. Plate 17, figures 1-3 Small, moderately thick-shelled, periphery rounded, but marked by a spiral thread. Body whorl somewhat pinched against suture. Whorls smooth between suture and periphery. Periphery and base near periphery sculptured with four or five relatively heavy spiral threads (three or four on immature shells). Umbilical callus completely, or not quite completely, filling umbilicus. Parietal callus narrow, overlapping umbilical callus. Junction of outer lip and parietal callus forming a faint gutter. Height 1 mm, diamter 1.5 mm (type). Type: USNM 561432. Paratype, USNM 561433. Paratypes, Stanford Univ. Type locality: 138a (Stanford Univ. locality 2656, Transisthmian Highway 1.6 km northeast of Canal Zone boundary, Panama; same as USGS 16909), lower part of Gatun formation. This sculptured Pseudorotella is represented by nine specimens collected by T. F. Thompson from the lower part of the Gatun formation. It seems to have no known close allies. Occurrence: Lower part of Gatun formation (middle Miocene), locality 138a. Subgenus Diaerecallus Woodring, n. subgen. Type: Teinostoma (Diaerecallus) sychnum Woodring, n. sp. Miocene, Gatun formation, Canal Zone. Small, thick-shelled, smooth or practically smooth. Suture strongly impressed. Umbilicus filled with callus. Edge of umbilical callus forming well defined ridge. Extension of parietal callus overlapping umbilical callus, deeply grooved adjoining columellar lip. Diaerecallus is characterized by the strongly impressed suture and the abrupt overlap of a grooved extension of the parietal callus. It may represent a modification of Aepystoma, or possibly of a teinostome more or less 72 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE similar to the subgenus Annulicallus Pilsbry and McGinty (1945-50, pt. 4, p. 17, 1946; type (orthotype): Teinostoma carinicallus Pilsbry and McGinty, Recent, Florida). Annulicallus has a sharp ridge at the edge of the umbilical callus, which is concave. Teinostoma (Diaerecallus) sychnum Woodring, n. sp. Plate 17, figures 28-30 Small, thick-shelled, periphery rounded. Apical whorl large for size of shell. Very faint microscopic spiral striae visible on penult or earlier whorls of some specimens. Umbilical callus bounded by ridge, which is overlapped by extension of parietal callus. Extension of parietal callus deeply grooved adjoining outer lip. Height 1.1 mm, diameter 1.7 mm (type). Height 1.6 mm, diameter 2.2 mm (largest specimen). Type: USNM 561316. Type locality: 147b (USGS 6033c, Panama Railroad, about 3,500 ft (1,065 m) southeast of Gatun railroad station, Canal Zone), middle part of Gatun formation. The curious callus, shown by four specimens from the type locality, at first glance suggests abnormality. The extension of the parietal callus is formed at a late growth stage. It is missing on three immature shells from the type locality and also on an immature shell from locality 155a, the only specimen from that locality. These immature shells resemble the subgenus Aepy- stoma, hut have a low ridge at the edge of the umbilical callus. The large apical whorl and strongly impressed suture of this species are noteworthy features. No close fossil or living allies are known. Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 147b, 155a. Genus Anticlimax Pilsbry and McGinty Subgenus Anticlimax s.s. Pilsbry and McGinty, Nautilus, v. 60, p. 12, 1946. Type (logotype (Pilsbry and McGinty, Nautilus, v. 59, p. 77, 1946) of Climacia Dall, 1903 (not M'Lachlan, 1869), renamed Climacina Aguayo and Borro, 1946 (not Gemmellaro, 1878), renamed Anticlimax): Teinostoma (Climacia) calliglyptum Dall, Pliocene, Florida. Perhaps Anticlimax, the second name proposed in rapid succession as replacement of the homonym Climacia, was not intended to be as derisive as it sounds. It recalls some of Jousseaume's names. Teinostoma (Climacia) calliglyptum was virtually the monotype of Climacia. Dall used that combination in a list of fossils and in the explanation of a plate (Dall, 1890-1903, pt. 6, p. 1,610, 1,633, 1903). He also used the combination Teinostoma (Climacia) radiata, Dall in the same list of fossils. There is, however, no indication that he intended that name for his Collonia radiata, no matter how unequivocal his intention proves to be. The species of Anticlimax have recently been reviewed by Pilsbry and Olsson. The genus is strongly dome- shaped and has axial folds or undulations of varying strength on the base of the shell. The subgenus Anticlimax s. s. is characterized by a narrow callus on the columellar lip, from which a ridge spirals up the widely open umbilicus. The earliest species occurs in the early Miocene Thomonde formation of Haiti. A Recent species is found in the Caribbean Sea and another possibly off Florida, but none so far in the Pan ami c region. Anticlimax (Anticlimax) gatunensis Pilsbry and Olsson Plate 18, figures 5-7 Anticlimax gatunensis Pilsbry and Olsson, Bull. Am. Paleontol- ogy, v. 33, No. 135, p. 7, pi. 2, figs. 5, 5a, 5b, 1950 (Miocene, Panama) . Dome-shaped, base flattened. Peripheral carina a relatively wide thin ledge. Upper surface sculptured with weak spiral striae, which disappear near periphery and on upper surface of peripheral ledge are replaced by microscopic axial threads. Base bearing 13 heavy axial folds. Outer half of base, including base of peripheral ledge, sculptured with spiral striae. Ridge bordering umbilicus moderately narrow. Height 1.7 mm, diameter (incomplete) 3 mm (figured specimen). Type: Acad. Nat. Sci. Phila. 18401. Type locality: Cut on Boyd-Roosevelt (Trans- isthmian) Highway, just below bridge over Rio Cativa and about 3% miles from road junction at Margarita, Panama (same as USGS 16909) lower part of Gatun formation. The figured specimen, a topotype, has a damaged peristome and carina. It is the only specimen in the U. S. National Museum collections; two smaller speci- mens are in the Stanford University collection from the same locality. The flattened base and wide peripheral carina are the most characteristic features of this species. These features distinguish it from the most closely related species, A. schumoi (Vanatta) (1913, p. 24, pi. 2, figs. 2, 7), a Recent species from British Honduras. A. derbyi (Maury) (1917, p. 156, pi. 24, fig. 20), the only other described Miocene species of Anticlimax s.s., occurs in the Cercado formation of the Dominican Republic and in the Thomonde forma- tion of Haiti. It has a more swollen base, narrower peripheral ledge, fewer and heavier folds on the base, and no spiral striae on the base. Occurrence: Lower part of Gatun formation (middle Miocene), localities 138, 138a. gastropods: trochidae to turritellidae 73 Subgenus Subclimax Pilsbry and Olsson Pilsbry and Olsson, Bull. Am. Paleontology, v. 33, No. 135, p. 5, 1950. Type (orthotype): Anticlimax hispaniolensis Pilsbry and Olsson, Miocene, Dominican Republic. Subclimax, which is somewhat intermediate between Anticlimax s.s. and dome-shaped species of Teinostoma, has the umbilicus partly or completely closed by a wide umbilical callus. It has, however, axial undula- tions or folds of varying strength on the base, like those of Anticlimax s. s. The earliest species, occurring in the early Miocene Baitoa formation of the Dominican Republic, is of the same age as the earliest species of Anticlimax s. s. Subclimax is living in the western Atlantic and the eastern Pacific. Anticlimax (Subclimax) teleospira hystata Woodring, n. subsp, Plate 18, figures 1-3 Dome-shaped, base slightly inflated. Periphery bluntly angular, except near outer lip, where it is drawn out into a ledge. Upper surface sculptured with faintly punctate spiral striae, which are indistinct or absent on middle third of body whorl and near outer lip. Base sculptured with faintly punctate spiral striae that disappear near umbilical margin and toward aperture, except on peripheral ledge. Base also bearing faint crude axial undulations. Umbilical callus filling um- bilicus, except a narrow niche adjoining parietal callus. Junction of outer and basal lips drawn out in an angular thickened spoutlike projection, broken on type. Height 1.5 mm, diameter (incomplete) 2.7 mm (type). Type: USNM 561319. Type locality: 185 (USGS 8383, Caribbean coast, west of Rio Miguel, station 26 plus 100 feet (30 m) Panama), upper part of Gatun formation. Anticlimax teleospira hystata is represented by two specimens from the upper part of the Gatun formation in the coastal area west of the Canal Zone. The spout- like projection of the peristome is like the projection of the type of Teinostoma. It is broken on the type but preserved on the other specimen, which is other- wise less complete. A. teleospira proper (Pilsbry and Olsson, 1950, p. 10, pi. 2, figs. 7, 7a), which occurs in the lower part of the Gatun formation but is not represented in the U. S. National Museum coUections, has a carinate periphery and stronger basal undulations. The closely related A. tholus (Pilsbry and McGinty) (1945-50, pt. 3, p. 79, pi. 8, figs. 1, la, lb, 2, 2a, 1946), a Recent species from Florida, has stronger spiral sculp- ture and lacks the extended peristome. An unde- scribed species, dredged at a depth of 6 to 9 fathoms off Beaufort, N. C, has a more angular periphery, narrower umbilical callus, and lacks the extended peri- stome. A. willetti Hertlein and Strong (1940-51, pt. 10, p. 112, pi. 9, figs. 13-15, 1951), from the Pacific coast of Costa Rica, is larger and has stronger basal undulations. The only other recorded Miocene species of Subclimax, A. hispaniolensis Pilsbry and Olsson, has a sunken apex and axial undulations on the upper surface of the body whorl. Both Gatun species of Anticlimax are more similar to Recent species than to contemporaneous or slightly older Miocene species in the Caribbean region so far described. Occurrence : Upper part of Gatun formation, western area (late Miocene), locality 185. Genus Cyclostremiscus Pilsbry and Olsson Pilsbry and Olsson, Acad. Nat. Sci. Phila. Proc, v. 97, p. 266, 1945. Type (orthotype): Vitrinella panamensis C. B. Adams, Recent, Pacific coast of Panamd,. Subgenus Ponocyclus Pilsbry Pilsbry, Acad. Nat. Sci. Phila. Mon. 8, p. 426, 1953. Type (orthotype): Adeorbis beauii Fischer, Recent, Florida and West Indies. Ponocyclus lacks the axial sculpture of the subgenus Cyclostremiscus s. s. Some species, however, are more oi less intermediate and Pilsbry realized that the name Ponocyclus may eventually be found to be superfluous. Cyclostremiscus (Ponocyclus) pentagonus (Gabb) Plate 17, figures 7-15 Cyclostrema pentagona Gabb, Am. Philos. Soc. Trans., n. ser., v. 15, p. 243, 1873 (Miocene, Dominican Republic). Vitrinella pentagona (Gabb), Gabb, Acad. Nat. Sci. Phila. Jour., 2d ser., v. 8, p. 368, pi. 47, fig. 68, 1881 (Miocene, Dominican Republic) . Cyclostrema quadrilineatum Toula, K. k. Geol. Reichsanstalt Jahrb., Band 61, p. 497, pi. 31, figs, lla-c, 1911 (Miocene, Canal Zone). Circulus pentagona (Gabb), Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 73, p. 397, 1922 (Miocene, Dominican Republic). "Circulus" pentagonus (Gabb), Woodring, Carnegie Inst. Wash- ington Pub. 385, p. 441, pi. 37, figs. 16-18, 1928 (Miocene, Jamaica) . Small, depressed, whorls 4)4, the first 2}i very slowly enlarging. Protoconch relatively large, rising abruptly. Body whorl bicarinate or, less commonly, tricarinate. Early whorls rounded between sutures. A carina ap- pears on later half of penult about midway between sutures and forms upper carina on body whorl. Basal carina generally weaker than upper. Periphery rounded, bluntly angular (the usual condition), or sharply angular, forming a third carina. A few speci- mens have one or more faint spiral threads on penult above carina, and a few have a low spiral thread on body whorl below and near upper carina or above and near lower carina. Umbilical wall bearing crude gen- 74 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE c rally faint spiral cords more or less roughened by growth threads. Upper part of peristome gently arched forward. Height 1 mm, diameter 1.6 mm (figured bicarinate specimen). Height 1.1 mm, diameter 2.3 mm (figured large specimen). Type: Acad. Nat. Sci. Phila. 2831. Type locality: Dominican Republic, Miocene. This small Cyclostremiscus occurs throughout the Gatun formation. It is rare in the lower part, rare to abundant in the middle part, and rare in the upper part. Several hundred specimens were collected from the middle part at locality 147b. These fossils show a considerable range of variation in the outline of the body whorl, in the presence or absence of spiral threads near the upper and lower carinae, and in the strength and coarseness of the spiral cords facing the umbilicus. The usual form is bicari- nate (pi. 17, figs. 7-9). Though tricarinate shells (pi. 17, figs. 10-12) are not common in the middle part of the Gatun formation, the few specimens from the lower and upper parts (one and two, respectively) are tri- carinate. Spiral threads, generally faint, near the up- per and lower carinae are exceptional. The umbilical spirals generally are weak. They are, however, ex- ceptionally strong on the large specimen shown on plate 17, figures 13-15. This large specimen, collected from the middle part of the Gatun foimation, shows a further modification in the rounded outline of the body whorl. At the beginning of the body whorl of this specimen the upper carina is moderately strong, the basal carina is weak, and the peripheral angulation is faint. These carinae and angulation rapidly disappear. This specimen is larger than the bicarinate and tricari- nate forms. Inasmuch as mature bicarinate and tri- carinate forms are rounded near the peristome, the ex- ceptional features of the rounded specimen aie pre- sumably correlated with its size. Toula's illustrations, however, show a shell of moderate size, the body whorl of which is rounded at an early stage. Cyclostremiscus pentagonus occurs in the Cercado formation of the Dominican Republic and in the Bow- den formation of Jamaica. The few available speci- mens from the Dominican Republic and Jamaica are tricarinate. It was formerly thought that the Gatun form could be differentiated by the weak sculphire on the umbilical wall (Woodring, 1928, p. 441). That sculpture, however, is too variable for consistent differ- entiation. Closely related forms are living in the western Atlantic and the eastern Pacific. "Circulus" trilix (Bush) (1897, p. 127, pi. 22, figs. 6, 10, 10a, 12, pi. 23, figs. 10, 15), ranging from Cape Hatteras to Cuba, is consistently tricarinate and enlarges more rapidly, so that with the same number of whorls (about 4}Q Recent shells are almost twice as large. Recent shells and those from the Gatun formation have the same kind of protoconch and aperture. Inasmuch as the degree of enlargement is the only character now apparent to differentiate Recent shells and tricarinate fossils, treat- ment of "C." trilix as a subspecies of C. pentagonus appears to be preferable. Fossils from the early Miocene Chipola formation and the middle Miocene Shoal River formation of Florida have been referred to "Circulus" trilix (Gardner, 1926-47, p. 600, 1947). These Florida fossils are tricarinate and are larger than those from the Gatun formation. "Circulus" cerrosensis Bartsch (1907, p. 173, figs. 9a, b, c), which ranges from Santa Catalina Island, Cali- fornia, to Baja California and the Gulf of California, and probably to Panama, is the eastern Pacific analog of "Circulus" trilix. It has not been determined whether Pacific and Atlantic shells can consistently be distinguished. Relatively strong spiral cords facing the umbilicus are more common in the few lots of Pacific shells. Shells from both oceans that are still lustrous show under strong light very faint micro- scopic spiral lineation. It is doubtful whether Cyclo- stremiscus glyptomphalus Pilsbry and Olsson (1945-52, p. 67, pi. 7, fig. 3, 1952), a Pleistocene form from the Pacific coasts of western Panama, can be distinguished from "Circulus" cerrosensis. Pilsbry and Olsson sug- gested the probability of local races of a widely spread species. Cyclostremiscus glyptobasis Pilsbry and Olsson (1945-52, p. 66, pi. 7, figs. 4, 4a, 1952), also from the Pleistocene of western Panama, probably is a variety, or subspecies, of "C." cerrosensis with a sculptured base. The Ecuadorean form "Circulus" cosmius Bartsch (1907, p. 173, figs. 8a, b, c) also is closely allied to "Circulus" cerrosensis, but is characterized by a slight downward bending of the upper margin of the peristome where it extends forward. Though the peristome of the type of "Circulus" cosmius is damaged, four speci- mens in the type (and only) lot have a perfect peristome. The seven specimens in the type lot have very weak umbilical sculpture. "Circulus" occidentalis Pilsbry and Olsson (1941, p. 48, pi. 9, fig. 3), from the Pliocene of Ecuador, shows downward bending of the peristome and should be compared with "Circulus" cosmius. Cyclostremiscus tricarinatus (C. B. Adams) (Pilsbry and Olsson, 1945, p. 271, pi. 28, figs. 3, 3a, 3b), living on the Pacific coast of Panama^, is similar to the tri- carinate species so far mentioned. It has, however, faint axial riblets between the periphery and suture, and therefore is intermediate between Ponocyclus and Cyclostremiscus s.s. Occurrence: Lower, middle, and upper parts of Gatun formation (middle and late Miocene). Lower gastropods: trochidae to turritellidae 75 part, localities 138, 138a. Middle part, eastern area, localities 146, 147b, 147f, 147g, 147h, 153a, 155c; western area, locality 161. Upper part, eastern area, locality 173; western area, locality 185. Cercado and Gurabo formations (middle Miocene), Dominican Republic. Bowden formation (middle Miocene), Ja- maica. Genus Solariorbis Conrad Conrad, American Jour. Conch., v. 1, p. 30, 1865. Type (logotype, Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 414, 1892): Delphinida depressa Lea, Eocene, Alabama. Subgenus Solariorbis s.s. The subgenus Soliariorbis s. s. is characterized by relatively large size, faint spiral sculpture (micro- scopically punctate in the type species), and a wide umbilical wall on the body whorl adjoining the aperture. Solariorbis (Solariorbis) strongylus Woodring, n. sp. Plate 17, figures 43-45 Of medium size, thick-shelled, moderately depressed. Periphery faintly and bluntly angulated, except at and near peristome where it is rounded. Penult and part of preceding whorl sculptured with closely spaced spiral threads. Spirals become faint and even disappear on body whorl, but most persistent near suture and just above periphery. Under strong light base shows barely discernible microscopic spiral stria tion. Umbilicus moderately narrow, asymmetrical, bounded by a crude spiral ridge, which is slightly roughened by growth wrinkles. Parietal callus thin. Height 1.3 mm, diameter 2.4 mm (type). Height 1.5 mm, diameter 3 mm (largest specimen). Type: USNM 561322; paratypes, Stanford Univ. Type locality: 138 (USGS 16909, Transisthmian Highway, 1.6 kilometers northeast of Canal Zone boundary, Panama), lower part of Gatun formation. The weak sculpture and moderately narrow asym- metrical umbilicus are characteristic features of this species. It is represented by 13 specimens, all from the type locality. Occurrence: Lower part of Gatun formation (middle Miocene), localities 138, 138a. Subgenus Hapalorbis Woodring, n. subgen. Type: Circulus liriope Bartsch, Recent, Gulf of California. The name Hapalorbis is proposed for a minor group of Solariorbis consisting of small carinate species that have a narrow umbilical wall on the body whorl adjoin- ing the aperture. The type species has a spiral thread above and below the peripheral carina-forming thread. Others have one to three threads below the periphery and one or two above. Still others have none below or above the periphery. The subgenus Systellomphalus (Pilsbry and Olsson, 1941, p. 48; type (orthotype): Systellomphalus perorna- tus Pilsbry and Olsson, Pliocene, Ecuador), with which Pilsbry and Olsson associated species closely allied to "Circulus" liriope, may be defined as embracing species that have axial riblets on spire whorls and axial wrinkles on the base of the body whorl adjoining the umbilicus. Hapalorbis is not known to have survived the Miocene in Caribbean waters. Solariorbis (Hapalorbis) hyptius hyptius Woodring, n. sp. and n. subsp. Plate 17, figures 16-18 Small, thick-shelled, depressed, body whorl increasing rapidly in diameter. Periphery sharply or moderately carinate, except at and near peristome. Umbilicus very narrow, asymmetrical. Umbilical wall very nar- row, the angulated umbilical border being inserted almost flush with base of body whorl where it emerges from umbilicus. Parietal callus moderately thick. Height 0.7 mm, diameter 1.4 mm (type). Type: USNM 561323; paratypes Stanford Univ. Type locality: 147b (USGS 6033c, Panama Railroad, about 3,500 feet (1,065 meters) southeast of Gatun railroad station, Canal Zone), middle part of Gatun formation. The very narrow and asymmetrical umbilicus, and very narrow umbilical wall are conspicuous and charac- teristic features of this species. It is closely related to the type of Hapalorbis: "Circulus" liriope Bartsch (1911, p. 231, pi. 40, figs. 7-9), which is represented by the type and an imperfect specimen, both dredged at a depth of 21 fathoms off La Paz, Lower California. The fossils are smaller, more depressed, have a smaller more asymmetrical umbilicus and narrower umbilical wall, and lack a spiral thread above and below the peripheral carina. Solariorbis hyptius proper was found in the lower and middle parts of the Gatun formation, but is rare except at the type locality. The 68 specimens collected at the type locality and the 2 additional specimens from the middle part of the Gatun have remarkably uniform characters. The five specimens from the lower part, however, are not so sharply carinate and reach a slightly larger size. Occurrence: Lower and middle parts of Gatun forma- tion (middle Miocene). Lower part, locality 138a. Middle part, localities 146, 147b, 147f. Solariorbis (Hapalorbis) hyptius anebus Woodring, n. subsp. Plate 17, figures 34-36 Resembling $. hyptius proper, but larger and umbilicus correspondingly larger. Peripheral carina flanked above and below by a narrow low spiral thread. 76 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Height 0.9 mm, diameter 1.5 mm (type). Type: USNM 561324. Type locality: 185 (USGS 8383, Caribbean coast, west of Rio Miguel, Panama), upper part of Gatun formation. This subspecies is based on two specimens from the upper part of the Gatun formation. Though the spirals flanking the periphery are narrower and lower than those of "Circulus" liriope, the sculptural pattern is the same, suggesting close relationship. As indicated by the name, however, alliance with the smaller Hapalorbis from the middle part of the Gatun formation is thought to be closer. Both Solariorbis hyptius proper and S. hyptius anebus have a depressed outline and very narrow umbilical wall, whereas "Circulus" liriope is less depressed and has a wider umbilical wall. A Pliocene species from Ecuador, "Pseudorotella" lens Plisbry and Olsson (1941, p. 47, pi. 9, fig. 2; 1945- 52, p. 51, 1952) has the same sculptural pattern as Solariorbis hyptius anebus and "Circulus" liriope, but has a heavy callus facet almost closing the umbilicus and is sculptured with two spiral threads above the periphery, The Recent Panamic "Vitrinella" seminuda C. B. Adams (Pilsbry and Olsson, 1945-52, p. 278, pi. 27, figs. 3, 3a, 3b, 1945; p. 51, 1952) lacks spirals above the periphery. Occurrence: Upper part of Gatun formation (middle and late Miocene), eastern area, locality 173, western area, locality 185. Genus Episcynia Mbrch Morch, Malakozool. Blatter, Band 22, p. 155, 1875. Type (monotype): Architectonica (Episcynia) inornata (d'Orbigny) (Solarium inornatum d'Orbigny), Recent, West Indies. In the western Atlantic Episcynia ranges from North Carolina to Brazil, and in the eastern Pacific from Santa Cruz Island, Calif., to Peru. Miocene species from Florida and the Caribbean region are the earliest known. Episcynia megalia Woodring, n. sp. Plate 18, figures 4, 8 Large, thin-shelled, whorls 5. Suture shallow, located on peripheral carina of preceding whorl, even at peristome. Peripberal carina minutely and irregularly roughened by exaggerated growth wrinkles. Similar growth wrinkles adjoin suture on later part of body whorl. Umbilical half of base and umbilical wall sculptured with more strongly emphasized growth wrinkles. Upper half of umbilical wall also sculptured with two narrow spiral threads that disappear near peristome. Umbilical border sharply angular. Height 2.7 mm, diameter 5.3 mm (type). Type: USNM 561325. Type locality: 138 (USGS 16909, Transisthmian Highway, 1.6 kilometers northeast of Canal Zone boundary, Panama), lower part of Gatun formation. Episcynia megalia, which is based on one specimen from the lower part of the Gatun formation, is the largest Episcynia so far described. It is most closely related to two species living in the eastern Pacific: E. nicholsoni (Strong and Hertlein) (1939, p. 241, pi. 22, figs. 2-4; Panama) and the closely allied E. bolivari Pilsbry and Olsson (1946, p. 11, pi. 1, figs. 6-8; Colombia and Peru; Pleistocene, western Panama). On both Recent forms the carina is exposed on the later whorls of the spire. E. nicholsoni evidently is more depressed than E. megalia, and E. bolivari has a slight angulation on the body whorl above the periphery. E. naso (Pilsbry and Johnson) (Pilsbry, 1922, p. 379, pi. 37, figs. 5, 5a), the only other described fossil species from the Caribbean region (Miocene, Dominican Republic and Jamaica), has strong regularly spaced serrations on the peripheral carina. Occurrence: Lower part of Gatun formation (middle Miocene), locality 138. Family RISSOIDAE Subfamily RISSOINAE Genus? "Alvania" aff. "A." epulata (Pilsbry and Johnson) Minute, rapidly enlarging. Protoconch very large for size of shell, consisting of 2% rapidly enlarging smooth whorls. Remaining 2% whorls sculptured with closety spaced axial ribs (17 on body whorl), between which are closely spaced spiral threads. Base sculp- tured with three wider and more widely spaced spirals. Outer lip varicose, its interior inaccessible. Height 1.2 mm, diameter 0.7 mm. Two minute specimens, both found by T. F. Thompson in the Gatun formation, are the only rissoids. They evidently are conspecific and are closely allied to "Rissoa" epulata Pilsbry and Johnson (Pilsbry, 1922, p. 384, pi. 34, fig. 5), a Miocene species from an unknown locality in the Dominican Republic. That species is narrowly umbilicate. The specimen from the lower part of the Gatun formation is immature and has a narrow umbilical groove, but the mature specimen from the upper part of the formation, of approximately the same dimensions as the type of "Rissoa" epulata, is completeh'" nonumbilicate. Rissoids more or less similar to the Gatun species are generally referred to the genus Alvania (Risso, 1826, p. 140; logotype, Nevill, 1884 [1885], p. 105, Alvania europea Risso=2 T ur&o cimex Linne, Recent, Mediter- ranean). The type of Alvania is four times as large, and has a relatively much smaller protoconch, coarser sculpture, and lirations on the interior of the outer lip. gastropods: trochidae to turritellidae 77 One or more of the numerous generic and subgeneric names proposed for European, Australian, and Neoze- lanic rissoids may possibly be suitable for ll Alvania" aff. "A." epulata. NevuTs designation for the type of Alvania — "type A. cimex Lin. [as Ah. europaea Kisso]" — appears to be the earliest valid designation. It has the same effect as numerous designations of Turbo cimex Linne and the much later designation of Alvania freminvillea Kisso, also a synonym of Turbo cimex (Gordon, 1939, p. 29). Occurrence : Lower and upper parts of Gatun forma- tion (middle Miocene). Lower part, locality 136a (1 immature). Upper part, eastern area locality 173 (1 mature, protoconch crushed during examination). Family RISSOINIDAE Genus Rissoina d'Orbigny d'Orbigny, Voyage dans l'Amerique Meridionale, t. 5 (Mol- lusques), p. 395, 1840. Type (monotype) : Rissoina inca d'Orbigny, Recent, Peru and Chile. Subgenus Zebinella Morch Morch, Malakozool. Blatter, Band 23, p. 47, 1876. Type (logotype, von Martens, Zool. Record, 1876, p. 30, 1877): Rissoina decussata (Montagu) (Helix decussata Montagu), Recent, West Indies and Florida (described as a British species) . Rissoina (Zebinella?) species A poorly preserved altered shell from the Culebra formation is assigned to Rissoina on the basis of outline and sculpture. The outer lip and aperture are not preserved. The sculpture, consisting of narrow axial ribs and fine spiral threads between the ribs, suggests the subgenus Zebinella. Occurrence: Cidebra formation (early Miocene), Gaillard Cut, locality 99b. Subgenus Phosinella Morch Morch, Malakozool. Blatter, Band 23, p. 51, 1876. Type (logotype, Nevill, Hand list of Mollusca in the Indian Museum, pt. 2, p. 73, 83, 1885) : Rissoina pulchra (C. B. Adams) (Rissoa pulchra C. B. Adams), Recent, West Indies. Rissoina (Phosinella) oncera Woodring. n. sp. Plate 23, Figure 3 Small, slender. Protoconch of Sji smooth rapidly enlarging whorls, the last half whorl obscurely angu- lated. Sculpture reticulate; axial ribs slightly wider than spiral threads. Four spirals at beginning of penult, five on later half. Outer lip strongly varicose. Fasciolelike swelling on base strongly inflated. Height 4.3 mm, diameter 1.7 mm (type). Type: USNM 561332. Type locality: 177c (USGS 5855, west side of Panama Railroad, opposite Mount Hope cemetery, Canal Zone), upper part of Gatun formation. The type (and only) specimen of this species was collected from the upper part of the Gatun formation at Mount Hope. It is closely allied to R. guppyi Cossmann (Woodring, 1928, p. 366, pi. 28, fig. 10), which occurs in the Bowden formation of Jamaica and in the Cercado and Gurabo formations of the Dominican Republic, but has a more widely expanding protoconch, slightly narrower spirals on the early whorls, more inflated fasciolelike swelling, and wider space between the swelling and the lowest spiral. The Recent West Indian and Florida species identified by Dall (1890-1903, pt. 2, p. 343, 1892) as R. cancellata Philippi has a smaller protoconch, coarser sculpture, and less inflated fasciolelike swelling. Occurrence: Upper part of Gatun formation (middle Miocene), eastern area, locality 177c. Family XENOPHORIDAE Genus Xenophora Fischer von Waldheim Fischer [von Waldheim], Museum-Demidoff, t. 3, p. 213, 1807. Type (logotype, Harris, Catalogue of Tertiary Mollusca in the British Museum; pt. 1, Australasian, p. 253, 1897): Xenophora laevigata Fischer [von Waldheim] ("Trochus conchyliophorus Gmel., Bosc, Born") = Trochus conchyliophorus Born, Recent, West Indies. Unidentified species of Xenophora are represented by two molds from the Gatuncillo formation and an incom- plete mold from the Culebra formation. Xenophora delecta (Guppy) Plate 22, figures 1, 2,4 Phorus agglutinans (Lamarck), Gabb, Am. Philos. Soc. Trans., n. ser., v. 15, p. 241, 1873 (Miocene, Dominican Republic). Phorus delecta Guppy, Geol. Soc. London Quart. Jour., v. 32, p. 529, pi. 28, fig. 10, 1876 (Miocene, Dominican Republic). Xenophora delecta (Guppy), Maury, Bull. Am. Paleontology, v. 5, no. 29, p. 134, pi. 23, figs. 8, 9, 1917 (Miocene, Dominican Republic). Pilsbry, 1922, Acad. Nat. Sci. Phila. Proc, v. 73, p. 385, pi. 32, figs. 7, 8, 1922 ("dilecla" by error; Miocene, Dominican Republic). Woodring, Carnegie Inst. Washington Pub. 385, p. 376, pi. 30, figs. 3, 4, 1928 (Miocene, Jamaica). Xenophora conchyliophora (Born), Maury, Bull. Am. Paleontol- ogy, v. 5, no. 29, p. 133, pi. 23, fig. 7, 1917 (Miocene, Dominican Republic) . Xenophora aff. trochiformis (Born), Rutsch, Schweizer. Palaeont. Gesell. Abh., Band 54, no. 3, p. 48, pi. 2, figs. 2, 3, 1934 (Miocene, Venezuela). Moderately large, widely umbilicate. Spire low, periphery somewhat extended. Sculpture above pe- riphery, between agglutinated shells and shell frag- ments, consisting of strongly protractive irregularly rippled threads. Base sculptured with more uniform rippled arcuate threads parallel to columeller lip, which is broken back. Height 25 mm, diameter (incomplete) 46 mm (figured specimen). 78 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Type: British Mus. (Nat. Hist.), Geol. Dept., Geol. Soc. London 12842. Type locality: Dominican Republic, Miocene. An incomplete Xenophora, found by T. F. Thompson in the upper part of the Gatun formation at Stanford University locality 2654 near Fort Davis, is referred to X. delecta. The attached shells and shell fragments with one exception (a fragment of the body whorl of a P/tos-like gastropod, attached by the exterior surface) consist of pelecypods, Aequipecten being most abundant. These pelecypods and pelecypod fragments are concave side upward, also with one exception: a fragment of a mature Aequipecten scissuratus. The generally open umbilicus and relatively strong sculpture differentiate X. delecta from the only Recent species in the Caribbean region, X. conchyliophora (Born). The Gatun fossil is widely umbilicate. On specimens of comparable size from the Dominican Republic the umbilicus is narrower and even reduced to a narrow groove. Rutsch's illustration of a specimen from the late Miocene Punta Gavilan formation of Venezuela also shows only a narrow groove. The type of X. delecta is a small specimen, like speci- mens from the Gurabo formation in the collections of the U. S. National Museum (maximum diameter 24 mm). Two imperfect shells from the Cercado forma- tion are even smaller. The Bowden formation of Jamaica also has yielded only small specimens (maxi- mum diameter 19 mm). The ripples on the base of these small specimens, from both the Dominican Re- public and Jamaica, are so strong that they form nodes. Pilsbry figured two large specimens (diameter 51 and 56 mm) that are in Gabb's collection of fossils from the Dominican Republic, and Maury illustrated, under the name X. conchxjliophora, a large specimen from the Gurabo formation. X. textilina Dall (Gardner, 1926-47, p. 561, pi. 58, figs. 31, 32, 1947), of the Chipola formation of Florida, evidently is an early form of X. delecta. It is umbili- cate, but its sculpture is not as strong as that of X. delecta. The larger of the two syntypes figured by Gardner is herewith designated the lectotype. The widely umbilicate strongly sculptured fragment from the Shoal River formation, doubtfully recorded as X. textilina, is indistinguishable from X. delecta. It might, however, be the high-spired subspecies of X. delecta, X. delecta floridana Mansfield (1930, p. 121, pi. 18, figs. 5, 6), which occurs in upper Miocene deposits in western Florida. X. delecta left no descendents in the Caribbean or Panamic regions. It is closely related, however, to X senegalensis Fischer, a Recent west African species, and its close Recent Mediterranean ally, X. crispa "Konig" Bronn, which occurs in rocks of late Miocene and Pliocene age in Italy. X. delecta has somewhat coarser sculpture than those species. The Recent Caribbean X. conchyliophora has a long history in the southeastern states and is one of the few Recent species recognized in the Eocene of that region. The Recent Panamic X. robusta Verrill, characterized by the deep orange-brown parietal callus and adjoining inner half of the interior of the body whorl, is better treated as a subspecies of conchyliophora. Occurrence: Upper part of Gatun formation (middle Miocene), eastern area, locality 173. Cercado and Gurabo formations (middle Miocene), Dominican Re- public. Bowden formation (middle Miocene), Jamaica. Punta Gavilan formation (late Miocene), Falcon, Venezuela. Family HIPPONICIDAE Genus Hipponix Defrance Defrance, Jour. Phys. Chim. Hist. Nat. Arts, t. 88, p. 217, 1819. Type (logotype, Gray, Zool. Soc. London Proc, p. 157, 1847) : Patella cornucopia (Patella cornucopia Lamarck), Eocene, Paris Basin. Hipponix species The Gatuncillo fossils from the Rio Casaya area include a small presumably immature Hipponix, shaped like a wide cornucopia. Some growth lamellae are exaggerated and there is a faint suggestion of fine radial sculpture. The muscle scar is not discernible. Length (not quite complete) 9 mm, width 7.5 mm, approximate height 6.5 mm. So far as this small specimen goes, it suggests a miniature replica of the type species of the genus. Occurrence: Gatuncillo formation (middle Eocene), Rio Casaya area, locality 38. Family HIPPONICIDAE? Hipponix? species A poorly preserved limpet-shaped fossil from the Culebra formation is doubtfully referred to Hipponix. It is moderately large and elongate, and the apex is near the posterior end. The apex is worn and prac- tically smooth. Preserved parts of the outer shell are sculptured with crude radial ribs overriden by crude concentric threads. The interior is inaccessible. Approximate dimensions: length 21 mm, width 17 mm, height 9 mm. If this fossil is an Hipponix, it is more similar to the Pacific H. pilosus (Deshayes) (an earlier name for H. barbatus Sowerby) than to Caribbean Recent species. H. pilosus ranges from California to Ecuador and the Galapagos, and is found in the western Pacific. It is recorded from the Miocene of the Dominican Republic (Pilsbry, 1922, p. 384). Occurrence : Culebra formation (early Miocene), Gail- lard Cut, locality 108c. gastropods: trochidae to turritellidae 79 Family CREPIDULIDAE Genus Crepidula Lamarck Lamarck, Soc. Hist. Nat. Paris Mem., p. 78, 1799. Type (monotype): Patella fornicata Linn6, Recent, eastern United States. Molds from the Culebra formation are identified as Crepidula sp. Crepidula cf. C. maculosa Conrad Plate 19, figures 4, 5 Crepidula gatunensis Toula, K. k. Geol. Reichsanstalt Jahrb., Band 61, p. 498, pi. 31, figs. 12a, b, 1911 (Miocene, Canal Zone). Of medium size, moderately narrow, moderately vaulted. Protoconch of small specimens consisting of about \)i whorls of neritoid outline. Deck of small specimens moderately deep seated, bearing a wide shallow median indentation. Length 28.5 mm, width 17.5 mm, approximate height 10.5 mm (figured specimen). A species of Crepidula from the Gatun formation is comparable to the Recent C. maculosa, to which atten- tion has recently been called (Stingley, 1952). As pointed out by Stingley, C. maculosa has a pedal muscle scar adjoining the adapical insertion of the deck and the edge of the deck has a very slight median indentation, whereas the better known and more northern C. fornicata (with which C. maculosa has been confused) lacks the muscle scar and has a pronounced median indentation. The only fairly large shell from Gatun (pi. 19, figs. 4, 5) is attached to a crab carapace and the interior is inaccessible. Owing presumably to inequalities on the carapace, this shell has two faint depressions and cor- respondingly modified growth lines. The other shells (all of which are small, ranging in length from 1.5 to 12 millimeters) evidently represent the same species as the fairly large specimen. Two that are moderately small show the muscle scar of C. maculosa. According to Toula's description and illustration, C. gatunensis was based on a small shell (length 2.8 millimeters) like those in the collections at hand. That name is available, should the name C. maculosa be found to be inappropriate for the fossils. Though C. fornicata is recorded from the Miocene of Trinidad (Maury, 1925, p. 244), it is unlikely that that species lived in the Caribbean Sea at any time. Occurrence: Lower, middle, and upper parts of Gatun formation (middle Miocene). Lower part, localities 137, 138. Middle part, eastern area, local- ities 147b, 155c, 157. Upper part, eastern area, locality 178. Crepidula plana Say Plate 19, figures 1-3 Crepidula plana Say, Acad. Nat. Sci. Phila. Jour., 1st ser., v. 2, p. 226, 1822 (Recent, Maryland to Florida). Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 358, 1892 (Miocene to Recent, eastern United States). Brown and Pilsbry, Acad. Nat. Sci. Phila. Proa, v. 63, p. 360, 1911 (Miocene, Canal Zone). Brown and Pilsbry, idem, v. 65, p. 495, 1913 (Pleis- tocene, Canal Zone). Pilsbry, idem, v. 73, p. 385, 1922 (Miocene, Dominican Republic). Olsson, Bull. Am. Pale- ontology, v. 9, no. 39, p. 159, 1922 (Miocene, northwestern Panama). Gardner, U. S. Geol. Survey Prof. Paper 142, p. 565, 1947 (Miocene, Florida) ; see this publication for other citations. Crypta fornicata (Linn6), Gabb, Am. Philos. Soc. Trans., v. 15, p. 242, 1873 (Miocene, Dominican Republic). Of medium size, narrow, compressed, flat or concave. Protoconch of immature shells consisting of 1% to 1% rapidly enlarging whorls of neritoid outline, destroyed at later stage by encroachment of aperture. Deck bearing a moderately deep narrow abapical marginal indentation and a moderately deep very wide median indentation. Length 15 mm, width 10.5 mm, height 2 mm (larger figured specimen). Slipper limpets recovered from the apertures of Gatun coiled gastropods agree closely with the Recent Crepidula plana. All the fossils were found in the lower part of the formation. C. plana is already recorded from the Gatun formation of the Canal Zone and from late Miocene strata in northwestern Panama. A species of Crepidula that has a similar outline and similar deck characters is living hi the eastern Pacific Panamic region. It presumably is C. nivea C. B. Adams, but is generally known as C. nummaria Gould. The few specimens of this species from Panama in the collection of the U. S. National Museum have slightly deeper deck indentations than C. plana. Occurrence: Lower part of Gatun formation (middle Miocene), localities 137a, 138, 138a. Middle part of Gatun formation (middle Miocene), eastern area (Brown and Pilsbry). Late Miocene, Water Cay, Panama. Miocene, Dominican Republic. Early to late Miocene, Maryland to Florida. Pliocene, North Carolina to Florida. Pleistocene, Massachusetts to Florida, Canal Zone. Recent, Prince Edward Island, Canada, to Texas and the West Indies. Family Calyptraeidae The genus Cheilea is not represented in the collections at hand. Cheilea princetonia Brown and Pilsbry (1911, p. 360, fig. 2), based on an internal and external mold from the Gatun formation, may be conspecific with the Cheilea from the Bowden formation of Jamaica so GEOLOGY AND PALEONTOLOGY OF CANAL ZONE identified as the Recent Caribbean form designated C. equestris (Linne) (Woodring, 1928, p. 375, pi. 30, figs. 1,2). Genus Calyptraea Lamarck Lamarck, Soc. Hist. Nat. Paris Mem., p. 78, 1799. Type (monotype) : Patella chinensis Linn6, Recent, western Europe. An unidentified small Calyptraea that has an eccentric apex is represented by poorly preserved specimens from the marine member of the Bohio(?) formation at Vamos Vamos. Calyptraea cf. C. aperta (Solander) Molds of a relatively large, relatively high-spired Calyptraea from the Gatuncillo formation of Madden basin are comparable to C. aperta, which is widely distributed in the Eocene and Oligocene of western Europe and southeastern United States. (For citation and synonomy see Palmer, 1937, p. 145.) In tropical America C. aperta, or a comparable form, is recorded from the Paleocene of Trinidad and the Eocene of Colombia and Peru. Occurrence: Gatuncillo formation (late Eocene), localities 9, 12. Calyptraea centralis (Conrad) Infundibnlum centralis Conrad, Am. Jour. Sci., 1st ser., v. 41, p. 348, 1841 (Miocene, North Carolina, p. 343). Conrad, Fossils of the Medial Tertiary of the United States, No. 3 (Fossils of the Miocene formation of the United States), p. 80, pi. 45, fig. 5, 1845 (Miocene, North Carolina). Trochita sp. indet., Gabb, Am. Philos. Soc. Trans., v. 15, p. 242, 1873 (Miocene, Dominican Republic). ? Trochita collinsii Gabb, Acad. Nat. Sci. Phila. Jour., 2d ser., v. 8, p. 342, pi. 44, figs. 11, 11a, 1881 (Miocene, Costa Rica). Calyptraea centralis (Conrad), Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 353, 1892 (Miocene to Recent). Maury, Acad. Nat. Sci. Phila, Jour., 2d ser., v. 15, p. 100, pi. L3, fig. 6, 1912 (Miocene, Trinidad). Maury, New York Acad. Sci., Scientific Survey of Porto Rico and Virgin Islands, v. 3, pt. 1, p. 48, 1920 (Miocene, Puerto Rico). Pilsbry, Acad. Nat, Sci. Phila. Proc, v. 73, p. 385, 1922 (Miocene, Dominican Republic). Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 243, pi. 43, fig. 2, 1925 (Miocene and Pliocene, Trinidad). Gardner, U. S. Geol. Survey Prof. Paper 142, p. 562, pi. 56, figs. 3-5, 1947 (Miocene, Florida); see this publication for other citations. ICalyptraea cf. centralis (Conrad), Hubbard, N. Y. Acad. Sci., Scientific Survey <>f Porto Rico and Virgin Islands, v. 3, pt. 2, p. 133, 1920 (Miocene, Puerto Rico). Maury, 1925, Brasil Serv. Geol. Min. Mon. 4, p. 65, pi. 1, figs. 5, 10, 1925 (Miocene Brazil). Of medium size, circular in ventral plan, apex central. Protoconch of about \% strongly Inflated, rapidly enlarg- ing whorls. Free edge of platform convex forward; reflected columella! edge not closely appressed, forming a relatively high umbilicuslike opening. Maximum diameter 16 mm, height 6 mm (largest specimen). Type: Apparently lost. Type locality: Natural Well, N. Car., Duplin formation (late Miocene). Specimens from the Culebra formation, identified as Calyptraea cf. C. centralis, are comparable in size and outline to C. centralis, but none shows the interior. All are molds, with the exception of one, which was collected at locality 108c and has much of the shell preserved. The description is based on specimens from the lower part of the Gatun formation. The only large specimen, from locality 138, is imperfect. The interior of the only specimen from the middle part of the Gatun formation is inacessible. It is listed as Calyptraea cf. C. centralis. The Gatun fossils that show the interior agree closely with topotypes of C. centralis collected at Natural Well, N. Car. As pointed out by Dall and Gardner, Recent specimens are smaller than those from the Miocene. Recent specimens in the collection of the U. S. National Museum, representing localities from Cape Hatteras to the West Indies, are not more than a third the size of large Miocene fossils. Two large Recent shells, how- ever, are exceptions. One, which has a maximum diameter of 11.5 millimeters, was cataloged at an early date and is labelled "West Indies." The other (maxi- mum diameter 15.5 millimeters) was in the Henderson collection and is labelled "Marco, Florida." The re- flected edge of the platform of both is closely appressed, like that of the western European C. chinensis, the type of the genus. They probably are specimens of that species with erroneous locality data. Should a name be desirable for the small Recent race, it may be designated Calyptraea centralis candeana (d'Orbigny), as indicated by Dall's synonymy. Pliocene fossils from the Caloosa- hatchee marl of Florida have a maximum diameter of 10 millimeters and therefore are intermediate in size. The Recent Panamic C. mamillaris Broderip is larger than C. centralis, and has a thicker shell and mottled brown color pattern. Occurrence: Culebra formation (early Miocene; Ca- lyptraea cf. C. centralis), Gaillard Cut, localities 99b, 99c, 100, 108c, 110a. Lower and middle parts of Gatun formation (middle Miocene); lower part, localities 137, 138, 138a; middle part, eastern area, locality 147j, (Calyptraea cf. C. centralis) . Early M iocene, Puerto Rico, ?Costa Rica, ?Brazil. Late Miocene(?), Trinidad. Miocene, Dominican Republic. Early to late Miocene, Maryland to Florida. Pliocene, Trinidad, Florida. Recent (small race) Cape Hatteras to West Indies. Genus Trochita Schumacher Schumacher, Essai d'un nouveau systeme des habitations des vers testaces, p. 57. 184, 1817. gastropods: trochidae to turritellidae 81 Type (logotype, Rehder, Biol. Soc. Washington Proc, v. 56, p. 41, 1943): Trochila spiralis Schumacher (=Trochus radi- ans Lamarck= Turbo trochiformis Born), Recent, Ecuador to Chile. Trochita has a thick shell, distinct suture, and moderately strong to strong radial sculpture. The free edge of the platform is convex forward, except at the distal margin, where it bears a narrow identation. The columellar edge of the platform is reflected only at its insertion. On adult shells this short reflected border is molded on the platform, like callus. The genus and its species were discussed by Rehder (1943) in the publica- tion cited for the type designation. Trochita heretofore has not been recorded from the Caribbean region. It is now extinct there, and in the western Atlantic is limited to the Falkland Islands and the coast of Argentina. Though it occurs in the Miocene and Pliocene of California, in the eastern Pacific it is now found only south of the equator. The survival of the genus in west African waters— a genus otherwise confined to the Peruvian, Magellanic, and South African provinces — is more readily understood in view of its occurrence in the Miocene of the Caribbean region and in the Pliocene and Pleistocene of west Africa. The West African species is considered conspecific with the Miocene Caribbean fossil and the Recent eastern Pacific species. It is an expectable fossil in the West African Miocene. Trochita trochiformis (Born) Plate 19, figures 11-14 Turbo trochiformis Born, Index Musei Caesarei Vindobonensis, p. 355, 1778 (sole citation: Knorr, pt. 3, pi. 29, figs. 1, 2, 1768, "Antillean Islands"). Trochus radians Lamarck, Encyclopedic methodique, Histoire naturelle des vers, t. 3, pi. 445, figs. 3a, b; Liste, p. 10, 1816. Lamarck, Histoire naturelle des animaux sans vertebres, t. 7, p. 11, 1822 (Recent, "mer des Antilles"). Calyptraea (Trochatella) trochiformis (Gmelin), d'Orbigny, Voy- age dans l'Amerique Meridionale, t. 5, pt. 3, p. 461, pi. 59, fig. 3, 1841 (Recent, Chile, Peru; Calyptraea radians in explana- tion of plate). Nickles, Manuels Ouest-Africains, t. 2, p. 73, fig. 99, 1950 (Recent, Angola). Lecointre, Morocco Service Geologique, Notes et Mem. 99, t. 2, p. 108, pi. 25, figs. 1-4, 1952 (Pleistocene, Morocco). Infundibulum trochiforme (Gmelin), d'Orbigny, Voyage dans l'Amerique Meridionale, t. 3, pt. 4 (Paleontologie), p. 158, 1842 (Pleistocene, Chile). Trochita radians (Lamarck), Reeve, Conchologia Iconica, v. 11, Trochita, pi. 1, species 3, 1859 (Recent, Chile). Sowerby, Thesaurus Conchyliorum, v. 5, p. 64, pi. 451, figs. 95, 96, 99, 1883 (Recent, Chile). Rehder, Biol. Soc. Washington Proc. v. 56, p. 42, 1943 (Recent, Ecuador to Chile) ; see this publica- tion for other citations and synonymy. Calyptraea (Trochita) trochiformis (Gmelin), Grant and Gale, San Diego Soc. Natural History Mem., v. 1, p. 795, pi. 31, fig. 11, 1931 (Miocene and Pliocene, California; Recent- Panama to Peru). Trochatella trochiformis (Gmelin), Lecointre, Jour. Conchyli- ologie, t. 90, p. 240, unnumbered pi., fig. 2, 1950 (Pliocene, Pleistocene, Morocco). Of medium size, moderately low spired or moderately high spired, apex broken. Sculpture consisting of heavy crude axial ribs. Platform broken back to insertion. Maximum diameter 28.8 mm, height (incomplete) 10.7 mm (smaller figured specimen). Maximum diam- eter 43.5 mm, height (almost complete) 27 mm (larger figured specimen). This calyptraeid is represented by two specimens from the lower part of the Gatun formation, both collected by T. F. Thompson. Though the interior of the larger specimen is inaccessible and the platform of the smaller is broken far back, they are identified with considerable confidence as Trochita trochiformis. The middle part of the Gatun formation in the western area at locality 151 yielded a worn thick-shelled apical frag- ment listed as Trochita? sp. Incomplete and poorly preserved fossils from the middle member of the Caimito formation in the Gatun Lake area and the Culebra formation suggest that the lineage of T. trochi- formis can be traced back to the late Oligocene. None of these Caimito and Culebra fossils, however, is un- equivocally identified. Trochita trochiformis now ranges from Manta, Ecua- dor, to Valparaiso, Chile. It is low spired to high spired. On low-spired shells the platform is almost flush with the base of the shell; on high-spired shells it is a considerable distance above the base. The heavy crude axial ribs are characteristic. The largest Recent specimen in the collection of the U. S. National Museum has a maximum diameter of 65 millimeters. A small form of Trochita trochiformis (recorded as T. radians) occurs in formations of Pliocene age in Cali- fornia as far north as the Santa Maria district (Arnold and Anderson, 1907, p. 60, pi. 21, fig. 1; Woodring and Bramlette, 1950 [1951], p. 72, pi. 13, fig. 19), in Santa Barbara County. Early and middle Miocene forms from California have been identified as Trochita costellata Conrad (Eldridge and Arnold, 1907, p. 148, pi. 32, fig. 3; Loel and Corey, 1932, p. 268, pi. 63, fig. 11), and late Miocene forms have been named "Calyptraea" dia- bloensis Clark (1915, p. 485, pi. 70, fig. 9) and "Calyp- traea" martini Clark (1915, p. 486, pi. 70, fig. 8). As suggested by Grant and Gale, these heavily ribbed Miocene forms, ranging in age from early to late Miocene, are probably to be referred to Trochita trochi- formis. The inadequate type material of Trochita costellata Conrad (1857b, p. 195, pi. 7, fig. 3) consists of two molds showing traces of relatively fine ribs. Addi- tional specimens from the type locality (Gaviota Pass in the western Santa Ynez Mountains, Santa Barbara 82 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE County, Calif.) have not been described and the age is still unknown. I am indebted to R. T. Abbott for pointing out that Bom's Turbo trochiformis is an earlier name for Lamarck's Trochus radians. Occurence: Middle member of Caimito formation (late Oligocene), Gatun Lake area, localities 57 (Trochita? sp.), 57a (Trochita cf. T. trochiformis). Culebra formation (early Miocene), Gaillard Cut, localities 115a (Trochita? cf. T. trochiformis), 115b (Trochita cf. T. trochiformis, 116 (Trochita cf. T. trochi- formis). Lower part of Gatun formation (middle Miocene), locality 136, 136a. Middle part of Gatun formation (middle Miocene), western area, locality 161c (Trochita? sp.). Miocene, California (identifica- tion doubtful). Pliocene, California, Morocco. Pleis- tocene, Chile, Cape Verde Islands, Morocco. Recent, Manta, Ecuador, to Valparaiso, Chile; Cape Verde Islands, Angola. Genus Crucibulum Schumacher Schumacher, Essai d'un nouveau systeme des habitations des vers testaces, p. 56, 182, 1817. Type (logotype, Burch, Conchological Club Southern Calif. Proc, no. 56, p. 19, 1946): Crucibulum planum Schumacher (■= Patella auricula Gmelin), Recent, Florida and West Indies. J. E. Gray's (1847, p. 157) designation of Patella auriculata as the type of Crucibulum is not valid in the strict sense, as Patella auriculata was not mentioned by Schumacher. Schumacher, however, based Crucibulum planum on Chemnitz's Patella auriculata without mentioning it by name. Both Crucibulum planum and Patella auriculata, given binomial standing by Dillwyn in the year when Schumacher published the generic name Crucibulum, are synonyms of Patella auricula Gmelin. The recent type designation by Burch, on the advice of Keen, appears to be the first valid designation. The question of possible virtual monotypy, raised by Keen, need not be considered. Whatever the status of Crucibulum rugoso-costatum, the only other species mentioned by Schumacher, may be, Crucibulum was not monotypic. Unidentified molds from the Culebra formation, the Alhajuela sandstone member of the Caimito formation, and the Chagrcs sandstone are listed as Crucibulum sp. Subgenus Crucibulum s. s. Crucibulum (Crucibulum) chipolanum Dall Plate 19, figures 6, 7 Crucibulum auricula var. chipolanum Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 349, 1892 (Miocene, Florida). Crucibulum chipolanum Dall, Gardner, U. S. Geol. Survey Prof. Paper 1 12, p. 567, pi. 56, figs. 10, 11, 1947 (Miocene, Florida). Of medium size, elliptical in ventral plan. Protoconch of about IK rapidly enlarging whorls. Shell smooth to diameter of lji to 3 mm. At that stage the shell is elliptical and the apex lies far to the rear. Sculpture consisting of closely spaced crudely roughened radial ribs, some of which bifurcate and a few of which unite as they extend outward. Right anterior border of cup sharply angulated, joined to side of shell at level far above ventral margin of cup. Maximum diameter 27 mm, height 16.5 mm (figured specimen). Type (lectotype, the specimen figured by Gardner): USNM 112783. Type locality: USGS 2212, Tenmile Creek, Fla., Chipola formation (early Miocene). Specimens from the middle part of the Gatun forma- tion at the Gatun Third Locks excavation closely resemble Crucibulum chipolanum in characters of pro- toconch, sculputre, and cup. The right side of the cup of the figured specimen was uncovered, but the shell is too fragile to uncover the entire cup. Locality 155c yielded a worn incomplete specimen. It shows the same kind of cup and traces of radial ribs, but is only tentatively identified as C. chipolanum. C. chipolanum was described as a variety of the Recent Caribbean C. auricula (Gmelin). Undoubtedly it is closely related to that species and to the Recent Panamic C. spinosum (Sowerby). The cups of all three are similar. Tlie sculpture of C. auricula is weaker and more varied than that of C. chipolanum. As pointed out by Gardner, the protoconch whorls of C. auricula are wider and emerge more obtusely. Both C. auricula and C. spinosum are recorded from the Miocene of the Dominican Republic (Pilsbry, 1922, p. 385). A species of Crucibulum from the Shoal River formation of Florida and its Oak Grove sand member, C. chipolanum dodoneum Gardner (1926-47, p. 567, pi. 56, figs. 18-20, 1947), has coarser sculpture than C. chipolanum . It presumably is not closely related, how- ever, to C. chipolanum, as its cup is attached to the side of the shell at the level of the ventral margin of the cup. Dall designated no type material for C. chipola num. In his description he mentioned only one locality: the Chipola River, a mile below Baileys Ferry. He also examined and identified, however, specimens from the nearby Tenmile Creek locality, a mile west of Baileys Ferry. The specimen from the Tenmile Creek locality figured by Gardner is herewith designated the lectotype. Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 155, 155b, 155c (including a doubtfully identified worn specimen). Chipola formation (early Miocene), Florida. gastropods: trochidae to turritellidae 83 Subgenus Dispotaea Say Say, Acad. Nat. Sci. Phila. Jour., 1st ser., v. 4, p. 131, 1824. Type (logotype, Olsson and Harbison, Acad. Nat. Sci. Phila. Mon. 8, p. 276, 1953): Calyptraea costata Say, Miocene, Maryland. After describing Calyptraea grandis, Say remarked that it does not properly belong in the genus Calyptraea and therefore proposed to place it in a new genus Dispotaea. He then assigned two other species to Dispotaea: Dispotaea tubifera, a new Recent species from South America, and his previously described Calyptraea costata (Say, 1820, p. 40; see p. 38 for locality data), a fossil species from Upper Marlborough, Maryland, associated with others now known to be Miocene. The types of these three species evidently are lost. So far as known Dispotaea tubifera has not been recognized. Calyptraea costata has been inter- preted in different ways by Dall (1890-1903, pt. 2, p. 349, 1892) and Martin (1904, p. 244, pi. 58, figs. 7a, b). Dall thought it is the strongly costate Cru- cibulum that occurs in the St. Marys formation of Maryland and assigned it varietal rank under Cru- cibulum auricula, the type of Crucibulum. According to Martin, it is the weakly costate Crucibulum found in the Calvert formation of Maryland. Martin's interpretation is reasonable in view of the locality cited by Say and in view of Say's statement that the cup is attached by one side to the wall of the shell. At all events Martin's identification is accepted. Olsson and Harbison, apparently not realizing that Say assigned the unequivocally identifiable Calyptraea grandis to Dispotaea, recently designated Calyptraea costata as the type of Dispotaea. The cup of Dispotaea is attached by the right side, or part of the right side, to the interior of the shell. The type species has a wide attachment area; Crucibu- lum grande has an attachment area of varied width. The Recent Crucibulum striatum (Say) (Nova Scotia to Florida), which has been cited as the type of Dispotaea b}? several authors, has a consistently wide attachment area. Crucibulum (Dispotaea) springvaleense Rutsch Plate 19, figures 8-10 tCapulus? gatunensis Toula, K. k. Geol. Reichsanstalt Jahrb., Band 58, p. 692, pi. 25, fig. 1, 1909 (Miocene, Canal Zone). Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 63, p. 360, 1911 (Toula's record). Capulus? sp., Toula, K. k. Geol. Reichsanstalt Jahrb., Band 58, p. 692, pi. 25, fig. 2, 1909 (Miocene, Canal Zone). Crucibulum (Dispotaea) gatunense (Toula), Anderson, Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 121, pi. 13, figs. 4-6, 1929 (Miocene, Canal Zone, Colombia). Crucibulum? springvaleense Rutsch, Naturf. Gesell. Basel Verhandl., Band 54, p. 138, pi. 4, fig. 8, 1942 (Miocene, Trinidad). Of medium size, circular to elliptical in ventral plan. Protoconch of 1% to iy 2 rapidly enlarging whorls. Shell smooth to a diameter of 3 to 6 mm. Shell at that stage circular and apex central or subcentral. Sculpture consisting of heavy widely spaced radial ribs, the interspaces bearing crude concentric lamellae, or consisting of closely spaced, generally narrower, roughened and pitted irregular ribs. Right side of cup widely attached to interior of shell. Maximum diameter 19.2 mm, height 11 mm (figured specimen). Maximum diameter 24.5 mm, height 14 mm (largest specimen). Type: 518/190 Basel Natural History Museum. Type locality: Springvale quarry, Trinidad, Spring- vale formation (late Miocene). Crucibulum springvaleense is widehy distributed in the Gatun formation. Though the interior of the Trinidad specimens, on which this species was based, is unknown, the Crucibulum from Panama is unequivo- cally identified. Coarsely sculptured specimens have the external characters of a topotype of C. spring- valeense kindly forwarded by Dr. Rutsch. Some fossils from Panama have only regular coarse sculpture, others only irregular generally finer sculpture, and still others, like the specimen figured, a combination of both. This species has left no descendants in the Caribbean region. It appears to be allied, however, to the Recent Panamic Crucibulum pectinatum Carpenter, which has fewer ribs than the coarsely sculptured typical form of C. springvaleense. C. pectinatum ranges from the southern part of the Gulf of California to Panama, possibly to Peru. It is unlikely that Crucibulum springvaleense is the species Toula described as Capulus? gatunensis. At a diameter of 11.5 millimeters, the greatest diameter of the type of Capulus? gatunensis, it should show traces of strong sculpture, if it were the Crucibulum. Accord- ing to a communication from Dr. Rutsch, who examined the types of Toula's Gatun gastropods, the type of Capulus? gatunensis is an unidentifiable mold retaining parts of the inner shell layer. In the text Toula cited figures 1 and 2 of plate 25 for Capulus? gatunensis. According to the explanation of the plate and the dimensions, however, figure 2 is his Capulus? sp. Figure 2 quite certainly represents a mold of the coarsely sculptured Crucibulum that occurs in the Gatun formation. Perhaps through this error in citation Anderson was led to use the name Crucibulum gatunense for that species. Occurrence: Lower, middle, and upper parts of Gatun formation (middle and late Miocene). Lower part, localities 137, 137a, 138, 138a, 139. Middle part, eastern area, localities 146, 147b, 147e, 147f (identifi- cation doubtful, immature specimens only), 147g, SI GEOLOGY AND PALEONTOLOGY OF CANAL ZONE 147h, 151, 152, 155, 155a, 155b, 155c, 159, 160 (Cruci- bulum cf. C. springvaleense) ; western area, locality 162a. Upper part, western area, locality 185. Springvale formation (late Miocene), Trinidad. Miocene, Bolivar, Colombia. Family NATICIDAE Subfamily NATICINAE Genus Natica Scopoli Scopoli, Introductio ad historiam naturalem, p. 392, 1777. Type (logotype, Harris, Catalogue of Tertiary Mollusca in the British Museum; pt. 1, Australasian, p. 255, 1897); Nerita vitellus Linne, Recent, tropical western Pacific. Anton (1839, p. 31) also designated Nerita vitellus as the type of Natica at a much earlier date than Harris. Anton's designation, however, is of doubtful validity, as it is a designation for Natica Lamarck. Subgenus Natica s. s.? Natica (Natica?) species The collections from the marine member of the Bohio(?) formation at Vamos Vamos include two naticid opercula that have a narrow marginal rib, separated by a shallow groove from a wider second rib. They represent Natica s. s. or possibly some other subgenus that has a similar operculum. The larger specimen has a restored length of about 12 millimeters and a width of 7.5 millimeters. Small poorly preserved shells from locality 42 may represent this species. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), localities 40, 40d, 42 (identification doubtful). Natica (Natica?) bolus Brown and Pilsbry Plate 20, figures 1-3 Natica bolus Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 64, p. 508, pi. 22, fig. 9, 1913 (Miocene, Canal Zone). Natica youngi Maury, Bull. Am. Paleontology, v. 5, no. 29, p. 135, pi. 23, figs. 11, 12, 1917 (Miocene, Dominican Republic). Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 73, p. 386, pi. 34, fig. 21, 1922 (Miocene, Dominican Republic). Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 239, pi. 40, fig. 4, 1925 (Miocene, Trinidad). Mansfield, U. S. Natl. Mus. Proc, v. 66, art. 22, p. 57, 1925 (Miocene, Trinidad). Natica finitima Pilsbry and Johnson, Acad. Nat. Sci. Phila. Proc, v. 69, p. 173, 1917 (Miocene, Dominican Republic). Not Natica youngi Maury, Li, Geol. Soc China Bull., v. 3, p. 266, pi. 6, figs. 47, 47a, 1930 (Miocene, Panama Bay; = Natica unifasciata Lamarck, fide Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 83, p. 132, 1931, Recent, Panama Bay). Not Natica (Polinices) cf. youngi Maury, Trechmann, Geol. Mag., v. 72, p. 550, pi. 20, figs. 3-5, 1935 (Miocene, Carriacou); = Polinices sp. Of medium size, thick-shelled, spire very low or mod- era I ely low, shoulder strongly or slightly inflated. Pro- toconch not clearly differentiated from remainder of shell, apical whorl large. Umbilicus wide, umbilical rib narrow , ending in a small callus lobe bearing a shallow anterior depression. A narrow deep groove lies in front of umbilical rib and callus pad, separating them from umbilical border. Parietal callus thick, especially in front of junction with outer lip, where it forms a ridge. On immature shells anterior part of parietal callus rela- tively wider than on mature shells and roofing over posterior end of umbilicus as it extends forward to join umbilical lobe. Operculum assumed to represent this species bearing a narrow marginal rib, separated by a narrow groove from a second rib that is as narrow as the marginal rib or slightly wider. Height 14.5 mm, diameter 15.2 mm (figured mature specimen). Height 9.7 mm, diameter 10.2 mm (figured immature specimen). Type: Acad. Nat. Sci. Phila. 3846. Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation. The type, the largest of 6 in the type lot, is a small immature shell (height 9 millimeters). On the type and other immature shells, such as that shown on plate 20, figure 3, the anterior part of the parietal callus is wide and roofs over the posterior end of the umbilicus. On mature shells more of the umbilicus is uncovered. The largest shell, which is incomplete, has a height of 19.5 millimeters. Very low-spired shells have an inflated shoulder, whereas shells that nave a higher spire have a less inflated shoulder. Two small opercula assumed to represent N. bolus were found in association with shells at locality 155c and another of medium size at locality 172. Though Natica bolus is fairly widespread in the Gatun formation, only a few specimens were collected at any locality, except locality 177b. N. youngi, from the Miocene of the Dominican Republic, reaches a some- what larger size (height 24 millimeters), but has the umbilical and callus features, as well as the outline, of N. bolus. N. youngi from the Miocene of Trinidad has a narrower umbilicus and less conspicuous umbilical rib than N. bolus, but is considered conspecific. N. youngi cocleana Olsson (1922, p. 155, pi. 13, fig. 8; Miocene, Costa Rica), however, has a narrow umbilicus, weak umbilical rib, and narrower umbilical callus lobe, and evidently is not closely related. An early Miocene spe- cies from Costa Rica, N. milleri Gabb (1881, p. 338, pi. 44, fig. 3) has a higher spire and weaker umbilical rib. N. castrenoides Woodring (1928, p. 377, pi. 30, fig. 5; Miocene, Jamaica) and its Recent Caribbean analog, N. castrensis Dall (1889, p. 293), have a wider and weaker umbilical rib and thinner parietal callus. N. bolus appears to have no close living allies in either Caribbean or Panamic waters. The strong, though narrow, umbilical rib indicates that N. bolus is not closely related to N. vitellus; it gastropods: trochidae to turritellidae 85 probably is to be assigned to an unnamed subgenus. As pointed out by Powell (1933, p. 165), undue emphasis on opercular characters in effecting a classification of naticids may lead to artificial alliances. Occurrence: Lower, middle, and upper parts of Gatun formation (middle Miocene). Lower part, locality 138. Middle part, eastern area, localities 142, 144 (incom- plete, identification doubtful), 147b, 147g, 155, 155a, 155b, 155c, 157, 159; western area, localities 161a, 161c, 161d. Upper part, eastern area, localities 172, 173, 175, 176a, 177, 177a (incomplete, identification doubtful), 177b, 178. Cercado and Gurabo formations (middle Miocene), Dominican Republic. Springvale formation (late Miocene), Trinidad. Subgenus Naticarius Dumeril Dumeiil, Zoologie analytique, p. 164, 1806; genus without species. Type (monotype, Froriep, C. Dumeril's analytische Zoologie, p. 165, 1806; quoted from Iredale, Malacol. Soc. London Proc, v. 12, p. 83, 1916): Nerita canrena Linn6, Recent, West Indies. The status of Dumeril's names, all of which end in "arius", will not be settled without a specific ruling, for they may be interpreted in various ways. According to Opinion 148 of the International Commission on Zoological Nomenclature, issued in 1943 A generic name published as an emendation of an earlier name of the same origin and meaning is to be rejected as a synonym of the earlier name, and the type of the genus bearing the emended name is automatically the same species as the type of the genus bearing the earlier name so proposed to be emended. Dumeril's names doubtless are emendations of earlier names of the same origin and meaning. All of them can be matched with earlier names that lack the "arius" termination. He probably emended the earlier names with the Latin suffix "arius" (pertaining to) as the name of the animal; Naticarius, for example, being the name of the animal "pertaining to" the shell Natica. His statement that "notre objet etoit de faire connoitre les animaux et non les couquilles que les revetent" supports that interpretation. In that event it could be argued that the names are to be rejected on the grounds that Dumeril adopted a system that results in two names for shell-bearing mollusks. If the names are to be accepted and are emendations, and therefore synonyms, is Naticarius a synonym of Natica Scopoli or of Natica Lamarck? If it is a synonym of Natica Lamarck, it is available in place of that name, which is a homonym of Natica Scopoli. Dumeril's names, however, were not admitted to be emendations when they were proposed. They therefore may be interpreted as entirely new names dating from his or Froriep's usage, depending on whether Dumeril's usage is considered nude. For the time being the view that they are new names is arbi- trarily adopted. In 1928 Naticarius was regarded as a substitute name for Natica Lamarck not Scopoli (Woodring, 1928, p. 378). That view, which followed Iredale's (1916, p. 82) interpretation, is far fetched, but has the same nomenclatorial effect as the view adopted in the present report. Natica s s., or naticids having similar opercula, occur in the Eocene (Harris and Palmer, 1946-47, p. 247, pi. 29, figs. 1, 2, 1947; Wrigley, 1949, p. 11, 13, figs. 1, 2, 8-12). Naticarius, however, evidently does not antedate the late Oligocene. The late Eocene (Jack- son) Natica permunda Conrad, which has been referred to Naticarius (Harris and Palmer, 1946-47, p. 246, 1947), lacks the axial grooves of that subgenus, and has a less rapidly enlarging umbilical rib and correspond- ingly narrower umbilical callus lobe. Naticarius is now found in western Atlantic and eastern Pacific tropical and subtropical waters. The Mediterranean N. mil- lepunctata Lamarck has a multiribbed operculum, sug- gesting alliance with Naticarius, but the ribs are very narrow and the shell has a narrow umbilical rib. This species has been erroneously assigned to Nacca Ptisso. An unidentified species of Naticarius occurs in the upper part of the Bohio formation and poorly preserved fossils from the middle member of the Caimito forma- tion in the Gatun Lake area and the Culebra formation are identified as Natica (Naticarius?) sp. They have a relatively high spire and short axial grooves adjoining the suture. Their umbilical features and opercula are unknown. Natica (Naticarius) stenopa Woodring, n. sp. Plate 20, figures 4-6 Of medium size, thin shelled, moderately inflated, whorls enlarging at moderate rate, spire high. Proto- conch of 2}{ to 3 whorls, apical whorl small. End of protoconch marked by slight change in texture of shell and beginning of sculpture. Sculpture consisting of short closely spaced retractive axial grooves, parallel to growth lines, extending from suture and ending on shoulder on later whorls. Umbilicus moderately wide, umbilical rib rapidly enlarging, ending in a wide callus lobe, the anterior part of wdiich is concave. A very narrow deep groove in front of umbilical rib and um- bilical callus lobe. Parietal callus moderately thick. Operculum bearing a marginal rib and 4 or 5 wider Hat ribs, all separated by deep grooves. Height 15.2 mm, diameter 14.8 mm (type). Height 21.5 mm, diameter 19.5 mm (largest specimen). Type: USNM 561340; paratype, USNM 561341; paratypes Stanford Univ. Type locality: 177b (USGS 5854, Mount Hope, west side of Panama Railroad near oil tanks, Canal Zone), upper part of Gatun formation. Natica stenopa is widespread and locally common in the Gatun formation, especially abundant in the upper N(i GEOLOGY AND PALEONTOLOGY OF CANAL ZONE part of the formation in the eastern area. Eighteen of the 21 lots, however, consist only of immature specimens, up to a maximum of 115 immature shells in one lot. The largest shells are imperfect. A shell of medium size from locality 177c has an operculum in place (pi. 20, fig. 6). An incomplete operculum of medium size, not associated with shells, was found at locality 161. A small incomplete operculum, col- lected at locality 162, has three ribs, an indeterminate number of other lower ribs being covered with a glaze of enamel. The identification of this operculum is uncertain. The axial grooves disappear on the body whorl of an incomplete doubtfully identified shell from locality 147h. Though Brown and Pilsbry (1913, p. 508) recorded N. canrena from the Gatun formation and though Olsson (1922, p. 155, pi. 13, fig. 9) figured a specimen of that Recent Caribbean species from the Gatun formation near Gatun, that species is not represented in the Gatun collections of the U. S. National Museum or Stanford University. N. stenopa is of meduim size and has a high spire, small apical whorl, closely spaced axial grooves, and 5 or 6 ribs on the operculum. N. canrena, on the contrary, is much larger and has more inflated and more rapidly enlarging whorls, low spire, large apical whorl, more widely spaced axial grooves, more rapidly enlarging umbilical rib and correspond- ingly larger umbilical callus lobe, and 8 or 9 ribs on the operculum. On the basis of shell characters N. stenopa is closely related to a Recent Panamic species identified by Dall as N. limacina Jousseaume (1874, p. 14, pi. 2, figs. 7, 8). Jousseaume's description and illustrations suggest that the identification is erroneous. The operculum of N. limacina is unknown and the type locality is indefinite: "West Indies(?)". Dall's N. limacina is represented in the collections of the U. S. National Museum by one shell dredged in Panama Bay at a depth of 33 fathoms. N. stenopa has a somewhat thinner shell, narrower groove in front of the umbilical rib and umbilical callus lobe, and wider umbilical opening back of the umbilical rib. Naticarius opercula, having 7 to 9 ribs, are represented by 2 lots from Panama Bay, and also by lots dredged in the Gulf of California off Guaymas and La Paz, but it is not known that the opercula are to be associated with Dall's N. limacina. They agree with the operculum of N. colima Strong and Hertlein (1937, p. 174, pi. 35, figs. 12, 13, 16), dredged near Manzanillo, Mexico. N. colima, however, is thin shelled and has a very narrow umbilical rib and small umbilical callus lobe. Nalica canrena or allied forms are widespread in the Caribbean region in formations of Miocene and Pliocene age. N. precanrena F. Hodson (Hodson, Hodson, and Harris, 1927, p. 68, pi. 36, figs. 2, 6, 9), a small Vene- zuelan early Miocene species (height 6.8 millimeters), has a high spire, small initial whorl, and closely spaced axial grooves. It has, however, a higher spire and a wider umbilicus than small specimens of N. stenopa. Occurrence: Lower, middle, and upper parts of Gatun formation (middle and late Miocene). Lower part, localities 136, 137, 137a, 138, 138a. Middle part, eastern area, localities 146, 147b, 147g, 147h (incomplete, identification doubtful), 151, 155, 155c, 157; western area, localities 161, 161a, 161c, 161d, 170, 170a. Upper part, eastern area, localities 175, 176a, 177b, 177c; western area, localities 183, 185. Genus Stigmaulax Morch Morch, Catalogus conchyliorium * * * Comes de Yoldi, pt. 1, p. 133, 1852. Type (logotype, Harris, Catalogue of Tertiary Mollusca in the British Museum; pt. 1, Australasian, p. 262, 1897): Nalica sulcata Born (Nerita sulcata Born), Recent, West Indies. Stigmaulax, like Naticarius, lives in American tropical and subtropical waters on both sides of Central America. It is found in the late Tertiary of the same region, the earliest species being of early Miocene age. Stigmaulax guppiana (Toula) Plate 20, figures 11-16 Natica guppiana Toula, K. k. Geol. Reichsanstalt Jahrb., Band 58, p. 696, pi. 25, fig. 6, 1909 (Miocene, Canal Zone). Hodson, Hodson, and Harris, Bull. Am. Paleontology, v. 13, no. 49, p. 67, pi. 36, figs. 1, 4, 1927 (Miocene, Venezuela). Natica guppyana Toula, Engerrand and Urbina, Soc. Geol. Mexicana Bol., v. 6, p. 130, pi. 60, figs .53, 54, 55 (reproduc- tion of Toula's illustration), 1910 (Miocene, Mexico). Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 63, p. 360, 1911 (Miocene, Canal Zone). Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 156, pi. 13, figs. 13-15, 1922 (Miocene, Panama, Costa Rica). Anderson, California Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 123, 1929 (Miocene, Colombia). Tucker and Wilson, Bull. Am. Paleontology, v. 18, no. 65, p. 13, pi. 2, figs. 3, 4, 1932 (Miocene, Florida). Mansfield, Florida Dept. Conservation, Geol. Bull. 12, p. 10, 13 (lists), 1935 (Miocene, Florida) . Natica (Stigmaulax) sulcata guppiana Toula, Rutsch, Schweizer. Palaeont. Gessel. Abh., Band 54, no. 3, p. 51, pi. 1, fig. 15 (type), 1934 (Miocene, Canal Zone). Natica (Naticarius) guppyana Toula, Oinomikado, Geol. Soc. Japan Jour., v. 46, p. 621, pi. 29, fig. 18, 1939 (Miocene, Colombia). Natica (Stigmaulax) guppiana Toula, Gardiner, U. S. Geol. Survey Prof. Paper 142, p. 546, pi. 59, fig. 9 (reproduction of Toula's illustration), 1947 (Miocene, Florida). Natica (Stigmaulax) guppiana toulana Gardner, idem, p. 547, pi. 59, figs. 7, 8, 1947 (Miocene, Florida). Natica (Stigmaulax) guppyana Toula, Marks, Bull. Am. Pale- ontology, v. 33, no. 139, p. 98, 1951 (Miocene, Ecuador). Operculum (sp.?), Toula, K. k. Geol. Reichsanstalt Jahrb., Band 61, p. 511, pi. 31, fig. 26, 1911 (Miocene, Canal Zone). gastropods: trochidae to turritellidae 87 Not Natica guppyana Toula, Li, Geol. Soc. China Bull., v. 3, p. 266, pi. 6, fig. 46, 1930 (Miocene, Panama Bay; = Natica elenae R6cluz, fide Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 83, p. 432, 1931, Recent, Panama Bay). Large, thick shelled, spire low, whorls strongly- inflated and rapidly enlarging. Protoconch of 2)i to 2% whorls, apical whorl small. Sculpture of relatively widely spaced retractive axial grooves, parallel to growth lines, extending away from suture and generally ending at or above periphery. On some shells they extend to umbilical region, but not on last half of body whorl of large shells. Umbilicus very wide, umbilical rib rapidly enlarging, ending in a moderately wide callus lobe, the anterior part of which is concave on large shells and strongly excavated on shells of small and medium size. On shells of large and medium size a more or less distinct supplementary rib lies on um- bilical rib at its posterior border and may modify outline of callus lobe. Groove in front of umbilical rib and umbilical callus lobe moderately wide on large shells, narrow on others. Parietal callus very thick. Operculum dominated by very wide thick warty central rib. Marginal rib very narrow, denticulate. Several minor ribs, two of which generally are undercut along their inner margin, lie between marginal and central ribs. Outermost minor rib irregularly roughened. Height 33.5 mm, diameter 30.5 mm (figured large specimen with short axial grooves). Height 30.5 mm, diameter 29 mm (figured large specimen with axial grooves extending from suture to umbilical region on first half of body whorl). Type: Tech. Hochschule, Vienna (temporarily at Geol. Inst., Univ. of Berne, Switzerland). Type locality: Presumably Gatun Locks excavation, Canal Zone, middle part of Gatun formation. Stigmaulax guppiana is the most widespread and most abundant of the Gatun naticids and was found in the Chagres sandstone at the mouth of Rio Indio. All of the numerous large shells and many of medium size have one or more healed breaks on the body whorl. The more widely spaced axial grooves and the excavated umbilical callus lobe differentiate very young shells from very young shells of Natica stenopa. The sculp- ture is variable. Shells of large and medium size on which the axial grooves extend to the umbilical region are common only in the upper part of the Gatun forma- tion in the eastern area. Locality 155c is the only locality in the middle part of that formation where all the specimens collected have grooves extending to the umbilical region. No large shell has grooves extending to the umbilical region on the later half of the body whorl. Though the body whorl of some large shells shows indistinct microscopic spiral lineation, like that on some specimens of Natica canrena, there is no gross spiral sculpture. The supplementary umbilical rib is of variable strength, but is visible on shells of large and medium size. Opercula are not rare. They were collected at 11 localities, as many as 10 at a locality. A large shell having the operculum in place (pi. 20, fig. 18) was collected by T. F. Thompson. The only other in place is in a minute shell, which has a height of 1.5 millimeters (locality 147b). Details of opercular sculpture are variable, especially the number of minor ribs. The fine denticles on the veiy narrow marginal rib are obscure on some large opercula. That the thick callus of the warty central rib conceals flat minor ribs, like those adjoining the central rib on some opercula, is shown by the mergence of such ribs on 2 large opercula, (pi. 20, figs. 13, 18). Toula described a small operculum without realizing that it belongs to a species he had named. Forms of Stigmaulax closely related to the Recent Caribbean S. sulcata (Born) are found in Miocene for- mations in Jamaica, Haiti, the Dominican Republic, Puerto Rico, and Brazil. S. guppiana, however, is not one of them. It lacks gross spiral sculpture and is more closely allied to the Recent Panamic S. broderi- piana (Recluz), as pointed out by Olsson (1932, p. 207). S. broderipiana is smaller and has a less depressed suture. The opercula of the two species are similar, but the central rib of S. broderipiana has a narrow crest. S. elenae (Recluz), also a Recent Panamic species, is another close ally. It also has a less depressed suture and its axial grooves are in general more closely spaced. The single available operculum has a narrower central rib. The color pattern, however, is the most distinctive feature of S. elenae. S. guppiana is found in the Gurabo formation of the Dominican Republic. A close ally of S. sulcata also occurs in the Gurabo formation, but not at the same localities. This close ally of S. sulcata was recorded as S. vererugosum (Cossmann) (Woodring, 1928, p. 383) and has been named Natica sulcata gurabensis by Rutsch (1934, p. 52, pi. 2, fig. 10). S. guppiana also occurs in deposits of middle and late Miocene age in Florida. The collection from Shell Bluff on Shoal River (USGS 3742) consists of numerous specimens, all smaller than large shells from the Canal Zone. The collection also includes 3 opercula which agree with opercula of S. guppiana. Two specimens from locality 3742 that have short axial grooves were named Natica guppiana toulana by Gardner. This is the common form in the lower and middle parts of the Gatun formation, and the numerous Gatun collections show gradation in the length of the grooves. The single specimen (height 22 millimeters) from Vaughan Creek (USGS 12046) agrees closely with Gatun shells ss GEOLOGY AND PALEONTOLOGY OF CANAL ZONE of medium size that have grooves extending to the umbilical region. According to Tucker and Wilson, S. guppiana occurs in upper Miocene deposits at Acline, Florida. A large Stigmaulax from the late Miocene Punt a Gavilan formation of Venezuela has been described as Natica (Stigmaulax) sulcata beaumonti Rutsch (1934, p. 50, pi. 2, figs. 6-8, pi. 3, fig. 5). I am indebted to Dr. Rutsch for two topotypes of this form. It is allied to S. guppiana and may be considered a subspecies of S. guppiana. It is considerably larger than S. guppiana proper (height 42 millimeters), but even on these large shells the axial grooves continue to the umbilical region almost to the outer lip. This large form, S. guppiana beaumonti, and the typical form of S. guppiana in the Chagres sandstone are the last Caribbean allies of S. broderipiana. Occurrence: Lower, middle, and upper parts of Gatun formation (middle and late Miocene). Lower part localities 137, 137a, 138, 138a, Middle part, eastern area, localities 142, 146, 147 (identification doubtful), 147b, 147f, 147g, 147h, 150a, 151, 153, 153a, 155, 155b, 155c, 156, 157, 158 (identification doubtful); western area, localities 161, 161c, 161d. Upper part, eastern area, localities 172, 175, 176, 176a, 177a, 177b, 177c, 178; western area, localities 182, 182a, 183, 185. Chagres sandstone (early Pliocene), locality 208. Miocene, Falcon, Venezuela. Middle Miocene, Bolivar and Choco, Colombia. Daule formation (middle Miocene), Ecuador. Middle Miocene, northeastern Panama and Costa Rica. Miocene, Chiapas, Mexico. Shoal River formation (middle Miocene), Florida, Late Miocene deposits at Acline, Florida. Genus Tectonatica Sacco Sacco, Mus. Zoologia Anatomia Comparata R. Univ. Torino Bol., v. 5, no. 86, p. 33, 1890. Type (monotype): Tectonatica teclula Bors. (error for Bon.) (Natica teclula Bonelli), Miocene and Pliocene, Italy. Though the name Tectonatica lias been used for small tropical American species (Woodring, 1928, p. 384), that usage was not entirely satisfactory, because no specimens of the type species were examined. Through the kindness of John Q. Burch, of Los Angeles, a speci- men of Natica tectula identified by Sacco is now avail- able. It is larger than the small tropical American species (height 7 millimeters; maximum height 12 millimeters, according to Sacco) and the umbilical callus lobe docs not completely fill the umbilicus, leaving a narrow unfilled space, comparable to the narrower space of varying width on the small American "Natica" pusilla Say. In his later description of Tectonatica. Sacco (1891, ]>. 81) described the operculum as cal- careous. He, evidently was reiving on allied Recent species, as in Ins description of Natica tectula the operculum is not mentioned. Though the operculum of that species evidently is still unknown, there is no reasonable doubt that Tectonatica is an appropriate name for the small American species. The t} T pe of Cryptonatica (Dall, 1890-1903, p. 362, 1892; type (logotype, Dall, 1909, p. 85): Natica clausa Broderip and Sowerby) is a large arctic and boreal species, on which the umbilical callus lobe completely fills the umbilicus. Like the small species, it has a smooth calcareous operculum. When the anatomy of the large arctic and small tropical species is known, both names (Tectonatica and Cryptonatica) may be found to be useful. Tectonatica has been recognized in the Eocene of England (Wrigley, 1949, p. 14). Tectonatica species Two imperfect specimens record the occurrence of a small inflated species of Tectonatica in the late Eocene or early Oligocene strata of Trinidad Island. The unbilical callus lobe is preserved on the smaller specimen, but is absent (presumably dissolved) on the larger. The larger specimen has a more strongly bulging body whorl than T. agna of the Gatun forma- tion. T. floridana (Dall) (1890-1903, pt. 2, p. 366, pi. 17, fig. 5, 1892), of the early Miocene Tampa lime- stone of Florida, is more than three times as large and is more elongate. Heretofore T. floridana was the earliest recorded east American species. The larger specimen has the following dimensions: height 2.4 mm, diameter 2.6 mm. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), Gatun Lake area, locality 42. Tectonatica agna Woodring, n. sp. Plate 17, figure 46 Very small, strongly inflated, spire low or moderately low. Protoconch not clearly differentiated from re- mainder of shell, apical whorl small. Umbilical callus lobe thick, completely filling umbilicus, hearing a shallow central depression. Edge of umbilical callus lobe raised above level of umbilical border. Parietal callus thick. Operculum unknown. Height 2.8 mm, diameter 2.4 mm (type). Type: USNM 561 348: paratopes. Stanford Univ. Type locality: 147 b (USGS 6033c, Panama Rail- road, about 3,500 feet (1,065 meters) southeast of Gatun railroad station, ('anal Zone), middle part of Gatun formation. This minute Tectonatica, like many other small species from the Gatun formation, is abundant at locality 147b, the type locality. The shallow, but distinct, depression on the umbilical callus lobe is its gastropods: trochidae to turritellidae n<) most distinctive feature. On a few shells the suture on the last half of the body whorl descends more sharply than on the common form, producing a cor- respondingly higher spire. The more distinct depression on the umbilical callus lobe and the narrower groove at the outer edge of the lobe differentiate Tectonatica agna from T. pusilla (Say), which moreover is slightly larger. T. pusilla is the only fossil Tectonatica recorded from the Caribbean region (Woodring, 1928, p. 384, pi. 30, fig. 12). It now ranges from Massachusetts to Florida. A Recent West Indian species, possibly T. sagraiana (d'Orbigny) also lacks the callus depression. No Recent Panamic species is represented in the U. S. National Museum collection. Occurrence: Middle and upper parts of Gatun for- mation (middle and late Miocene). Middle part, eastern area, localities 146, 147b, 147f, 147g, 147h, 151, 153a. Upper part, eastern area, locality 177c; western area, locality 185 (identification doubtful). Subfamily POLINICINAE Genus Polinices Montfort Montfort, Conchyliologie systematique, v. 2, p. 223, 1810. Type (orthotype): Polinices albus Montfort (= Natica mamillaris Lamarck = Natica brunnea Link), Recent, West Indies. Incomplete and poorly preserved naticids from the Gatuncillo formation, the marine member of the Bohio(?) formation, and the Culebra formation are doubtfully referred to Polinices. The umbilical fea- tures of these fossils, most of which are molds, are not known. Polinices canalizonalis (Brown and Pilsbry) Plate 20, figures 7, 8 Natica canalizonalis Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 64, p. 508, pi. 22, fig. 10, 1913 (Miocene, Canal Zone). Of medium size, thick-shelled. Body whorl ap- pressed at suture, strongly inflated below appressed area. Aperture small for size of shell. Apical whorl small. Faint microscopic spiral lineation visible on unworn parts of shell. Umbilicus wide. Umbilical rib strong on immature shells, somewhat flattened on mature shells, ending in a wide callus lobe. Parietal callus very thick, bearing a shallow transverse groove. Height 21 mm, diameter 18.7 mm (figured mature specimen). Height 11 mm, diameter 10 mm (figured immature specimen). Type: Acad. Nat, Sci. Phila. 3844. Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation. Polinices canalizonalis is the least abundant of the three Gatun species of Polinices. It also is the only one of the three that has a conspicuous umbilical rib. The type is an immature shell (height 8.2 millimeters). The well-defined umbilical rib indicates alliance with a Recent Caribbean species labelled P. porcellanus (d'Orbigny) in the U. S. National Museum collection. The Recent species has a stronger rib and is less ap- pressed at the suture. P. carolinianus (Conrad) (Mansfield, 1930, p. 127, pi. 19, fig. 1), which occurs in the Duplin formation of North Carolina and in deposits of late Miocene age in western Florida, is larger, less appressed at the suture, and has a stronger rib. A late Miocene species from Trinidad, P. boutakoffi Rutsch (1942, p. 139, pi. 6, figs. 7a, 7b), belongs in this group of species characterized by a strong umbilical rib. According to Rutsch's illustrations, it is more inflated, less appressed at the suture, and has a deeper groove on the parietal callus. Occurrence : Lower middle, and upper parts of Gatun formation (middle Miocene). Lower part, locality 136a. Middle part, eastern area, Gatun Locks excava- tion (Brown and Pilsbry); western area, locality 161a. Upper part, eastern area, localities 177b, 177c. Polinices brunneus subclausus (Sowerby) Plate 20, figure 9 Natica subclausa Sowerby, Geol. Soc. London Quart. Jour., v. 6, p. 51, 1850 (Miocene, Dominican Republic). Polinices subclausa (Sowerby), Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 63, p. 360, 1911 (Miocene, Canal Zone). Maury, Bull. Am. Paleontology, v. 5, no. 29. p. 136, pi. 23, fig. 14, 1917 (Miocene, Dominican Republic). Olsson, idem, v. 9, no. 39, p. 157, pi. 13, figs. 16-17, 1922 (Miocene, Costa Rica, Canal Zone). Hodson, Hodson, and Harris, idem, v. 13, no. 49, p. 69, pi. 36, fig. 5, 1927 (Miocene, Jamaica). Anderson, Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 124, 1929 (Miocene, Colombia, Canal Zone). Polinices brunnea subclausa (Sowerby), Woodring, Carnegie Inst. Washington Pub. 385, p. 385, pi. 30, fig. 13, 1928 (Miocene, Jamaica) ; see this publication for other citations. IPolinices (Mammilla) cf. brunnea Link, Weisbord, Bull. Am. Paleontology, v. 14, no. 54, p. 29, pi. 9, fig. 12, 1929 (Miocene, Colombia). Of medium size, thick shelled. Whorls strongly and smoothly appressed at suture. Apical whorl small. Umbilicus moderately narrow; umbilical rib almost flat. Umbilical callus lobe narrow, slightly widened by um- bilical rib. Parietal callus very thick, bearing a shal- low transverse groove. Height 20.3 mm, diameter 16.7 mm (figured speci- men). Type material: British Mus., Natural History, Geol. Depart., Geol. Soc. London 12826 (6 syntypes). Type locality: Dominican Republic, Miocene. This Polinices is fairly common in the middle part of the Gatun formation at locality 161c, west of Gatun Dam, and occurs at other localities, all in the middle part of the Gatun formation. The groove on the 90 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE parietal callus is relatively deep on some small speci- mens. The largest Gatun shells are half as large as the largest from the Miocene of the Dominican Republic and Bowden, Jamaica (height 40 millimeters), and are much smaller than large specimens of the Recent Caribbean P. brunneus proper (height 50 millimeters). Like the Miocene fossils from the Dominican Republic and Jamaica, the Gatun fossils have a slightly narrower umbilicus than Recent shells of the same size. The fairly wide umbilicus of Weisbord's Polinices cf. P. brun- nea indicates, however, that the Miocene form cannot con- sistently be distinguished by the width of the umbilicus. Recent shells that are not worn show a faint micro- scopic spiral lineation, which has not been observed on the fossils from the Canal Zone, the Dominican Re- public, and Jamaica. The apparent absence of linea- tion on the fossils, however, may be due to slight wear. A small form of P. brunneus subclausus from the Miocene of Banana River, Costa Rica, has faint spiral lineation and also has a deep groove on the parietal callus, as shown by Olsson's illustrations. A form of P. brunneus subclausus that has a notch between the parietal callus and the umbilical callus lobe has been recognized in the Miocene of Venezuela and Jamaica, and has been named P. subclausa lavelana F. Hodson (Hodson, Hodson, and Harris, 1927, p. 69, pi. 36, fig. 8, pi. 37, figs. 12, 14). Polinices nelsoni Olsson (1932, p. 208, pi. 24, figs. 8, 10), which is more slender than P. brunneus and has a narrower umbilicus, is a late Miocene Peruvian rela- tive of P. brunneus, but no close allies are known to be living in the Panamic region. Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 155b, 155c; western area, localities 161 (immature, identification doubtful), 161c, 161d, 170 (immature, identification doubtful). Cercado and Gurabo formations (middle Miocene), Dominican Republic. Bowden formation (middle Mio- cene), Jamaica. Middle Miocene, Costa Rica. Mio- cene, Bolivar, Colombia. Polinices stanislas-meunieri Maury Plate 21, figures 11-14 Polinices stanislas-meunieri Maury, Bull. Am. Paleontology, v. 5, no. 29, p. 136, pi. 23, figs. 15-16, 1917 (Miocene, Domin- ican Republic). Olsson, idem, v. 9, no. 39, p. 157, pi. 13, fig. 7, 1922 (Miocene, Costa Rica). Maury, idem, v. 10, no. 42, p. 240, pi. 40, fig. 7, 1925 (Miocene, Trinidad). Anderson, Calif. Acad. Sci. Proc. 4th ser., v. 18, no. 4, p. 124, 1929 (Miocene, Colombia). Polinices stanislas-meunieri venezuelana F. Hodson, Bull. Am. Paleontology, v. 13, no. 49, p. 70, pi. 37, figs. 10, 15, 1927 (Miocene, Venezuela). Not Polinices stanislas-meunieri Maury, Li, Geol. Soc. China Bull., v. 9, p. 267, pi. 6, fig. 48, 1930 (Miocene, Panama Bay; =P. uber (Valenciennes) and P. rapulum limi Pilsbry, fide Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 83, p. 432, 1931, Recent, Panama Bay). Polinices springvalensis Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 241, pi. 40, fig. 6, 1925 (Miocene, Trinidad). Moderately large, moderately thick-shelled, moder- ately slender to strongly inflated. Whorls not appressed at suture, except near outer lip or on most of body whorl of large specimens. Apical whorl small. Microscopic spiral lineation distinct on unworn shells. Umbilicus and umbilical callus lobe narrow. Parietal callus moderately thick, much wider than umbilical lobe, bearing a faint to distinct transverse groove on im- mature shells. Height 43.5 mm, diameter 33 mm (figured large slender specimen). Height 32.5 mm., diameter 28 mm (figured inflated specimen). Type: Cornell University 36931. Type locality: Rio Cana, Dominican Republic, Gurabo (?) formation (middle Miocene) . Polinices stanislas-meunieri is the most widespread of the Gatun species of Polinices. It is locally common in the lower part of the formation, but many of the speci- mens are relatively slender, like that shown on plate 21, figure 14. The large figured specimen (pi. 21, fig. 13) was collected by T. F. Thompson. The umbilical rib is so flat that it is virtually absent. Therefore the narrow umbilical callus lobe widens very slightly. The umbili- cus is of varying width on immature shells, and is practi- cally closed on one from locality 136 (height 6 milli- meters) . The transverse groove on the parietal callus is absent on shells of large and medium size, and generally is faint on small shells. Differentiation of P. stanislas-meunieri venezuelanus appears to be unwarranted. P. springvalensis is a shouldered form of P. stanislas-meunieri, but is not much more strongly shouldered than the Gatun specimen shown on plate 21, fig. 12. The early Miocene Costa Rican P. eminuloides (Gabb) (1881, p. 339, pi. 44, fig. 4) probably is related to P. stanislas-meunieri. The type, and only specimen, is high spired; the umbilical area is not completely exposed; and the parietal callus is damaged. P. stanislas-meunieri is widely distributed in the Miocene of the Caribbean region, but has no living allies there. It is closely related, however, to the Recent Panamic P. uber (Valenciennes). P. stanislas- meunieri is not much more than half as large, but its parietal callus is thicker than that of specimens of P. uber of the same size, indicating maturity. The outline of P. stanislas-meunieri ranges from strongly and smoothly inflated to moderately slender, whereas that of P. uber is more uniformly strongly and smoothly inflated. gastropods: trochidae to turritellidae 91 P. coensis (Dall) (Mansfield, 1930, p. 124, pi. 17, fig. 8) , which occurs in deposits of late Miocene age in west- ern Florida, and P. robustus Gardner (1926-47, p. 550, pi. 59, figs. 5, 14, 1947), a middle Miocene form, are the representatives of P. stanislas-meunieri in the Miocene of Florida. P. coensis is smaller than the Caribbean species. It has a more distinct notch between the umbilical callus lobe and parietal callus, thicker parietal callus, and the transverse groove on the parietal callus persists to a later stage than on Gatun fossils. P. robustus, which perhaps is to be considered a large high- spired subspecies of P. coensis, closely resembles high- spired Gatun shells, but has a thicker parietal callus. P. coensis is the type of the subgenus Dallitesta Mans- field (1930, pp. 124, 125), which was proposed without any discussion of differentiating characters. Perhaps it was proposed because of the distinct spiral lineation. Should the genus Polinices be subdivided into sub- genera, Dallitesta would be available for species that have a narrow umbilicus, virtually no umbilical rib, narrow umbilical callus lobe, and distinct spiral lineation. There are, however, gradations from a strong umbilical rib, like that P. canalizonalis, to virtually none; and many species, including P. brunneus, the type of the genus, have more or less distinct spiral lineation. Occurrence: Lower, middle, and upper parts of Gatun formation (middle and late Miocene). Lower part, localities 136, 136a, 137, 138, 138a. Middle part, east- ern area, localities 140, 146 (immature, identification doubtful), 147b (immature, identification doubtful), 147g (immature, identification doubtful), 147h (im- mature, identification doubtful), 155, 155c (incomplete, immature, identification doubtful), 157, 159a; western area, localities 161, 161c. Upper part, eastern area, localities 171, 173 (incomplete, identification doubtful), 177b; western area, localities 182, 182a, 183, 185 (im- mature, identification doubtful). Middle Miocene, Costa Rica. Gurabo(?) formation (middle Miocene), Dominican Republic. Miocene, Bolivar, Colombia. Miocene, Falcon, Venezuela. Springvale formation (late Miocene), Trinidad. Genus Neverita Risso Risso, Histoire naturelle des principales productions de l'Europe meridionale, v. 4, p. 149, 1826. Type (monotype) : Neverita josephinia Risso, Recent, Mediter- ranean Sea. The Gatuncillo and Culebra formations, Emperador limestone member of the Culebra formation, and the La Boca marine member of the Panama formation yielded molds of low-spired naticids identified as Neverita? sp. A large low-spued naticid from the marine member of the Bohio(?) formation near Palen- quilla Point (diameter 39 millimeters), the umbilicus of which is not exposed, also is identified as Neverita? sp. Subgenus Glossaulax Pilsbry Pilsbry, Nautilus, v. 42, p. 113, 1929. Type (orthotype) : Neverita reclusiana (Deshayes) (Natica reclusiana Deshayes), Recent, southern California to Gulf of California. The subgenus Glossaulax embraces neverites that have a groove on the umbilical callus, dividing it into anterior and posterior lobes. The groove of the type species is located on the anterior part of the callus. Glossaulax is widely distributed on both sides of the northern Pacific and is represented in the Eocene of western North America by a typical species, N. secta Gabb, which Stewart (1927, p. 325) suggested may be treated better as a subspecies of N. reclusiana. This subgenus formerly had a more extensive distribution. It is represented in the Eocene of southeastern United States by N. limula (Conrad) (Palmer, 1937, p. 125, pi. 13, figs. 13, 14, 16, 19-22, pi. 80, figs. 13, 16), in the Eocene of the Caribbean region by N. bolivarensis Clark, and in the Eocene or Oligocene of Peru by N. subreclusiana (Olsson). These early Tertiary species are hardly typical, as the umbilical callus groove is not consistently present. Typical species, however, men- tioned under N. reclusiana xena, are found in the Miocene of Florida and the Caribbean region. Neverita (Glossaulax) bolivarensis tapina Woodring, n. subsp. Plate 15, figures 7, 8, 11 Of medium size, depressed, conical. Umbilical callus partly filling umbilicus, the wide unfilled space decreas- ing in width toward parietal callus, but extending to junction of umbilical and parietal callus. Parietal callus set off from umbilical callus by a faint groove. Posterior part of umbilical callus bearing a faint groove. Umbilical wall faintly striate. Height 14.5 mm, diameter 19 mm (type). Height 16.5 mm, diameter 26.5 mm (largest specimen). Type: USNM 561354. Paratype, USNM 561442. Type locality: 40d (USGS 6028a, Gatun Lake area, lower bed at Vamos Vamos, off Palenquilla Point, Canal Zone, now submerged), marine member of Bohio(?) formation. Though Neverita bolivarensis tapina is represented by 12 specimens from the marine member of the Bohio(?) formation, only a few show the callus features. The callus is completely exposed on the type and paratype, both of which have a relatively wide unfilled umbilical space, a faint groove between the umbilical and parietal callus, and a faint groove on the posterior part of the umbilical callus. The groove on the umbilical callus of the type probably is modified by an artificial crack. The paratype has a shallow groove that disappears before reaching the umbilical border. Enough of the umbilical callus is exposed on two other specimens to 92 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE show that a considerable part of the umbilicus is not filled. This neverite is considered a subspecies of N. boli- varensis Clark (Clark and Durham, 1946, p. 16, pi. 15, figs. 10, 11, 14, 15, 18-20, 22, 26)— a subspecies charac- terized by its depressed outline and wide umbilical space gradually tapering toward the parietal callus. The specimen of N. bolivarensis proper shown by Clark on plate 15, figure 11, is depressed and has a wide umbilical space. The umbilical space, however, separates the callus from the entire umbilical wall. N. bolivarensis proper occurs in the late Eocene of Colombia. It and the subspecies from Panama are related to N. sub- reclusiana (Olsson) (1931, p. 68, pi. 10, figs. 1, 4), of the late Eocene or early Oligocene Chira shale of Peru. That species has a high spire and practically filled umbilicus. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), Gatun Lake area, localities 40, 40a, 40d, 41 (immature). Neverita (Glossaulax) reclusiana xena Woodring, n. subsp. Plate 21, figures 5, 8, 9 Of medium size, generally low spired. Spiral linea- tion visible on umbilical wall, but not elsewhere, pre- sumably due to slight wear. Posterior lobe of umbilical callus longer than anterior lobe, reaching umbilical wall. Space between umbilical wall and anterior lobe of umbilical callus narrow or very narrow. Height 25 mm, diameter 27 mm (type). Height 34 mm, diameter (incomplete) 35 mm (figured large high- spired specimen). Type: USNM 561355; paratypes, Stanford Univ. Type locality: 137 (USGS 16911, Transisthmian Highway, 1.7 kilometers northwest of Sabanita, Pana- ma), lower part of Gatun formation. Neverita reclusiana zena is based on 12 specimens from the lower part of the Gatun formation and one from the middle part. It is remarkably similar to a small form of N. reclusiana (Deshayes) found along the outer coast of Baja California and along the Gulf of Cali- fornia. The Gatun neverite in general has a narrower space between the umbilical wall and the anterior callus lobe. Some small Recent shells, however, are practically indistinguishable from the fossils. This Mexican form has been listed as a variety of N. re- clusiana (Pilsbry and Lowe, 1932, p. 126), but its status is not yet satisfactorily determined. Typical species of Glossaulax are found in the Miocene of Florida and the Caribbean region: N. chipolana (Dall) (Gardner, 1926-47, p. 551, pi. 59, fig. 22, 1947; Chipola formation, Florida), N. subporcana (F. Hodson) (Hodson, Hodson, and Harris, 1927, p. 70, pi. 36, fig. 3, pi. 37, figs. 5, 9, 16; Miocene, Venezuela), and A 7 . cuspidata (Guppy) (Maury, 1925, p. 239, pi. 40, figs. 9, 10; Putsch, 1942, p. 140; Springvale formation, Trinidad). N. chipolana has a short anterior callus lobe; N. subporcana has a narrow anterior lobe and the posterior lobe leaves part of the umbilicus unfilled; N. cuspidata is very large (height 60 mm) and has short subequal lobes. There are no living species of Glossau- lax in the Caribbean Sea or elsewhere in the western Atlantic. The late Miocene N. cuspidata is the last Caribbean species. Inasmuch as N. reclusiana has a long history in the eastern Pacific going back to the Miocene, if not earlier, N. reclusiana xena evidently is a migrant from the Pacific. The present distribution of N. reclusiana and its allies, which are not found south of the Gulf of California, shows a marked reduction since Miocene time. Occurrence: Lower and middle parts of Gatun for- mation (middle Miocene). Lower part, localities 136a, 137, 137a. Middle part, eastern area, localit}' 155. Subgenus Hypterita Woodring, n. subgen. Type: Nalica helicoides Gray, Recent, Baja California to Peru. Hypterita is proposed for neverites that are greatly depressed, and have a very wide umbilicus with gently sloping wall, a thin umbilical callus lobe perched on a narrow or moderately wide umbilical rib, and a very thin wash of parietal callus. This well defined group of neverites includes only two known species: the type species and the Miocene Caribbean Neverita nereidis. The type species is generally known as Neverita glauca (Lesson). Neverita (Hypterita) helicoides (Gray) Plate 18, figures 15, 16 Nalica patula G. B. Sowerby, Zool. Jour., vol. 1, p. 60, pi. 5, fig. 4, 1824 (Recent, locality unknown, but another specimen cited as South American). Barnes, Lyceum Natural History New York Annals, vol. 1, p. 136, 1824 (Recent, Peru). Not Nalica patula J. Sowerby, 1822. Nalica helicoides Gray, Zool. Jour., vol. 1, p. 511, footnote, 1825 (cited as manuscript name of Barnes). Nalica glauca "Humboldt", Lesson, Voyage autour du monde * * la Coquille * *, Zoologie, vol. 2, pt. 1, p. 369, pi. 11, figs. 1, 1', 1830 (Recent, Peru). Nalica bonplandi Valenciennes, in Humboldt, and Bonpland, Voyage aux regions equinoxiales du nouveau continent, pt. 2, Recueil d'observations de zoologie, vol. 2, p. 264, pi. 57, figs. 3a, 3b, 1832 (Recent, Acapulco, Mexico; not seen). ? Neverita nereidis Maury, Olsson, Bull. Am. Paleontology, vol. 9, no. 39, p. 158, 1922 (Miocene, Costa Rica). Polinices (Neverita) glauca Humboldt, Olsson, idem, vol. 27, no. 106, p. 20 (list), 1942 (Pliocene, Costa Rica). Polinices helicoides (Gray), Hertlein and Strong, Am. Mus. Natural History Bull., vol. 107, art. 2, p. 287, 1955 (Recent, Baja California to Peru; see this publication for other citations) . gastropods: trochidae to turritellidae 93 Of medium size. Microscopic spiral lineation of fresh Recent shells not apparent, presumably due to slight wear. Umbilical rib narrow, slowly enlarging; unfilled umbilical space wide. Height (incomplete) 16 mm, diameter (incomplete) 34 mm (figured specimen). The Gatun formation yielded three incomplete fossils that closely resemble Recent shells of Neverita helicoides of medium size. The largest fossil, if it were complete, would have a diameter of about 45 millimeters. The largest Recent shells of N. helicoides in the U. S. National Museum collections have a diameter of between 55 and 60 millimeters. Slightly worn Recent shells do not show the very fine slightly wavy micro- scopic lineation of fresh shells. Neverita nereidis Maury (1917, p. 137, pi. 23, figs. 17, 18), which occurs in the Cercado formation of the Dominican Republic, is closely allied to N. helicoides. Like the Gatun fossils, it is smaller than N. helicoides (diameter 35 mm). Moreover it has a wider umbilical rib than the Recent species. However remarkable it may be to recognize two very closely related species of Hypterita in the Miocene of the Caribbean region, the Gatun fossils are identified as N. helicoides on the basis of their narrow umbilical rib. The fragment from the Miocene of Banana River, Costa Rica, identified by Olsson as N. nereidis, is not accessible at the present time. A fragment from that area, however, in the collections of the U. S. National Museum has a narrow umbilical rib and is doubtfully identified as N. helicoides. Gray's name is far from satisfactory. He cited it as Barnes' manuscript name, a name that was still-born so far as Barnes' mention of it is concerned. Unfor- frunately the name, as Gray's name, is nomenclaturally available and therefore, as pointed out by Hertlein and Strong, replaces the well known name Neverita glauca. Occurrence: Lower and middle parts of Gatun for- mation (middle Miocene). Lower part, locality 136a. Middle part, eastern area, locality 155b; western area, locality 161c. Middle Miocene, eastern Costa Rica (identification doubtful). Pliocene, western Costa Rica. Recent, Magdalena Bay, Baja California, and Gulf of California to Peru. Subfamily SININAE Genus Sinum Roding Roding, Museum Boltenianum, pt. 2, p. 14, 1798. Type (logotype, Dall, U. S. Natl. Mus. Bull. 90, p. 109, 1915): Helix haliotoidea Linne (cited by Roding as Helix halioloidea Gmelin), Recent, western Pacific(?). The collections from the Gatuncillo formation, the marine member of the Bohio(?) formation, and the 413788—57 7 Caimito and Culebra formations include unidentified species of Sinum, represented by poorly preserved speci- mens. The Culebra Sinum may be the species from the Anguilla formation, of the island of Anguilla, re- corded as Sinum chipolanum (Dall) (Cooke, 1919, p. 124, pi. 5, figs. 6a, 6b), but the species so identified is smaller and more depressed than S. chipolanum. A species from the Gatun formation, Sinum gatunense (Toula) (1909, p. 697, pi. 28, figs. 3a, 3b, 3c) is not represented in the collections examined. It was com- pared by Toula with the Recent West Indian S. per- spectivum (Say) and, according to his illustrations, is closely related to that species and the Recent Panamic S. noyesi Dall. Toula's species is greatly depressed and has a very narrow base. S. gatunense has been recog- nized in the Cercado formation of the Dominican Republic (Maury, 1917, p. 138, pi. 24, fig. 2) and in the Bowden formation of Jamaica (Woodring, 1928, p. 390, pi. 31, figs. 3, 4). S. dodonum Gardner (1926^7, p. 554, pi. 59, figs. 37, 39, 1947), of the Oak Grove sand member of the Shoal River formation of Florida, probably is a large form of S. gatunense. Though Toula's illustration shows no faint spirals on the base, some specimens of the species from the Dominican Republic and Jamaica identified as S. gatunense have faint basal spirals like those on the type of S. dodonum. Sinum euryhedra Woodring, n. sp. Plate 21, figures 4, 7, 10 Sinum species, Woodring, Carnegie Inst. Washington Pub. 385, p. 390, 1928 (Miocene, Jamaica). Of medium size, moderately depressed, base relatively very wide. Protoconch consisting of about lji smooth whorls. Spire whorls and body whorl between peri- phery and suture sculptured with spiral bands, sepa- rated by grooves that, for the most part, are of about same width as the bands, but near suture are twice as wade as the bands. Base smooth except for exagger- ated growth lines. A narrow groove lies behind pos- terior part of everted columellar lip. Height (incomplete, spire crushed) 11 mm, diameter (incomplete) 27 mm (type). Type: USNM 561441. Type locality: 137a (Stanford University locality 2655, Transisthmian Highway, 1.7 kilometers north- west of Sabanita, Panama; same as USGS 16911), lower part of Gatun formation. The type, an incomplete and somewhat crushed speci- men collected from the lower part of the Gatun forma- tion by T. F. Thompson, is the only representative of this species. It is characterized by moderate depres- sion, wide base, and strong sculpture. Owing to crush- ing, the spire is too low in apertural aspect (pi. 21, fig. 4). 94 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE There are no known close allies of this species in Caribbean and Panamic waters. S. macuLatum (Say), a Recent Floridian and West Indian species, has a narrower base, thinner columellar lip and parietal callus, and weaker sculpture. The small incomplete Sinum from the Miocene of Jamaica, so far as it goes, has the characters of S. euryhedra. Occurrence: Lower part of Gatun formation (middle Miocene), locality 137a. Bowden formation (middle Miocene), Jamaica. Sinum gabbi (Brown and Pilsbry) Plate 21, figures 3, 6 Sigaretus (Eunalicina) gabbi Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 64, p. 509, pi. 22, fig. 13, 1913 (Miocene, Canal Zone). ISinum quirosanum F. Hodson, Bull. Am. Paleontology, v. 13, no. 49, p. 67, pi. 36, figs. 10, 12, 1927 [Miocene (Oligocene- Miocene of Hodson), Zulia, Venezuela]. Reaching a large size, not depressed, body whorl strongly inflated. Spire low or relatively high. Proto- conch of 2%. smooth slowly enlarging whorls. Sculpture of narrow closely spaced spiral threads of two or three orders. Spirals of early whorls variably crinkled by growth lines. A very narrow umbilical groove lies behind posterior part of everted columellar lip of adult shells. Immature shells umbilicate. Height 23 mm, diameter 23 mm (figured specimen). Height 27 mm, diameter 24 mm (largest complete specimen). Estimated diameter 35 mm (largest speci- men, incomplete). Type: Acad. Nat. Sci. Phila. 3845. Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation. The type is a very small shell 6.5 millimeters high. The largest complete specimen (height 27 mm), col- lected at locality 175, has a higher spire than the others, but is associated with a smaller low-spired shell. That this species reaches a considerably larger size is shown by half of a body whorl (locality 176), which indicates a diameter of about 35 millimeters. The Venezuelan S. quirosanum is small, agreeing with S. gabbi in outline and sculpture, and may represent a small early Miocene race of S. gabbi. S. nolani Maury (1917, p. 139, pi. 24, fig. 1), a species that occurs in the Gurabo formation of the Dominican Republic, is more inflated than S. gabbi. S. gabbi is a nondepressed species related to the Recent Peruvian £. concavum (Lamarck), the largest species of the genus (height 48 mm). The fossils, except the high-spired specimen, have a similar outline, but have spirals of less uniform width. No similar species is living in the western Atlantic. Occurrence: Middle and upper parts of Gatun forma- tion (middle Miocene). Middle part, eastern area, localities 1476, 155, 155a, 155b, 155c (very small), 157. Upper part, eastern area, localities 175, 176, 177c. Subfamily GLOBULARIINAE Data concerning the anatomy of Cernina fluctuata (Sowerby), the only surviving globularine, are desirable as a basis for consideration of the subfamily or family status of that species and its numerous fossil allies. Wrigley (1946, p. 88) has proposed a useful termi- nology for features in the umbilical region and on the columellar lip of globularines. The sheath (the limbe of French authors and the callus or fasciole of American authors) is the shell layer emerging from the umbilicus of umbilicated species. Its outer edge is designated the rim. The downward extension of the parietal callus, overlapping the sheath, is designated the lobe of the columellar border, or simply the lobe. The outer edge of the lobe, where it overlaps the sheath below the umbilicus, is either fairly sharp or indefinite. The sheath of some nonumbilicated species, such as Globularia sigaretina (Lamarck), is as well defined as that of umbilicated species, but the umbilicus is repre- sented only by a slight depression at the posterior end of the sheath, formed by the outer edge of the lobe. On other nonumbilicated or narrowly umbilicated species a sheath is not recognizable. If present, it is concealed by the lobe, which forms an everted columellar lip that has an outer edge as sharp as a rim. Genus Globularia Swainson Swainson, A treatise on malacology, p. 345, 1840. Type (logotype, Herrmannsen, Indicis generum malacozoorum, v. 1, p. 480, 1847): Natica sigaretina Lamarck, Eocene, Paris basin. Subgenus Globularia s.s. Globularia (Globularia) aff. G. fischeri (Dall) Plate 15, figures 9, 17, 18 Moderately large, weakly shouldered, greatly inflated. Spire low, turreted. A narrow sloping shelf lies be- tween suture and shoulder. Aperture greatly expanded. Sheath moderately wide on immature specimens. Pos- terior part of lobe well defined on immature specimens. Umbilicus closed. Height (almost complete) 35.5 mm, diameter 31 mm (large figured specimen). Height 18.5 mm, diameter (incomplete) 15.5 mm (small figured specimen). This greatly inflated Globularia, represented by more or less incomplete and poorly preserved specimens from the middle member of the Caimito formation of the Gatun Lake area and the Culebra formation, is closely related to Globularia fischeri (Gardner, 1926-47, p. 556, pi. 59, fig. 28, 1947). G. fischeri occurs in the Chipola gastropods: trochidae to turritellidae 95 formation of Florida. Young shells of G. fischeri, up to a height of 13 millimeters, are narrowly umbilicated. With further growth the umbilicus is closed and the outer edge of the lobe is less well defined. A large in- complete specimen (diameter 60 mm) of G. fischeri has a very wide sheath, apparently almost completely covered by the thin lobe. Characters distinguishing the moderately large G. anguillana (Cooke) (1919, p. 123, pi. 4, figs. 9a, b; Anguilla formation, Anguilla) from G. fischeri are not evident. The type of G. anguil- lana has a very wide sheath ; the umbilicus apparently is closed. G. streptostoma (Heilprin) (Dall, 1915, p. 107, pi. 12, fig. 27), from the Tampa limestone of Florida, like young shells of G. fischeri, is narrowly umbilicated. The umbilicus persists, however, on the largest avail- able specimen (height 30 millimeters). G. fischeri is the youngest Globularia in southeastern United States. In the Caribbean region the last repre- sentatives of the genus are found in slightly older strata: the Anguilla formation and its equivalents, which are correlated with the Tampa limestone. Occurrence: Middle member of Caimito formation (late Oligocene), Gatun Lake area, localities 56, 57, 57a. Culebra formation (early Miocene) Gaillard Cut, localities 99g (Globularia? cf. G. fischeri), 100b. Subgenus Ampulella Cox Cox, Royal Soc. Edinburgh Trans., v. 57, p. 38, 1931. Type (orthotype): Ampullaria depressa Lamarck, Eocene, Paris basin. Ampulella, typical Ampullina of former usage, lacks the greatly expanded aperture and body whorl of Globularia s.s. Globularia (Ampulella) species Plate 15, figure 13 Small, weakly shouldered, strongly inflated. Spire low, turreted. A narrow sloping to slightly concave shelf lies between suture and shoulder. Faint micro- scopic lineation visible on some specimens. Aperture moderately expanded. Umbilicus narrow. Sheath moderately wide. Lobe narrow, its outer edge indefi- nite below umbilicus. Height (incomplete) 21 mm, diameter (modified by dorso-ventral crushing) 19.3 mm (figured specimen). This small Globularia, evidently a new species, is represented by poorly preserved fossils from the marine member of the Bohio(?) formation of the Gatun Lake area. The umbilicus is not exposed on the figured specimen and the upper part of the sheath is missing. The outline suggests the Eocene Paris basin species Globularia parisiensis (d'Orbigny), which occurs also in the late Eocene and early Oligocene of England (Wrigley, 1946, p. 92, figs. 6, 9). G. parisiensis, how- ever, has a wider sheath and axially arranged micro- scopic punctae. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene) Gatun Lake area, localities 40a, 40d, 41. Globularia (Ampulella?) nana Woodring, n. sp. Plate 15, figures 3, 4 Very small, strongly inflated. Spire high, faintly turreted. Upper part of body whorl sculptured with faint microscopic spirals, lower part with widely spaced spiral grooves. Umbilicus practically closed. Sheath not recognizable. Lobe forming a very wide everted columellar lip. Height (not quite complete) 7 mm, diameter 5 mm (type). Type: USNM 561361. Type locality: 42 (USGS 17692, northeast coast of Trinidad Island, Canal Zone), marine member of Bohio(?) formation. This minute globularine is fairly common in the Bohio(?) formation of Trinidad Island and occurs in the same formation near Palenquilla Point. The very wide everted columellar lip — that is, very wide for the size of the shell — widely spaced spiral grooves on the lower part of the body whorl, and minute size indicate that it represents an unnamed minor subdivision of Globularia or Ampulella. Amaurellina garzaensis Vokes (1939, p. 173, pi. 22, figs. 9, 12, 16), a middle Eocene species from California, is of comparable size, but has a narrower columellar lip and relatively strong, evenly spaced spiral grooves. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), Gatun Lake area, localities 41, 42. Genus Amaurellina Fischer? Fischer, Manuel de conchyliologie, p. 766, 1885. Type (monotype): Ampullina spirata (Lamarck) (Ampullaria spirata Lamarck), Eocene, Paris Basin. Amaurellina? species Plate 14, figure 4 Molds from limestone of the Gatuncillo formation are doubtfully referred to Amaurellina. They are large, strongly inflated, shouldered, and have a mod- erately high turreted spire. The wide space between the shoulder and the preceding whorl indicates a wide shelf or channel adjoining the suture. Height (incomplete) 53 mm, diameter 52 mm (largest specimen). Height (incomplete) 46 mm, diameter 38 mm (figured specimen). If these molds represent an Amaurellina, it is an exceptionally large species. 96 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Occurrence: Gatuncillo formation (late Eocene), Madden basin, localities 9, 12, 15. Genus Pachycrommium Woodring? Woodring, Carnegie Inst. Washington Pub. 385, p. 391, 1028. Type (orthotype): Amaura guppyi Gabb, Miocene, Dominican Republic. Pachycrommium? solenaeum Woodring, n. sp. Plate 1 l, figure 1 Of medium size, shouldered, moderately inflated. Spire high, turreted. A narrow channel adjoins suture. Aperture short. Sheath narrow, rim low. Posterior pari of sheath overlapped by narrow lobe, which becomes low and unrecognizable anteriorly. Umbilicus closed. Height (not quite complete) 32.5 mm, diameter (somewhat crushed) 22 mm (type). Type: USNM 561364. Type locality: 38 (USGS 17166, Rio Casaya area, Quebrada de Oro, a northwestward-flowing tributary of Rio Casaya, 3.3 kilometers southeast of east end of Gamboa bridge, Canal Zone), Gatuncillo formation. The type (and only specimen) of this species is a silicified fossil from the Gatuncillo formation. The owl line of body whorl and aperture is somewhat dis- torted by lateral crushing. The replacing silica is granular. The generic assignment of this species is doubtful. The type of Pachycrommium, has a gently sloping shelf between the suture and the shoulder, and a more elongate aperture. Moreover, sheath and lobe can be distinguished only on immature specimens, the lobe of mature shells forming a wider and more strongly edged everted columella]- lip than that of Pachycrommium? so- lenat um . Nevertheless a species that appears to be prop- erly referred to Pachycrommium has a channel adjoining the suture and separation of sheath and lobe evidently depends on growth stage. "Amauropsis" burnsii meri- dianalis Pilsbry (1922, p. 387, pi. 34, figs. 23, 24; Miocene, Dominican Republic), which is discussed under Pachycrommium? cf. P. trinitatensis (p. 97), has a channel adjoining the suture. Lobe and sheath are well defined on the posterior part of the sheath on the only specimen in the U. S. National Museum, but not on the type, according to Pilsbry 's illustration. Eocene high-spired globularines from America and other regions have been referred to Pachycrommium. It is doubtful, however, how many of them including species mentioned when the generic name was proposed, as noted by Palmer (1937, p. 136-137) — are closely related to / 'achycrommium g uppyi. Occurrence: Gatuncillo formation (middle Eocene), Rio Casaya area, locality 38. Pachycrommium? proinum Woodring, n. sp. Plate 15, figure 12 L a liia perovata (Conrad), Dall in Hill, Mus. Comp. Zool. Harvard College Bull., v. 28, p. 273, 1898 (list; Eocene, Canal Zone). Brown and Pilsbry, Acad. Nat. Sci. Philadelphia Proc. v. 63, p. 360, 1911 (Dall's record). Of medium size, shouldered, strongly inflated. Spire high, turreted. Whorls sloping from suture to shoulder. Aperture elongate. Sheath narrow, for most part not preserved. Lobe narrow, imperfect. Umbilicus closed. Very faint microscopic .spiral lineation visible on some specimens on and near shoulder. Type and two other specimens show narrow retractive dark axial bands. Height (incomplete) 26 mm, diameter 19 mm (type). Height (not quite complete) 35 mm, diameter 22 mm. Type: USNM 135200. Type locality: 40a (USGS 2683, Vamos Vamos, off Palenquilla Point, Canal Zone, now submerged), marine member of Bohio(?) formation. Though this globularine is represented by 15 speci- mens collected at Vamos Vamos and at locality 41 near Plaenquilla Point, none completely shows the columellar lip. The lobe is shown on five specimens, on all of which it is narrow, and an imperfect narrow sheath is visible on the type. Dark axial bands are well shown on the body whorl of three specimens. They may possibly indicate axial bands differing in shell texture rather than color bands. Incomplete as these fossils are, they suggest a Pachycrommium that is less inflated than P. guppyi and has whorls characterized by a steeper slope between the suture and the shoulder. Dall identified this globularine as the Claiborne (middle Eocene) species "Lupia" perovata (Conrad), an identification that doubtless had much influence on his conclusion that the strata at Vamos Vamos, and by inference at Gatun, are Eocene. "Lupia" perovata has a higher less turreted spire. In outline of whorls Pachycrommium? proinum is more similar to the Jackson (late Eocene) species "Amauropsis" jacksonensis Harris, which, like "Lupia" perovata, has a higher spire. Mansfield's (1940, p. 222, pi. 27, fig. 44) late Oligocene Pachycrommium sp., from the lower part of the Chicka- saw hay marl of Alabama, is less inflated than the species from Panama and has a higher spire. Pachycrommium? proinum is closeh* related to Pseudocrommium gabrielensis Clark (Clark and Dur- ham, 1946, p. 19, pi. 16, figs. 14, 15), from the late Eocene of Colombia, but is smaller and has a more turreted spire. The paratype of Pseudocrommium gabrielensis has indistinct alternating dark and light axial bands. Pseudocrommium carmenensis Clark (Clark and Durham, 1946, p. 19, pi. 16, fig. 7) evidently is conspecific with /'. gabrielensis. gastropods: trochidae to turritellidae 97 Both "Lupia" perovata and "Amauropsis" jackson- ensis have been considered high-spired species of Crommium (Palmer, 1937, p. 136, pi. 14, figs. 5, 9; Harris and Palmer, 1946-47, p. 256, pi. 30, fig. 5, 1947). Should the names Euspirocrommium or Pachy- crommium prove to be inappropriate for tbese high- spired species that evidently are related to Crommium, Pseudocrommium (Clark, in Clark and Durham, 1946, p. 18; type (orthotype): Pseudocrommium carmenensis Clark), based on a late Eocene species from Colombia, is available for them and has recently been used for them (Richards and Palmer, 1953, p. 27). Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), Gatun Lake area, localities 40a, 40b, 40d, 41. Pachycrommium? cf. P.? trinitatensis (Mansfield) Plate 16, figure 11 Large, shouldered, strongly inflated. Spire high, tur- reted. Aperture moderately elongate. Other aper- tural features unknown. Height (incomplete) 50 mm, diameter (exaggerated by crushing i 39 mm (figured specimen). Molds of a large high-spired globularine, which occur in the middle member of the Caimito formation in the Gatun Lake area and in the Culebra formation, resemble the type of " Amauropsis " trinitatensis (Mansfield, 1925, p. 58, pi. 10, figs. 4, 5). The type of that species is a mold from early Miocene strata in Trinidad. Mansfield's (1937, p. 177, pi. 9, fig. 7) "Amauropsis" afl*. "A." burnsii meridionalis Pilsbry, a late Oligocene form represented by molds from Georgia and Florida, also resembles the type of "Amauropsis" trinitatensis. "Amauropsis" burnsii meridionalis (Pilsbry, 1922, p. 387, pi. 34, figs. 23, 24) occurs in the Miocene of the Dominican Republic. Despite its wide deep channel adjoining the suture, it appears to be a Pachycrommium. Mansfield's (1940, p. 223, pi. 27, fig. 8) late Oligocene 1 :hycrommium? sp., a mold from the lower part of Chickasawhay marl, has a similar sutural channel, but is larger and has a higher spire. Though "Amauropsis" burnsii meridionalis has a sutural channel like that of the Chipola species "Polinices (Amauropsis)" burnsii Dall (Gardner, 1926-47, p. 557, pi. 59, fig. 12, 1947), a close relationship between the two forms is doubtful. The Chipola species has a wide expanded aperture and thickened outer lip. It is a remarkable globularine. If the unknown apertural features of both "Amaurop- sis" trinitatensis and the fossils from Panama could be ignored, the fossils from Panama would be unequivo- cally identified as the Trinidad species. The outline of the figured mold is distorted by dorso-ventral crushing. Should "Amauropsis" trinitatensis prove to be a Pachycrommium, it would be the largest species of the genus. "Nalica" phasianelloides d'Orbigny [1852(?), p. 9, pi. 1, fig. 7] may be an earlier name for it. Occurrence: Middle member of Caimito formation (late Oligocene), Gatun Lake area, locality 60. Culebra formation (early Miocene), Gaillard Cut, locality 108c. Pachycrommium? cf. P. guppyi (Gabb) Plate 16, figure 12 Of medium size, strongly inflated, strongly shouldered. Spire high, strongly turreted. Gently sloping shelf extends from suture to shoulder. Apertural features unknown. Height (not quite complete) 27 mm, diameter 21.5 mm (figured specimen). The Culebra formation yielded three incomplete high-spired globularines. The most nearly complete specimen, which is figured (and probably also the other two) is comparable in outline to the strongly shouldered form of Pachycrommium guppyi (Pilsbry, 1922, p. 386, pi. 34, figs. 25-27). P. guppyi occurs in the early Miocene Baitoa formation of the Dominican Republic and also in the middle Miocene Cercado and Gurabo formations. Mansfield (1937, p. 174) considered "Amauropsis" Jloridana Dall (1915, p. 108, pi. 5, fig. 11), a small Pachycrommium from the early Miocene Tampa limestone of Florida, to be indistinguishable from P. guppyi. P. floridanum, however, has a more expanded aperture and correspondingly more inflated body whorl. The middle Miocene Oak Grove form, P. dodonum Gardner (1926-47, p. 557, pi. 59, figs. 4, 13, 1947), agrees with the strongly shouldered form of P. guppyi. Though Pachycrommium guppyi occurs in formation correlated with the Gatun formation, the genus has not been found in the Gatun formation. Pachycrommium? cf. P. guppyi is the youngest of the high-spired globu- larines in the Canal Zone. Occurrence: Culebra formation (early Miocene"). Gaillard Cut, localities 112, 115a. Family TURRITELLIDAE Genus Turritella Lamarck Lamarck, Soc. Histoire Nat. Paris Mem., p. 74, 1799. Type (monotype): Turbo terebra Linne, Recent, tropical western Pacific. Turritella occurs in all marine formations of the Canal Zone and adjoining parts of Panama, except the Chagres sandstone proper. The number of forms therefore is large: 17 species and 3 subspecies. The Gatun formation, which contains 6 species and 2 named minor forms, has the largest number of species. Not more than 4 species, however, were found in the Gatun formation at any one locality. 98 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE The importance of the sculpture of the early whorls and the growth line in a study of the affinities of turri- tellas was emphasized by Merriam in his monograph of fossil turritellas from the Pacific coast of North America. His term "growth-line angle" (Merriam, 1941, p. 59) is adopted for the angle between the axis of the shell and a line extending from the posterior end of the growth line to the anterior end on spire whorls, or to the apex of the forward bend, if such a bend is present near the anterior suture. Merriam pointed out that among the several hundred described species of Turritella, groups of closely allied species are as distinctive as groups of species in other families — groups that are given generic and subgeneric rank in other families. Nevertheless he was reluctant to assign superspeeific names to the groups of species he recognized, as suitable material for consideration of many of the superspeeific names proposed for turritellids was not available to him. He therefore grouped his species into stocks named for a typical species (Merriam, 1941, p. 33-55). At an earlier date Guillaume (1924) classified European Tertiary species in groups, also named for a typical species. Merriam's stocks, how- ever, are more restricted than Guillaume's groups and afford a much better basis for a satisfactory classifica- tion. Guillaume relied on the growth line, ignoring the development of the sculpture and other features. Though no exhaustive study has been attempted, only one subgenus of turritellas from the Canal Zone and adjoining parts of Panama appears to have a suit- able name: Torcula; in fact, two names (Torcula and Bactrospira) are available for that subgenus, which corresponds to Merriam's T. altilira stock. Subgenus? (?Guillaume's T. hybrida group, in part) Turritella cf. T. carinata Lea Plate 14, figure 2 Moderately large, moderately slender. Whorls slightly concave, the profile modified by a spiral form- ing a basal carina immediately adjoining anterior suture. Remainder of late whorls apparently smooth; remainder of intermediate whorls apparently smooth or sculptured with a low spiral at anterior third. Poorly preserved early whorls show a spiral at about anterior third, but no other sculpture apparent. Growth line not known. Height (incomplete, 7+ whorls) 41.5 mm, diameter 16 mm (figured specimen). The figured specimen and fragments consisting of several intermediate and late whorls are silicified fossils from the Gatuncillo formation in the Rio Casaya area. The basal carina suggests affinity with the Claiborne (middle Eocene) species Turritella carinata. (Palmer, 1937, p. 189, pi. 24, figs. 5, 6, 8, 9, 12). The last few whorls of some large specimens of T. carinata have no macroscopic spirals other than the basal carina, like the figured fossil from Panama. On other large speci- mens of T. carinata, however, the last few whorls have one to several additional spirals. Though the figured specimen reaches a greater diameter than T. carinata, even the last whorl tightly clasps the preceding whorl, whereas the last few whorls of large shells of T. carinata gradually withdraw from the carina. T. carinata has microscopic spiral lineation, but such sculpture would not be reproduced by the granular silica of the fossils from Panama. The early whorls of T. carinata are sculptured with three spirals; the growth-line sinus is very deep and the growth-line angle very narrow. The middle Eocene Peruvian T. bosworthi Woods (Woods and others, in Bosworth, 1922, p. 80, pi. 8, figs. 8-10) is more strongly carinate. T. carinata evidently represents, in part, Guillaume's T. hybrida group (Guillaume, 1924, pp. 286-290). Occurrence: Gatuncillo formation (middle Eocene), Rio Casaya area, locality 38. Subgenus? Turritella cf. T. collazica Maury Plate 16, figure 13 Large, late whorls rapidly enlarging. Whorls slightly concave, the profile dominated by a wide swollen basal carina occupying anterior third, or a little more, of whorl. Other sculpture obscure or absent. Sculpture of early whorls and growth line unknown. Height (incomplete, 4-f whorls) 56 mm, diameter (exaggerated by crushing) 25 mm (figured specimen) . The basal limestone of the La Boca marine member of the Panama formation on Rio Masambi yielded a poorly preserved crushed Turritella characterized by a wide swollen basal carina. The Oligocene Puerto Rican T. collazica has a similar basal carina (Maury, 1920, p. 51, pi. 8, fig. 5). According to Maury's illustration, the basal carina bears a groove and the remainder of the whorl is sculptured with six low spiral threads. A fragment from the Culebra formation at locality 5857, listed as Turritella sp., resembles the La Boca species, but its preservation is too poor to permit identification. Occurrence: Limestone at base of La Boca marine members of Panama formation (early Miocene) Rio Masambi, locality 123. Subgenus? (?Merriam's T. buwaldana stock) Turritella cf. T. samanensis Olsson Moderately large, slender. Whorls slightly convex or flat, sculptured with about 10 subequal low spirals. On at least some intermediate and late whorls the basal gastropods: trochidae to turritellidae 99 spiral and another near middle of whorl are slightly stronger than others. Sculpture of early whorls and growth line unknown. Height (incomplete, 3+ whorls) 25 mm, diameter 15 mm. This species is represented by poorly preserved frag- ments from calcareous sandstone in the Gatuncillo formation of the Rio Frijol area. The slightly convex or flat whorls and the subequal spirals resemble features of the late Eocene Peruvian Turritella samanensis (Olsson, 1928, p. 65, pi. 14, figs. 3, 4, 6-8; 1931, p. 74), which is recorded from the late Eocene of Colombia (Clark, in Clark and Durham, 1946, p. 26, pi. 23, figs. 1, 4). T. masinguiensis Clark (in Clark and Durham, 1946, p. 24, pi. 23, figs. 3, 5-7, 9, 10), also from the late Eocene of Colombia, appears to be T. samanensis. According to Olsson, the early whorls of T. samanensis have three spirals. Therefore it is unlikely that it is related to T. uvasana Conrad, of the Eocene of Cali- fornia, the early whorls of which have two spirals (Merriam, 1941, p. 89.) Probably it is a representative of Merriam's T. buwaldana stock (Merriam, 1941, p. 42). Occurrence : Gatuncillo formation (late Eocene) , Rio Frijol area, localitA' 34. Subgenus? Turritella species Large, slender. Late whorls slightly concave, a narrow carina lying near anterior suture and a wider carina near posterior suture. Intermediate whorls sculptured with a spiral at anterior third, one or two spirals at posterior third, and microscopic minor spirals. Sculpture of early and late whorls and growth line unknown. Height (incomplete, 3 whorls) 43 mm, diameter 24 mm. The affinities of this species, which occurs in the Gatuncillo formation, are undetermined. Late whorls are represented only by molds. Occurrence: Gatuncillo formation (late Eocene), Madden basin, localities 12, 15; Rio Frijol area, localities 32, 34. Subgenus? (Merriam's T. uvasana stock) Turritella adela Woodring, n. sp. Plate 15, figures 5, 6 Turitella gatunensis Conrad, Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 310 (part, not pi. 17, fig. 10= T. atacta Dall), 1892 (Miocene, Vamos Vanios, Panama). Dall, in Hill, Mus. Comp. Zool. Harvard College Bull., v. 28, p. 273 (part), 1898 (list; Eocene, Vamos Vamos, Panama). Of medium size, slender. Whorls moderately com vex. Sculpture of late whorls consisting of 9 or 10 primary spirals, the 3 or 4 on anterior half of whorls slightly stronger than those on posterior half. Minor spirals of unequal strength lie between primaries. Earliest preserved whorls sculptured with two spirals: One at middle of whorl, the other midway between it and anterior suture. Spirals persist as the posterior- most and third (numbered anteriorly from middle of whorl), respectively, of the strong spirals on anterior half of late whorls. Base sculptured with numerous minor spirals of unequal strength and two stronger spirals adjoining periphery. Growth-line sinus mod- erately deep, the apex at middle of whorl; growth-line angle narrow. Height (incomplete) 25 mm, diameter 7.5 mm (type). Height (incomplete, 3 whorls) 22.5 mm, diameter 12 mm (para type). Type: USNM 561370; paratype, USNM 561371. Type locality: 41 (USGS 17716, east side of prom- ontory 375 meters southeast of Palenquilla Point, Canal Zone), marine member of Bohio(?) formation. Turritella adela is abundant in the marine member of the Bohio(?) formation near Palenquilla Point and at the nearby submerged Vamos Vamos locality. All the specimens, however, are incomplete. In general fea- tures it resembles T. galvesia Olsson (1931, p. 78, pi. 14, figs. 2-7), of the Oligocene of Peru, but has more inflated whorls and a deeper growth-line sinus. The lower limb of the sinus of T. galvesia is practically vertical. The sculptural pattern and growth line of the Oligocene Venezuelan T. andreasi Hodson (1926, p. 37, pi. 24, figs. 7-9, 12, pi. 25, fig. 2) suggest relation- ship. Though the early sculpture of T. andreasi is unknown, intermediate whorls do not have the two strong spirals characteristic of T. adela at the same diameter. The early sculpture, the subsequent sculptural pat- tern, and the growth line indicate that T. adela is a medium-sized late Eocene or early Oligocene species of Merriam's T. uvasana stock, which reached its acme in the Eocene of the Pacific coast of North America and continued through the Oligocene (Merriam, 1941, p. 42-44). Dall identified T. adela as T. gatunensis Conrad. If he had specimens from Vamos Vamos in mind, he was justified in claiming that his T. gatunensis is closely related to T. uvasana. Occurrence: Marine member of Bohio(?) formation (late Eocene or early Oligocene), Gatun Lake area, localities 40, 40a, 40d, 41. Turritella meroensis Olsson Plate 15, figure 19 Turritella gatunensis Conrad, Joukowsky, Soc. Phys. Histoire Nat. Geneva Mem., v. 35, p. 163 (list), pi. 6, figs. 26, 27, 1906 (Oligocene, Panama). Turritella meroensis Olsson, Bull. Am. Paleontology, v. 17, no 63, p. 76, pi. 13, figs. 1-4, 1931 (Oligocene, Peru, Ecuador), 100 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE Moderately large, slender. Whorls strongly inflated, sculptured with strong subequal spirals, 5 on inter- mediate whorls, 5 or 6 on late whorls. Late whorls bearing a gradually enlarging secondary spiral between anteriormost primary and suture, and between posterior- most and suture. Well-preserved whorls showing microscopic spirals between primaries. Sculpture of early whorls and growth line not known. Height (incomplete, 3+ whorls) 39 mm, diameter 21 mm (figured specimen). Type: Paleontological Research Institution, Ithaca, N. Y., 2051. Type locality: Caleto Mero, Peru, Heath formation (late Oligocene). Turritella meroensis occurs in the middle member of the Caimito formation in the Gatun Lake area and in the Quebrancha limestone member of the same forma- tion in the Quebrancha syncline. Preservation of the specimens from the Quebrancha limestone member is poor. This species has already been recorded by Olsson (1942, p. 239) from strata in the Canal Zone now assigned to the Caimito formation, and he thought also that Joukowsky's T. gatunensis is T. tristis or T. meroensis (Olsson, 1942, p. 241). Wherever T. meroensis has been found, in Peru, Ecuador, and Panama, it occurs in formations of late Oligocene age. The later whorls of this Turritella are Mesalia-like, as pointed out by Olsson. The specimens from the Caimito formation closely agree with the form from the type locality shown in Olsson's figure 1 and with Joukowsky's illustrations of his T. gatunensis from late Oligocene strata in the Santiago area, Panama, and also with specimens from that region. The growth line- is not shown on specimens from the Caimito formation. On specimens from the type locality the sinus is of moderate depth and its apex is near the middle of the whorl; the growth-line angle is narrow. Also on speci- mens from the type locality the growth lines form threads on unworn primary spirals. T. vientoensis Clark (in Clark and Durham, 1946, p. 27, pi. 23, figs. 2, 11-13, 17, 18), a late Eocene species from Colombia, is closely allied to T. meroensis, but the later whorls of T. vientoensis have more numerous spirals. T. saltoensis Clark (in Clark and Dm ham, 1946, p. 26, pi. 23, fig. 28) evidently is a form of T. vientoensis differing in details of sculpture. There arc no known descendents of T. meroensis. Though this well-defined species was identified by Joukowsky as T. gatunensis, it needs no comparison with that species. According to the growth line and the early sculpture of two spirals (Olsson, 1931, p. 76), T. meroensis is a representative of Merriam's T. uvasana stock, which is not known to have survived the Oligo- cene. The heavy spirals and strongly inflated whorls suggest affinity with T. variata lorenzana Wagner and Schilling (Merriam, 1941, p. 99, pi. 18, fig. 3, pi. 19, figs. 9, 12-14), of the Oligocene of California. Gabb's illustrations of his T. gatunensis (Gabb, 1881, p. 342, pi. 44, fig. 10, 10a), which does not even remotely resemble T. gatunensis and was named T. tristis by Brown and Pilsbry (1911, p. 358, footnote), suggest a species resembling T. meroensis, but more slender. Three incomplete specimens are in the type (and only) lot (Acad. Nat. Sci. Philadelphia 3532). The largest, which has a height of 28 millimeters and a diameter of 8 millimeters, evidently is the original of Gabb's freely drawn figure 10 and is herewith designated the lecto- type. The whorls enlarge very slowly. The earliest whorls are bicarinate, but also have a weak posterior spiral; at the same stage T. meroensis has similar sculp- ture. A fragment of late whorls has five primary spirals, the third from the base being carinate. The third specimen, also a fragment of late whorls, is sculp- tured with five primary spirals and very fine second- aries; that is, the sculpture is much like that of late whorls of T. meroensis. On the basis of this inadequate material T. tristis may be a very slender ally of T. meroensis. The stratigraphic relations of the black shale on Oronli Creek, in southern Costa Rica — the type locality of T. tristis — are unknown, but, according to the fossils Gabb found there, its age probably is Oligo- cene. Apparently no geologist has seen it since Gabb's visit. Occurrence: Middle member of Caimito formation (late Oligocene), Gatun Lake area, locality 56. Que- brancha limestone member of Caimito formation (late Oligocene), Quebrancha syncline, locality 62. Late Oligocene, Santiago area, Panama. Late Oligocene, Posorja, Ecuador. Heath formation (late Oligocene), Peru. Subgenus? Turritella cf. T. caleta Olsson Plate 15, figures 14-16 Small, slender, more or less bicarinate. Early whorls sculptured with three equally spaced spirals. Anterior and posterior spirals emphasized on intermediate whorls, producing a bicarinate outline, and generally empha- sized on late whorls. Intermediate and late whorls also sculptured with unequal minor spirals, including original middle spiral. Primary and some minor spirals of well-preserved specimens slightly noded by growth lines. Growth-line sinus deep, apex slightly back of middle of whorl; growth-line angle very narrow. Height (incomplete, 2+ whorls) 13.5 mm, diameter 9.5 mm (figured fragment of large specimen). Height (incomplete, 4 whorls) 13 mm, diameter 6.5 mm (figured fragment of specimen of intermediate size). gastropods: trochidae to turritellidae 101 Variation affects the strength of the spirals and there- fore the whorl profile. Though late whorls are typically bicarinate, the bicarinate outline is somewhat obscured on some specimens by weakening of one or both pri- maries, or by development of posterior minor spirals that are almost as strong as the posterior primary (pi. 15, fig. 16). Turritella cf. T. caleta occurs in the marine member of the Bobio(?) formation. It is represented by nu- merous fragments and immature specimens, or shell tips, in collections from Vamos Vamos and Trinidad Island, and was found near Palenquilla Point. Appar- ently it is related to the Oligocene Peruvian T. caleta Olsson (1931, p. 79, pi. 12, figs. 9, 11, 12, 15), but the early sculpture of that species is unknown. The late whorls of T. caleta have a weak posterior primary spiral. The bicarinate outline and growth line suggest rela- tionship to T. altilira Conrad. That suggestion, how- ever, is not supported by the sculpture of the early whorls. The bicarinate outline and growth line also suggest relationship to T. olssoni Clark (Clark and Durham, 1946, p. 25, pi. 23, figs. 14-16, 22), a late Eocene Colombian species, which has less strongly beaded late whorls. T. olssoni was claimed to be an early member of the T. altilira group. Specimens that show the early sculpture, available through the kind- ness of J. Wyatt Durham, substantiate that claim, the earliest sculptured whorls bearing an anterior spiral, a weaker posterior spiral appearing later. T. cf. T. caleta therefore is not related to T. olssoni. Occurrence: Marine member of Bohio(?) formation (late Eocene or Oligocene"), Gatun Lake area, localities 40, 40a, 40b, 40d, 41, 42, 42c. Subgenus Torcula Gray Gray, Proc. Zool. Soc. London, p. 155, 1847. Type (orthotype): Turbo exoletus Linne, Recent, Florida and West Indies. The subgenus Torcula is characterized by an anterior spiral on the earliest sculptured whorls, an intermediate sculpture of two widely spaced spirals, typically a similar mature sculpture of two primary carina-forming spirals, and also a deep growth-line sinus and a narrow growth-line angle. The intermediate sculpture of the type species is weak, five or six whorls sculptured with two weak spirals following the first two whorls sculp- tured with a stronger anterior spiral. The intermediate sculpture of T. altilira and its close allies is much stronger. Most of the lots of T. exoleta in the U. S. National Museum collections are from depths of 35 to 85 fathoms. A few lots, however, were dredged at shallower depths; one lot from Conch Key, Fla., at a depth of 1 to 5 feet. As orally pointed out by R. T. Abbott, it is remarkable 413788—57 8 that a species almost unobtainable except by dredging was available to Linne. Bactrospira Cossmann (1895-1924, pt. 9, p. 129, 1912; type [orthotype], Turritella perattenuata Heilprin, Pliocene, Florida) is available as a name for a minor group under Torcula, including T. altilira and its close allies. T. altilira has more rapidly enlarging early whorls than T. perattenuata. Eury torus Gardner (1926-47, p. 596, 1947; type [orthotype], Turritella mixta Dall, Miocene, Florida), proposed as a section of Torcula, has the growth line and early and intermediate sculpture of Torcula. The whorls enlarge so rapidly, however, and on mature whorls two or three original secondary spirals are so strong that subgeneric rank may be justified. T. amaras is by no means a typical species of Torcula in plan of mature sculpture. It is somewhat compar- able to Eurytorus in divergence from the basic pattern of Torcula, but diverges in a different direction. Turritella (Torcula?j amaras Woodring, n. sp. Plate 16, figures 4-7, 10 Large, rapidly enlarging. Whorls typically flat; suture typically obscured by overhanging anterior spiral. Intermediate and late whorls of some speci- mens carinate at the anterior spiral, the suture being exposed. Sculpture consisting of three strong subequal primary spirals. Earliest preserved whorls sculptured with two spirals, anterior one at about anterior third of whorl, posterior one at about posterior third; an- terior spiral slightly stronger. These spirals are mid- dle and posterior spirals of subsequent whorls. An- terior spiral, adjoining suture, appearing at early stage and gradually increasing in size. Middle and posterior spirals farther apart than middle and anterior, the mid- dle spiral lying in front of middle of whorl. One to three weak secondary spirals generally present between middle and posterior primaries, and between posterior primary and suture. Well-preserved shell surfaces show microscopic spiral striae. Primary and secondary spirals of some whorls obscurely noded by growth lines. Growth-line sinus deep, the apex at about middle of whorl between middle and posterior spirals; growth-line angle narrow. Height (incomplete) 47 mm, diameter 14.5 mm (type, a specimen of intermediate size). Height (incomplete, 3+ whorls) 43 mm, diameter 24.5 mm (figured frag- ment of large specimen). Type: USNM 561373. Type locality: 116 (USGS 5853, west side of Gaillard Cut, Canal station 1863, Canal Zone, Culebra forma- tion. The only important variation affects the whorl pro- file. Carinate whorls owe their profile to loose clasp- 102 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE ing, which completely exposes the anterior spiral and the part of the whorl lying immediately in front of it (pi. 16, fig. 6). This is not a late-growth feature, for some specimens of intermediate size have carinate whorls and many large specimens have tightly clasped whorls. On the typical flat-whorled form the suture is obscured by the overhanging anterior spiral. How- ever obscure the suture may be, the base of a whorl may be identified by the narrow space between the anterior and middle spirals. Apparent variation af- fecting minor sculptural features may be due princi- pally to differences in preservation rather than to original variation. This well-defined species is widespread and abundant in the Culebra formation. It occurs in sandstone, principally in the upper part of the Culebra and in the transition zone between the Culebra and Cucaracha formations. Like other Culebra fossils, most of the specimens have some calcareous sandstone adhering to them or are otherwise poorly preserved. The type, of intermediate size, was collected from pebbly sandstone in the Paraiso region. Its earliest preserved whorls are strongly worn and the others are somewhat worn. Turritella caparonis Maury (1925, p. 234, pi. 42, figs. 1,2), from strata of late early Miocene age in Trinidad, is a related species. It has four equally spaced spirals, the anteriormost (adjoining and obscuring the suture) not quite as strong as the others. The more distinct nodes on the spirals, as compared with T. amaras, are probably the result of better preservation. The two species are similar in growth line. T. amaras may be more closely related to the Oligocene Puerto Rican T. mitchelli Hubbard (1920, p. 137, pi. 22, fig. 3), which has three similarly spaced primary spirals and appears to have a similar growth line. According to the illus- tration of the imperfect type (and only specimen), it has two strong secondary spirals between the middle and posterior primaries, minor spirals superimposed on the primaries, and fairly strong nodes, particularly on the secondary spirals. Merriam's (1941, pi. 24, fig. 2) Turritella aff. T. altilira, from the Miocene of Colombia, needs comparison with T. amaras. T. amaras and its allies represent a minor offshoot from the stock of T. altilira, that failed to survive the Miocene. Occurrence: Culebra formation (early Miocene), Gaillard Cut, localities 98, 99b, 107, 108b, 108c, 110, 110a, Ilia, 111b, 112, 112a, 116. Turritella (Torcula) altilira altilira Conrad Plate 23, figures 1, 7, 12, 13 Turritella altilira Conrad, Pacific R. It. Expl., v. 6, Geol. Itept., p. 72, pi. 5, fig. 19, 1857 (Miocene, Gatun, Panama). (Re- Printed U. S. Geol. Survey Prof. Paper 59, p. 178, 1909.) Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 63, p. 358, pi. 27, figs. 2, 3, 1911 (Miocene, Canal Zone). Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 150, pi. 14, figs. 6, 7, 1922 (Miocene, Canal Zone). Hodson, idem, v. 11, no. 45, p. 45, pi. 26, fig. 1, pi. 28, fig. 3, pi. 29, fig. 1, 1926 (Miocene, Canal Zone). Oinomikado, Geol. Soc. Japan Jour., v. 46, p. 620, pi. 29, fig. 2, 1939 (Miocene, Colombia). Merriam, Calif. Univ. Dept. Geol. Sci. Bull., v. 26, p. 44, pi. 24, figs. 3, 4, 1941 (Miocene, Canal Zone). Turritella gabbi Toula, K. k. Geol. Reichsanstalt Jahrb., Band 58, p. 695, pi. 25, fig. 5, 1909 (Miocene, Canal Zone). Turritella altilira urumacoensis Hodson, Bull. Am. Paleontology, v. 11, no. 45, p. 44, pi. 26, figs. 4, 7, pi. 27, figs. 3-7, 10, 1926 (Miocene, Venezuela). Not Turritella altilirata Conrad (error for T. altilira), Gabb, Acad. Nat. Sci. Phila. Jour., 2d ser., v. 8, p. 341, pi. 44, figs. 9, 9a, 1881 (Miocene, Costa Rica;=T. sapolensis Brown and Pilsbry). Grzybowski, Neues Jahrb., Beilage-Band 12, p. 645, pi. 20, fig. 7, 1899 (Miocene, Peru; subsp. of T. altilira). Not Turritella altilira Conrad, Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 64, p. 503 (list), 1913 (Miocene, Culebra Cut, Canal Zone; subsp. of T. altilira). Spieker, Johns Hopkins Univ. Studies in Geology, no. 3, p. 59, pi. 2, fig. 12, 1922 (Miocene, Peru; subsp. of T. altilira). Anderson, Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 118, pi. 17, figs. 4, 5, 1929 (Miocene, Colombia; subsp. of T. altilira). Marks, Bull. Am. Paleontology, v. 33, no. 139, p. 99, 1951 (Miocene, Ecuador; subsp. of T. altilira). Large, slender, strongly bicarinate. Protoconch small, bulbous, consisting of about 1% whorls. End of protoconch marked by gradual appearance of anterior primary spiral, which rapidly enlarges on first sculptured whorl. Posterior primary spiral appearing on latter part of third or on fourth sculptured whorl, slowly en- larging until on sixth to tenth sculptured whorl it generally is as stong as anterior spiral Even, however, on intermediate whorls of some specimens anterior primary is larger. Unequal minor spirals appearing between primaries on sixth to eighth sculputured whorl. Almost as soon as they appear they are noded (at first microscopically), and a few whorls later nodes appear on primaries. Primary spirals of late whorls flangelike and strongly noded. Posterior primary wider than anterior, generally unequally doubled by partial coalescene of an original strong minor spiral lying in front of it. Minor spirals between primaries conspicu- ously noded; one minor spiral generally stronger than others. A wide, but low and moderately noded, minor spiral adjoins anterior suture. Minor spirals absent between posterior primary and suture. Well- preserved specimens show microscopic spirals over entire whorl, including primaries. On last whorl, or a little more, of mature shells, nodes subdued, widely and irregularly spaced, and growth line emphasized at irregular intervals. Minor spiral adjoining anterior suture of spire whorls emerging on base of body whorl as a stong spiral. Remainder of base sculptured with ver3* weak minor or microscopic spirals fading out to- gastropods: trochidae to turritellidae 103 ward columellar lip. Growth-line sinus deep, its apex a little behind middle of whorl; growth-line angle narrow. Height (incomplete, 6 whorls) 43.5 mm, diameter 17.5 mm (topotype). Height (incomplete 7 4- whorls), 63 mm, diameter 19 mm (figured fragment of large specimen). Height (incomplete) 73 mm, diameter 13 mm (figured almost complete large, specimen). Type material: Lectotype, Acad. Nat. Sci. Phila. 3513. Type locality: Gatun, Canal Zone. Locality of topotype: 150a (USGS 10997, Panama Railroad, high cut about 0.4 mile (650 meters) southeast of Gatun railroad station, Canal Zone), middle part of Gatun formation. In February, 1957, Ellen James Trumbull, of the Geological Survey, found at the Academy of Natural Sciences of Philadelphia a poorly preserved 4-whorled specimen of TurriteUa altUira that was collected by Newberry. It is all that is left of the type lot and is an obligatory lectotype, if not the remains of the 7- whorled type illustrated by Conrad. The specimen shown on plate 23, figure 7, was collected close to, if not at, the type locality. In 1855, when Newberry gathered a few fossils on his way to California, Gatun was located on the banks of the Chagres at the west end of the bluffs formed by the Quebrancha Hills. Presumably he found his fossils, including T. altUira, in a railroad cut. In the French literature on the geology of the present Canal Zone, T. altUira is desig- nated T. tornata (T. tornata Guppy=!T. guppyi Coss- mann, a subspecies of T. altUira). The typical form, which has flangelike strongly noded primary spirals, is rare in the lower part of the Gatun formation, but is widespread and abundant in the middle and upper parts in the Canal Zone. The pos- terior primary is almost invariably wider than the anterior on late whorls and, with few exceptions, is unequally doubled. Details of sculpture and the de- gree of whorl constriction between the posterior primary and the suture are variable. No specimens of the typical form are in the U. S. National Museum collec- tions from the lower part of the Gatun formation, but T. F. Thompson collected from the lower part three specimens identified as T. altUira altUira. Only one specimen (from locality 138a), however, is really typi- cal. One of the other two — a large specimen from locality 137a — has anterior and posterior primary spi- rals of equal width. The other (from locality 138a) has a nonflanged posterior primary; that is, it combines characters of the typical form and T. altUira praecellens, with which it is associated. On specimens from about the lower half of the middle part of the Gatun, including strata in the type region, one of the minor spirals in the concave area between the primaries is stronger and more coarsely noded than the others, and the suture is deeply impressed, as the result of strong whorl con- striction (pi. 23, fig. 7). On specimens from about the upper half of the middle part, no minor spiral domi- nates the others and the suture is not so deeply im- pressed (pi. 23, fig. 12). On specimens from still higher strata in the upper part of the formation, however, a minor spiral is dominant on about half of the specimens, and most of them have a deeply impressed suture. Shells from a U. S. Geological Survey locality repre- senting the upper part of the formation near Mount Hope (locality 175) have been illustrated by Merriam (1941, pi. 24, figs. 3, 4). Plate 23, figure 13 shows one of the few shells that have a simple posterior primary. On this specimen the posterior face of the posterior primary is not deeply concave. The shell was damaged and repaired while the second preserved whorl was being formed and after the repair the posterior primary is farther from the suture. This specimen therefore is abnormal, but the posterior primary is not doubled preceding the repair. Maturity, as indicated by suppression of the nodes, is reached at a diameter of 15 to 20 millimeters. Healed breaks are conspicuous on the body whorl of mature shells and are not unusual on spire whorls. About 200 perfectly preserved shell tips from locality 147b and a considerable number from several other localities show the protoconch and early sculptured whorls (pi. 23, fig. 1). In the Canal Zone and adjoining parts of Panama the earliest forms of TurriteUa altUira appear in the upper Oligocene part of the Caimito formation and in the lower Miocene Emperador limestone member of the Culebra formation; the last in the Toro limestone mem- ber of the Chagres sandstone. The Caimito and Em- perador fossils are discussed under the next heading. The earliest occurrence of the typical form is in the lower Miocene part of the Caimito formation in Madden basin. A poorly preserved small specimen from Mad- den basin, probably from the calcareous sandstone member of the Caimito formation, and molds (including one of a large specimen) from the overlying Alhajuela sandstone member are referred to the typical form. Though some details of the sculpture are partly or completely lacking, the identification is made with con- siderable confidence, for the primaries are flangelike, and the posterior primary is wider than the anterior and is unequally doubled. Other specimens from the Miocene part of the Caimito formation are too small or too imperfect for identification, other than in the un- restricted sense. A subspecies (or variety), discussed under a separate heading, is represented hi the lower part of the Gatun formation and apparently occurs in 104 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE the middle part. The acme of the typical form is reached in the middle and upper parts of the Gatun. The typical form is less abundant in the middle part wesl of the canal than east of the canal, and no form was found in the upper part in the coastal area west of the Canal Zone. Most of the lots collected in the middle part west of the canal are small specimens identifiable only in the unrestricted sense. A mold of a small specimen records the presence of the species in the Toro limestone member of the Chagres sandstone. According to current age assignments, Turritella altilira, in the unrestricted sense, therefore ranges from late Oligocene to early Pliocene; the typical form from late early Miocene to middle Miocene. T. altilira and its immediate close allies are widely distributed in the upper Oligocene deposits of Puerto Rico, Antigua, Trinidad, Venezuela, and Panama; the lower Miocene of Haiti, Dominican Republic, Puerto Rico, Anguilla, Brazil, Trinidad, Venezuela, Colombia, Panama, and Costa Rica; the middle Miocene of Jamaica, Dominican Republic, Trinidad, Venezuela, Colombia, Panama, Costa Rica, southeastern Mexico, Florida, Ecuador, and Peru; the upper Miocene of Trinidad, Venezuela, Colombia, Panama, Costa Rica, the Colorado Desert of southern California; and the lower Pliocene of Panama. Nineteen names have been proposed for forms of the T. altilira group. Some doubtless are superfluous, but many are to be regarded as subspecies of T. altilira; indeed six were described as subspecies or varieties. A study of the stratigraphic and geographic grades would be certain to yield valuable results, but would be a lengthy diversion. Only a few of the described forms combine flange-like, strongly noded primary spirals and a posterior primary wider than the anterior. Nevertheless middle Miocene fos- sils from southwestern and northern Colombia and Venezuela have flange-like, strongly noded primary spirals, and some have a posterior primary wider than the anterior. They so closely approach the typical form that they are referred to it. That is, the typical form occurs in the central Panama area, along the south border of the Caribbean Sea, and at the south end of the Miocene Atrato Valley strait. The T. altilira group reached southeastern United States in middle Miocene time. Gardner's (1926-47, ]). 595, pi. 57, fig. 17, 1947) Turritella cf. T. altilira, found in the Shoal River formation of Florida, repre- sents a form of T. altilira, but like many Caribbean forms it lacks flangelike primaries. Merriam's (1941, p. 44-47) Pacific coast T. altilira stock consists of T. inezana Conrad and T. imperialis Hanna. T. inezana appears in the early Miocene of California as a migrant. Though the immediate predecessor of T. inezana has not been recognized, the presence of a subspecies of the closely related T. altilira in the late Oligocene of Panama shows that tropical America was a potential reservoir for the lineage leading to T. inezana, as had been inferred. Merriam has pointed out that T. im- perialis, of disputed Miocene or Pliocene age (preferably late Miocene) is practically indistinguishable from some forms of T. altilira that lack flangelike primaries. It presumably is to be treated as a subspecies of T. altilira. T. altilira has living allies in the Caribbean Sea and in the Panamic region: T. exoleta (Linne) and T. rnariana Dall, respectively. Neither closely resembles the typical form of T. altilira. T. exoleta is the type of Torcula. Occurrence: Calcareous sandstone(?) member of Caimito formation (early Miocene), Madden basin, localities 77 (T. cf. T. altilira), 80. Alhajuela sand- stone member of Caimito formation (early Miocene), Madden basin, localities 88 (T. altilira s. 1.), 89, 92 (T. altilira s. 1.). Lower, middle, and upper parts of Gatun formation (middle Miocene). Lower part, local- ities 137a, 138a, 139 (T. altilira s. 1.). Middle part, eastern area, localities 141, 142, 143 (T. cf. T. altilira), 146, 147b, 147c, (T. cf. T. altilira,), 147e (T. altilira s. 1.), 147f, 147g, 147h, 150a, 151, 152 (T. altilira s. 1.), 153, 153a, 154, 155, 155a, 155b, 155c, 157, 158, 159, 159a, 160 (T. altilira. s. 1.); western area, localities 161c, 161d (T. altilira s. 1.), 162 (T. altilira s. 1.). 162a (T. altilira s. 1.) 165 (T altilira s. 1.), 166 {T. altilira s. 1.), 168 {T. altilira s.L), 170a. Upper part, eastern areas, localities 171, 173a, 174, 175, 176, 177, 177c, 177d (T. altilira s. 1.), 178. Toro limestone member of Chagres sandstone (early Pliocene) locality 195 (T. altilira s. 1.). Middle Miocene, Choco, southwestern Colombia; northern Colombia. Middle Miocene, Falcon, Venezuela. Turritella (Torcula) altilira Conrad, subspecies Plate 15, figure 10 ?Turritella aff. T. perattenuata praecellens Pilsbry and Brown, Mansfield, U. S. Natl. Mus. l'roc, v. 66, art. 22, p. 55, pi. 9, figs. 7, 8, 1925 (Miocene, Trinidad). Moderately large, moderately slender. Primary spirals relatively low, strongly noded. Posterior face of posterior primary slightly concave. Posterior pri- mary wider than anterior, doubled or tripled. Minor spirals between primaries of unequal strength. Sculp- ture of early whorls unknown. Growth line like that of typical T. altilira. Height (incomplete, 5+ whorls) 29.5 mm, diameter 13.3 mm (figured specimen). Height (incomplete, 7 whorls) 41.5 mm, diameter 17 mm. The shell tapers more gently than that of the typical form of Turritella altilira. The most conspicuous differ- ence, however, lies in the features of the primary spirals, gastropods: trochidae to turritellidae 105 which are not flangelike. The difference is particularly marked on the wide posterior primary, the posterior face of which is only slightly concave. On most of the specimens the posterior primary is doubled — on a few it is tripled. Though the primaries are strongly noded, the nodes are not as conspicuous as on the typical form, possibly owing to slight wear. Mansfield's Turritella aff. T. perattenuata praecellens Pilsbry and Brown, of the early Miocene at Machapure (or Machapoorie) Quarry, Trinidad, has similar heavy strongly noded primaries. This unnamed subspecies of T. altilira is found in the middle member of the Caimito formation in the Gatun Lake area and in the Quebrancha limestone member of the Caimito in the Quebrancha syncline. The Quebrancha limestone fossils are poorly preserved. A mold of a small specimen from the Emperador lime- stone member of the Culebra formation evidently is more similar to the typical form, as intermediate whorls have high primaries. Occurrence: Middle member of Caimito formation (late Oligocene), Gatun Lake area, locality 56. Que- brancha limestone member of Caimito formation (late Oligocene), Quebrancha syncline, locality 62. Empera- dor limestone member of Culebra formation (early Miocene), Gaillard Cut, locality 120 (T. altilira s. 1.). Turritella (Torcula) altilira praecellens Pilsbry and Brown Plate 23, figures 2, 8 Turritella perattenuata praecellens Pilsbry and Brown, Acad. Nat. Sci. Phila. Proc, v. 69, p. 36, footnote, pi. 5, fig. 12, 1917 (Miocene, Dominican Republic). Of medium size, slender. Primary spirals relatively low, moderately or weakly noded. Posterior face of posterior primary slightly concave. Posterior primary wider than anterior, generally doubled. Minor spirals between primaries of subequal strength. Sculpture of early whorls like that of typical T. altilira, but minor spirals appearing several whorls later. Growth line like that of typical T. altilira. Height (incomplete, 8 whorls) 42 mm, diameter 12.5 mm (larger figured specimen). Height (incomplete, 4+ whorls) 30.5 mm, diameter 13 mm (smaller figured specimen). Type: Acad. Nat. Sci. Phila. 2608. Type locality: Dominican Republic, Miocene (pre- sumably Baitoa formation, late early Miocene). This form of Turritella altilira, like the subspecies in the Caimito formation, lacks flangelike primary spirals. It is more slender than the Caimito subspecies and its primaries are not as strongly noded. Suppression of the nodes at a diameter of 12 millimeters suggests that it does not reach a large size. The fossils from Panama may represent a local race of T. altilira not of the same genetic stock as T. altilira praecellens. Nevertheless the identification empha- sizes the direction of differentiation from the typical form. Collections of T. altilira praecellens from the Baitoa formation of the Dominican Republic include larger specimens than those from Panama and some that have more strongly noded primaries. Though T. altilira praecellens was described as a subspecies of T. perattenuata Heilprin, of the Pliocene of Florida, it apparently lacks the greatly attenuated whorls of that species and evidently is more closely related to T. altilira. T. perattenuata, however, also is a nonflanged member of the T. altilira group. T. montserratensis (Mansfield, 1925, p. 53, pi. 9, figs. 5, 6), which occurs in the Telemaque sand member of the Springvale formation (late Miocene) of Trinidad and should be assigned subspecific rank under T. altilira, is very similar, but its posterior spiral is not doubled. The form of T. altilira identified as T. altilira prae- cellens occurs in the lower part of the Gatun formation. It is, indeed, the only altilira-like Turritella in the U. S. National Museum collections from that part of the formation. A form comparable to T. altilira praecellens, but very weakly noded and less slender, is found in the middle part of the Gatun at locality 144. The lower Gatun subspecies (or variety) and the typical T. altilira are represented in Hill's Gatun collection labelled Vamos Vamos (locality 158). Occurrence: Lower and middle parts of Gatun forma- tion (middle Miocene). Lower part, localities 136a, 137, 138, 138a. Middle part, eastern area, localities 144 (T. altilira subsp., cf. T. altilira praecellens), 158. Baitoa formation (late early Miocene), Dominican Republic. Subgenus? (Merriam's T. ocoyana stock) Turritella cf. T. subgrundifera Dall Plate 16, figure 3 Small, slender, strongly carinate at about anterior fourth of whorl. Sculpture consisting of 6 or 7 widely spaced spirals. Spiral immediately in front of and behind carina-forming spiral and 1 or 2 near posterior suture weaker than others. Sculpture of early whorls and growth line not known. Height (incomplete, 3 whorls) 18 mm, diameter 5 mm (figured specimen). Height (incomplete, 3 whorls) 25 mm, diameter 15 mm (increased by crushing). The whorl profile, slender outline, and widely spaced spirals of this species, represented by two poorly pre- served fragments from the Culebra formation, strongly suggest Turritella subgrundifera, of the Chipola forma- tion of Florida (Gardner, 1926-47, p. 590, pi. 57, fig. 1, 106 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE 1947). Though the early whorls and growth line of the species from Panama are not known, it is without much doubt a close ally of T. subgrundifera, if not that species. The protoconch of T. subgrundifera is cylin- drical, consisting of 1% strongly inflated whorls. Three spirals appear gradually and practically simultaneously on the first sculptured whorl: a strong middle spiral, a moderately strong anterior spiral (the carina-forming spiral of later whorls), and a weak posterior spiral. The growth-line sinus is very shallow and wide, and the growth-line angle very wide. T. subgrundifera is recorded from the Miocene of Colombia (Pilsbry and Brown, 1917, p. 35). Occurrence : Culebra formation (early Miocene) , Gail- lard Cut, locality 99d. Turritella venezuelana Hodson Plato 16, figures 8, 9 Turritella venezuelana Hodson, Bull. Am. Paleontology, v. 11, no. 45, p. 32, pi. 21, figs. 4, 8, pi. 22, figs. 1, 6, 1926 [Miocene (Oligocene-Miocene of Hodson), Venezuela). Turritella venezuelana quirosana Hodson, idem, p. 34, pi. 22, figs. 9, 10, pi. 24, fig. 1, 1926 [Miocene (Oligocene-Miocene of Hodson), Venezuela]. Turritella venezuelana watkinsi Hodson, idem, p. 34, pi. 22, fig. 8, 1926. [Miocene (Oligocene-Miocene of Hodson), Venezuela]. Small, early whorls rapidly enlarging. Whorls moderately carinate at about anterior fourth or rounded. Sculpture consisting of 6 or 7 primary spirals. On some specimens a minor spiral is present in some interspaces. Earliest preserved whorls sculptured with three spirals, the posteriormost weak and the anteriormost forming the carina on later carinate whorls. Base sculptured with weak closely spaced minor spirals. Growth-line sinus very shallow and wide; growth-line angle very wide. Height (incomplete, 6 whorls) 15.3 mm, diameter 5.4 mm (larger figured specimen). Height (incomplete, 4 whorls) 23.5 mm, diameter 9.5 mm. Type: Paleontological Research Institution, Ithaca, N. Y. Type locality: Locality 6, Oil seep at Mene de Sala- dillo, 1% kilometers southwest of Quiros, District of Miranda, Zulia, Venezuela (Hodson and Hodson, 1931, p. 5), La Rosa formation (Sutton, 1946, p. 1694), early Miocene. This small species occurs in the Culebra formation. It shows considerable variation in whorl profile, in width of primary spirals, and in presence or absence of minor spirals. According to Hodson, it is variable in Venezuela also. The types of the three forms named by him were found at the same locality. Turritella venezuelana is closely related to T. sub- grundifera, but evidently is not a small form of that species. T. subgrundifera is carinate (except the late whorls of a few specimens) , its early whorls enlarge less rapidly, and the posteriormost of the three spirals of early whorls appear at an earlier stage. Both species are representatives of Merriam's T. ocoyana stock (Merriam, 1941, p. 47). Occurrence: Culebra formation (early Miocene), Gaillard Cut, localities 99b, 107, 110, Ilia, 112, 112a, 114. La Rosa formation (early Miocene), Zulia, Venezuela. Turritella abrupta Spieker Plate 23, figures 6, 15, 16 Turritella (Haustator) robusta Grzybowski, Neues Jahrb., Beilage-Band 12, p. 646, pi. 20, fig. 3, 1899 (Miocene, Peru). Not T. robusta Gabb, 1864. Turritella robusta Grzybowski, Woods, in Bosworth, Geology of the Tertiary and Quaternary periods in the north-west part of Peru, p. 110, pi. 18, fig. 4, pi. 19, fig. 1, 1922 (Miocene, Peru). Spieker, Johns Hopkins Univ. Studies in Geology, no. 3, p. 84, pi. 4, fig. 5, 1922 (Miocene, Peru). Turritella robusta var. abrupta Spieker, idem, p. 85, pi. 4, fig. 6, 1922 (Miocene, Peru). Turritella charana Spieker, idem, p. 86, pi. 4, fig. 7, 1922 (Mio- cene, Peru). Turritella supraconcava Hanna and Israelsky, Calif. Acad. Sci. Proc, 4th ser.,v. 14, no. 2, p. 59, 1925 (new name for T. robusta Grzybowski). Turritella robusta fredeai Hodson, Bull. Am. Paleontology, v. 11, no. 45, p. 13, pi. 5, figs. 1, 3, pi. 6, figs. 2, 5,pl. 7, figs. 1, 6, 7, pi. 9, fig. 7, pi. 29, fig. 6, 1926 (Miocene, Venezuela). Turritella supraconcava var. fredeai Hodson, Weisbord, idem, v. 14, no. 54,p. 30, pi. 9, figs. 3, 4, 1929 (Miocene, Colombia). Turritella fredeai Hodson, Anderson, Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 119, pi. 17, fig. 1, 1929 (Miocene, Colombia) . Turritella abrupta Spieker, Olsson, Bull. Am. Paleontology, v. 19, no. 68, p. 200, 1932 (Miocene, Peru). Merriam, Calif. Univ. Dept, Geol. Sci. Bull., v. 26, p. 48, pi. 29, fig. 4 ("cf."), pi. 30, fig. 6, pi. 31, figs. 2-4, 1941 (Miocene, Colombia, Venezuela). Marks, Bull. Am. Paleontology, v. 33, no. 139, p. 99, 1951 (Miocene, Ecuador). Moderately large, rapidly enlarging. Whorls veiy strongly and sharply carinate at about anterior fourth. Sculpture consisting of 8 or 9 widely spaced spirals. Protoconch of about 1% inflated whorls. Two strong spirals appear on first sculptured whorl: one at middle of whorl, the other halfway between it and anterior suture. A low narrow spiral adjoining anterior suture also appears on first sculptured whorl. Anterior of the two strong spirals gradually increasing in size until on about sixth sculptured whorl it is stronger than middle spiral and forms the carina. At about same stage weak spirals appear between middle spiral and posterior suture, and elsewhere. On late whorls a spiral adjoins anterior suture and a weaker spiral lies between it and carina. Anterior sutural spiral emerging on base as a strong spiral. Base between this spiral and columel- lar lip sculptured with weak spirals. Growth-line gastropods: trochidae to turritellidae 107 sinus very shallow and wide, the apex just above carina; growth-line angle very wide. Height (incomplete, 4 whorls) 39 mm, diameter 23 mm (largest figured specimen). Type: Johns Hopkins University. Type locality: Zorritos, Peru, Zorritos formation (early Miocene). Turritella abrupta occurs in the middle part of the Gatun formation, but is rare. It is represented by the figured specimen of moderate size, collected in the east- ern area, and by very small specimens from the western area. Adhering calcareous sandstone somewhat masks the strength and sharpness of the carina on the largest figured specimen. This overnamed Turritella, which reaches a relatively gigantic size (height about 200 mm), is found in Peru, Ecuador, the Darien basin of Panama, the Chiriqui area of Panama, Colombia, and Venezuela, generally in formations of middle Miocene age. In Peru, how- ever, it occurs both in the upper Zorritos and Cardalitos formations, dated as late early and middle Miocene, respectively, by Olsson (1932, fig. 2, p. 42). The occurrence of T. abrupta in the Miocene of the Isthmus of Tehuantepec (Woodring, 1928, pp. 66, 98) cannot be confirmed at the present time. The fossils on which that record was based have been mislaid or were misidentified. On the basis of the characters of intermediate and late whorls, T. abrupta may be considered a large very strongly and sharply carinate subspecies of T. ocoyana Conrad, of the middle Miocene of California. Never- theless these two forms show a considerable difference in development of sculpture. According to Merriam's (1941, pi. 31, fig. 1) illustration of the early whorls of T. ocoyana, fairly strong spirals, other than the middle and anterior spiral, appear at an early stage. On the early whorls of the Gatun specimens of T. abrupta such spirals are weaker and appear at a later stage. Until additional data on the sculpture of the early whorls are available, specific rank is retained for T. abrupta. T. trinitaria Maury (1925, p. 230, pi. 42, fig. 10; Yokes, 1938, p. 26, fig. 29; Rutsch, 1942, p. 129), from the late Miocene Springvale formation of Trinidad, presumably is a less strongly carinate subspecies of T. abrupta. T. abrupta trinitaria and T. matarucana, representing different lineages, are the last survivors of the T. ocoyana group in the Caribbean and nearby areas. T. ocoyana is widespread in the middle Miocene of California, but has no predecessors there. The infer- ence that it is a migrant from tropical America is justified, for there are earlier closely related species in that region. Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, locality 144a; western area, localities 161c, 161d, 170a. Upper part of Zorritos formation (early Miocene) and Cardalitos formation (middle Miocene), Peru. Progreso formation (middle Miocene), Ecuador. Middle Miocene, Darien area, Panama. Middle Miocene, Chiriqui area, Panama. Middle Miocene, Bolivar, Colombia. Miocene, Falcon, Venezuela. Turritella matarucana Hodson Plate 22, figures 11, 12 Turritella matarucana Hodson, Bull. Am. Paleontology, v. 11, no. 45, p. 31, pi. 20, fig. 4. pi. 21, figs. 1, 9, 1926 (Miocene, Venezuela) . Turritella plebeia A-L-Owensi Hodson, idem, p. 31, pi. 20, figs. 1, 2, 5, 6, pi. 23, fig. 2, pi. 28, fig. 1, 1926 (Miocene, Venezuela). Moderately large, early whorls rapidly enlarging, late whorls slowly enlarging. Intermediate whorls moderately convex, late whorls slightly convex. Late whorls narrowly beveled at posterior suture. Sculp- ture consisting of numerous closely spaced spirals some of which are narrower and more closely spaced than others. Earliest preserved whorls sculptured with two spirals: one at middle of whorl, the other halfway between it and anterior suture. Base sculp- tured with very weak spirals disappearing toward columellar lip. Growth-line sinus very wide and shallow; growth-line angle very wide. Height (incomplete, 5 whorls) 44.5 nun, diameter 16 mm (larger figured specimen). Type: Paleontological Research Institution, Ithaca, N. Y. Type locality: Locality 197, Rio Mataruca, Buena Vista anticline, near La Vela, District of Colina, Falcon, Venezuela, La Vela formation (late Miocene). Turritella plebeia alowensi, 3 also from the Miocene of Falcon, Venezuela, was based on specimens that have moderately inflated whorls. They are similar to T. matarucana in sculptural pattern and growth line, and evidently represent a form of that species having mod- erately inflated whorls even at a late stage. Despite the absence of a carina and the presence of numerous closely spaced spirals, T. matarucana is allied to T. abrupta and other species of the T. ocoyana group, according to the sculpture of the early whorls and the growth line. In whorl profile and sculpture it more closely resembles the larger, more rapidly enlarg- ing, and more convex-whorled Miocene European species T. terebralis Lamarck, which has similar early sculpture and growth line. The whorl profile and 3 Though "the original orthography of a name is to be preserved unless an error of transcription, a lapsus calami, or a typographical error Is evident" (International Rules of Zoological Nomencalture, Article 19), a name like "A-L-Owensi" is so objec- tionable that alteration to "alowensi" appears to be justified. 108 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE sculpture suggest T. plebeia Say, of the Miocene of Maryland. T. plebeia has similar early sculpture, but its growth-line sinus is narrower and deeper, and its growth-line angle is narrower. T. matarucana occurs in the Gatun formation. It is locally abundant in the lower part of the formation and rare in the middle part. Occurrence: Lower and middle parts of Gatun forma- tion (middle Miocene). Lower part, localities 135 (identification doubtful), 136, 136a, 137, 137a, 138a. Middle part, eastern area, locality 144a (identification doubtful); western area, locality 161c. Uramaco (mid- dle Miocene) and La Vela (late Miocene) formations, Falcon, Venezuela. Subgenus? Turritella gatunensis gatunensis Conrad Plate 23, figures 4, 5, 9, 14 Turritella gatunensis Conrad, Pacific R. R. Expl., v. 6, Geol. Rept., p. 72, pi. 5, fig. 20, 1857 (Miocene, Gatun, Panama). (Reprinted, U. S. Geol. Survey Prof. Paper 59, p. 178, 1909.) Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 310 (part, not pi. 17, fig. 10= T. atacta Dall), 1892 (Miocene, Gatun, Panama). Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 63, p. 358, pi. 27, figs. 4, 5. 9, 1911 (Miocene, Canal Zone). Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 148, pi. 14, figs. 12, 13, 1922 (Miocene, northwestern Panama, Costa Rica). Anderson, Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 120, 1929 (Miocene, Colombia). Li, Geol. Soc. China Bull., v. 9, p. 267, pi. 6, fig. 49, 1930 (Miocene, Panama Bay; Miocene, Gatun, fide Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 83, p. 432, 1931). Marks, Bull. Am. Paleontology, v. 33, no. 139, p. 100, 1951 (Miocene, Ecuador). Turritella cf. T. gatunensis Conrad, Weisbord, Bull. Am. Paleon- tology, v. 14, no. 54, p. 33, pi. 9, fig. 7, 1929 (Miocene, Colom- bia). Turritella gatunensis lavelana Hodson, idem, v. 11, no. 45, p. 23, pi. 18, fig. 6, pi. 19, fig. 7, 1926 (Miocene, Venezuela). Turritella conradi Toula, K. k. Geol. Reichsanstalt Jahrb., Band 58, p. 694, pi. 25, fig. 4, 1909 (Miocene, Canal Zone). Not Turritella gatunensis Conrad, Gabb, Acad. Nat. Sci. Phila. Jour., 2d ser., v. 8, p. 342, pi. 44, figs. 10, 10a, 1881 (Oligo- cene(?), Costa Rica;=T. tristis Brown and Pilsbry). Jou- kowsky, Soc. Phys. Histoire Nat. Geneva M6m., t. 35, p. 163 (list), pi. 6, figs. 26, 27, 1906 (Oligocene, Panama;=T. mero- ensis Olsson). Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 229, pi. 42, fig. 12, 1925 (Miocene, Trinidad;=T. caronensis Mansfield, described as a subspecies of T. gatunensis) . Mans- field, Washington Acad. Sci. Jour., v. 28, p. 102, figs. 1-3, 6, 1938 (Oligocene, Florida). Moderately large, slender. Posterior part of whorls constricted, anterior part concave between primary spirals. Sculpture consisting of a primary spiral near, but generally behind, middle of whorl, a second primary at anterior third to fourth, and numerous minor spirals. Microscopic spirals generally visible on late whorls. A minor spiral lying behind, and close to, middle pri- mary is almost, or quite, as strong as primaries on some specimens. On a few specimens a minor spiral in front of anterior primary or between primaries is accentuated. Primaries decreasing in strength on last whorl or two of some specimens. As they decrease, anterior part of whorl becomes more inflated. Spirals slightly un- dulated by axial waves on a few specimens. Pro- toconch cylindrical, of two inflated whorls. Early sculptured whorls attenuated. A very strong middle spiral, forming a strong median carina, a very weak spiral adjoining anterior suture, and a very weak spiral half-way between them appear on first sculptured whorl. The strong middle spiral is the middle primary of later whorls. The weak spiral adjoining the anterior suture gradually enlarges and becomes the anterior primary. Other weak spirals appear on third or fourth sculptured whorl. Base sculptured with numerous low minor spirals. Growth-line sinus wide and shallow, the apex between primaries; growth-line angle wide. Interior of late whorls smooth or bearing narrow spiral ridges of varying strength. Height (almost complete) 58.5 mm, diameter 15 mm (largest figured specimen) . Type: Lost. Type locality : Gatun, Canal Zone. Turritella gatunensis, like T. altilira, was based on fossils collected by Newberry at Gatun. The type of T. gatunensis is lost. As Conrad's illustration is even cruder than his representation of T. altilira, the identi- fication rests primarily on the brief and unsatisfactory description. The collection that furnished a topotype of T. altilira (locality 150a) includes the traditional T. gatunensis, but the preservation is not good enough for designation of a neotype. The specimens shown on plate 23, figures 4, 9, collected at the Gatun Locks site, 250 meters west of Gatun, are considered repre- sentative of the typical form. The typical form of T. gatunensis probably is repre- sented in the calcareous sandstone member of the Caimito formation in Madden basin. It is locally abundant in the lower part of the Gatun formation, widespread and locally abundant in the middle part, rare in the upper part in the eastern area, and probably occurs in the Toro limestone member of the Chagres sandstone. Intermediate whorls are characterized by the two primary spirals and the concave space between them. Early sculptured whorls are attenuated and are very strongly carinate at the middle of the whorl. Late whorls, however, are variable in sculpture and whorl profile. Nevertheless the basic pattern of a middle and anterior primary is more or less discernible. This basic pattern, the constriction of the posterior part of whorls, and the growth line are the most reliable fea- tures for identification of late whorls. Most of the shells from the lower part of the Gatun formation are gastropods: trochidae to turritellidae 109 relatively flat-whorled and have strong primaries (pi. 23, fig. 14). Strong minor spirals are less common in the lower part of the formation than in the middle part. Specimens that have axial waves were not found in the lower part and are not common in the middle part, except at localities where the subspecies (or variety), described under the next heading was collected. Some specimens in the collection from locality 150a, which is close to, if not at, the type locality, have weak axial waves. The profile, sculpture, and growth line of late whorls indicate that the typical form, or closely related forms, occur in the Miocene of northwestern Panama, Costa Rica, Colombia, Ecuador, and Venezuela. Confirma- tion, based on the sculpture of the early whorls, is desirable. Weisbord s T. cf. T. gatunensis, from the Miocene of Colombia, may be referred to the typical form, despite its wide primaries. The early sculptured whorls of T. gatunensis caronensis Mansfield (1925, p. 51, pi. 8, figs. 12-14), of the Miocene of Trinidad, are not attenuated; the first few sculptured whorls are weakly carinate; and later early whorls are not as strongly carinate as those of T. gatunensis. This Trinidad species of Turritella is closely related to T. gatunensis, but presumably is to be given specific rank. There seem to be no close relatives of T. gatunensis in the Miocene of southeastern United States. Though intermediate and late whorls of T. gatunensis bloun- tensis Mansfield (1935, p. 41, pi. 4, figs. 1, 2), from deposits of middle Miocene age in western Florida, are practically indistinguishable in sculpture and growth line from specimens of T. gatunensis that have a strong posterior minor spiral, they enlarge less rapidly. The earliest preserved whorls (not quite the earliest sculp- tured whorls) are not carinate and are sculptured with 6 or 7 spirals. T. blountensis therefore is not a sub- species of T. gatunensis. The small specimens from the Shoal River formation of Florida doubtfully recorded as T. gatunensis blountensis (Gardner, 1926- 47, p. 592, pi. 57, figs. 11, 12, 1947) are less like T. gatunensis in whorl profile. The earliest preserved whorls are not carinate and are sculptured with three strong spirals. Mansfield's T. gatunensis, from the late Oligocene of Florida, has the sculptural pattern of that species, but late whorls are more or less uniformly convex. The earliest preserved whorls have two spirals. One speci- men shows a suggestion of a moderately deep growth- line sinus, with the apex a little behind the middle of the whorl, and a narrow growth-line angle. This species of Turritella is without much doubt related to the species from Vamos Vamos, T. adela: the species mentioned by Mansfield as T. gatunensis, following Dall's identification. According to Mansfield, a form of T. gatunensis from the "lower faunal zone" of the Gatun formation has early whorls like those of the species of Turritella from Vamos Vamos. That obser- vation, however, evidently was based on some mis- understanding, for no specimen of T. gatunensis from the Gatun formation that shows the early whorls has such sculpture. The affinities of Mansfield's (1940, p. 218, pi. 27, figs. 56, 57) Turritella cf. T. gatunensis, from the late Oligocene Chickasawhay marl, are uncertain. The growth line is unknown and the early whorls of the only specimen that shows them are too poorly preserved to reveal the sculpture. Occurrence : Calcareous sandstone member of Caimito formation (early Miocene), Madden basin, locality 82 (mold, identification doubtful). Lower, middle, and upper parts of Gatun formation (middle Miocene). Lower part, localities 136a, 137, 137a, 138, 138a. Middle part, eastern area, localities 140, 141, 144, 144a (identification doubtful), 147a, 147d, 147e, 147i, 150a, 153, 155, 155b, 155c, 156, 157, 158, 159, 159a, 159b, 160; western area, localities 161, 161a, 169. Upper part, eastern area, localities 163, 172. Toro limestone member of Chagres sandstone (early Pliocene ; molds, identification doubtful), localities 194, 196. Late Miocene, Water Cay, Panama. Middle Miocene, Costa Rica. Middle Miocene, Bolivar, Colombia. Miocene, Falc6n, Venezuela. Subibaja formation (early Miocene) and Progreso formation (middle Miocene), Ecuador. Turritella gatunensis rhytodes Woodring, n. subsp. Plate 23, figures 10, 11, 17 Moderately large, slender. Protoconch and early whorls like those of typical form. Posterior part of intermediate and late whorls strongly constricted. On intermediate whorls minor spirals, particularly one or more between primaries, increase in strength until on late intermediate and late whorls they are as strong as primaries, the whorls losing the typical T. gatunensis profile. Spirals of intermediate whorls more or less undulated by axial waves on most specimens. Growth line like that of typical form. Height (incomplete) 66 mm, diameter 16.5 mm (type). Type: USNM 561395; paratypes, Stanford Univ. Type locality: 162a (USGS 8359, lower trail on west side of Rio Chagres northwest of Gatun Dam, Canal Zone), middle part of Gatun formation. Turritella gatunensis rhytodes is abundant in the middle part of the Gatun formation at localities 162 and 162a on the west side of Rio Chagres northwest of Gatun Dam. Presumably it is a local subspecies or variety. The typical form occurs in the middle part of the Gatun at nearby localities, but is not represented 110 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE in the collections from localities 162 and 162a. As shown by the illustrations, the sculpture is variable. On some specimens the axial waves are so strong that the sculpture has a cerithid appearance; on a few they are absent or practically absent. The strong con- striction of the posterior part of the whorls and the strong minor spirals are characteristic features. In whorl profile T. gatunensis rhytodes closely resembles T. gatunensis willistoni Hodson (1926, p. 25, pi. 18, figs. 2-4), which, however, has strongly differentiated primary and secondary spirals on late whorls. Axial waves were cited as the characteristic feature of T. gatunensis taratarana Hodson (1926, p. 25, pi. 18, figs. 5, 7). The posterior part of the whorls of that form are not strongly constricted. The presence or absence of axial waves evidently is a variable character in different forms of T. gatunensis, including the typical form. T. gatunensis willistoni and T. gatunensis taratarana appear to be varieties of T. gatunensis. They are found together at some localities in Miocene strata in Falcon, Venezuela, and at a few localities are recorded in association with T. gatunensis lavelana, which, as indicated by the synonomy citation under T. gatunensis, is considered the typical form. The typical form of Turritella subannulata Heflprin (1887, p. 89, pi. 8, fig. 17), a Pliocene species from Florida, has cerithid axial sculpture, two primary spirals on intermediate and late whorls, and a growth line similar to that of T. gatunensis. The development of the sculpture, however, indicates that it is not closely allied to T. gatunensis. "Turritella gatunensis" tarataranoides Haas (1942, p. 315, figs. 3, 4), and also " Crepitacella" altispira Haas (idem, p. 315, figs. 5, 6) and "Crepitacella" n. sp. indet. aff. "C." altispira Haas (idem, p. 316), are fresh-water snails, as the editor of the Journal of Paleontology was informed when Haas' manuscript and illustrations were received. The type material of these species is so poorly preserved that their affinities are uncertain, but the "Turritella" seems to beaPachychilus. Not only is the type material poorly preserved, these species also were collected at an unknown Costa Rican locality (Idem, p. 310). Despite these deficiencies, they were given an unqualified middle Miocene age. Specimens of these fresh-water snails, collected in 1910 in a tunnel at Brasil (in the Meseta Central west of San Jose), are in the collections of the U. S. National Museum. They were presented to W. H. Dall by Don Anastasio Alfaro, Director of the Museo Nacional at San Jose, during a visit to Washington. Occurrence: Middle part of Gatun formation (middle Miocene), localities 162, 162a. Subgenus? Turritella cf. T. berjadinensis cocoditana Hodson A whorl fragment from the Culebra formation has a strong carina-forming spiral at the anterior fourth, two primary spirals near the middle, two weaker spirals between the carina and the anterior suture, and closely spaced fine minor spirals over the entire whorl. Though its middle spirals are of subequal strength, this fragment is comparable to the Miocene Venezuelan Turritella berjadinensis cocoditana (Hodson, 1926, p. 29, pi. 19, fig. 5, pi. 20, figs. 3, 7, 10). Occurrence: Culebra formation (early Miocene), Gaillard Cut, locality 115b. Subgenus? (Merriam's T. broderipiana stock) Turritella mimetes Brown and Pilsbry Plate 22, figures 6-9 Turritella mimetes Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc, v. 63, p. 357, pi. 27, fig. 1, 1911 (Miocene, Canal Zone). Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 149, pi. 14, fig. 5, 1922 (Miocene, Canal Zone). Turritella {Haustator) aff. T. hanleyana Reeve, Toula, K. k. Geol. Reichsanstalt Jahrb., Band 61, p. 498, pi. 30, fig. 6, 1911 (Miocene, Canal Zone). ? Turritella mimetes Brown and Pilsbry, Anderson, Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 120, 1929 (Miocene, Colombia; not described, possibly T. lloydsmithi Pilsbry and Brown) . Not Turritella cf. T. mimetes Brown and Pilsbry, Merriam, Calif. Univ. Dept. Geol. Sci. BuU., v. 26, no. 1, pi. 38, fig. 7, 1941 (Miocene, Colombia; = T. lloydsmithi Pilsbry and Brown). Moderately large, slender. Whorl profile flat or slightly concave. Late intermediate and late whorls generally loosely clasping, producing a weak basal carina. Protoconch cylindrical, of 1% inflated whorls. Early sculptured whorls attenuated, strongly inflated. A middle spiral, forming a weak carina, and minor spirals appear on first sculptured whorl. Middle spiral decreasing in strength on next whorl and lost among minor spirals covering entire whorl. Second and succeeding sculptured whorls therefore not medially carinate. On some specimens a median spiral again attains slight prominence on sixth or seventh sculp- tured whorl. Late whorls sculptured with spirals roughly representing three ranks, the third rank being microscopic. Base sculptured with numerous spirals. Growth-line sinus wide and shallow; growth-line angle wide. Interior of late whorls smooth or bearing narrow spiral ridges. Height (incomplete) 73 mm. diameter 17.5 mm (largest figured specimen). Type: Acad. Nat. Sci. Phila. 1734. gastropods: trochidae to turritellidae 111 Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation. Turritella mimetes is widespread in the middle pari of the Gatun formation, fairly common in the upper part in the western area, and probably occurs in the Toro limestone member of the Chagres sandstone. The whorl profile, determined by clasping of the succeeding whorl, and the sculpture are variable. The shells from the upper part of the Gatun, all collected in the western area, are relatively small. Their early whorls are not preserved, but their early intermediate whorls are like those of specimens from the middle part of the forma- tion. T. mimetes is related to the Recent Caribbean T. variegata (Linne). In fact, the marked similarity of late whorls in profile, sculpture, and growth line suggests that it is a subspecies of T. variegata. The early and early intermediate whorls of T. variegata, however, are medially carinate and rapidly enlarging. Allies of T. variegata are widespread in the Miocene of the Carib- bean region. It is not known whether any of them are closely related to T. mimetes. T. lloydsmithi Pilsbry and Brown (1917, p. 35, pi. 5, fig. 11), a middle and late(?) Miocene Colombian species, has more crowded spirals separated by very narrow grooves. Its early intermediate whorls are medially carinate and rapidly enlarging. It therefore is a close ally of T. variegata, possibly a subspecies. T. planigyrata Guppy (Mans- field, 1925, p. 55, pi. 9, figs. 1, 9; Rutsch, 1942, p. 131, pi. 8, fig. 5), the first of these Miocene Caribbean allies of T. variegata to be named, was based on fossils from the late Miocene Springvale formation of Trinidad. Its medially carinate and rapidly enlarging early inter- mediate whorls link it closely with T. variegata. Its sculpture is uniformly fine like that of some specimens of T. variegata. T. mimetes is also related to the Recent Panamic T. leucostoma Valenciennes, as identified by Kiener. The Recent species has attenuated early whorls, which, however, are medially carinate and have fewer spirals. Occurrence: Middle and upper parts of Gatun forma- tion (middle and late Miocene). Middle part, eastern area, localities 141 (identification doubtful), 150, 154 (identification doubtful), 155, 155a, 155b, 157, 159; western area, localities 161, 161b, 161c, 162, 165 (identification doubtful), 170. Upper part, western area, localities 182, 182a, 183, 184, 185. Toro lime- stone member of Chagres sandstone (early Pliocene), locality 196 (identification doubtful). Turritella bifastigata Nelson Plate 22, figure 10 Turritella bifastigata Nelson, Conn. Acad. Arts Sci. Trans., v. 2, p. 189, 1870 (Miocene, Peru). Spieker, Johns Hopkins Univ. Studies in Geology no. 3, p. 63, pi. 3, fig. 1, 1922 (Miocene, Peru). Hodson, Bull. Am. Paleontology, v. 11, no. 45, p. 48, pi. 30, fig. 1, 1926 (Miocene, Peru). Olsson, idem, v. 19, no. 68, p. 198, 1932 (Miocene, Peru). Turritella gothica Grzybowski, Neues Jahrb., Beilage-Band 12, p. 645, pi. 20, fig. 10, 1899 (Miocene, Peru). Woods, in Bos- worth, Geology of the Tertiary and Quaternary periods in the north-west part of Peru, p. 110, 1922 (Miocene, Peru). Moderately large. Intermediate whorls rapidly en- larging; late whorls slowly enlarging. Last whorl or two loosely clasping. Early intermediate whorls med- ially carinate; late intermediate whorls slightly convex; late whorls slightly concave between a faint collar adjoining posterior suture and a more distinct, but narrower, collar adjoining anterior suture. Anterior collar forming a carina on whorls preceded by a loosely clasping whorl and on body whorl. Sculpture of early whorls not known. Early intermediate whorls sculp- tured with three subequal primary spirals (a median spiral forming a carina, a spiral adjoining anterior suture, and another halfway between them) and minor spirals. Anterior spiral developing into anterior collar, the other two gradually weaken. Late whorls sculp- tured with faint minor and microscopic spirals, the strongest of which corresponds to the second (from anterior suture) primary of intermediate whorls. Base sculptured with low wide spirals, between which and on which are fine minor spirals. Growth-line sinus moderately deep, the apex at middle of whorl; growth- line angle wide. Height (not quite complete) 66 mm, diameter 18.5 mm (figured specimen). Lectotype: Peabody Museum, Yale Univ. 534. Type locality: Zorritos, Peru, Zorritos formation, late early Miocene. Late whorls are characterized by the sutural collars, producing a slightly concave profile, and faint spiral sculpture between the collars. Several names have been proposed for Miocene Caribbean allies of Turritella bifastigata, all of which probably are to be assigned subspecific rank under that species or the Recent T. broderipiana. The Colombian T. cartagenensis Pilsbry and Brown (1917, p. 34, pi. 5, fig. 13; Weisbord, 1929, p. 30, pi. 9, figs. 1, 2) has stronger spirals. The Costa Rican T. oreodoxa Olsson (1922, p. 152, pi. 14, fig. 1) has a wide posterior collar, no anterior collar, and stronger spirals. Hodson (1926, pp. 48-50, pi. 29, fig. 3, pi. 30, figs. 2-6) described fossils from the Miocene of Falcon, Venezuela, as T. bifastigata maracaibensis and T. bifastigata democra- ciana. They are recorded together at numerous localities and evidently represent a variable form that probably is to be identified as T. bifastigata cartagenensis which also is recorded from the Miocene of Trinidad (Maury, 1925, p. 233, pi. 42, fig. 13). 112 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE T. bijastigata was found only in the lower part of the Gatun formation. Though it has no living allies in the Caribbean Sea, it is closely related to T. broderi- piana d'Orbigny, a living Panamic species that lacks sutural collars or has greatly subdued collars. The early intermediate whorls of T. broderipiana are like those of T. bijastigata, but the middle spiral and the spiral adjoining the anterior suture are stronger, and the spiral midway between them is weaker. The early whorls of T. broderipiana enlarge rapidty. A middle spiral and one on both sides of it appear on the first sculptured whorl, and an anterior sutural spiral on the next whorl. With further growth the middle and anterior sutural spirals increase in strength, the others diminish. The middle spiral strongly carinates the early whorls, except the first. The first three whorls bear slightly arcuate exaggerated growth lines above the carina. T. bijastigata and T. mimetes represent Merriam's T. broderipiana stock (Merriam, 1941, pp. 50-51). Occurrence : Lower part of Gatun formation (middle Miocene), localities 137, 137a. Upper part of Zorritos formation (late early Miocene), Peru. LOCALITIES AT WHICH FOSSILS WERE COLLECTED The localities at which fossils were collected are described in the following list and the numbers used for them in the present report are correlated with the permanent numbers recorded in the Geological Survey's Cenozoic invertebrate register. The list includes not only localities that yielded fossil mollusks, but also some important localities where only other kinds of fossils were collected. Unless otherwise specified, the report locality numbers are plotted on the general geologic map (pi. 1). As noted in the list, localities in the Gaillard Cut area are plotted on the large-scale geologic map of that area (pi. 2). Some early collections have such inadequate data that they cannot be plotted, and other localities are not plotted to avoid congestion of the map. Early localities that are now submerged are shown on plate 1 and plate 2 by a special symbol, even though the plotted location may be only approxi- mate. Some submerged localities, however, cannot be plotted even approximately. Before the construction of the canal, Rio Chagres flowed southwestward to the present site of Gamboa and there turned northwestward to the Caribbean Sea. It was first dammed near Gatun to form Gatun Lake and later was dammed upstream from Gamboa to form Madden Lake. The course of the river and the location of the Panama Railroad before the canal was built are shown on the map accompanying the publication cited under Bertrand and Zurcher (1899). The relocated line of the Panama Railroad, cited in the following list, is the present line constructed in 1911-13. No. used in this report USGS Cenozoic No. Field No. 131 la 8400 17433 17432 131a 132 150 118 114 115 Description of locality GATUNCILLO FORMATION Madden basin, Panama. South side of Rio Pequeni near head of Madden Lake, 120 meters west of former Canal Zone Pequeni Police Sub- station. Thin-bedded limestone, 2.5 meters above base of Gatuncillo formation. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Same locality. Thin-bedded nodular- weathering limestone, 5.5 to 7 meters higher stratigraphically. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Not plotted. Madden basin, Panama. West shore of Madden Lake at abandoned Sala- manca Gaging station. Fairly soft limestone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Madden basin, Panama. San Juan de Pequeni, on Rio Pequeni about 1 kilometer upstream from junction with Rio Chagres. Fragmental limestone. E. R. Lloyd, 1919. Now submerged. Topotypes of Lepido- cyclina chaperi and other larger Foraminifera (Vaughan, 1926). For location of San Juan de Pequeni see Reeves and Ross, 1930, pi. 5. Madden basin, Panama. Trail west of Madden Lake, 4.8 kilometers north of Madden Dam. Limestone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Madden basin, Panama. Trail north of Rio Puente, 2 kilometers north- east of Natural Bridge (Puente Natural). Thin-bedded limestone. T. F. Thompson and W. P. Wood- ring, 1949. Larger Foraminifera. Madden basin, Panama. Lumber road north of Rio Puente, 1.7 kilometers east-southeast of Natural Bridge. Limestone. T. F. Thompson and W. P. Woodring, 1949. Madden basin, Panama. Lumber road north of Rio Puente, 1.6 kilometers east-southeast of Natural Bridge. Limestone. T. F. Thompson and W. P. Woodring, 1949. gastropods: trochidae to turritellidae 113 No. used in this report USGS Cenozoic No. 17161 10 11 16889 12 1762 13 14 15 Field No. 116 113 108 15 107 106 105 129 Description of locality gatuncillo formation — continued Madden basin, Panama. Trail south of Rio Puente, 800 meters southeast of Natural Bridge. Limestone. T. F. Thompson and W. P. Woodring, 1949. Corals. Madden basin, Panama. Lumber road south of Rio Puente, 1.5 kilometers southeast of Natural Bridge. Marly limestone. T. F. Thompson, 1948. Also a collection by T. F. Thompson and W. P. Woodring, 1949. Madden basin, Panama. Road to Madden Airfield, 650 meters north- east of Casa Larga. Marly lime- stone. T. F. Thompson, 1948. Also a collection by T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Madden basin, Panama. Madden Air- field, about 300 meters north of north end of paved runway, 1.7 kilometers east of Casa Larga. Limestone. J. R. Schultz, T. F. Thompson, and W. P. Woodring, 1947. Also larger Fo- raminifera (Cole, 1952 [1953j), corals, and echinoids (Cooke, 1948). Madden basin, Panama. Lumber road south of Rio Puente, 4 kilometers east of Casa Larga. Marly lime- stone. T. F. Thompson, 1948. Also a collection by T. F. Thompson and W. P. Woodring, 1949. Also corals. Madden basin, Panama. Road from Casa Larga to Laguna, 1 kilometer south-southeast of Rio Chilibrillo bridge. Marly limestone. T. F. Thompson, 1948. Also a collection by T. F. Thompson and W. P. Woodring, 1949. Larger Foraminif- era. Madden basin, Panama. 325 meters east of road from Casa Larga to Laguna, 1.1 kilometers southeast of Rio Chilibrillo bridge. Limestone. T. F. Thompson, 1948. Also a col- lection by T. F. Thompson and W. P. Woodring, 1949. Larger Foram- inifera. Madden basin, Panama. Road from Casa Larga to Laguna, 1 kilometer west of Laguna. Limestone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera. 16 17 18 19 20 21 22 23 USGS Cenozoic No. 17434 Field No. 128 117 146 145 19 20 124 125 Description of locality gatuncillo formation — continued Madden basin, Panama. Road from Casa Larga to Laguna, south side of Rio Lim6n immediately south of Laguna. Limestone. T. F. Thomp- son and W. P. Woodring, 1949. Also corals. Quebranchasyncline, Panama. Stream about 50 meters west of trail on east side of Rio Gatuncillo, 4.5 kilometers northeast of Transisthmian Highway bridge across Rio Gatuncillo. Mud- stone and siltstone. W. P. Wood- ring, 1949. Smaller Foraminifera. Quebrancha syncline, Panama. Trail on east side of Rio Gatuncillo, 3.3 kilometers northeast of TransiMh- mian Highway bridge across Rio Gatuncillo. Limestone. W. P. Woodring, 1949. Larger Foraminif- era. Quebrancha syncline, Panama. Trail on east side of Rio Gatuncillo, 2 kilometers northeast of Transisth- mian Highway bridge across Rio Gatuncillo. Soft limestone. W. P. Woodring, 1949. Larger Foraminif- era (Cole, 1952 [1953]). Quebrancha syncline, Panama. North side of Transisthmian Highway, 50 meters east of bridge across Rio Gatuncillo. Limestone. J. R. Schultz and W. P. Woodring, 1947. Larger Foraminifera. Quebrancha syncline, Panama. East bank of Rio Quebrancha about 100 meters northeast of Transisthmian Highway bridge. Mudstone. J. R. Schultz and W. P. Woodring, 1947. Smaller Foraminifera. Quebrancha syncline, Panama. Road to Nuevo San Juan, 0.5 kilometer southwest of junction with Transisth- mian Highway. Fairly soft lime- stone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminif- era (Cole, 1952 [1953]). Quebrancha syncline, Panama. Road to Nuevo San Juan, 2 kilometers southwest of junction with Trans- isthmian Highway. Fairly soft lime- stone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminif- era (Cole, 1952 [1953]). 114 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. 23a 24 25 26 27 27a 16931 28 29 Field No. 21 139 23 22 22a 140 Description of locality gatuncillo formation — continued Rfo Agua Sucia area, Panama. About 30 meters southeast of trail, 2 kilo- meters southwest of Nuevo San Juan. Limestone. T. F. Thompson and W. P. Woodring, 1949. Larger Fo- raminifera, not collected. Rio Agua Sucia area, Panama. Trans- isthmian Highway, 3.5 kilometers northwest of Rfo Gatuncillo bridge. Silty mudstone. J. R. Schultz and W. P. Woodring, 1947. Smaller Fo- raminifera. Rfo Agua Sucia area, Panama. Half a kilometer northeast of Transisth- mian Highway and 5.5 kilometers northwest of Transisthmian High- way bridge across Rfo Gatuncillo. Limestone. T. F. Thompson and VV. P. Woodring, 1949. Larger Fo- raminifera. Rfo Agua Sucia area, Panama. Trans- isthmian Highway, 5.7 kilometers northwest of Rfo Gatuncillo bridge. Calcareous mudstone. J. R. Schultz and W. P. Woodring, 1947. Larger Foraminifera (Cole, 1952 [1953]) and corals. Rio Agua Sucia area, Panama. Trans- isthmian Highway, 6.5 kilometers northwest of Rio Gatuncillo bridge. Siltstone. J. R. Schultz and W. P. Woodring, 1947. Same locality, calcareous sandstone 0.5 to 1 centimeter thick, about 6 meters lower stratigraphically. J. R. Schultz and W. P. Woodring, 1947. Larger Foraminifera (Cole, 1952 [1953]). Not plotted. Rio Agua Sucia area, Panama. Trans- isthmian Highway, 7.3 kilometers northwest of Rio Gatuncillo bridge. Poorly sorted gritty sandstone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Rfo Agua Salud area, Canal Zone. Core hole SL-84, 5.7 kilometers north-northwest of Frijoles station on Panama Railroad and 300 meters south of head of Quebrada La Chin- ilia arm of Gatun Lake. Depth 22.5 meters, silty limestone. Drilled in 1947. Also outcrop float limestone at same locality. Larger Foraminif- era (Cole, 1949). No. used in this report 30 31 32 33 34 35 36 38 USGS Cenozoic No. 17163 17165 17700 17166 Field No. 136 137 135 134 138a 119 Description of locality gatuncillo formatiox — continued Rio Agua Salud area, Canal Zone. Core hole SL-99, 2.2 kilometers- southeast of Frijoles station on Panama Railroad. Mostly siltstone. Drilled in 1947. Foraminifera. Rio Agua Salud area, Canal Zone. Core hole SL-100, 3.3 kilometers southeast of Frijoles station on Panama Railroad. Depth 40.5 to 40.8 meters, siltstone. Drilled in 1947. Foraminifera. Rio Frijol area, Canal Zone. Rio Frijol 6 kilometers northwest of west end of Gamboa bridge. Sandstone. T. F. Thompson, 1948. Also a collection by W. P. Woodring, 1949. Rio Frijol area, Canal Zone. Pipe-line road, 6.5 kilometers northwest of west end of Gamboa bridge. Fairly soft limestone. W. P. Woodring, 1949. Larger Foraminifera (Cole r 1952 [1953]). Rio Frijol area, Canal Zone. Rfo Frijol, 6.5 kilometers northwest of west end of Gamboa bridge. Sand- stone. T. F. Thompson, 1948. Rio Frijol area, Canal Zone. Pipe-line road, 5 kilometers northwest of west end of Gamboa bridge. Silty mud- stone. W. P. Woodring, 1949. Also smaller Foraminifera. Rio Frijol area, Canal Zone. Pipe-line road, 3.3 kilometers northwest of west end of Gamboa bridge. Lime- stone. W. P. Woodring, 1949. Larger Foraminifera. Gamboa area, Canal Zone. 1.9 kilo- meters north-northwest of west end of Gamboa bridge, on road to core holes SL-94 and SL-96, 15 meters south of bridge across drainage ditch. Fairly soft limestone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Rio Casava area, Canal Zone. Que- brada de Oro, a northwestward- flowing tributary of Rio Casava, 3.3 kilometers southeast of east end of Gamboa bridge. Partly silicified sandy limestone. R. H. Stewart, I 'tis. Also collections by T. F. Thompson, 1948, and W. P. Wood- ring, 1949. gastropods: trochidae to turritellidae 115 No. used in this report USGS Cenozoic No. 39 40 40a 40b 2683 2685 40c 40d 40e 41 2687 6028a 6028b 17716 41a 18838 Field No. 127 19 26 148 208 Description of locality GRAYWACKE GRIT MEMBER OF BOHIO FORMATION QUEBRANCHA SYNCLINE, PANAMA South bank of eastward-flowing tribu- tary of Rio Quebrancha, 375 meters west-northwest of Transisthmian Highway bridge across Rio Que- brancha. Sandy siltstone in basal part of graywacke grit member of Bohio formation. T. F. Thompson and W. P. Woodring, 1949. Smaller Foraminifera. MARINE MEMBER OF BOHIo(?) FORMA- TION GATUN LAKE AREA, CANAL ZONE Vamos Vamos station, Panama Canal, in a cut about 2 meters above level of canal. Collected by F. Sensa, received from Alexander Agassiz, 1891. [A submerged locality off Palenquilla Point west of Barro Colorado Island, originally on south bank of French Canal.] Location approximate. Vamos Vamos, lot 1. R, T. Hill, 1895. [The six collections from Vamos Vamos are presumably from the same locality.] Not plotted. Panama Canal at Vamos Vamos and 10.5 kilometers from Col6n. R. T. Hill, 1895. [The designation "and 10.5 kilometers from Colon" should be deleted. Vamos Vamos was about 20 kilometers from Col6n.] Not plotted. Vamos Vamos, lot 2. R. T. Hill, 1895. Not plotted. Vamos Vamos, lower bed. D. F. Mac- Donald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 542, pi. 154). Not plotted. Vamos Vamos, upper sandstone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 542). Poorly preserved molds in weathered sand- stone. Not plotted. East side of promontory 375 meters southeast of Palenquilla Point, west of Barro Colorado Island. Loose calcareous concretions at water's edge. T. F. Thompson and W. P. Woodring, 1949. East side of Palenquilla Point, wide cove east of triangulation station. Approximately same as locality 41a, but from soft weathered medium- grained sandstone. W. P. Wood- ring, 1954. Not plotted. No. used in this report 41b 42 42a 42b 42c 42d 42e 42f USGS Cenozoic No. 18839 17692 17693 17965 18837 18835 18836 Field No. 209 149 149a 149b 149c 207 205 206 Description of locality MARINE MEMBER OF BOHIO(?) FORMA- TION GATUN LAKE AREA, CANAL zone — continued East side of Palenquilla Point, head of cove north of triangulation station and southwest of Corozo Island. Calcareous concretion in soft sand- stone. W. P. Woodring, 1954. Not plotted. Northeast coast of Trinidad Island. Sandy siltstone, basal 3 meters of exposed section. T. F. Thompson and W. P. Woodring, 1949. Also larger Foraminifera (Cole, 1952 [1953]). Same locality and same part of section, but from thin calcareous layer. T. F. Thompson and W. P. Wood- ring, 1949. Not plotted. Same locality, about 3 meters higher stratigraphically. One-meter ledge- forming silty medium-grained cal- careous sandstone containing few small pebbles, few worn small heads of calcareous algae, and worn shell tips of Turritella. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Not plotted. Same locality, sandy siltstone about 4.5 meters stratigraphically above locality 42b. T. F. Thompson and W. P. Woodring, 1949. Not plotted. BOHIO FORMATION, GATUN LAKE AREA, CANAL ZONE Barro Colorado Island, northern part of island, stream heading west of Miller Trail near Miller 17,* about 100 meters above mouth. Some- what calcareous medium-grained subgraywacke. W. P. Woodring, 1954. Barro Colorado Island, northern part of island, stream southeast of Fuertes House, about 275 meters above mouth. Conglomerate. W. P. Woodring, 1954. Not plotted. Barro Colorado Island, same stream as that for locality 42e, but about 60 meters upstream and from slide on west side of stream. Poorly sorted subgraywacke. W. P. Wood- ring, 1954. Not plotted. * The trails on Barro Colorado Island have consecutively numbered signs at in- tervals of 1 hectometer, starting from the laboratory at the launch landing or at the end of the trail heading toward the laboratory. 116 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. Field No. 42g 18832 203 42h 215 42i 18845 215a 43 39 44 17435 109 45 18375 38 46 41 47 42 48 43 Description of locality BOHIO FORMATION, GATUN LAKE AREA, canal zone — continued Barro Colorado Island, northern part of island, stream crossing Pearson Trail at Pearson 6, about 365 meters above mouth. Poorly sorted sub- graywacke. W. P. Woodring, 1954. Barro Colorado Island, eastern part of island, stream east of Shannon Trail, about 365 meters southeast of Shan- non 1 . Somewhat calcareous coarse- grained gritty subgraywacke. W. P. Woodring, 1954. Larger Forami- nifera. Barro Colorado Island, same stream as that for locality 54b, but 30 meters downstream. Soft muddy subgray- wacke. W. P. Woodring, 1954. Not plotted. BOHIO FORMATION, PACIFIC COASTAL, AREA, PANAMA Transisthmian Highway, 9 kilometers north- northwest of junction with Panama National Highway, about 100 meters north of Continental divide. Lens of algal limestone. J. A. Tavelli and W. P. Woodring, 1947. Larger Foraminifera (Cole, 1952 [1953]). 375 meters north-northwest of locality 43. Lens of algal limestone. W. P. Woodring, 1949. Transisthmian Highway, 1 kilometer north-northwest of junction with Panama National Highway. Lens of algal limestone. J. A. Tavelli and W. P. Woodring, 1947. Also larger Foraminifera (Cole, 1952 [1953]). MIDDLE MEMBER OF CAIMITO FORMATION, GATUN LAKE AREA, CANAL ZONE Peninsula 2 kilometers east-southeast of Darien. Limestone. S. M. Jones and W. P. Woodring, 1947. Larger Foraminifera. East side of peninsula 1.3 kilometers east-southeast of Darien. Lime- stone. S. M. Jones and W. P. Woodring, 1947. Larger Foraminif- era. About 45 meters eastward up path from west landing at Darien. Algal lime- stone. S. M. Jones and W. P. Wood- ring, 1947. Larger Foraminifera (Cole, 1952 [1953]). No. used in this report 49 50 51 52 USGS Cenozoic No. 6021 6024b 52a 53 54 Field No. 44 45 Description of locality 5908 53 46 MIDDLE MEMBER OF CAiMITO FORMA- TION, GATUN LAKE AREA, CANAL zone — continued Limestone on relocated line of Panama Bail road opposite San Pablo. First limestone outcrop north of Caimito station, about 4 miles (6.5 kilome- ters) north [west] of Gamboa bridge. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 539, pi. 154). [Type locality of Lepidocyclina vaughani. First cut northwest of Darien, now covered with soil and vegetation. A later collection from same locality was given the perma- nent number 6673.] Trail 1.2 kilometers north of Darien. Calcareous tuffaceous sandstone. S. M. Jones and W. P. Woodring, 1947. Larger Foraminifera. Field in peninsula 3 kilometers south- southeast of Frijoles. Pebbly cal- careous tuffaceous sandstone. S. M. Jones and W. P. Woodring, 1947. Larger Foraminifera (Cole 1952 [1953]). Limestone above foraminiferal marl at Rio Agua Salud bridge, about 0.3 mile (475 meters) north of Frijoles, relocated Panama Bailroad. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 540, pi. 154). Also corals (Vaughan, 1919a, p. 209). [A submerged locality, originally downstream from Rio Agua Salud culvert] Location ap- proximate. Limestone 1 mile or less (0.5 kilome- ters) north of Frijoles on relocated Panama Railroad. D. F. MacDon- ald, 1911. Presumably same as locality 52. Not plotted. Low islet 400 meters northeast of land- ing at Barro Colorado Island. Soft sandy calcareous siltstone. S. M. Jones and W. P. Woodring, 1947. Larger Foraminifera (Cole, 1952 [1953]). Barro Colorado Island, northeastern part of island, stream immediately east of laboratory clearing, 150 meters upstream from mouth at launch landing. Calcareous tuffa- ceous sandstone. W. P. Woodring, 1947. Larger Foraminifera. gastropods: trochidae to turritellidae 117 No. used in this report USGS Cenozoic No. Field No. 54a 214 54d 202 54e 202a 54f 201 54g 18840 210 54h 18841 210a 54i 211 54j 18833 204 54k 18834 204a Description of locality MIDDLE MEMBER OF CAIMITO FORMA- TION, GATUN LAKE AREA, CANAL zone — continued Barro Colorado Island, northeastern part of island, second stream east of laboratory clearing, 150 meters above mouth. Soft sandstone. W. P. Woodring, 1954. Larger Foramini- fera. Not plotted. Barro Colorado Island, northwestern part of island, stream heading north of Zetek Trail at Zetek 9, about 550 meters in direct line north-northwest of Zetek 9. Calcareous tuffaceous sandstone. W. P. Woodring, 1954. Larger Foraminifera. Not plotted. Barro Colorado Island, same stream as that for locality 54d, but about 200 meters downstream. Soft limestone. W. P. Woodring, 1954. Larger For- aminifera. Not plotted. Barro Colorado Island, northwestern part of island, stream crossing Stand- ley Trail at 60 meters northwest of Standley 11, about 30 meters down- stream from trail. Soft limestone. W. P. Woodring, 1954. Larger Foraminifera. Barro Colorado Island, western part of island, first stream north of Zetek House, about 300 meters above mouth. Soft medium-grained sand- stone. W. P. Woodring, 1954. Barro Colorado Island, same stream as that for locality 54g, but at mouth. Soft sandstone containing calcareous lumps. W. P. Woodring, 1954. Not plotted. Barro Colorado Island, western part of island, mouth of small stream 450 meters in direct line south-southeast of Zetek House. Soft sandstone. W. P. Woodring, 1954. Larger Fo- raminifera. Barro Colorado Island, southwestern part of island, stream crossing Con- rad Trail at Conrad 2, about 365 meters upstream from mouth. Soft sandstone. W. P. Woodring, 1954. Barro Colorado Island, same stream as that for locality 54j, but about 60 meters upstream above mouth. Soft sandstone. W. P. Woodring, 1954. Not plotted. No. used in this report 541 54m 54n 55 55a 55b 56 56a USGS Cenozoic No. 18842 18843 18844 18846 18847 6025 Field No. 212 213 213a 216 216a 55 Description of locality MIDDLE MEMBER OF CAIMITO FORMA- TION, GATUN LAKE AREA, CANAL zone — continued Barro Colorado Island, southwestern part of island, second stream north- west of end of Armour Trail, 60 meters above mouth. Gritty sandstone con- taining larger Foraminifera and mol- lusks, and somewhat calcareous sand- stone containing mollusks. W. P. Woodring, 1954. Barro Colorado Island, southwestern part of island, small stream 400 meters northeast of end of Armour Trail, 15 meters above mouth. Medium-grained sandstone contain- ing somewhat calcareous lumps. W. P. Woodring, 1954. Barro Colorado Island, same stream as that for locality 54m, but 100 meters above mouth. Fine-grained silty sandstone containing small Foram- inifera and mollusks. W. P. Wood- ring, 1954. Not plotted. Pefia Blanca. Type locality of Lepido- cyclina canellei. A submerged local- ity, originally on west bank of Rio Chagres. Location approximate. Pato Horqueto Island, south coast about 200 meters west of southeast end of island. Tuffaceous siltstone containing small Foraminifera and mollusks. W. P. Woodring, 1954. Pato Horqueto Island, south coast about 75 meters west of southeast end of island. Conglomerate. W. P. Woodring, 1954. Not plotted. Foraminiferal marl and coarse sand- stone about 200 yards (200 meters) south of southern end of switch at Bohio Ridge station, relocated Pan- ama Railroad. D. F. MacDonald and T. W. Vaughan, 1911 (Mac- Donald, 1919, p. 540, pi. 154). [Type locality of Lepidocyclina pan- canalis, Operculinoides panamensis, and Miogypsina panamensis.] Panama Railroad, east side of second cut southeast of Bohio Peninsula. Soft calcareous tuffaceous sandstone. S. M. Jones and W. P. Woodring, 1947. Larger Foraminifera (Cole, 1952 [1953]). Same as locality 56. Not plotted. 118 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. 57 6026 57a 5901 58 59 60 61 17685 62 16939 Field No. 54 110 111 112 11 Description of locality MIDDLE MEMBER OF CAIMITO FORMA- TION, GATUN LAKE AREA, CANAL zone — continued Foraminiferal coarse sandy marl about halfway between Monte Lirio and Bohio Ridge, relocated Panama Rail- road. D. F. MacDonald and T. W. Vaughan, 1911. (MacDonald, 1919, p. 541, pi. 154). Also corals (Vaughan, 1919a, p. 208). Relocated Panama Railroad about 2 miles (3 kilometers) south of Mitch- elville [Monte Lirio]. D. F. Mac- Donald, 1911. Same as locality 57 Not plotted. UPPER MEMBER OF CAIMITO FORMATION, GATUN LAKE AREA, CANAL ZONE Puma Island, in front of shed near crest of island. Hard calcareous sandstone. S. M. Jones and W. P. Woodring, 1947. Larger Forami- nifera (Cole, 1952 [1953]). UNDIFFERENTIATED CAIMITO FORMA- TION, RIO MANDINGA AREA, CANAL ZONE Northward-flowing tributary of Rio Mandinga, 3.3 kilometers southwest of west end of Gamboa bridge. Medium-grained poorly sorted silty tuffaceous sandstone. R. H. Stew- art, 1948. Also collection by W. P. Woodring, 1949. Larger Forami- nifera (Cole, 1952 [1953]). 300 meters upstream from locality 59. Pebbly calcareous tuffaceous sand- stone. W. P. Woodring, 1949. About 45 meters west of pipe-line road and 3.5 kilometers west-southwest of west end of Gamboa bridge. Limestone. W. P. Woodring, 1949. Corals. QUEBRANCHA LIMESTONE MEMBER OF CAIMITO FORMATION, QUEBRANCHA SYNCLINE, PANAMA North side of Transisthmian Highway at entrance to plant of Cfa. Cemento Panama, S. A., 125 meters north- west of Transisthmian Highway bridge across Rio Gatuncillo. Lower part of limestone. T. F. Thompson and W. P. Woodring, 1947. No. used in this report 62a 63 64 65 66 67 USGS Cenozoic No. 5907 susc. Field No. 11a 29 30 121 120 Description of locality QUEBRANCHA LIMESTONE MEMBER OF CAIMITO FORMATION, QUEBRANCHA syncline, Panama — continued Quarry of Cia. Cemento Panama, S. A., 150 meters northwest of locality 11. Middle part of limestone. J. R. Schultz and W. P. Woodring, 1947. Larger Foraminifera (Cole, 1952 [1953]). Not plotted. LOWER PART OF CAIMITO FORMATION, MADDEN BASIN, PANAMA Transisthmian Highway, 4 kilometers north-northwest of Rio Chagres bridge. Sandy limestone in cal- careous sandstone-siltstone member. W. P. Woodring, 1947. Larger Foraminifera. Transisthmian Highway, 3.3 kilome- ters north-northwest of Rio Chagres bridge. Medium-grained calcareous tuffaceous sandstone in calcareous sandstone-siltstone member. W. P. Woodring, 1947. Larger Foraminif- era (Cole, 1952 [1953]). Rio Chagres at locality where trail from Alhajuela reaches river, about 6 miles (10 kilometers) by river above Alhajuela. D. F. MacDonald, 1911. [A submerged locality.] Rio Chagres about a mile (1.5 kilome- ters) below mouth of Rio Pequenf, limestone at Marcelito, just below Bajilla Rain Gage Station. A. A. Olsson, 1919. [A submerged local- ity.] Location approximate. Rio Chilibrillo, 650 meters above bridge on road to Casa Larga. Coarse- grained poorly sorted calcareous somewhat tuffaceous sandstone in calcareous sandstone-siltstone mem- ber, about 15 meters above base of Caimito formation. W. P. Wood- ring, 1949. Larger Foraminifera (Cole, 1952 [1953]). Rio Chilibrillo, 325 meters above bridge on road to Casa Larga. Very fine- grained silty sandstone in calcareous sandstone-siltstone member. W. P. Woodring, 1949. Smaller Forami- nifera. gastropods: trochidae to turritellidae 119 No. used in this report USGS Cenozoic No. Field No. 69 123 70 130 71 16945 6 72 16957 40 73 16944 7 74 17439 142 74a 17493 142a 75 17437 133 76 5906a Description of locality LOWER PART OF CAIMITO FORMATION, madden basin Panama — continued Rio Chilibrillo, 1 kilometer below bridge on road to Casa Larga. Medium-grained somewhat calcare- ous and somewhat tuffaceous sand- stone in calcareous sandstone-silt- stone member, about 300 meters above base of Caimito formation. W. P. Woodring, 1949. Larger Fo- raminifera (Cole, 1952 [1953]). Rio Chilibrillo, 1.5 kilometers below bridge on road to Casa Larga. Sandy siltstone in calcareous sand- stone-siltstone member. W. P. Wood- ring, 1949. Smaller Foraminifera. Transisthmian Highway, 1 kilometer northwest of Madden Highway over- pass. Limestone in pyroclastic-clay member. J. R. Schultz and W. P. Woodring, 1947. Madden Highway, 1.7 kilometers northwest of Transisthmian High- way underpass. Limestone in pyro- clastic-clay member. J. A. Tavelli and W. P. Woodring, 1947. Transisthmian Highway, 2 kilometers northwest of Madden Highway over- pass. Limestone in pyroclastic-clay member. J. R. Schultz and W. P. Woodring, 1947. Transisthmian Highway, 1.5 kilometers south of Rio Chilibrillo bridge. Conglomerate near top of pyro- clastic-clay member. W. P. Wood- ring, 1949. Same locality. Coarse-grained sand- stone overlying conglomerate. W. P. Woodring, 1949. Not plotted. Transisthmian Highway, 0.5 kilometer north of Rio Chagres bridge. Clay at top of pyroclastic-clay member. T. F. Thompson and W. P. Wood- ring, 1949. Also smaller Forami- nifera. UPPER PART OF CAIMITO FORMATION, MADDEN BASIN, PANAMA Rfo Chagres about 1.5 miles (2.5 kilo- meters) above Alhajuela, about 50 to 75 feet (15 to 23 meters) strati- graphically below 17c (5905), in lighter colored limestone. D. F. MacDonald, 1911. [A submerged locality.] Location approximate. No. used in this report 76a 79 80 81 82 82a 83 84 84a USGS Cenozoic No. 5906b 5905 S399 8398 7289 16932 16929 17494 16930 17941 17942 Field No. 24 10 10a 10b Description of locality UPPER PART OF CAIMITO FORMATION, madden basin, panamA — continued Same locality, 10 to 25 feet (3 to 7 meters) lower stratigraphically, in hard limestone. D. F. MacDonald, 1911. [A submerged locality.] Not plotted. Rfo Chagres about 1.25 miles (2 kilo- meters) above Alhajuela, about 50 to 75 feet (15 to 23 meters) strati- graphically below 17b (5904). D. F. MacDonald, 1911. [A submerged locality, about 375 meters southwest of locality 76.] Not plotted. Rio Chagres, pebbly limy sandstone at Purgatorio, about 2 miles (3.2 kilometers) below mouth of Rio Pequinf. E. R. Lloyd, 1919. [A submerged locality, probably about 750 meters northeast of locality 76.] Not plotted. Rio Chilibrillo. A. A. Olsson, 1919. [Location indefinite.] Not plotted. Cave near Chilibre River, about 6 miles (10 kilometers) from Alhajuela. August Busck, 1911. [Matrix con- sists of sandstone. Presumably near locality 81.] Not plotted. Transisthmian Highway, 1.2 kilome- ters south-southwest of Rio Chili- brillo bridge, about 150 meters west of highway. Chilibrillo limestone member. J. R. Schultz and W. P. Woodring, 1947. Transisthmian Highway, 650 meters south-southeast of Rio Chilibrillo bridge. Calcareous sandstone mem- ber. J. R. Schultz and W. P. Wood- ring, 1947. Transisthmian Highway, 75 meters south of locality 82. Calcareous sandstone member. W. P. Wood- ring, 1949. Not plotted. Transisthmian Highway, 400 meters north of Rio Chagres bridge. Cal- careous sandstone member. J. R. Schultz and W. P. Woodring, 1947. Transisthmian Highway, west end of north abutment of Rio Chagres bridge. Calcareous sandstone mem- ber. T. F. Thompson and W. P. Woodring, 1949. Same locality, but at east end of abutment. Calcareous sandstone member. W. P. Woodring, 1949. Not plotted. 