URBANA ILLINOIS STATE GEOLOGICAL SURVEY 3 3051 00000 2810 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/administrativere23illi STATE OF ILLINOIS STATE GEOLOGICAL SURVEY FRANK W. DEWOLF. Director BULLETIN No. 23 BIENNIAL REPORT FOR 1911 AND 1912 ADMINISTRATIVE REPORT AND EGONOMIG AND GEOLOGIGAL PAPERS CERTAIN REPORTS IN COOPERATION^ WITH U. S. GEOLOGICAL SURVEY PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS ILLINOIS STATE GEOLOGICAL SURVEY UNIVERSITY OF ILLINOIS URBANA 1917 55T STATE GEOLOGICAL COMMISSION Frank O. Lowden, Chairman Governor of Illinois Thomas C. Chamberlin, Vice-Chairman Edmund J. James, Secretary President of the University of Illinois Frank W. DeWolf, Director Fred H. Kay, Asst. State Geologist LETTER OF TRANSMITTAL State Geological Survey University of Illinois, March 12, 1917. Governor Frank O. Lozvden, Chairman, and Members of the Geological Commission, Gentlemen : I submit herewith my administrative report for the biennium ended June 30, 1913, and recommend that it be printed as Bulletin No. 23. The financial statements in the report have previously been submitted to the Commission, but are now offered for printing as a public record. Similarly the accompanying miscellaneous papers of econ- omic interest have to some extent already been issued as preliminary ex- tracts from Bulletin 23 at a time when congestion in printing made it im- practicable to publish the entire volume. Very respectfully, Frank W. DeWolf, Director. (7) CONTENTS PAGE Administrative Report, by F. W. DeWolf 11 Mineral Statistics for Illinois in 1911 and 1912, by Helen J. Skewes 25 Oil and Gas in Colchester and Macomb Quadrangles, by Henry Hinds 45 Plymouth Oil Field, by Raymond S. Blatchley 51 Geology of La Salle and Hennepin Quadrangles, by G. H. Cady 55 Stratigraphy and Paleontology of the Alexandrian Series in Illinois and Missouri, by T. E. Savage 67 (9) ADMINISTRATIVE REPORT FROM JULY 1, 1911 TO JUNE 30, 1913 By F. W. DeWolf OUTLINE PAGE Introduction 11 General statement 11 Organization and personnel 11 Cooperation 14 Geologic section 14 Stratigraphy 14 Coal " 14 Oil and gas 15 Clay 15 Drainage work 16 Educational bulletins 16 Mineral statistics 16 Bureau of information 16 Topographic and drainage sections 17 Publications 21 Expenditures 22 PLATE I. Map showing progress of topographic surveys 16 TABLES 1. Progress of field work by the topographic and drainage sections for fiscal years, 1912 and 1913 18 2. Total expenditures July 1, 1911, to June 30, 1913 22 Introduction general statement The increasing development of the natural resources of Illinois makes necessary a gradual broadening of the Survey's activities. Coal and petroleum continue to hold a large share of attention. Detailed statistics for the calendar years of 1911 and 1912 appear in this bulletin. ORGANIZATION AND PERSONNEL The organization of the Survey remained the same as before and included a general office and three technical sections — geologic, topo- (11) 12 P.FKNNIAL REPORT graphic, and drainage — besides the Mine Rescue Service, which was maintained under cooperation at Urbana. The geologic section was ad- ministered by F. W. DeWolf, Director, and in his absence by Fred H. Kay, who was appointed Assistant State Geologist in 1911. The topo- graphic section was in general charge of R. B. Marshall, Chief Geog- rapher, and in immediate charge of W. H. Herron, Geographer of the Central Division for the U. S. Geological Survey. The drainage section was supervised by Mr. Herron and the director. Cooperative work was further increased by the establishment of the Illinois Coal Mining In- vestigations by an agreement between the State Geological Survey, the U. S. Bureau of Mines, and the Department of Mining Engineering, University of Illinois. Mrs. C. S. Hyatt acted as chief clerk from July 1, 1911, until Decem- ber 6, 1913, when Miss C. IT. Thory was appointed to fill the vacancy caused by her resigation. The chief clerk was assisted by Miss Blanche Fowler, as stenographer and clerk. Professors Salisbury and Grant served as consulting geologists and Professors Parr and Bartow as con- sulting chemists. Professor A. V. Bleininger, Consulting Ceramist, with R. T. Stull, Ceramist, continued in general charge of the clay studies. Professors Weller, Savage, and J. A. Udden have given part-time service to the Survey as geologists. G. H. Cady was employed tempor- arily on the geology of the La Salle-Hennepin quadrangles and the New Haven- West Frankfort quadrangles. R. S. Blatchley with assistants continued studies in the oil fields of the State. L. G. Donnelly and C. O. Sauer made field studies for educational bulletins under the direction of Professor Salisbury. Mining study required the services of Mr. Kay, with Mr. K. D. White as assistant, and a number of chemists under the general direction of Professor Parr. Coal analysis and various chemical studies were carried on by J. M. Lindgren and D. F. McFarland, chem- ists, under the general direction of Professor Parr. They were assisted by J. F. Kohout, F. H. Whittum, L. T. Fairhall, C. W. Sievert, and S. C. Taylor. C. C. W r iley and C. W. Smith acted as draftsmen. A number of other men served for short periods of time in the field and in the office. The organization of the Survey was as follows : COMMISSIONERS Governor C. S. Deneen, Chairman until January 1, 1913 Governor E. F. Dunne, Chairman Professor T. C. Chamberlin, Vice Chairman President E. J. James, Secretary ADMINISTRATIVE REPORT ADMINISTRATIVE WORK F. W. DeWolf, Director Fred H. Kay, Assistant State Geologist C. S. Hyatt, Chief Clerk, resigned C. H. Thory, Chief Clerk GEOLOGICAL SECTION R. D. Salisbury, Consulting Geologist U. S. Grant, Consulting Geologist S. W. Parr, Consulting Chemist Edward Bartow, Consulting Chemist A. V. Bleininger, Consulting Ceramist F. W. DeWolf, Geologist H. H. Barrows, Geologist Stuart Weller, Geologist T. E. Savage, Geologist W. S. Bayley, Geologist J. A. Udden, Geologist Fred H. Kay, Geologist R. S. Blatchley, Assistant Geologist G. H. Cady, Assistant Geologist K. D. White, Assistant Geologist C. O. Sauer, Assistant Geologist L. C. Donnelly, Assistant Geologist G. H. Cox, Assistant Geologist E. W. Shaw, Assistant Geologist R. T. Stull, Ceramist J. M. Lindgren, Chemist D. F. McFarland, Chemist F. H. Whittum, Analyst S. C. Taylor, Analyst J. T. Kohout, Analyst G. Simpson, Analyst C. W. Sievert, Analyst L. T. Fairhall, Analyst M. G. Mehl, Field Assistant Svante Udden, Field Assistant S. T. Wallage, Field Assistant C. S. Corbett, Field Assistant D. C. Thompson, Field Assistant C. S. Ross, Field Assistant B. H. Schockel, Field Assistant Howard Ferguson, Office Assistant Wilber H. Ponder, Office Assistant V. J. Ingold, Office Assistant Naomi Doub, Office Assistant O. F. Brooks, Office Assistant R. S. Scholl, Office Assistant Harry Almond, Office Assistant 14 BIENNIAL REPORT COOPERATION Formal cooperation with the U. S. Geological Survey has been maintained as before in topographic work, in geological surveys of quad- rangle areas, and in the collection of mineral statistics. Surveys of over- flowed lands were carried on as usual in cooperation with the U. S. Geological Survey and the Rivers and Lakes Commission. An extensive chemical study of Illinois coals was carried on in cooperation with the Department of Applied Chemistry, University of Illinois. Formal cooperation has also been maintained between the State Geological Survey, the Department of Mining Engineering of the Univer- sity of Illinois, and the U. S. Bureau of Mines. To the numerous firms and individuals throughout the State who have shown generous cooperation in furnishing drill records and other information, hearty acknowledgment is due. Geologic Section stratigraphy A strong