120 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. s:, 85a 86 5903 8385 5904 5874 89 90 17682 1695C 17683 90a 91 92 17684 16952 16940 Field No. 143 17 I I I 144a 16 Description of locality UPPER PART OF CAIMITO FORMATION, madden basin, panamA — continued Rio Chagres, top of hill opposite Alhajuela. [Alhajuela sandstone member.] D. F. MacDonald, 1911. [For location of Alhajuela see Reeves and Ross, 1930, pi. 5.] Rio Chagres, top of hill opposite Alhajuela. [Alhajuela sandstone member.] A. A. Olsson, 1919. Same as locality 85. Not plotted. Rio Chagres, % to }i mile (200 to 400 meters) above Alhajuela. [Alha- juela sandstone member.] D. F. MacDonald, 1911. [A submerged locality, about 400 meters north of locality 85.] Not plotted. Rio Chagres between Alhajuela and El Vigia. [Presumably Alhajuela sand- stone member.] H. Pittier, 1911. [For location of El Vigia see Reeves and Ross, 1930, pi. 5. [A submerged locality, too indefinite to plot.] 1.6 kilometers northwest of Madden Dam, on abandoned Public Roads Administration road to powder mag- azine. Alhajuela sandstone mem- ber. W. P. Woodring, 1949. Madden Highway, 1 kilometer north- west of Madden Dam. Alhajuela sandstone member. J. R. Schultz, T. F. Thompson, and W. P. Wood- ring, 1947. 1.2 kilometers south-southwest of Madden Dam, on road between Madden Highway and Transisth- mian Highway. Alhajuela sand- stone member. W. P. Woodring, 1949. 30 meters southwest of locality 90. Alhajuela sandstone member. W. P. Woodring, 1949. Not plotted. Transisthmian Highway, 1.3 kilome- ters southeast of Rio Chagres bridge. Alhajuela sandstone member. J. R. Schultz and W. P. Woodring, 1947. Madden Highway, 2 kilometers south- southeast of Madden Dam. Alha- juela sandstone member. J. R. Schultz, T. F. Thompson, and W. P. Woodring, 1947. No. used in this report 93 94 94a 95 96 96a 97 USGS Cenozoic No. 6509 6510 Field No. 126 37 104 18 Description of locality UNDIFFERENTIATED CAIMITO FORMATION, RIO CHAGRES AREA, CANAL ZONE Trail 750 meters southwest of Nuevo San Juan. Coarse-grained conglom- eratic pebbly sandstone. T. F. Thompson and W. P. Woodring, 1949. Larger Foraminifera. Rio Chagres, limestone at and a little above Las Cruces. D. F. Mac- Donald, 1913. [A submerged local- ity.] Location approximate. Rio Chagres, limestone a little below Las Cruces, on north bank of river. D. F. MacDonald, 1913. [A sub- merged locality a short distance south of locality 94.] Not plotted. LOWER PART OF CAIMITO FORMATION, PACIFIC COASTAL AREA, PANAMA Transisthmian Highway, 325 meters north of junction with Panama National Highway. Thin lens of algal limestone in tuff and tuffaceous sandstone. J. A. Tavelli and W. P. Woodring, 1947. Larger Foraminif- era (Cole, 1952 [1953]). Panama National Highway, about 175 meters northeast of junction with Transisthmian Highway. Lens of algal limestone in tuff and tuffaceous sandstone. T. F. Thompson and W. P. Woodring, 1947. Larger Foraminifera. Borrow pit on north side of road to housing development, about 3.2 kilometers northeast of Tocumen. Fine-grained tuff. T. F. Thompson and W. P. Woodring, 1947. Larger Foraminifera. LOWER PART OF CAIMITO FORMATION, MADDEN HIGHWAY AREA, CANAL ZONE Stream about 100 meters west of Madden Highway and 1.6 kilometers northeast of junction with Gaillard Highway. Limestone T. F. Thompson and W. P Woodring, 1947. Larger Foraminifera gastropods: trochidae to turritellidae 121 Xo. used in this report 98 99 99a 99b 99c 99d 99e 99f 99g USGS Cenozoic No. 16942 6019 6019a 6019b 6019c 6019d 6019e 6019f 6019g Field No. 35a Description of locality CULEBRA FORMATION, GAILLARD CUT, CANAL ZONE West side of Gaillard Cut, canal sta- tion 1600. 5 Float from Culebra for- mation. T. G. Moran and W. P. Woodring, 1947. Not plotted, same as locality 120. Lower half of section near Las Cas- cades, exact horizon not known. D. F. MacDonald and T. W. Vaughan, 1911. [Presumably float near canal station 1610.] Not plotted. Near canal station 1611. D. F. Mac- Donald and T. W. Vaughan, 1911. Also larger Foraminifera (Cole 1953a). Plotted on plate 2. [Local- ities 6019a to 6019g, inclusive, are located between canal stations 1606 and 1611 and are arranged in up- ward sequence in that order. For stratigraphic section see MacDonald, 1919, p. 537-538 and for general location see MacDonald, 1919, pi. 154. Location with reference to the canal stations are taken from man- uscript structure sections prepared by MacDonald. The construction- period localities in Gaillard Cut pre- sumably represent the excavated prism of rock. Those plotted are shown by the symbol for submerged localities, though many may be above the level of the canal.] Near canal station 1611. D. F. Mac- Donald and T. W. Vaughan, 1911. Not plotted. Canal station 1610. Donald and T. W. Not plotted. Canal station 1609. Donald and T. W. Not plotted. Near canal station 1608. D. F. Mac- Donald and T. W. Vaughan, 1911. Not plotted. Near canal station 1607. D. F. Mac- Donald and T. W. Vaughan, 1911. Also larger Foraminifera (Cole, 1953a). Not plotted. Canal station 1606. D. F. Mac- Donald and T. W. Vaughan, 1911. Also larger Foraminifera (Cole, 1953a). Plotted on plate 2. [As- signed by MacDonald to Emperador limestone member, but apparently represents a sandy limestone referable to the Culebra formation proper.] 1 The canal stations are located along the center alinement of the canal at inter- vals of 100 feet (30 5 meters) and are numbered from the Caribbean terminus to the Pacific terminus. D. F. Mac- Vaughan, 1911. D. F. Mac- Vaughan, 1911. No. used in this report 99h 100 KID:, 100b 101 102 102a 103 104 104a 104b 105 USGS Cenozoic No. 5857 6020a 6020b 6020c 16943 6012a 6507 6012b 16933 6976 5863 6517 Field No. 34 31 Description of locality CULEBRA FORMATION, GAILLARD CUT, canal zone — -continued Near canal station 1610. D. F. Mac- Donald, 1911. Not plotted, prac- tically same as locality 99c. Near canal station 1614. D. F. Mac- Donald and T. W. Vaughan, 1911. Plotted on plate 2. [Localities 6020a to 6020c, inclusive, underlie 6019a (MacDonald, 1919, p. 538). Type locality of "Orbitolites" americana.] Near canal station 1614. D. F. Mac. Donald and T. W. Vaughan, 1911. Not plotted. Near canal station 1613. D. F. Mac- Donald and T. W. Vaughan, 1911. Also corals (Vaughan, 1919a, p. 208). Not plotted. West side of Gaillard Cut, canal sta- tion 1619. Black clay 60 centi- meters below base of limestone. T. G. Moran and W. P. Woodring, 1947. Plotted on plate 2. Near canal station 1723. D. F. Mac- Donald and T. W. Vaughan, 1911. Plotted on plate 2. [For strati- graphic section including localities 6012a and 6012b see MacDonald, 1919, p. 537 and for general location see pi. 154.] Lower part of Culebra formation about 0.25 mile (300 meters) south of Empire bridge, altitude 55 feet (17 meters). D. F. MacDonald, 1911. (Probably near canal station 1720.) Not plotted. Near canal station 1717. D. F. MacDonald and T. W. Vaughan, 1911. Plotted on plate 2. Wes1 side of Gaillard Cut, canal sta- tion 1730. Sandy pebble bed in almost black mudstone. T. G. Moran and W. P. Woodring, 1947. Plotted on plate 2. Culebra (Gaillard) Cut, about midway between Empire and Culebra, about 50 feet (15 meters) below original surface. Received from George Gaillard, 1909. [Presumably near canal station 1730.] Not plotted. Conglomerate near canal station 1731, about 0.3 mile (0.5 kilometer) below Empire bridge. D. F. MacDonald, 1911. Not plotted. East side of canal opposite Culebra railroad station. D. F. MacDonald, 1913. [Between canal stations 1750 and 1760.] Not plotted. 122 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. 106 6012c 107 601 2d 108 108a 108b 16951 4897 108c 109 5859 6013 110 16886 110a 6508 Field No. la Description of locality CULEBRA FORMATION, GA1LLARD CUT, canal zone — continued Near canal station 1759. D. F. Mac- Donald and T. W. Vaughan, 1911. Plotted on place 2. [For strati- graphic sections including localities 6012a to 6012e inclusive, see Mac- Donald, 1919, p. 536-537 and for general locations see plate 154.] Near canal station 1768. Calcareous sandstone. D. F. MacDonald and T. W. Vaughan, 1911. Also larger Foraminifera. [Type locality of Miogypsina cushmani.] Plotted on plate 2. West side of Gaillard Cut, canal station 1759. Dark gray calcareous mud- stone 1.5 meters above water level. See stratigraphic section, page 35 J. R. Schultz and W. P. Woodring, 1947. Smaller Foraminifera. Not plotted. Same locality, float 7.5 meters below uppermost calcareous sandstone of Culebra formation. J. R. Schultz and W. P. Woodring, 1947. Not plotted. East side of Culebra [Gaillard] Cut, about three-fourths mile (1.2 kilo- meters) northwest of Gold Hill. Sidney Paige, 1908. [Presumably near canal station 1760.] Not plotted. West side of canal, canal station 1760 D. F. MacDonald, 1911. Not plotted. East side of Culebra [Gaillard] Cut, opposite Culebra. Pebbly calcareous sandstone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 536, plate 154). [Canal sta- tion 1762.] Plotted on plate 2. East side of Gaillard Cut, canal station 1754, about 60 meters northeast of edge of canal and about 100 meters northwest of northwest edge of Culebra Extension slide. Tuffaceous sandstone and calcareous concretions in transition zone between Culebra and Cucaracha formations. J. R. Schultz and W. P. Woodring, 1947. Plotted on plate 2. East Bide of Culebra [Gaillard] Cut, canal station 1755, upper part of Culebra formation. D. F. Mac- Donald, 1913. Not plotted; ap- proximately same as locality 110. No. used in this report 111 Ilia 111b 112 112a 113 114 115 115a USGS Cenozoic No. 16887 KiSSS 16910 16927 6011 5860 6505 6515 Field No. 25 25a Description of locality CULEBRA FORMATION, GAILLARD CUT, canal zone — continued Stanford University locality 2701, west side of Gaillard Cut, canal station 1754, altitude 140 feet (42.5 meters). T. F. Thompson, 1943. Plotted on plate 2. West side of Gaillard Cut, canal sta- tion 1755 and 30 meters northwest- ward along strike, about 45 meters southwest of edge of canal. Cal- careous concretions in sandy siltstone corresponding to top of bed 13 of section on page 35. J. R. Schultz and W. P. Woodring, 1947. Not plotted; same as locality 111. West side of Gaillard Cut, canal station 1754, from dirty sandstone brought to surface by test explosion, evi- dently from base of bed 13 of section on page 35. J. R. Schultz and W. P. Woodring, 1947. Not plotted; same as locality Ilia. West side of Gaillard Cut, canal station 1759, about 30 meters southwest of edge of canal. Basal part of bed 13 of section on page 35. J. R. Schultz and W. P. Woodring, 1947. Plotted on plate 2. Same locality, top of bed 13 of section on page 35. J. R. Schultz and W. P. Woodring, 1947. Not plotted. East side of Culebra [Gaillard] Cut, near canal station 1845, between Paraiso and Gold Hill. Foramin- iferal limy sandstone. D. F. Mac- Donald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 535, pi. 154). Plotted on plate 2. West side of Culebra [Gaillard] Cut, canal station 1847 plus 25 feet (6.2 meters). D. F. MacDonald, 1913. Plotted on plate 2. West side of Culebra [Gaillard] Cut, near canal station 1860. Lower part of limy sandstone. D. F. Mac- Donald, 1913. Also larger Foramin- ifera: Miogypsina intermedia (Drooger, 1952, p. 36). Plotted on plate 2. West side of Culebra [Gaillard] Cut, about one-third mile (500 meters) north [northwest] of Paraiso. D. F. MacDonald, 1913. Not plotted; apparently close to locality 115. gastropods: trochidae to turritellidae 123 No. used in this report USQS Cenozoic No. 115b 6443 116 5853 Field No. 117 6014 118 6016 118a 119 6444 5858 119a 5866 Description of locality CULEBRA FORMATION, GAILLARD CUT, canal zone — continued A mile (1.6 kilometers) south of Cu- lebra Cut. Ralph Arnold and D. F. MacDonald, 1913. [The locality data are indefinite, but this pre- sumably is the collection to which MacDonald referred in a notation on his label for 6515: "Arnold took fossils from here."] Not plotted; evidently same as locality 115a. West side of Culebra [Gaillard] Cut, canal station 1863. Pebbly tuffa- ceous sandstone about 2.5 feet (75 centimeters) thick. D. F. MacDon- ald, 1911. Also coral (Vaughan, 1919a, p. 208, cited as locality 5863). Plotted on plate 2. EMPERADOR LIMESTONE MEMBER OF CULEBRA FORMATION, CANAL ZONE Limestone on street near railroad at Empire, 0.25 or 0.3 mile (400 or 500 meters) north-northwest of railroad station. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, pi. 154). Plotted on plate 2; location approximate, based on Mac- Donald's plotted location. Old quarry 0.3 mile (500 meters) west- northwest of Empire. D. F. Mac- Donald and T. W. Vaughan, 1911 (MacDonald, 1919, pi. 154). Also corals (Vaughan, 1919a, p. 208-209). Plotted on plate 2, location approxi- mate, based on MacDonald's plotted location. Quarry at Empire. Ralph Arnold, 1913. Not plotted; presumably same as locality 118 or nearby. Lower part of upper limestone near tower N. Thought to be equivalent of fossil lot 6a [5856], but bed is not directly traceable. D. F. MacDon- ald, 1911. [Tower N was a signal tower on the original line of the Panama Railroad near Las Cascades. The right-of-way, still recognizable at some places as a low artificial ridge, immediately adjoins the left bank of the canal in the Las Cas- cades area. Locality 119 presum- ably is near locality 120.] Not plotted. Upper limestone bed near tower N. Same as fossil lot 6c [5858]. D. F. MacDonald, 1911. Also larger Fo- raminifera (Cole, 1953a). Not plotted; same as locality 119. No. used in this report 119b 119c 120 120a 121 USGS Cenozoic No. 122 123 124 125 6669 5856 16958 8043 1 61111 Field No. 35 6012e 16955 5852 34a 33 32 Description of locality EMPERADOR LIMESTONE MEMBER OF CULEBRA FORMATION, CANAL ZONE continued Upper bed of limestone near tower N. D. F. MacDonald, 1913. Not plotted; same as locality 119. Highest limestone near tower N, be- tween towers M and N. D. F. Mac- Donald, 1911. Not plotted; near locality 119. West side of Gaillard Cut, canal sta- tion 1600. Calcareous siltstone and limestone. T. G. Moran and W. P. Woodring, 1947. Plotted on plate 2. Las Cascades [west side of Gaillard Cut, canal station 1600]. Lime- stone. W. P. Woodring, 1917. Not plotted; same as locality 120. West side of Gaillard Cut, canal sta- tion 1619. Limestone overlying clay and siltstone. T. G. Moran and W. P. Woodring, 1947. Not plotted; same as locality 101. CUCARACHA FORMATION, CANAL ZONE East side of Gaillard Cut, one-eighth mile (200 meters) north of Gold Hill [near canal station 1775]. Black carbonaceous shale. D. F. Mac- Donald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 535-536). Plotted on plate 2. LA BOCA MARINE MEMBER OF PANAMA FORMATION, CANAL ZONE East of Gaillard Cut, 200 meters up Rio Masambf from east bank of canal. Rio Masambf enters the canal at canal station 1696. Coral- liferous limestone at base of La Boca member. T. G. Moran and W. P. Woodring, 1947. Plotted on plate 2. East side of Gaillard Cut, canal station 1702. Dark, almost black mud- stone. T. G. Moran and W. P. Woodring, 1947. Smaller Foraminif- era. Plotted on plate 2. East side of Gaillard Cut near Empire bridge. [The Empire bridge was located approximately at canal sta- tion 1709.] D. F. MacDonald, 1911. Plotted on plate 2; location approxi- mate. 124 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. 126 6267 127 cms 127a 626s 127b 6336 128 1694: 129 1 695 I Field No. 1-1 a Description of locality LA BOCA MARINE MEMBER OF PANAMA formation, canal zone — continued Relocated line of Panama Railroad, a little south of station at New Culebra, about opposite Catholic church at Culebra, half a mile (750 meters) northwest of 6268. Same formation as 6268 and 6018. Yel- lowish spherically weathering limy sandstone. D. F. MacDonald,1912. [Possibly the unnumbered fossil locality west of 6018 on MacDonald's map (MacDonald, 1919, pi. 154)]. Plotted on plate 2; location approxi- mate. Cut on relocated line of Panama Rail- road opposite Empire, near road from Empire to Las Cascades Plantation. Tuffaceous calcare- ous(?) sandstone. D. F. MacDonald and T. W. Vaughan, 1911 (Mac- Donald, 1919, pi. 154). Plotted on plate 2; location approximate. Relocated line of Panama Railroad, junction with track leading down to Canal between Gold Hill and Em- pire bridge. Yellowish spherically weathering limy sandstone. D. F. MacDonald, 1912, 1913. Not plot- ted; presumably near locality 127. Relocated line of Panama Railroad, junction with track leading down to Canal between Gold Hill and Em- pire bridge. Light-colored tuff and kaolinitic beds overlying light gray and buff spherically weathering sandstone. Hill's Panama forma- tion. D. F. MacDonald, 1913. Not plotted; same as locality 127a, but from overlying tuff. Abandoned quarry on north side of Old Gaillard Highway, 230 meters southwest of New Gaillard Highway entrance to Summit Experimental Gardens. Massive calcareous sand- stone. J. R. Schultz and W. P. Woodring, 1947. Plotted on plate 2. South side of New Gaillard Highway ai milepost 11, about 400 meters northwest of Madden Highway turn- off. Relatively soft yellowish coral- liferous limestone with marly part- ings at base of La Boca marine member of Panama formation. J. R. Schultz, T. F. Thompson, and \Y. P. Woodring, 1917. Also corals. No. used in this report 129a 130 131 131a 132 USGS Cenozoic No. 16953 6010 6256 6257 16939 Field No. 14 Description of locality LA BOCA MARINE MEMBER OF PANAMA formation, canal zone — continued South side of New Gaillard Highway, 100 meters southeast of locality 129. Hard grayish limestone overlying limestone at locality 129, but part of same unit. J. R. Schultz, T. F. Thompson and W. P. Woodring, 1947. Not plotted. Near Canal station 1910, northwest of Pedro Miguel Locks. [About 600 meters northwest of north end of Pedro Miguel Locks.] Mudstone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 534, pi. 154). Also smaller Foraminifera; type locality of Sipho- generina transversa. Plotted on plate 2. One-eighth mile (200 meters) east of wagon road at Bald Hill, 1.5 miles (2.4 kilometers) south of Miraflores. Limestone. D. F. MacDonald, 1912. Corals (Vaughan, 1919a, p. 209). Presumably near locality 132. • [Bald Hill is identified as the cur- rently unnamed hill immediately northeast of Red Tank. For a section at Bald Hill see MacDonald (1919, p. 534). His manuscript on the geology of Panama includes a sketch of the strata at this locality labeled, in his writing, "Section at Bald Hill, a mile (1.6 kilometers) south [southeast] of Pedro Miguel and 100 yards (100 meters) east of the main road." The locality data just quoted approximately fit the specified identification of Bald Hill. The data in the Cenozoic register evidently are erroneous.] Not plotted. Practically same limestone bed as 6256, but about 10 feet (3 meters) higher stratigraphically. D. F. MacDonald, 1912. Also larger Foraminifera (Cole, 1953a). Not plotted. 1.6 kilometers north-northwest of north end of Miraflores Locks, on inciner- ator road leading off Gaillard High- way on west side of middle arm of Miraflores Lake. Fine-grained tuff and tuffaceous siltstone. T. F. Thompson and W. P. Woodring, 1947. gastropods: trochidae to turritellidae 125 No. used in this report usas Cenozoic No. Field No. 132a 6255 133 6237 134 135 136 17691 17690 16912 102 101 12 136a 137 137a 16911 138 16909 26 27 Description of locality LA BOCA MARINE MEMBER OF PANAMA formation, canal zone — continued Fossiliferous limy sandstone }i mile (750 meters) south of Mirafiores station, on wagon road to Panama. D. F. MacDonald, 1912. Larger Foraminifera (Cole, 1953a). Type locality of Lepidocyclina mirafloren- sis. Apparently submerged. Not plotted. Limestone in swamp north of Ancon Hill, about }i mile (400 meters) south of Diablo Ridge. D. F. MacDonald, 1912. [The swamp and any out- crops in it are now covered with fill.] Not plotted. LOWER PART OF GATTJN FORMATION Road from Sabanita to Maria Chiquita, cut on south side of ridge, 1.3 kilo- meters south-southwest of Maria Chiquita, Panama. Silty sandstone. W. P. Woodring, 1949. Cut on west side of Transisthmian Highway at south edge of Sabanita, Panama. Ferrugineous concretions in sandstone interbedded with con- glomerate. W. P. Woodring, 1949. North side of Transisthmian Highway, knoll about 30 meters north of high- way, 1.2 kilometers northwest of Sabanita, Panama. Silty fine- grained sandstone. T. F. Thompson and W. P. Woodring, 1947. Same locality. Stanford University locality 2611. Latitude 9°21' N, plus 1,100 feet (335 meters), longi- tude 79°49' W. T. F. Thompson, 1942. Not plotted. South side of Transisthmian Highway, 1.7 kilometers northwest of Sabanita, Panama. Soft silty fine-grained sandstone. W. P. Woodring, 1947. Same locality. Stanford University locality 2655. Latitude 9°21' N., plus 3,000 feet (915 meters), longi- tude 79°49' W., plus 1,100 feet (335 meters). T. F. Thompson, 1942. Not plotted. North and south sides of Transisth- mian Highway, 1.6 kilometers north- east of Canal Zone boundary, Panama. Soft silty fine-grained sandstone. W. P. Woodring, 1947. No. used in this report USOS Cenozoic Field No. No. 138a 139 140 141 6667 Description of locality 142 143 144 16948 6030 6029a 28 LOWER PART OF GATUN FORMATION continued Same locality. Stanford University locality 2656. Latitude 9°21' N., plus 5,000 feet (1,525 meters), longi- tude 79°50' W., plus 1,000 feet (300 meters). T. F. Thompson, 1942. Not plotted. Steep ridge about 2.5 miles (4 kilo- meters) northeast [north] of Monte Lirio, overlooking and about 250 feet above Gatun Lake, Canal Zone. D. F. MacDonald, 1913. [Southern part of Zorra Island.] Location approximate. MIDDLE PART OF GATUN FORMATION, EASTERN AREA Stanford University locality 2708. Latitude 9°21' N, plus 4,200 feet (1,280 meters), longitude 79°51' W., plus 800 feet (245 meters). T. F. Thompson, 1943. [500 meters northwest of intersection of Trans- isthmian Highway and Canal Zone boundary, Canal Zone.] About 100 meters northwest of Trans- isthmian Highway, on secondary road entering Highway 600 meters west of Canal Zone boundary, Canal Zone. Medium-grained sandstone. W. P. Woodring, 1947. Stanford University locality 2698. Northeast of Fort Gulick, latitude 9°20' N, longitude 79°52' W., plus 1,010 feet (310 meters). T. F. Thompson, 1943. [1.1 kilometers southeast of junction of Trans- isthmian Highway and road to Fort Gulick, Canal Zone.] Relocated Panama Railroad, 85-foot (25 meter) cut 1.5 to 2 miles (2.4 to 3.2 kilometers) east of Camp Cotton, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 542, pi. 154). Relocated Panama Railroad, big cut }i to Yi mile (0.6 to 0.8 kilometers) northeast of Camp Cotton, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 542, pi. 154). 413788—57- 126 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report I Ita 144b 144c I 1 Id 145 ] 46 1 17 I I7.i I t7h 147c USGS Cenozoic No. Field No. 6029b 6335 6235 6334 6031 5845 6033a 6033b 6033c 6003 Description of locality MIDDLE PART OF GATUN FORMATION, eastern area — continued Same locality, from overlying 32 to 42 feet (10 to 13 meters). D. F. Mac- Donald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 542). Not plotted. Relocated Panama Railroad, lowest bed in big cut about Yi mile (0.8 kilometer) east of Camp Cotton, Canal Zone. Same locality as lot 17 of 1911 [6029a]. D. F. Mac- Donald, 1913. Same as locality 144. Not plotted. Relocated Panama Railroad, 3.5 miles (5.6 kilometers) out from Gatun, Canal Zone. Above fuller's earth beds. D. F. MacDonald, 1912. [Apparently same as locality 144a.] Not plotted. Relocated Panama Railroad, big curved cut about 1 mile (1.6 kilometers) east of Camp Cotton, Canal Zone. Above fuller's earth beds. D. F. MacDonald, 1913. [Probably close to locality 144a.] Not plotted. Relocated Panama Railroad, % mile (0.8 kilometer) west of Camp Cotton, Canal Zone. Basal part of section; conglomerate and 1 foot above con- glomerate. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 543, pi. 154). Quebrancha Hills overlooking Gatun Lake, 1.5 miles (2.4 kilometers) northeast [east-southeast] of Gatun, Canal Zone. D. F. MacDonald, 1911. [Presumably in railroad cut.] Location approximate. Panama Railroad, about 3,500 feet (1,065 meters) southeast of Gatun railroad station, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 543, pi. 154). Same locality, from overlying 4 feet (1.2 meters). D. F. MacDonald and T. W. Vaughan, 1911 (Mac- Donald, 1919, p. 543). Not plotted. Same locality, from overlying 15 to 20 feet (4.5 to 6 meters). D. F. Mac- Donald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 543). Not plotted. Same locality and bed as locality 147. D. F. MacDonald, 1911 (Mac- Donald, 1919, p. 543). Not plotted. No. used in this report 147d 147e 147f 147g J17h 1171 H7 j 148 149 150 150a 151 152 USGS Cenozoic No. 6004 6005 6006 58'. (9 6442 8376 8379 S3SII s:;si 8377 10997 s:;ss 8483 Field No. Description of locality MIDDLE PART OF GATUN FORMATION, eastern area — continued Same locality, but higher stratigraphi- cally. D. F. MacDonald, 1911. Not plotted. Same locality, but higher stratigraphi- cally. D. F. MacDonald, 1911. Not plotted. Same locality, but higher stratigraphi- cally. D. F. MacDonald, 1911. Not plotted. Highest fossil-bearing beds, Que- brancha Hills, % mile (1.2 kilo- meters) out from Gatun, Canal Zone. D. F. MacDonald, 1911. Probably same as locality 147b. Not plotted. Half a mile (750 meters) south [south- east] of Gatun, Canal Zone. Ralph Arnold and D. F. MacDonald, 1913. [Probably at or near locality 147.] Not plotted. Panama Railroad, southeast of Gatun, station 6 plus 20, Canal Zone. A. A. Olsson, 1918. [Probably near locality 147.] Not plotted. Panama Railroad, southeast of Gatun, station 4A, Canal Zone. A. A. Olsson, 1918. [Probably near local- ity 147.] Not plotted. Lower Gatun along Panama Railroad between Monte Lirio and Gatun, station 4, Canal Zone. A. A. Olsson, 1918. Echinoid. Location indefinite; not plotted. Panama Railroad, southeast of Gatun, station C, Canal Zone. A. A. Olsson, 1918. Locality indefinite; not plotted. Panama Railroad, first cut south of Gatun, Canal Zone. A. A. Olsson, 1918. Panama Railroad, high cut about 0.4 mile (650 meters) southeast of Gatun railroad station, Canal Zone. W. P. Woodring, 1923. [Same as locality 150.] Not plotted. Gatun, station B, Canal Zone. Lower Gatun, lower Turrilella altilira zone. A. A. Olsson, 1918. [In Gatun area, but location indefinite.] Not plot- ted. Gatun area, station B, Canal Zone. A. A. Olsson, 1918. Location in- definite; not plotted. gastropods: trochidae to turritellidae 127 No. used in this] report 153 USGS Cenozoic No. 16950 153a Field No. 47 154 16935 155 155a 155b 16970 16949 155c 16915 156 16928 49 50 13 Description of locality MIDDLE PART OF GATUN FORMATION, eastern area — continued Gatun Third Locks excavation, plug at south end of excavation, Canal Zone. Unit 1 of section on p. 44; silty to marly sandstone. T. F. Thompson and W. P. Woodring, 1947. Stanford University locality 2657. Gatun Third Locks excavation, south end of excavation, Canal Zone. Latitude 9°15' N., plus 5,600 feet (1,705 meters), longitude 79°54' W., plus 5,150 feet (1,570 meters). Unit 3 of section on p. 44; medium- grained to very fine-grained sand- stone. T. F. Thompson, 1942. 425 feet (130 meters) north of locality 153. Not plotted. Gatun Third Locks excavation, west side of excavation 0.6 mile (1 kilo- meter) north of Gatun Lake, Canal Zone. Unit 10 of section on p. 44; conglomerate. T. F. Thompson and W. P. Woodring, 1947. Stanford University locality 2653. Gatun Third Locks excavation, Canal Zone. Latitude 9°16' N., plus 4,700 feet (1,430 meters), longi- tude 79°54' W., plus 5,800 feet (1,770 meters). Units 11 and 12 of section on p. 44; fine-grained sand- stone and marly siltstone. T. F. Thompson, 1942. Spoil dump of Gatun Third Locks excavation, Canal Zone. T. F. Thompson, 1945. [Essentially same stratigraphic range as locality 155.] Not plotted. Spoil dump of Gatun Third Locks excavation, Canal Zone. T. F. Thompson and W. P. Woodring, 1947. Essentially same stratigraph- ic range as locality 155. Not plotted. Gatun Third Locks excavation, east side of excavation 1 mile (1.6 kilo- meters) north of Gatun Lake, Canal Zone. Turritella-bea,ring marly silt- stone in lower part of unit 12b of section on p. 44. T. F. Thompson and W. P. Woodring, 1947. In- cluded in stratigraphic range of locality 155. Not plotted. Jadwin Road at crossing of Panama Railroad, northern part of Gatun, Canal Zone. Turritella-bearmg marly siltstone. T. F. Thompson and W. P. Woodring, 1947. 157 158 USGS Cenozoic No. Field No. 16926 2682 159 159a 159b 159c 160 160a 161 161a ltilh 161c 161d Description of locality 56 17 5211 5414 6273 5662 5846 8369 8365 8395 8375 8382 8366 MIDDLE PART OF GATUN FORMATION, eastern area — continued Westernmost cut on Panama Railroad cutoff south of Fort Davis, 1.2 miles (1.9 kilometers) northeast of Gatun railroad station, Canal Zone. Silt- stone and silty sandstone. W. P. Woodring, 1947. Vamos a Vamos, Canal Zone. R. T. Hill, 1895. [Locality erroneous; it apparently should be "French Canal, 10.5 kilometers from Col6n"; that is, near Gatun. See remarks under locality 173a.] Not plotted. Lock site at Gatun, Canal Zone. W. S. Standifer, 1909. Not plotted. Upper lock site at Gatun, Canal Zone. W. J. Ergenzinger, 1910(?). Not plotted. Lock site [at Gatun], Canal Zone, 10 to 50 feet (3 to 15 meters) below surface. Dan St. Clair, 1912(?). Not plotted. Near Gatun Dam site, Canal Zone. D. F. MacDonald, 1911. Not plot- ted. Near spillway at Gatun Dam site, Canal Zone. D. F. MacDonald, 1911. Chagres Dam spillway, station 5, Canal Zone. Just above contact with Caimito sandstone. A. A. Olsson, 1918. [At or near locality 160.] Not plotted. MIDDLE PART OF GATUN FORMATION, WESTERN AREA Railroad cuts west of Gatun Dam, station C, Canal Zone. A. A. Olsson, 1918. Location approxi- mate. Railroad cuts west of Gatun Dam, station D, Canal Zone. A. A. Olsson, 1918. [Near locality 161.] Not plotted. Cuts west of Gatun Dam, station 4 plus 5, Canal Zone. A. A. Olsson, 1918. [Near locality 161.] Not plotted. Railroad cuts west of Gatun Dam, station B, Canal Zone. A. A. Olsson, 1918. [Near locality 161.] Not plotted. Cuts west of Gatun Dam, station 3a, Canal Zone. A. A. Olsson, 1918. [Near locality 161.] Not plotted. 128 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USDS Cenozoic No. Field No. Description of locality MIDDLE PART OF GATUN FORMATION, western area- — continued 162 8396 Lower trail on west side of Rfo Chagres, a mile (1.6 kilometers) north [west- northwest] of Gatun Dam, Canal Zone. A. A. Olsson, 1918. Loca- tion approximate. 162a 8359 Lower trail on west side of Rfo Chagres northwest of Gatun Dam, Canal Zone. D. D. Condit and A. A. Olsson, 1918. [Probably near lo- cality 162.] Not plotted. 163 8394 Trail on east side of Rio Chagres, halfway between Gatun Dam and mouth of river, station 2, Canal Zone. A. A. Olsson, 1918. Loca- tion approximate. Represents upper part of formation. 164 8391 Bluff on west side of Gatun Lake, Canal Zone. D. D. Condit, 1918. Location indefinite; not plotted. 165 8372 Headwaters of Rfo Pifia, station 14b, Canal Zone. Middle Gatun. A. A. Olsson, 1918. Location approxi- mate. 166 8357 Pina triangulation station region, sta- tion 6c, Canal Zone. Base of upper Gatun. D. F. MacDonald and A. A. Olsson, 1918. Location approxi- mate. 167 8374 Tick Creek, station 56B, Canal Zone. Top of middle Gatun, oyster bed. A. A. Olsson, 1918. Location ap- proximate. 168 8361 Tick Creek, station 27, Canal Zone. Base of upper Gatun. A. A. Olsson, 1918. [Downstream from locality 167.] Not plotted. 169 8360 West of Gatun Lake, Tick Camp sheet, station 6c, Canal Zone. A. A. Olsson, 1918. [Probably near lo- cality 167.] Location indefinite; not plotted. 170 8368 Headwaters of Quebrada Cana [Rfo Cano Quebrado], station 4a, Panama. Base of upper Gatun. A. A. Olsson, 1918. Location approximate. 170a 8411 Headquarters of Quebrada Cana [Rfo Cano Quebrado], station 2 plus 50, Panama. A. A. Olsson, 1918. Near locality 170. Not plotted. No. used in this report 171 172 173 173a 174 175 176 176a 177 usos Cenozoic No. 6035 2688 2690 8410 8358 SJII'.I Field No. 48 29 49 Description of locality UPPER PART OF GATUN FORMATION, EASTERN AREA Stanford University locality 2707. Drainage ditch 500 feet (150 meters) west of French Canal, Canal Zone. Latitude 9°17' N., plus 3,500 feet (1,065 meters), longitude 79°55' W., plus 4,000 feet (1,220 meters). T. F. Thompson, 1943. Mindi Hill cut, near bottom of canal, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 544, pi. 154). A submerged locality. Stanford University locality 2654. Panama Railroad realignment [Third Locks realignment] cut about % mile (1 kilometer) north of north end of Gatun Third Locks excavation, Canal Zone. Latitude 9°18' N., longitude 79°55' W., plus 200 feet (60 meters). T. F. Thompson, 1942. [French Canal] 10.5 kilometers from Col6n, Canal Zone. R. T. Hill, 1895. [According to Dall (Hill, 1898, p. 271), Hill's no. 48 repre- sents Hill's Monkey Hill beds. The locality record probably should read 6 kilometers from Col6n. See re- marks under locality 158.] Not plotted. Deviation [Diversion] cut south of Monkey Hill [Mount Hope], Canal Zone. R. T. Hill, 1895. Location approximate. Cuts on north [west] side of French Canal [East Diversion], Mount Hope, Canal Zone. A. A. Olsson, 1918. Location approximate. Road bordering French Canal [East Diversion], near Mount Hope, Canal Zone. A. A. Olsson, 1918. Loca- tion approximate. Road on south [east] side of French Canal [East Diversion], Canal Zone. A. A. Olsson, 1918. [Probably near locality 176.] Not plotted. Monkey Hill [Mount Hope], near Gatun, Canal Zone. J. Rowell, 1857 and possibly later. [Some specimens have early Smithsonian Institution catalog numbers, but most have later U. S. National Museum numbers.] gastropods: trochidae to turritellidae 129 No. used in this report US'.'S Cenozoic No. 177a 177b 177c 177d 4895 5854 5855 6036 Field No. 178 179 180 181 182 182a 8413 8362 8364 8408 8488 Description of locality UPPER PART OF GATUN FORMATION, eastern area — continued Mount Hope, west side of Panama Railroad, Canal Zone. Ernest Howe, 1908. [Essentially same as locality 177.] Not plotted. Mount Hope, west side of Panama Railroad near oil tanks, Canal Zone. D. F. MacDonald, 1911. [Essen- tially same as locality 177.] Not plotted. [West side of Panama Railroad] op- posite Mount Hope Cemetery, Canal Zone. D. F. MacDonald, 1911. [Essentially same as locality 177.] Not plotted. Mount Hope, about )i mile (270 meters) south of railroad station, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 544, pi. 154). [Essentially same as locality 177.] Not plotted. Stanford University locality 2672. Old quarry % mile (1 kilometer) west-southwest of junction of Trans- isthmian Highway and Coco Solo road, Canal Zone. Latitude 9°20' N., plus 2,000 feet (600 meters), longitude 79°53' W., plus 4,000 feet (1,200 meters). T. F. Thompson, 1943. UPPER PART OF GATUN FORMATION, WESTERN AREA Upper edge of Chilas [Chila] village, Rio Indios [Indio], Panama. D. D. Condit and Strohm, 1918. Plotted on figure 3. Caribbean coast 8 miles (13 kilometers) west of Rio Indies [Indio], Panama. Strohm, 1918. Plotted on figure 3. Caribbean coast 10 miles (16 kilom- eters) west of Rio Indios [Indio], Panama. Strohm, 1918. Between locality 180 and Rio Miguel. Not plotted. Caribbean coast east of San Miguel [Rio Miguel], station 25 plus 600 feet (150 meters), Panama. E. R. Smith, 1918. [Between locality 180 and Rio Miguel.] Not plotted. Caribbean coast east of San Miguel [Rio Miguel], station 25 plus 400 feet (120 meters), Panama. E. R. Smith, 1918. [Between locality 180 and Rio Miguel.] Not plotted. No. used in this report 183 184 185 USGS Cenozoic No. 186 186a 186b 187 188 188a 188b 188c 8487 8363 8383 Field No. Description of locality 6037 6675 8440 16946 5909 6034 6668 51 UPPER PART OF GATUN FORMATION, western area — continued Caribbean coast east of Rio San Miguel [Rio Miguel], station 4 plus 40 feet (12 meters), Panama. E. R. Smith, 1918. [Between locality 180 and Rio Miguel.] Not plotted. Rio San Miguel [Rio Miguel] 4 miles (6.5 kilometers) above mouth, Pan- ama. Strohm, 1918. Plotted on figure 3. Caribbean coast, west of Rio San Miguel [Rfo Miguel], station 26 plus 100 (30 meters), Panama. E. R. Smith, 1918. Location approximate. Plotted on figure 3. toro limestone member of chagres sandstone Coquina limestone at Toro Point, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 545). Coquina rock at Toro Point, Canal Zone. D. F. MacDonald, 1913. [Same as locality 186.] Not plotted. Toro Point, Canal Zone. D. F. Mac- Donald and A. A. Olsson, 1918. [Same as locality 186.] Not plotted. Stanford University locality 2700. Be- tween Limon Bay and Rio Chagres, Canal Zone. Latitude 9° 18' N., plus 1,000 feet (300 meters), longitude 79°56' W. T. F. Thompson, 1943. Rio Pifia road, 0.9 mile (1.4 kilometers) southwest of Gatun Dam spillway bridge, Canal Zone. Coquina lime- stone. T. F. Thompson and W. P. Woodring, 1947. Limestone overlying Gatun formation west of Gatun Dam, Canal Zone. D. F. MacDonald, 1911. [Approxi- mately same as locality 188.] Not plotted. Top of ridge at west end of Gatun Dam, Canal Zone. D. F. MacDonald and T. W. Vaughan, 1911 (MacDonald, 1919, p. 543). [Approximately same as locality 188.] Not plotted. Coquina limestone on crest of ridge west of Gatun Dam, Canal Zone. D. F. MacDonald, 1913. [Approxi- mately same as locality 188.] Not plotted. 130 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE No. used in this report USGS Cenozoic No. 1SS.I 188e 189 190 191 192 193 194 195 19G 0236 8442 8392 8402 8371 SUM 8401 s:;::; 8403 ski;, 197 8482 198 SIS I Field No. Description of locality TORO LIMESTONE MEMBER OF CHAGRES sandstone — continued Borrow pit west of Gatun Dam, Canal Zone. Limestone overlying Gatun formation. D. F. MacDonald, 1912. [Approximately same as locality 188.] Not plotted. Hill southwest of Gatun locks, Canal Zone. A. A. Olsson, 1918. [Approxi- mately same as locality 188.] Not plotted. Rio Indio trail from Gaturj to Chagres, Canal Zone. A. A. Olsson, 1918. Location approximate. Tick Creek, station 4H, Panama(?). Anomia zone. A. A. Olsson, 1918. [Probably downstream from locality 167.] Not plotted. Headwaters of Rio Pifia, station 40, Canal Zone. Anomia zone. E. R. Lloyd and G. M. Bevier, 1918. Location approximate. Pifia triangulation station region, sta- tion O, Canal Zone. Anomia zone. D. F. MacDonald and A. A. Olsson, 1918. Location approximate. 