effort was made to secure records of all new drilling in the State. The manuscript for Dr. Udden's report on the examination of well samples from 35 deep wells was submitted. Work was completed on the Alexandrian formations by Professor Savage, and a report was submitted for publication. Professor Weller, with assistants, spent con- siderable time in southwestern Illinois completing his studies on the Chester formations. He also submitted the manuscript for his mono- graph on the Mississippian brachiopods. General stratigraphic studies were carried on in the following quad- rangles : Hennepin, La Salle, Hardinville, Sumner, and Baldwin by the State, and in the Centralia, Colchester, Macomb, and special areas by the United States. COAL The Forty-seventh General Assembly of the State of Illinois, with a view of conserving the lives of the mine workers in the mineral re- sources of the State, authorized an investigation of the coal resources and mining practices of Illinois by the State Geological Survey in cooperation with the Department of Mining Engineering of the University of Illinois and the United States Bureau of Mines. A cooperative agreement was approved by the Secretary of the Interior and by representatives of the State of Illinois. Under this agreement Mr. Kay, assisted by Mr. K. D. White, spent a large amount of time in the detailed investigation of the coal resources ADMINISTRATIVE REPORT 15 of the State. About 100 typical mines were examined in detail, and material was collected looking toward the publication of reports on each of eight districts, covering the entire Illinois field. Office work was begun on the reports for two of these districts. . The Survey also carried on an exhaustive chemical study of Illinois coals from samples collected in the 100 typical mines selected. The chemical work was done by Mr. J. M. Lindgren and assistants, under the general supervision of Professor S. W. Parr of the Department of Applied Chemistry, University of Illinois. During the sampling cam- paign incident to this study new methods of sampling were devised, and the result of the entire campaign will be a distinct contribution to our knowledge of Illinois coals. Detailed studies of the coal resources of La Salle, Hennepin, Canton, Galatia, Sumner, Hardinville, New Haven, and West Frankfort quad- rangles were continued by Messrs. Grant, Cady, Savage, Udden, and various assistants. OIL AND GAS Mr. Blatchley has spent considerable time in the field and in the prep- aration of his detailed report on the geology of the main oil fields of Illinois. The manuscript for this report was submitted to the printer in November, 1912. After the completion of the Sumner and Hardinville topographic maps Mr. Blatchley continued to collect material in the area looking toward the publication of a geological folio in cooperation with the U. S. Geological Survey. The stratigraphic work on these quadrangles was done by Professor Savage. In the fall of 1911 Mr. Kay spent two weeks in the Carlinville area mapping the Carlinville field, running levels to all of the wells, and secur- ing logs for a report which was published in Extract from Bulletin 20. This extract contains also a report on the Carlyle field and surrounding territory which was prepared by Mr. E. W. Shaw of the U. S. Geological Survey in cooperation with the State Geological Survey. CLAY In connection with the Coal Mining Investigations the geologists representing the Survey have collected a number of roof shale and floor clay samples from representative mines in the State and these samples have been submitted to Ceramics Department of the University of Illinois for testing. 16 BIENNIAL REPORT DRAINAGE WORK The Commission recommended last summer that we prepare and publish a plan for reclamation of the overflowed lands in the Embarrass Valley, inasmuch as the maps which we had submitted to the Rivers and Lakes Commission were not being utilized because of lack of funds. Accordingly the Director arranged for the work to be done by the Har- man Engineering Company and the maps to be engraved from the bal- ance of our appropriation. The report is now finished for early distri- bution. The Spoon River maps are awaiting engineering study, and the Saline River survey lacks completion. Our supply of maps of the Kas- kaskia and Big Muddy valleys is exhausted and should be replenished. EDUCATIONAL BULLETINS Mr Sauer continued office work on his report on the upper Illinois Valley, and his manuscript was submitted for publication. The congested condition of the State printer's office would not permit of publication during the biennium. It is expected that the manuscript for the report on the Kaskaskia Valley will be submitted shortly. All of this work has been carried on under the direction of Professor R. D. Salisbury of the University of Chicago. MINERAL STATISTICS The Survey continued to cooperate with the U. S. Geological Sur- vey in the collection of mineral statistics. Mr. Cady, with assistants, spent considerable time in the collection of this material. The totals for 1910 and 1911 are given on a later page. BUREAU OF INFORMATION The Survey maintains a bureau of information for the convenience of inquirers about mineral resources of Illinois. Requests are received in great numbers both from inside and outside the State. When possible a bulletin containing the desired information is mailed. Frequently, how- ever, it is necessary to make special study and to reply by letter at some length. Many requests for the identification of minerals are received and answered promptly ; others for analysis of specimens are, for the most part, necessarily refused. It has been found that the collection of a representative sample of a material, and the investigation of its favorable occurrence for development, is quite as essential and requires expert advice, just as does chemical analysis. As a rule, therefore, unless a rep- resentative of the Survey investigates and samples a mineral deposit, an analysis at public expense is not justified, particularly because otherwise U. S. GEOU GEORGE Dl (»H<1 sttft a BE0U061CM. SttWCT a r occ adv rese anal ADMINISTRATIVE REPORT 17 Survey funds would be seriously depleted by work which frequently is of no permanent value. Preliminary examinations and opinions as to probable value of minerals are always cheerfully given. Topographic and Drainage Sections In accordance with the cooperative agreement signed May 25, 1911. by George Otis Smith, Director, for the United States Geological Survey, and by Charles S. Deneen, Chairman of the State Geological Commis- sion, and Frank W. DeWolf, Director of the State Geological Survey, August 10, 1911. for the State of Illinois, the Federal and State surveys each allotted $10,000 for cooperative topographic surveys in the State of Illinois during the fiscal year beginning May 25, 1911, and ending June 30, 1912; $8,000 was allotted by each for the year July 1, 1912, to June 30, 1913. Table 1 is a summary of the field and office work accomplished dur- ing the period from July 1, 1911, to June 30, 1913. under the general direction of R. B. Marshall, Chief Geographer, and under the immediate supervision of W. H. Herron, Geographer of the Central Division. The work from May 25 to June 30, 1911, was reported in the results accom- plished during the fiscal year 1910-11. The allotment of $3,750 for overflowed lands made by the State for the fiscal year, 1912, was met by an allotment of $1,250 by the Federal Survey. Under this L. L. Lee and J. B. Leavitt completed the survey of the Spoon River project, in Fulton County, the area mapped being 26 square miles. The survey of the Embarrass River project, in Jasper and Cumberland counties, was completed by