200 feet (60 meters) below and 500 feet (150 meters) southeast of Ramos triangulation station, Canal Zone. Anomia zone. A. A. Olsson, 1918. Location approximate. Trail from Gatun Dam to Escobal, sta- tion 28, Canal Zone. Anomia zone limestone. G. M. Bevier and A. A. Olsson, 1918. Location indefinite; not plotted. Trail from Escobal to Lagarto, station 1, Panama. Anomia zone. A.*A. Olsson, 1918. [Possibly along Rfo Arriero.] Not plotted. Trail from Escobal to Lagarto, sta- tion 6, Panama. Anomia zone lime- stone. A. A. Olsson, 1918. [Possibly along Rio Arriero.] Not plotted. chagres sandstone proper Rfo Indio area, station 4, Canal Zone. A. A. Olsson, 1918. [This Rfo Indio is the minor tributary of Rio Chagres west and northwest of Gatun Dam; unnamed on plate 1.] Location approximate. Pifia region, station 33, Canal Zone. A. A. Olsson and G. M. Bevier, 1918. | Probably along Rfo Pifia.J Not plotted. No. used in this report I! I! I 200 201 202 203 204 205 206 206a 206b 207 208 USGS Cenozoic No. 8443 SUM, 8439 8389 8436 8441 8387 16937 16938 16969 8437 Field No. 52 52a Description of locality chagres sandstone proper — con- tinued Pifia region, station 34, Canal Zone. A. A. Olsson and G. M. Bevier, 1918. [Probably along Rfo Pifia.] Not plotted. Headwaters of Quebrada Cafia [Rio Cafio Quebrado], station 32 plus 100 feet (30 meters), Panama. A. A. Olsson, 1918. Location approximate. Quebrada Cafia [Rio Cafio Quebradoj region, station 2 plus 200 feet (60 meters), Panama. A. A. Olsson, 1918. [Probably along Rio Cafio Quebrado or Rio Arriero.] Not plotted. Trail from Escobal to Lagarto, station 2 plus 100 feet (30 meters). A. A. Olsson, 1918. [Probably along Rfo Cafio Quebrado or Rio Arriero.] Not plotted. Rio Pavolina, a tributary of Rio Lagarto, station 4, Panama. A. A. Olsson, 1918. Location indefinite; not plotted. 1.5 miles (2. 4 kilometers) east [north- east] of mouth of Rio Chagres, 1,000 feet (300 meters) from ocean, Canal Zone. A. A. Olsson, 1918. Caribbean coast between Rio Chagres and Pifia, near Pifia, Canal Zone. A. A. Olsson, 1918. Not plotted. Caribbean coast near mouth of Rfo Pifia; road cut on west side of river about 90 meters west of road fork, Panama. Massive fine-grained sandstone. T. F. Thompson and W. P. Woodring, 1947. Stanford University locality 2699. Same locality. Latitude 9°16' N., plus 4,200 feet (1,280 meters), longi- tude 80°3' W. T. F. Thompson, 1943. Not plotted. Caribbean coast near mouth of Rio Pifia; road cut about 90 meters west of locality 206, Panama. Massive fine-grained sandstone. T. F. Thomp- son and W. P. Woodring, 1947. Not plotted. Caribbean coast; road cut on south side of Rio Lagarto about 230 meters south of Lagarto, Panama. S. M. Jones, 1917. Caribbean coast at mouth of Rfo Indios [Indio], station 5, Panama. A. A. Olsson, 1918. Plotted on figure 3. REFERENCES CITED 131 REFERENCES CITED Anderson, F. M., 1929, Marine Miocene and related deposits of north Colombia: Calif. Acad. Sci. Proc, 4th ser., v. 18, no. 4, p. 73-213, pis. 8-23. Anton, H. E., 1839, Verzeichniss der Conchylien, 110 p., Halle. Arnold, Ralph, and Anderson, Robert, 1907, Geology and oil resources of the Santa Maria oil district, Santa Barbara County, Calif.: U. S. Geol. Survey Bull. 322, 161 p., 26 pis. Bartsch, Paul, 1907, New mollusks of the family Vitrinellidae from the west coast of America: U. S. Natl. Mus. Proc, v. 32, p. 167-176, 11 figs. ■ 1911, Descriptions of new mollusks of the family Vitrin- ellidae from the west coast of America: Idem, v. 39. p. 229-234, pis. 39-40. Bequaert, J. C, 1943, The genus Littorina in the western Atlan- tic: Harvard Univ., Mus. Comp. Zool., Dept. Mollusks, Johnsonia, no. 7, 28 p., 7 pis. Bermiidez, P. J., 1950, Contribucfon al estudio Cenozoico cubano: Soc. Cubana Hist. Nat. 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B., Reclus, Armand, and Sosa, P., 1879, Rapports sur les eludes de la commission internationale d'exploration de l'isthme americain, 294 p., 2 maps, Paris. INDEX A Page abbrei'iata, Marginulina cf 17 abrupta, Turritella 48, 106-107, pi. 23 robusta... -_ 106 trinitaria, Turritella 107 Acila cf. A. islhmica 40 Acknowledgments 4-5 Acropora saludensis 42 acufiai, Cubanaster 22 acutauricularis, Saracenaria 18 acuticostata, Lagena 17 adela, Turritella.-- 24, 99, 109, pi. 15 adelinensis, Uvigerina 19 Uvigerina cf .- 27 advena, Siphoning.- ... 18 Virgulina cf 19 Aepystoma _ _ 70,71 agglutinans, Phorus... 77 agna, Tectonatica 48, 88-89, pi. 17 alabamensis, Hantkenina 17,19 Alabamina cf. A. scitula 26 Alabamina sp.. 16 alazanensis, Anomalina cf 16 Bolivina 16,26 Bulimina 16,26 Ceratobulimina.- . 16 Dentalina 26 Gaudryina (Pseudogaudryina) .. 26 Plectofrondicularia 26 Robulus cf 27 Vaginulinopsis 27 alcicorn is, Millepora aff _ . . 21 Allomorphina trigona 16 A-L-Owensi, Turritella plebeia 107 alowensi, Turritella plebeia _ 107 alternans, Pleurostomella 18,27 altilira, Turritella 33, 37, 46, 47, 50, 101, 102-104, 105, 108 Turritella aff 102 Turritella cf 27,33,104 Turritella altilira _ _ 103 (Torcula) 31,48, pi. 15 altilira 48, 102-104, pi- 23 altilira, Turritella 103 (Torcula) 48, 102-104, pi. 23 praecellens, Turritella 47,103,105 (Torcula) 48, /05, pi. 23 urumacoensis, Turritella 102 altilira subsp. , Turritella 102, 105 Turritella cf. T. altilira praecellens 105 (Torcula) _ 104-105 altilirata, Turritella 102 altispira, " Crepitacella" _ 110 " Crepitacella" n. sp. indet. aff 110 Alvania 76 "Alvania" aS."A." epulata 48, 76, 77 amaras, Turritella 101 (Torcula?) _ 37, 101-102, pi. 16 Amaurellinat 95 Amaurellina garzaensis 95 Amaurellinat sp ___ _ 21,96-96, pi. 14 " Amauropsis" burnsii meridionalis 96,97 aff. "A." burnsii meridionalis 97 floridana _. 97 jacksonensis 96,97 trinitatensis 97 amerkana, " Orbitolites" _ 36, 121 Ammospirata meiicana 26 Ampulella _ __. 95 Ampullina 95 Ampullinopsis spenceri 31 Anadara 39 [Italic numbers indicate descriptions] Page Andesite 54 andreasi, Turritella 99 andrium, Teinostoma (Aepystoma)... 48, 70-7/, pis. 17, 18 anebus, Solariorbis (Hapalorbis) hyptius 48, 75-75, pi. 17 anguillana, Globularia.. 95 angulatum, Teinostoma 70 trochalum, Teinostoma (Idioraphe)... 48, 70, pi. 17 angulifera, Littorina 36,70,71 LittorinaaS 37, 38, 68, pi. 16 Angulogerina sanjuanensis 16 Angulogerina sp 16, 26 annectens, Encope 47 Annulicallus _ __ 72 annulijera, Siphonodosaria cf . 18 Anomalina cf. A. alazanensis 16 paeoraensis 16 Anomalina sp... 16 Anomalinoides sp _. 16 anomalum, Teinostoma 69 Anticlimax 72 Anticlimai s. s 72,73 derbyi 72 hispaniolensis 73 schumoi 72 teleospira 73 tholus _ 73 willetti 73 (Anticlimai) gatunensis _ 48,72, pi. 18 (Subclimax) teleospira hystata 48, 73, pi. 18 teleospira _. 48 Antiguan coral fauna 27-28 antillea, Heterostegina.. 27,30,33 Miogypsina 27 (Miogypsina) 30,33 Antillia cf. A. hadleyi 21 aperta, Calyptraea 80 Calyptraea cf 21,80 Aquitanian, age... _ 38-39 araucana, Discorbis 26 Archaias compressus 27,30 arenasensis, Karreriella _.. _. 17 armiger, Schizaster __ 22 articulutus texanus, Robulus ... 27 asperum, Chrysalogonium 26 Chrysalogonium cf 16 Astacolus nuttalli 26 Astacolus sp 16, 26 Asterocyclina georgiana 20,61 mariannensis _ 20 minima.-. _ 20 asterodisca, Lepidocyclina (Lepidocyclina) 30 Astreopora n. sp 21 Astrocoenia incrustans 21 atacta, Turritella 99,108 atriformis, Hemisinus (Longiverena) n. sp., cf.. 27 attenuata, Marginulina cf 17 atwilli, Uvigerina __ 19 auricula, Crucibulum 82 aurora, Calliostoma -. 63 australis, Buccinum 65 B Background, historical 2-3 Bactospira .._ 98, 101 balkanicus, Velates 66 barbalus, Hipponix _ 78 Bas Obispo formation, age 32 stratigraphy and lithology 31-32 Basalt 54 Page Bathysiphon eocenica 16, 26 beaumonti, Natica (Stigmaulax) sulcata 88 Stigmaulax guppiana 88 berjadinensis cocoditana, Turritella 110 Turritella cf 37, 110 Bermudez, P. J., quoted 19,26-27 Bibliography, annotated 5-10 bierigi, Pleurostomella. 27 bifastigata, Turritella.. 48, lll-112,p\. 22 cartagenensis, Turritella Ill democraciana, Turritella 111 maracaibensis, Turritella 111 bipartita spirifera, Terebra 46 blountensis, Turritella 109 gatunensis 109 Bohio formation, description 24-25 fossiliferous localities 115-116 fossils and age... 23-24,26-28 marine member 22-24 stratigraphy and lithology 22-23,25-26 structural history. 57 boliimrensis, Neverita 91,92 tapina, Neverita (Glossaulax) 24, 91-92, pi. 15 bolivari, Episcynia 76 Bolivina alazanensis 16,26 byramensis 16, 26 gracilis 16 cf. B. gracilis 16,26 jacksonensis _ 16 cf. B. jacksonensis 16 maculata 16 cf. B. maculata 16 malkinae 16 plicatella mera 26 rhomboidalis 26 tectiformis 26 cf. B. ventricosa 16 Bolivina sp __ 16, 26 bolus, Natica 84 (Natica?) 48, 84-85, pi. 20 bondplandi, Natica. 92 bosworthi, Turritella 98 boutakoffi, Polinices 89 bowersi, Clypeaster 50 Clypeaster aff 50 brevis, " Phasianella (Eucosmia)" 66 briani, Calliostoma 63 broderipiana, Stigmaulax __ 87,88 Turritella 110,111,112 brunnea, Polinices cf 90 (Mammila) cf 89 brunneus, Polinices.. 90,91 subclausus, Polinices 48, 89-90, pi. 20 Buccinum australis 65 tritonis 65 Bulimina alazanensis 16, 26 consanguinea _. 16 cf. B. cooperensis 16 guat/abalensis 16 cf. B. impendens 16 jacksonensis 16, 19 cf. B. jacksonensis cuneata 16 palmerae 16 cf. B. palmerae 16 pupoides 16 cf. B. pyrula _. 16 tuxpamensis.. 16 Bulimina sp 16 Buliminella sp 16 bulloides, Pullenia cf 18 burnsii," Polinices (Amauropsis)" _ 97 buwaldana, Turritella.. 98,99 137 138 INDEX Page byramensis, Bolivina 16,26 Guttulina 26 C Caimito formation, exclusive of Madden basin and Pacific coastal area 28-31 fossiliferous localities - 116-120 fossils and age 29-31 Madden Basin and Pacific coastal area.. 12, 32-34 stratigraphy and lithology.-. 28-29,32-33 structural history _ - 57 caleta, Turritella 101 Turritellact 24, 100-101, pi. 15 californicus, Velates 67 calliglyptum, Teinostoma (Climacia) 72 Calliostoma.. 62,63 Calliostoma s. s 63 Calliostoma aurora 63 tiriani _ 63 distant 63 grabaui 64 mancinella 64 metalium 50 sayanum - -- 64 Calliostoma? sp 50 Calliostoma (Calliostoma) metalium 63, pi. 18 (Leiotrochus) eremum 48, 63-64, pi. 22 Calliostomatinae 63 Callopoma 04 cahjpta, Tricolia 24,65-66, pi. 15 Calyptraea 80 aperta — - --- 80 cf C. aperta — - 21,80 centralis 48, 80 cf. C. centralis --- - 37,80 centralis candeana 80 chinensis - -- -- 80 " Calyptraea" diabloensis 81 Calyptraea mamillaris.. 80 "Calyptraea" martini 81 Calyptraea sp -- 24,31,80 Calyptraea? sp - 31 Calyptraea (Trochatella) trochiformis 81 (Trochita) trochiformis _ 81 Calyptraeidae -.- — 79 canalizonalis, Natica... _._ 89 Polinkes 48,89, 91, pi. 20 cancellata, Rissoina _ - 77 candeana, Calyptraea centralis. - 80 canellei, Lepidocyclina.. 27,29,30,33,36,117 {Lepidocyclina) _ 30,33 canrena, Natica. _._ 86,87 (Natkarius) - -- 48 caparonis, Turritella.. 102 Capulus? galunensis _ 83 Capulus? sp 83 Cardium (Fragum) gatunense 23 carinata, Turritella _ . 98 Turritella cf ---- 21, 22, 98, pi. 14 carinatum, Teinostoma --- 70 Teinostoma cf - - - 69, 70 carinicallus, Teinostoma 72 carmenensis, Pseudocrommium 96,97 carolinianus, Polinices 89 caronensis, Turritella 108 gatunensis .. - 109 caroniense, Teinostoma. 71 cartagenensis, Turritella . HI bifastigata -- HI cascadensis, Gonioporaef... 30 Cassidulina crassa 16 havanensis --- 16 subglobosa 16, 26 Cassidulina sp - - 16 Cassidulinoides sp 16 castaneus, Turbo 64 Turbo aff - 50 Turbo (Marmarostoma) aff 48, 61,-65, pi. 20 (Senectus) cf 65 castrenoides, Natica 84 Page castrensis, Natica 84 cecinella, Teinostoma 70 centralis, Calyptraea _ 48,80 Calyptraeact _ 37,80 Globorotalia 17, 19 In fit ndibulum 80 Ceratobulimina aluzanensis 16 Cernina fluctuata _ 94 cerrosensis, " Cir cuius" 74 Chagres sandstone, description 12,47 fossiliferous localities ... 129-130 fossils and age. _ 50 stratigraphy and lithology .-. 47,50 structural history 57 chagresensis, Lagenoglandulina subovata. 17 chilostoma, Karreriella 17 chaperi, Lepidocyclina 19,20,21,61,112 (Nephrolepidina) 20 charana, Turritella 106 Cheilea -- 79 equestris _ _ 80 princetonia 48, 79 Chilibrillo limestone.. 32 Chilostomella mexicana 16 cf. C. ot'oidea 16 Chilostomella sp 16 Chilostomelloides oviformis 16 chinensis, Calyptraea _-. 80 chipolana, Neritina 68 Neverita .— 92 chipolanum, Crucibulum -_. 82 auricula - . 82 (Crucibulum) 82, pi. 19 chipolanum, Sinum .-_ 93 chirana, Nodosaria 17 Uvigeri na - 27 Uvigerina cf -- 19 Chrysalogonium asperum 26 cf. C. asperum 16 elongatum 16 Chrysalogonium sp 16, 26 chrysostomus, Turbo 64 Cibicides cocoanesis 16 cf. C. concentricus 16 cf. C.cookei 16 leoni 16 meiicanus 16, 26 perlucidus.. 16, 26 cf. C. perlucidus _._ 16 cf. C. pseudoungerianus 16 Cibicides n. spp - 16 Cibicides sp --- 16 Cibicides spp - 26 ciperoensis, Globigerina 17,26 "Circulus" cerrosensis 74 cosmius.. _ 74 liriope 75,76 occidentalis --- 74 Circulus pentagona 73 "Circulus" pentagonus _ 73 triliz - — 74 clausa, Nutica --- - 88 Clavulinoides cubensis 16, 26 Inn an ensis --- 16 Clavulinoides sp - 16 dementia dariena _ 46 clevei, Kupatagus 22 Climacia . - - - 72 Clypeaster bowersi 50 aff. C. bowersi. 50 concavus ._ 31 concavus? - 42 gatuni... 42,47 lanceolatus 33, 37 cf. C.pinarensis 33 cocleana, Natica youngi 84 cocoaensis, Cibicides 16 Afarginulinopsis 17 cocoditana, Turritella berjadinensis 110 Turritella cf. T. berjadinensis — 37. 110 Page coensis, Polinkes. 91 Cole, W. S„ quoted 20,30,33 colima, Natica 86 collazica, Turritella... 98 Turritella cf.. 42,98, pi. 16 collinsii, Trochita 80 Collonia radiata 72 Colpophyllia sp.. 21 communis, Dentalina cf 16 compressus, Archaias 27,30 concavum, Sinum 94 concavus, Clypeaster 31 concavus?, Clypeaster 42 concentricus, Cibicides cf 16 conchyliophora, Xenophora 77,78 conica, Pseudoglandtilina 27 conradi, Turritella 108 consanguinea, Bulimina 16 cookei, Cibicides cf 16 Plectofrondicularia 18 cooperensis, Bulimina cf 16 Dentalina cf 16 Corals, from Caimito formation^ 30 from Culebra formation 36 from Gatuncillo formation 21 from Panama formation 42 from Pleistocene series.. 50 Corn uspira olygogyra 16 cosmius, " Circulus" 74 costata, Mon tastrea.. 42 costelluta, Trochita 81 crassa, Cassidulina 16 crassolamelluta, Diploastrea n. sp., aff 21 Crassostrea 39 crenulatoides, Turbo 65 crenulatus, Turbo 64 castaneus 65 Crepidula 79 Jornicata 79 galunensis 79 maatlosa 79 cf. C. maculosa 48,79,pl.l9 nivea 79 nummaria - 79 plana 48, 79, pi. 19 Crepidula sp... 37,42,79 Crepidula? sp 27 Crepidulidae 79 " Crepitacella" altispira 110 n. sp. indet. aff. "C." altispira 110 Cretaceous rocks 52 Cretaceous system, stratigraphy 13 crispa, Xenophora "8 Crommium 97 Crucibulum... . 85,83 Crucibulum s. s 82 Crucibulum auricula - 82,83 chipolanum 82 Crucibulum chipolanum 82 dodoneum 82 pectinatum 83 spinosum. — 82 Crucibulum? springvaleense 83 Crucibulum cf. C. springvaleense 84 Crucibulum sp 37, 50,82 (Crucibulum) chipolanum 48, 8«, pi. 19 (Dispotaea) gatunense.. --- 83 springvaleense 48, 89-84, pi- 19 Crypta fornicata -- 79 Cryptonatka 88 cryptospira, Teinostoma.. .. - --- 70 cubae, Weisbordella - 22 Cubanaster acunai 22 cubensis, Clavulinoides 16,26 Fabiania - 20,21,23 Gumbelina 17,26 Cucaracha formation, description 39 fosstliferous localities 123 fossils and age... - - 39 mammal - - 39 INDEX 139 Page Cucaiacha formation — Continued stratigraphy and lithology 39 Culebra formation, description 34 fossiliferous localities 121-123 fossils and age.. 36-39 mammal 37-38 stratigraphy and lithology 34-36 cuneata, Bulimina jacksonensis cf — 16 curta, Uvigerina . 19 curratura, Siphonodosaria aff 18 cushmani,Miogypsina 36, 122 Yalvulineria 19 cuspidata, Neverita 92 Cyclammina cf. C. deformis 26 cf. C. pacified. 16 Cyclammina sp 16 Cyclostrema pentagona 73 quadrilineatum 73 Cyclostremiscus 73, 74 Cyclostremiscus s. s 73, 74 Cyclostremiscus glyptobasis 74 glyptomphalus _ . 74 tricarinatvs 74 (Ponocyclus) penlagonus 48, 73-75, pi. 17 •ylindrica, Dorothia 17 D Daeite _- 53,51 dalli, Loxostoma 17 Weisbordella 22 Dallitesta 91 danvillense, Nonion 18 danvillensis, Virgulina cf... 19 dariena, dementia 46 dariensis , Mactra (Mactrellaf) 23 dartoni, Lepidocyclina (Nephrolepidina) 30 deformis, Cyclammina cf_ 26 delecta, Phorus 77 Xenophora 48, 77-78, pi. 22 democraciana, Turritella bifastigata 111 Dentalina alazanensis 26 cf. D. communis 16 cf. D. cooperensis 16 cf. D. mucronata 16, 26 semilaevis 16,26 Dentalina sp 16,26 Dentalina spp 16 dentaliniformis, Siphonodosaria cf. __ 18 depressa, Solariella n. sp., cf 27 derbyi, Anticlimax 72 diabloensis, " Calyptraea" 81 Diaerecallus 71-72 dibollensis, Haplophragmoides cf 17 Virgulina cf 19,27 dicampylus, Robulus cf 18 Dike rocks 54 Diorite - 53-54 Diploastrea n. sp. aff. D. crassolamellata 21 Discorbis araucana 26 Discorbis sp 16 Dispotaea... 8$ distans, Calliostoma 63 dodoneum, Crucibulum chipolanum 82 dodonum, Pachycrommium 97 Sinum 93 Dorothia cylindrica... _ 17 cf. D. nuttalli 17 Dorothia sp 17 douvillei, Porites cf 42 E Echinoids, from Caimito formation 31 from Chagres sandstone 50 from Culebra formation 37 from Gatun formation.. 47 from Gatuncillo formation 22 from Panama formation 42 Echin ola mpas semiorbis 37 elegans, Hoglundina 17 elenae, Stigmaulai 87 Page Ellipsogla ndulinalabiata 17 mullicostata 17 elongatum, Chrysalogonium 10 emaciata, Siphonodosaria verneuili 18 emendorferi, Hannatoma 68 Hannatomat cf 21, 22, 68, pi. 14 eminuloides, Polinices 90 Emperador limestone. 34,36,59 Encope annectens 47 megatrema 47 plutytata 47 Entosolenia cf. E. laevigata 17 cf. E.marginata 17 orbignyana 17 Entosolenia sp 17 eocanica, Hastigerinella 17 Eocene or Oligocene series 22-24 Eocene series 13-22 eocenica, Bathysiphon 16,26 Episcynia 76 bolivari 76 megalia.. 48,7tf, pi. 18 naso.. 76 n icholson i 76 Eponides jacksonensis 17 cf. E. rutteni 17 umbonatus 17 multisepta 17,26 epulata, "Alvania" aff 48, 74 64 fluctuosus... . . 64 marmoratus 64 saxosus. 64 trochiformis... . 81,82 (Marmarostoma) : > IT" . '/'. castaneus 48, 64-65, pi. 20 (Si utctus) cf. castaneus 65 Turbo (Senectus) sp 65 TurriteUa - 97-98 abrupta ... 48, 106-107, pi. 23 trinitaria .. 107 adela 24,99, 109, pi. 15 altilira 33, 37, 46, 17, 60, 101, 102- 104, 105, 108 aft. T. iilliliru 102 cf. T. altilirii . 27. 33, 104 iillilira altilira 103 praecellens. . - 47,103,105 urumacoensis 102 iillilira subsp 102,105 Page Turritella— Continued altilira subsp., cf. T. altilira praecellens.. 105 altilirata. 102 amaras 101 andreasi 99 atacta 99,108 berjadinensis cocoditana .. llo cf. T. berjadinensis cocoditana. . . 37, 110 bifastigata 48, 111-112, pi. 22 cartage nensis. 111 democraciana ill maracaibensis 111 blountensis 109 bosworthi 9s broderipiana 110, 111, 112 buwaldana 98, 99 caleta. 101 Cf. T. caleta 24, 100-101, pi. 15 caparonis 102 carinata 98 cf. T. carinata 21, 22, 98, pi. 14 caronensis 108 cartagenensis 111 char ana 106 collazica 98 cf. T. collazica 42, 98, pi. 16 conradi 108 exoleta 101,104 fredeai 106 gabbi. 102 galvesia 99 gatunensis 47, 99, 100, 108-109, 1 10 until ue nsis? 33, 50 Cf. T. nut 11 in nsis 108,109 until ne nsis blountensis 109 caronensis 109 gatunensis 48, 108-109, pi. 23 lavelana 108,110 rhytodes 48, 109-110, pi. 23 taratarana. 110 " Turritella gatunensis" tarataranoides 110 Turritella gatunensis willistoni 110 gothica 111 (luppyi 103 hybrida 98 imperialis .. 104 inezana 104 leucostoma 111 lloydsmithi 110,111 mariana — 104 masinguiensis 99 matarucana.... 48, 107-108, pi. 22 meroensis.... 31, 99-100, 108, pi. 15 minutes.. .. 48,110-111, 112. pi. 22 mimetes? 51 cf. T. mimetes 110 mitchelli ... 102 mixta. . 101 montserratensis 105 ocoyana 105,106,107 olssoni 101 oreodoxa 111 perattenuata 101, 105 praecellens... 105 aff. T. perattenuata praecellens 104.105 planigyrata... m plebeia 108 A-L-Owensi 107 alowensi 107 robusta 106 abrupta.. 106 fredeai - - 100 saltoensis 100 samanensis 99 cf. T. samanensis 21,98 supoti usis 102 subannulnta .. 110 subgrundifera 105-106 Cf. T. subgrundifera 37, 38, 105-106, pi. 16 Page Turn'M/a— Continued su pruconcava 100 fredeai.. 106 terebralis... 107 tornata 103 trinitaria 107 tristis 100, 108 uvasana 99, 100 variata lorenzana 100 variegata ... .. ... ill venezuelana 37, 106, pi. 16 n. sp., aff. T. venezuelana.. 27 venezuelana quirosana 100 watkinsi 106 vientoensis 100 Turritella sp 21,31,37,98,99 (Haustator) aff. T. hanleyana 110 robusta 106 (Tore ula) altilira 31, 48, pi. 15 altilira 48, 102-104, pi- 23 praecellens 48, 105, pi. 23 altilira subsp 104-105 (Torcula?) amaras 37, 101-102. pi. 16 Turrit rllidae 97 In 1 pamensis, Bulimina. 16 U uber, Polinices.. 90 ultimum, Teinostoma potitum 69 umbilicatum, Teinostoma 70 11 mbonatus, Eponides 17 multisepta, Eponides 17,26 iiniliisa, Lepidocyclina (Eulepidina) 30 undulata, Marmarostoma 04 undulatum, Marmarostoma 64 11 11 ifusciata, Natica 84 urumacoensis, Turritella altilira 102 uvasana, Turritella 99,100 Uvigerina adelinensis 19 cf. U. adelinensis 27 cf. U.atwilli 19 chirana 27 cf. U. chirana 19 curta 19 gardnerae nuttalliana 19, 27 spinicostata 19, 27 spin ulosa — 19 cf. U.spinulosa.. 19 Uvigerina sp 19. 27 V Vaginulina sp 27 Vaginulinopsis alazanensis 27 mexicanus 19 cf. V. mexicanus - 19 I 'ntji 11 ulinopsis sp 19 Valvulineria cushmani 19 gasparensis . — 19 Vamos Vamos, marine member of Bohio formation 22 variegata, I'hasianella... 05 Turritella HI vaughani, Lepidocyclina 27,29,30,33, 116 (Nephrolepidina) 27, 30, 33 Operculinoides 20 Plectofrondicularia 18, 26 Velates 66,67 balkanicus 66 marginatum — 66 calif or n icus - - - 67 floridanus 67 noetlingi — -- 67 perversus - 22, 66, 67 perversus subsp.? 21, 66-67, pi. 14 schmideliana — 66 vokesi. - - - - 67 venezuelana, Polinices stanislas-meunieri 90 TurriteUa -- 37, fOS.pl. 16 Turritella u. sp., aff— - 27 INDEX 1 1;» Page venezue lana— Continued guirosana, Turritella lOfi watkinsi, Turritella 106 venlricosa, Bolivina cf 16 vererugostiin, Stigmaulax. 87 verneuili. Siphonod03aria 18 verneuili emaciata, Siphonodosaria 18 vientoensis, Turritella 100 virginea, Neritina 67. 68 (ViHaf) cf 48, 67-S8, pi. 21 Virgulina cf. V. advena 19 cf. V. danvillensis. 19 cf. V.dibollensis 19,27 pachgheilus 19 Virgulina sp 19 vitellus, Natica. 84 vitreum, Teinostoma.. 71 Vitrinella pentagona 73 " \'itrinella" seminuda 76 Vitrinellidae — 69 Vitta.— 67 vokesi, Velates... .. 67 Page Volcanic and intrusive rocks, Cretaceous 52-53 Tertiary, age 56-57 chemical composition 55 dike rocks 54 granular intrusive rocks 53-54 tuft 13.54 Vulvulina pachgheilus 27 W watkinsi, Turritella venezuelana 106 waylandvaughani, Lepidocyclina 27, 36 (Lepidocydina) 27,30 ll'eisbordellu citbae 22 dalli 22 weisbordi, Favia cf 21 Wells. J. W., quoted 21,42 Willi tti. Anticlimax 73 ■willistoni, Turritella gatunensis 110 wuellerstorfi, Planulinacf 26 X xena, Neverita reclusiana 91 (Glossaulax) reclusiana 48,9?. pi. 21 Page Xenophora 77,78 conchyliophora 77,78 crispa 78 delecta 48, 77-78, pi. 22 floridana... 78 robusta 78 senegalensis 78 textilina . 78 all'. Irocliiliirmis 77 Xenophora sp . 21,37 Xenophoridae 77 Y Yaberinella jamaicensis 20,21, 22 goungi, Natica 84 yoiingi, Natica (Polinices) cf 84 yurnagunensis, Lepidocgclina (Lepidocyclina).. 27.30 morganopsis, Lepidocyclina (Lepidocyclina) 27, 30,33 Z Zebinella 77 PLATES 3-23 <;koi.o<:icat, sihvkv PROI ESSION VI. PAPER 306 l'l.\ II. :i w ^>8 :;:) i V, v * V;, *> v , . ' "J it I ';;#. J .^vy- ¥m&±£>£t ,..)- •..- I* ■m Sa*. ..? ^ 4 FORAMIMFERAL LIMESTONE FROM GATUNCILLO FORMATION OF MADDEN BASIN, PANAMA Nummulites striatoreticulatus represented by dark silicified specimens standing out in relief and partly siliciiied sections. The large partly silicified orbit oid presumably is Lepidocyclina chaperi. Natural size. (,i;oi.(x;icai. SURVEY PROFESSIONAL PAPER 306 PLATE 4 ECHINOID-BEARING LIMESTONE FROM GATUNCILLO FORMATION OF MADDEN BASIN, PANAMA Cubanaster arunai. Natural size. T ,111 -i<->/.^ fr.y '.' » -fflr F*P si/ "til* #' ^, •■■■ / •''-• i -*"^*B ,■ < •»» §1, »j vm \ v «n -4: Jr».«i *>*».■;» «j"x ,< y.*w ^ «*< l*A ■)i *j J '« ■'.»•' •»' ;V:v iy» ,: > A, :.V -I-.'' ■■> ■ x : i f> »*; t» >. I •Ml •7. - I - _ U f — Z -5 c — a < * <^ i — » ~ 2 k .= Sod t Z- £ <;> .5 FQ b J _ Z-< 2 -^2 a. feM « - 2 - |g "1 s -& -J 2 C u PS en -J O H c < o ftfc&SMt^S - - < z < — e 2 z — E OS — ■ ^ r K a <| a _) u w — £ M ?3 '- C_ — J" ~ § K [53 OS > 5 a E- C K ^ c _: '5b _ c !*j W en s H 3 O* U en - c , 6. Turritella adela Woodring, n. sp. (p. 99). Locality 41. Marine member of Bohio(?) format ion. 5. Paratype. Height (incomplete, 3 whorls) 22.5 mm, diameter 12 mm. USNM 561371. 6. Type. Height (incomplete) 25 mm, diameter 7.5 mm, USNM 561370. 7, 8, 11. Neverita (Glossaulax) bolivarensis tapina Woodring, n. subsp. (p. 91). Locality 40d. Marine member of Bohio(?) formation. 7. 11. Type. Height 14.5 mm, diameter 19 mm. USNM 561354. 8. Paratype. Diameter 18.5 mm. USNM 561442. 9, 17, 18. Globularia (Globularia) aff. G. fischeri (Dall) (p. 94). Locality 56. Middle member of Caimito formation. 9. Height 18.5 mm, diameter (incomplete) 15.5 mm. USNM 561359. 17, 18. Height (almost complete) 35.5 mm, diameter 31 mm. USNM 561358. 10. Turritella (Torcula) altilira Conrad, subsp. (p. 104). Wright (incomplete, 5+ whorls) 29.5 mm, diameter 13.3 mm. Locality 56. Middle member of Caimito formation. USNM 561382. 12. Pachycrommium? proinum Woodring, n. sp. (p. 96). Type. Height (incomplete) 26 mm, diameter 19 mm. Locality 40a. Marine member of Bohio(?) formation. USNM 135200. 13. Globularia ( Am paella) sp. (p. 95). Height (incomplete) 21 mm, diameter (modified by dorso-ventral crushing) 19.3 mm. Locality 40d. Marine member of Bohio(?) formation. USNM 561360. 14-16. Turritella cf. T. caleta Olsson (p. 100). Marine member of Bohio(?) formation. 14. Height (incomplete, 3+ whorls) 7.9 mm, diameter 6.5 mm. Locality 406. USNM 135166. 15. Height (incomplete, 4 whorls) 13 mm, diameter 6.5 mm. Locality 42c. USNM 561369. 16. Height (incomplete, 2+ whorls) 13.5 mm, diameter 9.5 mm. Locality 42c. USNM 561369. 19. Turritella meroensis Olsson (p. 99). Height (incomplete, 3+ whorls) 39 mm, diameter 21 mm. Locality 56. Middle member of Caimito formation. USNM 561372. flEOLOOICAI. SURVEY PROFESSIONAL PAPER 306 PLATE IS 19% x i ^ LATE EOCENE OR -EARLY ¥ OLIGOCENE MOLLUSKS FROM MARINE MEMBER OF BOHIO(?) FORMATION AND L4TE OLIGOCENE MOLLUSKS FROM MIDDLE MEMBER OF CAIMITO FORMATION IN GATUN LAKE AREA GEOLOGICAL SURVEY PROFESSIONAL PAPER 306 PLATE 16 X2 x 1H IK- x lk 11 12 EARLY MK CENE MOLLUSKS FROM CULEBRA FORMATION AND LA BOCA MARINE MEMBER OF PANAMA FORMATION PLATE 16 Figure 1,2. Littorina aff. L. angulifera (Lamarck) (p. 68). Height (practically complete) 12 mm, diameter 8.5 mm. Locality 110. Uppermost part of Culebra formation. USNM 561331. 3. Turritella cf. T. subgrundifera Dall (p. 105). Height (incomplete, 3 whorls) 18 mm, diameter 5 mm. Locality 99o\ Culebra formation. USNM 561384. 4-7, 10. Turritella (Torcula?) amaras Woodring, n. sp. (p. 101). Culebra formation. 4. Height (incomplete, 5 whorls), 23.5 mm, diameter 10 mm. Locality 107. USNM 561374. 5. Height (incomplete, 7 whorls) 8 mm, diameter 2.7 mm. Locality 996. USNM 561377. 6. Height (incomplete, 3+ whorls) 43 mm, diameter 24.5 mm. Locality 98. USNM 561376. 7. Type. Height (incomplete) 47 mm, diameter 14.5 mm. Locality 116. USNM 561373. 10. Height (incomplete, 4+ whorls) 30 mm, diameter 18 mm. Locality 112. USNM 561375. 8, 9. Turritella venezuelana Hodson (p. 106). Culebra formation. 8. Height (incomplete, 2 whorls) 6.8 mm, diameter 6 mm. Locality 110. USNM 561386. 9. Height (incomplete, 6 whorls) 15.3 mm, diameter 5.4 mm. Locality 112a. USNM 561385. 11. Pachycrommium? cf. P.? irinitatensis (Mansfield) (p. 97). Height (incomplete) 50 mm, diameter (exaggerated by crushing) 39 mm. Locality 99ft. Culebra formation. USNM 561365. 12. Pachycrommium? cf. P. guppyi (Gabb) (p. 97). Height (not quite complete) 27 mm, diameter 21.5 mm. Locality 115a. Culebra formation. USNM 561366. 13. Turritella cf. T. collazica Maury (p. 98). Height (incomplete, 4+ whorls) 56 mm, diameter (exaggerated by crushing) 25 mm. Locality 123. La Boca marine member of Panama formation. USNM 561368. PLATE 17 Figure 1-3. Teinostoma (Pseudorotella) stemonium Woodring, n. sp. (p. 71). Type. Height 1 mm, diameter 1.5 mm. Locality 138a. Lower part of Gatun formation, middle Miocene. USNM 561432. 4-6. Teinostoma (Idioraphe) angulatum trochalum Woodring, n. subsp. (p. 70). Type. Height 1 mm, diameter (incomplete) 1.7 mm. Locality 137. Lower part of Gatun formation, middle Miocene. USNM 561431. 7-15. Cyclostremiscus (Ponocyclus) pentagonus (Gabb) (p. 73). Middle part of Gatun formation, middle Miocene. 7-9. Bicarinate specimen. Height 1 mm, diameter 1.6 mm. Locality 1476. USNM 561320. 10-12. Tricarinate specimen. Height 1 mm, diameter 1.8 mm. Locality 1476. USNM 561320. 13-15. Exceptionally large specimen. Height 1.1 mm, diameter 2.3 mm. Locality 155c. USNM 561321. 16-18. Solariorbis (Hapalorbis) hyplius hyplius Woodring, n. sp. and n. subsp. (p. 75). Type. Height 0.7 mm, diameter 1.4 mm. Locality 1476. Middle part of Gatun formation, middle Miocene. USNM 561323. 19-24, 31-33, 37-39. Teinosloma (Idioraphe) spermatia Woodring, n. sp. (p. 69). Locality 1476. Middle part of Gatun formation, middle Miocene 19-21. Sculptured specimen. Height 0.8 mm, diameter 1.6 mm. USNM 561313. 22-24. Small specimen. Height 0.6 mm, diameter 1.2 mm. USNM 561313. 31-33. Large form. Height 1.1 mm, diameter 2.6 mm. USNM 561313. 37-39. Type. Height 0.7 mm, diameter 1.8 mm. USNM 561312. 25-27. Teinostoma (Pseudorotella) pyenum (Woodring). (p. 71). Height 0.8 mm, diameter 1.3 mm. Locality 1476. Middle part of Gatun formation, middle Miocene. USNM 561317. 28-30. Teinostoma (Diaerecallus) sychnum Woodring, n. sp. (p. 72). Type. Height 1.1 mm, diameter 1.7 mm. Locality 1476. Middle part of Gatun formation, middle Miocene. USNM 561316. 34-36. Solariorbis (Hapalorbis) hyplius anebus Woodring, n. subsp. (p. 75). Type. Height 0.9 mm, diameter 1.5 mm. Locality 185. Upper part of Gatun formation, western area, late Miocene. USNM 561324. 40-42. Teinostoma (Aepystoma) andrium Woodring, n. sp. (p. 70). Height 1.2 mm, diameter 2.1 mm. Locality 137. Lower part of Gatun formation, middle Miocene. USNM 56131 1. 43-45. Solariorbis (Solariorbis) strongylus Woodring, n. sp. (p. 75). Type. Height 1.3 mm, diameter 2.1 mm. Locality 138. Lower part of Gatun formation, middle Miocene. USNM 561322. Hi. Tectonatica agna Woodring, n. sp. (p. 88). Type. Height 2.8 mm, diameter 2.4 mm. Locality 1476. Middle part of Gatun formation, middle Miocene. USNM 56134s. 47. Tricolia? syntoma Woodring, n. sp. (p. 66). Type. Height 2.2 mm, diameter 2.2 mm. Locality 170a. Middle part of Gatun formation, middle Miocene. USNM 561328. GEOLOGICAL SURVEY PROFESSIONAL PAPER 306 PLATE 17 #t -a 1 3 ^^^^xio ^^^ 10 6 §i) 9 A XIO X1 ° "^^^" X10 X10 10 u xio 13 14 is •^aP^xio . a >^. 16 X10 18 x io 17 I -^^ X 19 20 XIO 21 i J 4 22 23 XIO XIO 24 ^^ XIO 25 5 « 26 27 XIO 28 XIO 29 «fe 30 XIO 31 XIO 32 XIO xio — —"XIO 33 34 35 36 XIO XIO ^^^XIO 37 38 39 XIO 40 XIO XIO 41 42 XIO XIO 43 XIO 45 44 XIO XIO 46 47 X10 MIDDLE AND LATE MIOCENE MOLLUSKS FROM GATUN FORMATION GEOLOGICAL SURVEY PROFESSIONAL PAPER 30fi PLATE 18 X10 ^ X10 12 xio X10 XIO 10 XIO MIDDLE AM) LATE MIOCENE MOLLUSKS FROM GATUN FORMATION AND EARLY PLIOCENE MOLLUSK FROM CH ACRES SANDSTONE PLATE 18 Figure 1-3. Anticlimax (Subcli max) teleospira hystata Woodring, n. subsp. (p. 73). Type. Height 1.5 mm, diameter (incomplete) 2.7 mm. Locality 185. Upper part of Gatun formation, western area, late Miocene. USNM 561319. 4, 8. Episcynia megalia Woodring, n. sp. (p. 76). Type. Height 2.7 mm, diameter 5.3 mm. Locality 138. Lower part of Gatun formation, middle Miocene. USNM 561325. 5-7. Anticlimax (Anticlimax) gatunensis Pilsbry and Olsson (p. 72) Topotype. Height 1.7 mm, diameter (incomplete) 3 mm. Locality 138. Lower part of Gatun formation, middle Miocene. USNM 561318 9-11. Teinostoma (Aepystoma) andrium Woodring, n. sp. (p. 70). Type. Height 2 mm, diameter 4.7 mm. Locality 137. Lower part of Gatun formation, middle Miocene. USNM 561315. 12-14. Calliostoma (Calliostoma) metal iu in Woodring, n. sp. (p. 63). Type. Height (almost complete, but crushed) 19.5 mm, diameter (incomplete) 24 mm. Locality 206a. Chagres sandstone, early Pliocene. USNM 561430. 15, 16. Neverita (Hypterita) helicoides (Gray) (p. 92). Height (incomplete) 16 mm, diameter (incomplete) 34 mm. Locality 1556. Middle part of Gatun forma- tion, middle Miocene. l^SNM 561356. PLATE 19 Figure 1-3. Crepidula plana Say (p. 79). Locality 138. Lower part of Gatun formation. USNM 561334. 1. Length 17.5 mm, width 10.6 mm, height 4 mm. 2, 3. Length 15 mm, width 10.5 mm, height 2 mm. 4, 5. Crepidula cf. C. rnaculosa Conrad (p. 79). Length 28.5 mm, width 17.5 mm, approximate height 10.5 mm. Locality 155c. Middle part of Gatun formation. USNM 561333. 6, 7. Crucibulum (Crucibulum) chipolanum Dall (p. 82). Height 16.5 mm, maximum diameter 27 mm. Locality 1556. Middle part of Gatun formation. USNM 561336. 8-10. Crucibulum (Dispotaea) springvaleense Rutsch (p. 83). Height 11 mm, maximum diameter 19.2 mm. Locality 155a. Middle part of Gatun formation. USXM 561337. 11-14. Trochila trochiformis (Born) (p. 81). Lower part of Gatun formation. 11, 12. Height (incomplete) 10.7 mm, maximum diameter 28.8 mm. Locality 136. USNM 561335. 13, 14. Height (almost complete) 27 mm, maximum diameter 43.5 mm. Locality 136a. Stanford Univ. paleont. coll. 8072. GEOLOGICAL SURVEY PROFESSION W. PAPER HOfi v\.\n |{ MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION < '"-% X2 X2 PROFESSIONAL PAPER 30fi PLATE 20 11 13 16 M IDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION PLATE 20 Figure 1-3. Natica (Natica?) bolus Brown and Pilsbry (p. 84). I, 2. Height 14.5 mm, diameter 15.2 mm. Locality 159. Middle part of Gatun formation. USNM 561338. 3. Height 9.7 mm, diameter 10.2 mm. Locality 175. Upper part of Gatun formation, eastern area. USNM 561339. 4-6. Natica (Naticarius) stenopa Woodring, n. sp. (p. 85). Upper part of Gatun formation, eastern area. 4, 5. Type. Height 15.2 mm, diameter 14.8 mm. Locality 177b. USNM 561340. 6. Paratype. Height 12 mm, diameter 11 mm. Locality 177c. USNM 561341. 7. 8. Polinices canalizonalis (Brown and Pilsbry) (p. 89). Locality 1776. Upper part of Gatun formation, eastern ana. USNM 561349. 7. Height 21 mm, diameter 18.7 mm. 8. Height 11 mm, diameter 10 mm. 9. Polinices brunneus subclausus (Sowerby) (p. 89). Height 20.3 mm, diameter 16.7 mm. Locality 1556. Middle part of Gatun formation. USNM 561350. 10. Turbo (Marmarostoma) aff. T. castaneus Gmelin (p. 64). Height (not quite complete) 20.5 mm, diameter (incomplete) 18 mm. Locality 1556. Middle part of Gatun for- mation. USNM 561326. 11-16. Stigmaulax guppiana (Toula) (p. 86). II, 12. Height 22.5 mm, diameter 20.8 mm. Locality 155c. Middle part of Gatun formation. USNM 561344. 13. Length 18.5 mm, width 10.7 mm. Locality \47g. Middle part of Gatun formation. USNM 561345. 14. Length 17.5 mm, width 10 mm. Locality 1476. Middle part of Gatun formation. USNM 561446. 15. Length 19.5 mm, width 10.9 mm. Locality 151. Middle part of Gatun formation. USNM 561347. 16. Height 33.5 mm, diameter 30.5 mm. Locality 1476. Middle part of Gatun formation. USNM 561342. 17. Height 30.5 mm, diameter 29 mm. Locality 1776. Upper part of Gatun formation, eastern area. USNM 561343. 18. Height 31.4 mm, diameter 28 mm. Locality 142. Middle part of Gatun formation. USNM 561428. PLATE 21 Figure 1, 2. Neritina (Vitta?) cf. N. virginea (Linne) (p. 67). Height (incomplete), 3.6 mm, diameter 3.6 mm. Locality 161c. Middle part of Gatun formation, middle Miocene. USNM 561330. 3, 6. Sinum gabbi (Brown and Pilsbry) (p. 94). Height 23 mm, diameter 23 mm. Locality 1556. Middle part of Gatun formation, middle Miocene. USNM 561357. 4, 7, 10. Sinum euryhedra Woodring, n. sp. (p. 93). Type. Height (incomplete), 11 mm, diameter (incomplete) 27 mm. Locality 137a. Lower part of Gatun forma- tion, middle Miocene. USNM 561441. 5, 8, 9. Neverita (Glossaulax) reclusiana xena Woodring, n. subsp. (p. 92). Lower part of Gatun formation, middle Miocene. 5, 9. Type. Height 25 mm, diameter 27 mm. Locality 137. USNM 561355. 8. Large high-spired specimen. Height 34 mm, diameter (incomplete) 35 mm. Locality 137a. USNM 561440. 11-14. Polinices Stanislas- meunieri Maury (p. 90). 11. Small specimen. Height 11.5 mm, diameter 10 mm. Locality 138. Lower part of Gatun formation, middle Miocene. USNM 561353. 12. Inflated specimen. Height 32.5 mm, diameter 28 mm. Locality 182. Upper part of Gatun formation, western .iica, late Miocene. USNM 561351. 13. Large slender specimen. Height 43.5 mm, diameter 33 mm. Locality 138a. Lower part of Gatun formation, middle Miocene. USNM 561439. 14. Slender specimen. Height 22.5 mm, diameter 16.5 mm. Locality 136. Lower part of Gatun formation, middle Miocene. USNM 561352. GEOLOGICAL SURVEY PROFESSIONAL PAPER 300 PLATE 21 MIDDLE AND LATE MIOCENE MOLLUSKS FROM GATUN FORMATION GEOLOGICAL SURVE1 PROFESSIONAL PAPER 306 PLATE 22 X " : ^>* .Sa%£- & e * «;■ *1 X 1 !>£ x i is 7 x 1H 8 X1} * l0 MIDDLE AND LATE MIOCENE MOLLUSKS FROM GATUN FORMATION PLATE 22 Figure 1, 2, 4. Xenophora delecla (Guppy) (p. 77). Height 25 mm, diameter (incomplete) 46 mm. Locality 173. Upper part of Gatun formation, eastern area. middle Miocene. USNM 561434. 3, 5. Calliostoma (Leiotrochus) eremum Woodring, n. sp. (p. 63). Type. Height (incomplete) 17.5 mm, diameter 19 mm. Locality 155c. Middle part of Gatun formation, middle Miocene. USNM 561311. 6-9. Turritella mimetes Brown and 'Pilsbry (p. 110). 6. Height (incomplete) 73 mm, diameter 17.5 mm. Locality 1556. Middle part of Gatun formation, middle Miocene. USNM 561396. 7. Height (incomplete) 56 mm, diameter 15.3 mm. Locality 185. Upper part of Gatun formation, western area, late Miocene. USNM 561397. 8. Height (incomplete) 45 mm, diameter 18 mm. Locality 155a. Middle part of Gatun formation, middle Miocene. USNM 561398. 9. Height (incomplete) 7 mm. ilia meter 2.4 mm. Locality 16 1. Middle part of Gatun formation, middle Miocene USNM 561399. 10. Turritella bifastigata Nelson (p. 111). Height (not quite complete) 66 mm, diameter IS. 5 mm. Locality 137. Lower part of Gatun formation, middle Miocene. USNM 561400. 11, 12. Turritella matarucana Hodson (p. 107). Lower part of Gatun formation, middle Miocene. 11. Height (incomplete) 23 mm, diameter 7.5 mm. Locality 136. USNM 561391. 12. Height (incomplete) 44.5 mm, diameter 16 mm. Locality 137. USNM 561390. PLATE 23 Figurk 1, 7, 12, 13. Turritella (Torcula) altilira altilira Conrad (p. 102). Middle part of Gatun formation. 1. Height (incomplete) 7.6 mm, diameter 1.2 mm. Locality 1476. USNM 561381. 7. Topotype. Height (incomplete) 43.5 mm, diameter 17.5 mm. Locality 150a. USNM 561378. 12. Height (incomplete) 73 mm, diameter 13 mm. Locality 1556. USNM 561379. 13. Height (incomplete) 63 mm, diameter 19 mm. Locality 159. USNM 561380. 2, 8. Turritella {Torcula) altilira praecellens Pilsbry and Brown (p. 105). Locality 138. Lower part of Gatun formation. USNM 561383. 2. Height (incomplete) 30.5 mm, diameter 13 mm. 8. Height (incomplete) 42 mm, diameter 12.5 mm. 3. Rissoina (Phosinella) oncera Woodring, n. sp. (p. 77). Type. Height 4.3 mm, diameter 1.7 mm. Locality 177c. Upper part of Gatun formation, eastern area. USNM 561332. 4, 5, 9, 14. Turritella gatunensis gatunensis Conrad (p. 108). 4. 9. Locality 159. Middle part of Gatun formation. USNM 561392. 4, Height (incomplete) 31.4 mm, diameter 9 mm. 9, Height (incomplete) 42.5 mm, diameter 15.2 mm. 5. Height (incomplete) 7.3 mm, diameter 2.5 mm. Locality 138. Lower part of Gatun formation USNM 561394 14. Height (almost complete) 58.5 mm, diameter 15 mm. Locality 138. Lower part of Gatun formation. USNM 561393. 6, 15, 16. Turritella abrupta Spieker (p. 106). Middle part of Gatun formation. 6. Height (incomplete) 8 mm, diameter 3.6 mm. Locality 161d. USNM 561388. 15. Height 1.8 mm, diameter 1 mm. Locality 170a, USNM 561389. 16. Height (incomplete) 39 mm, diameter 23 mm. Locality 144a. USNM 561387. 10, 11, 17. Turritella gatunensis rhytodes Woodring, n. subsp. (p. 109). Locality 162a. Middle part of Gatun formation. 10. Height (incomplete) 41.7 mm, diameter 13 mm. USNM 561429. 11. Height (incomplete) 38.7 mm, diameter 11.8 mm. USNM 561429. 17. Type. Height (incomplete) 66 mm, diameter 16.5 mm. USNM 561395. CEOI.OfilCAL SURVEY PROFESSIONAL PAPER 306 PLATE 23 13 14 16 MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION 17 x 1% UNIVERSITY OF FLORIDA ISIflllllllllllllllllllllllllllllllllll 3 1262 09114 0268 I