Messrs. Lee and Leavitt and H. W. Peabody, the area mapped being 24 square miles. This work was for publication on the scale of 1 :24,000, with a contour interval of 5 feet. For the control of the Spoon River project Mr. Leavitt ran 33 miles of primary levels and established 10 permanent bench marks. For the con- trol of the Embarrass River project R. G. Clinite ran 27 miles of primary levels and established 18 permanent bench marks. For the control of the Saline River project, in Saline, Gallatin, Williamson, and Hardin counties, Air. Clinite ran 120 miles of primary levels and established 35 permanent bench marks, and J. R. Ellis ran 164 miles of primary traverse and set 14 permanent marks. No allotment for overflowed lands was made by the State or Federal surveys for the fiscal vear 1913. 18 BIENNIAL REPORT g 5 E-* . • i-i o o o O o o o O o O O o o O O o O o o O O o O o o o o o o o o o o — O o o O c o o o o c o e o o LO LO U ; io If/ io m If, If, IO • r , ir. lO LO in W; LO lO • ', in IO LO LO ir, OJ N N CM CM N CN CM CM CM CM N CM <~\ CM CM N N N CM CM CM CM vo VO 'O O vo VO VO VO vO VO O VO vo VO "O o VO VO vO vo VO VO o VO o '-' M k." vV . i> O 5 P. §• c 9- E tO O en .« r— . O v 5? ~ -M O CJ ctj i_i co -i QQtdt-fa co CSh h-> JW C ~ D o — ^ — 2 a. o>2 b c c a 3 o o •fh.MfjJ M o >„ ° 5 3 - C •= c > bc^trto 2 £ ~ ~ ^ a ?oi2rt(jc c 'o S2 rt o u «*H o « « ^ ^ w 20 BIENNIAL REPORT 1 ■ Cl fO 1 CM • • ^t- • • • i-i >n ■-> ON Tf CM CM o • (M • • .-1 CO *H„^.H • i-i • i-i CM CM • • • CO CM ■j • oo • • CM . ■ no i-l • 7-1 CM • ON ir> on 00 00 co ■ O M\ oo • CO CM •NO • OS ON Os On NO ^ CM . co & o 2 <" T3 ■ t: c c « r ■1H . 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CM Ov lo ^ cm" vo" • cm" i-i oo (N n ca m _ in 00 TfTj-OOLOOvSCM lo i-i vo m i-i r^ ^ tJ- Ov 00 o Cv) o CO lO c ro r^ o ro VO CM 1-1 I- o • VO <* • ri VO Ov O • CM ,_, X o LO • -r o • o -r VO co CM • vo t c~ o "* • 01 in • CO CM CM VO • CO lO m o Ov ' o Tt t^ LO CO t^ * CO 00 vo LO . o ts, ■* o in VO »t • LO «^ CM i-i • co 00 • r. m -' ^ a o 4J +J C o c O a d _c 3 C „ 6 E « »- S^S oo fe^ 3. 3, O c" r> s 3 u j3 rt — S c3 = „ 3 V > S3 ^ 3 iJ^^S^Pn^COtxitXlCXlHNS cd 3 > o » C C £ o H u 3 o '_ Tl Cj 3 C 3 fe 28 BIENNIAL REPORT i MINERAL RESOURCES IN 1911 AND 1912 29 COAL The coal-mining industry in Illinois has grown very rapidly the last 30 years. Figure 1 shows the average yearly production for each five- year period since 1853. Commercial mining began about 1833 when St. Louis was furnished with coal from small mines in St. Clair County, an area that developed rapidly and has always held a high rank amongst the coal-producing counties. The La Salle area developed very soon after the completion of the Illinois and Michigan Canal and supplied Chicago with fuel. With the building of railroads other parts of Illinois opened mines, until now the area of most recent development and interest is the Franklin-Williamson county district which promises to grow to tremendous proportion. The coal of this part of the State is of high grade and of good thickness. In 1911 and 1912 Illinois ranked third as a coal-producing State, having been preceded by Pennsylvania and West Virginia. In total out- put of coal during the history of the industry, a rank of second has been maintained since 1866. A comparison of values of coal for each of these two years gives Illinois second place, as our coal sells at a higher price than the West Virginia coal ; Illinois operators are favored with large consuming markets close at hand where a slightly higher price per ton is more desirable than the tremendous transportation expenses from more distant fields. In 1911 a new record in production was established, the tonnage having increased 16.9 per cent over the previous year and the value 13.6 per cent. In spite of the increased wages paid as a result of the big strike of 1910, the average price per ton fell from $1.14 to $1.11. Whereas the output of the Eastern States was seriously affected by the depression in the iron and steel industry, coal mining in Illinois was unaffected, as our coals are non-coking and therefore not used in that way. Of the 102 counties in Illinois, 51 reported an output of coal in 1911. In decreasing order of tonnage for those counties exceeding three million short tons they are Williamson, Sangamon, Macoupin, St. Clair, Saline, Franklin, Vermilion, and Madison. Sixteen counties produced more than a million tons. In 1912 another record in output was made, the increase over the previous year having been 11.6 per cent in quantity and 18.1 per cent in value. The average price per ton increased from $1.11 in 1911 to $1.17 in 1912. The leading counties were in decreasing order Williamson, Sangamon, Macoupin, St. Clair, Franklin, Saline, and Madison. The only changes in order are the relative positions of Franklin and Saline. 30 BIENNIAL REPORT Franklin County has shown a marked yearly increase from the beginning of its history of production in 1903. Table 4 presents the detailed statistics for coal production by counties in 1911 and 1912. Table 4. — Coal production of Illinois in 1911 and 1912, by counties, in short tons 1911 County >T3 >, V oj en ^ S <0 mo. , ,_ o 0) X « u a* o *j c e « rt •" ^g £3 § 2E < o Bureau Christian Clinton Franklin Fulton Gallatin Grundy Henry Jackson Knox La Salle Livingston Logan McDonough Macon Macoupin Madison Marion Marshall Menard Mercer Montgomery Peoria Perry Randolph Rock Island St. Clair Saline Sangamon Shelby Stark Tazewell Vermilion Will Williamson Other counties and small mines. 1,560,490 1,250,722 978,791 4,282,721 2,337,698 48,977 480,549 17,000 629,550 1,156,290 24,918 392,374 3,178 148,443 4,791,107 3,804,878 1,451,864 361,335 116,431 364,886 ■ 2,092,984 1,097,830 1,361,180 752,609 15,456 4,437,137 4,293,635 5,260,048 153,045 10,881 192,423 3,179,572 111,833 6,982,822 1,160,873 48,706 68,121 152,163 64,961 12,947 48,741 39,878 119,685 54,323 61,403 14,399 868 30,690 29,548 39,863 1,750 29,806 43,834 21,417 876 307,696 73,605 39,219 1,637 56,638 17,516 10,954 314 136,047 7,100 80,155 115,312 124,515 96,485 48,313 48,526 66,443 21,882 53,797 7,350 15,635 12,497 43,122 46,717 101,958 25,786 31,128 51,806 30,924 14,630 47,477 3,884 182,573 115,130 34,699 89,540 298,353 156,341 24,210 8,246 21,845 1,450 71,224 7,674 201,243 54,108 14,063 4,910 69,188 302,497 238,250 62,105 793,861 1,786,835 1,677,317 1,467,846 1,040,479 4,442,284 2,453,424 64,244 540,787 58,613 703,190 22,293 1,537,591 65,774 466,528 14,446 291,590 4,986,574 4,025,878 1,548,703 449,660 177,578 393,018 2,182,823 1,225,574 1,444,114 798,163 66,817 4,734,840 4,417,874 5,714,742 185,501 34,176 271,321 3,434,923 130,806 7,354,507 1,461,228 59,885,226 $70,294 $2,736,737 1,687,823 1,073,188 5,389,076 3,193,202 72,295 963,365 104,602 968,303 39,765 2,706,718 130,847 574,713 31,820 413,179 4,894,191 4,386,620 1,666,346 812,020 240,850 594,171 2,348,084 1,580,021 1,518,746 814,922 107,377 4,656,454 4,924,839 6,335,965 252,865 57,128 348,063 3,940,780 242,805 8,214,769 2,271,689 $1.63 224 1.15 167 1.03 171 1.21 204 1.30 201 1.13 147 1.78 162 1.78 174 1.38 160 1.78 163 1.76 224 1.99 216 1.23 186 2.20 178 1.42 163 .98 206 1.09 184 1.08 212 1.81 240 1.36 169 1.51 209 1.08 192 1.29 213 1.05 146 1.02 138 1.61 180 .98 162 1.11 204 1.11 178 1.36 142 1.67 188 1.28 325 1.15 234 1.86 201 1.12 187 1.56 237 $1.17 194 2,075 1,336 4,499 3,578 164 1,595 126 1,068 60 3,275 127 678 48 581 5,061 4,466 1,651 1,065 335 479 2,665 1,721 1,968 1,116 122 5,799 5,204 7,030 339 43 376 4,149 408 8,602 2,481 "Bond, Calhoun, Edgar, Greene, Jefferson, McLean, Morgan, Moultrie, Putnam, Schuyler, Scott, Warren, Washington, White, and Woodford counties. 32 BIENNIAL REPORT COKE Most of the coal for the coking establishments in Illinois comes from West Virginia; this imported material is used with Illinois coal in a proportion of 4 to 1, a mixture that makes a very satisfactory product. All the coke produced in Illinois in 1911 and 1912 was made in retort ovens. In 1911 the output exceeded that of the previous year, but as the price fell from $4.43 to $3.97 the value of the total State production was considerably lower. At South Chicago 200 Semet-Solvay by-product ovens operated, and at Joliet were 280 Koppers regenerator by-product ovens. In 1912 a record in total quantity and in total value of output was made, but in spite of this the rank of Illinois amongst other states fell to fifth due to the enlargement of the establishment at Gary, Indiana, thus advancing that State from fifth to third rank. The By-Products Coal Corporation at South Chicago built 40 new ovens ; the North Shore Gas Company at Waukegan began operations with 13 ovens; and the Coal Products Manufacturing Company at Joliet also opened up business in 1912 with 35 ovens. The Illinois Steel Company at Joliet made no enlargements during this year. The drop in average yield of coal in coke is due probably to larger proportion of Illinois coal. Table 5 shows the statistics for the manufacture of coke in Illinois for the past 4 years. Table 5. — Statistics of the manufacture of coke in Illinois, 1909-1912 Establish- ments Ovens Coal used Yield of coal in coke Coke produced Total value of coke at ovens Value of coke at Built Building ovens per ton 1909 1910 1911 1912 5 5 6 6 468 508 506 «594 40 48 MO Short tons 1,682,122 1,972,955 2,087,870 2,316,307 Per cent 75.9 76.8 77.1 76.2 Short tons 1,276,956 1,514,504 1,610,212 1,764,944 $5,361,510 6,712,550 6,390,251 8,069,903 $4.20 4.43 3.97 4.57 "Includes 253 Semet-Solvay, 1315 Koppers, and 24 Belgian ovens. & Semet-Solvay ovens. PIG IRON The pig iron of Illinois is made from ore shipped by lake to the Chicago smelters from the northern iron-ore districts. For this reason the value of this product is not included in the total value of mineral production for Illinois. In both 1911 and 1912 a rank of third among the states was maintained, having been preceded by Pennsylvania and Ohio. MINERAL RESOURCES IN 1911 AND 1912 33 In 1911 a marked decline in output of pig iron prevailed in all the states producing this material. Illinois suffered a drop of 21.9 per cent as compared with 1910; but in 1912 an increase prevailed throughout the country, and Illinois put out 37.8 per cent more than the preceding year. Table 6.- — Statistics of pig iron marketed in Illinois, 1910-1912 Year Quantity Value Average price per ton Percentage of U. S. total quantity 1910 Long tons 2,606,335 2,036,081 2,806,378 $41,465,543 31,152,927 42,828,816 $15.91 15.30 15.26 9.02 1911 8.71 1912 9.29 PETROLEUM The main oil field of Illinois is a feature of the La Salle anticline that extends from La Salle south and east through St. Francisville and into Indiana. The oil-bearing sands are in the Pennsylvanian and Miss- issippian series, the richest of these being known as the Kirkwood and McClosky sands, both of Mississippian age. Oil and gas was discovered near Casey in 1865, but development of the field did not begin till 1904. As shown by Table 7, the production of petroleum in Illinois increased phenomenally till a maximum was reached in 1908. In 1909 a decline was suffered, but the following year active drilling in Lawrence County revealed new possibilities in two previously unknown sands, the Tracey and McClosky ; also the Centralia-Sandoval field was developed follow- ing recommendations by the State Geological Survey. In 1911 the rank of third amongst oil-producing states was main- tained, but a drop in total output of 5.5 per cent resulted from the lack of new prolific fields. The Carlyle area was developed as a result of Survey investigations, and about 120 wells yielded approximately 4,500 barrels daily ; this field is very limited and probably will not last long. Oil and considerable gas were found near Carlinville late in 1911, but the production did not affect the statistics for that year. Further decline in total production (S.7 per cent) in Illinois was felt in 1912, as no great extensions of the producing fields were developed. The marked increase in prices, however, made the total value greater than the previous year. The chief interest lay in northern Wabash County where a 200-barrel well caused considerable prospecting, and only 13 of the 40 borings yielded over 100 barrels daily ; 20 were dry. Table 7 shows the production and value of oil in Illinois from 1889 to 1912. 34 BIENNIAL REPORT Table 7. — Marketed production in barrels and value of petroleum in Illinois, 1889-1912 Year Marketed production Percentage of U. S. Value Yearly average price production per barrel 1889-1904 6,576 1905 181,084 0.14 $ 116,561 $0,644 1906 4,397,050 3.47 3,274,818 0.745 . 1907 24,281,973 14.62 16,432,947 0.677 1908 33,686,238 18.76 22,649,561 0.672 1909 30,898,339 16.87 19,788,864 0.640 1910 33,143,362 15.82 19,669,383 0.593 1911 31,317,038 14.21 19,734,339 0.630 1912 28,601,308 12.88 24,332,605 0.851 In the following table are the dates of changes and changes in prices at wells of different grades of petroleum from 1910 to 1912. Table 8. — Fluctuation in prices of Illinois petroleum per barrel, 1910-1912 Date Below 30° B. Above 30° B. Date Below 30° B. Above 30° B. 1910 Jan. 1.. 1911 Jan. 1.. May 2. . June 14. Sept. 15 Sept. 19 1912 Jan. 1.. Jan. 2.. Jan. 3.. Jan. 24. Feb. 1.. Mar. 4. Apr. 24. $0.60 .60 .63 .65 .67 .67 .67 .70 .72 .75 .78 .81 .83 $0.52 .52 .55 .55 .55 .57 .57 .60 .62 .65 .68 .71 .73 1912 — con. May 24 June 13 . . . June 27 July 25 Sept. 12 . . . Oct. 28 Nov. 9 Nov. 15 ..., Nov. 25 Dec. 2 Dec. 9 Dec. 16 Dec. 20 Dec. 23 $0.85 .87 .90 .92 .94 .96 .99 1.02 1.05 1.08 $0.75 .77 .79 .82 .84 .87 .89 .91 .93 .96 .99 1.02 1.05 1.08 By far the large proportion of drilling for the past three years has been in Lawrence and Crawford counties. Table 9 presents by counties the number of wells drilled, the total initial and average initial daily output of new wells from 1910 to 1912 inclusive. MINERAL RESOURCES IN 1911 AND 1912 35 s ■*- Ov "Q On 6 5 • NO cm o — © c»5 • o o ts rvr <= 3 3 " co cm vo to on C3 fs l< ON CM to CM i-h o CM VO ial pro petrol well ,_, • y-> O O VO Is is oo IO vo o c »-H ' is iri in »0 v6 VO NO to ,-H to to ^ On CVl -h oo ON NO "£«**!> '""' c o a "" o © vo • to oo in O O is NO vo 41 ON vo cm' * vo is,' cm' u-, O CM = • vo *"< CM CM — i CM ^h i-h O - vo • 00 Is vo in o CJ • vo CO o NO . Is CM is O 00 On On vC 00 VD i-H i-H IS VO NO • -h .— © CM O O CM Is vo to C." CM • iO CM CM «o O vo n NO CM O . VO 00 NO vo C\ CO to <— i o Is CM CNJ NO to On CM . O vo — h O CM ,_, . vo ,_, CM ^ H O . vo to -h 1- • On CM 00 On fO M- On """ ,_, . vo ro CM On NO to NO CM ^r _ _ . M" CM NO NO ^ NO O on ■-H tO ^r o o — O • TT O to _ 1- ■*■ _f On 00 vo i-i On to On vo NO ■ T to OJ On rH ,_, ■-i O] • -ON • ON rt rt ^f O On O h t • • NO CM rt • NO vo vo ts ~ . CM to vo NO 00 tt t-H tS ^r •* ^H • o CM rs . i-. — 1 On tS VO On CM >> 1-1 ON vo On • to ts ,_ CM 00 IS f" in M t -On to CM NO Q On CM O vo 00 to i-i Tf CM _ CM •* ON CM ,_ NO !-H . Tf to CM i-i ts CM CM On CM to ^ • CM 00 NO -3- O NO I-H VO ,_, , ^- NO ,_, • CM to O . NO TJ- r-, VO oo CM • M" NO ON "* vo CM ^ i-h i— i , c 3 o U « ^ O : : : "2 * : c 3 1 -1 — 1 i / • i \ • \ ■:■:■:■. d i i i i i i i i '■■■■■k ■ 1 1 I l ! i c o 8 c 0., ®- . 1 \ '% 1 I 1 1 f *. 1 \ 1 ) ■ | / * | 1 / o be C J t« P3 § s ■s-a rt 3 J"<5 Seu 3 O^S ^ -t-> ;-. «j rt o co O •SO CD rt o oooo-*-*c~cmoo©05ocmcmoo os •>* O M 00* IflO* f WM00 cUOSOt-'OOO 8 § rt " S S *=- *• 2 d § 8 S <°' fCOMIOWCOCOOOONOOCO O 23 i-H O i— I O iH lO IB d N US l-l CO © CM tH 00 CUt-OOOOOO oo h d d d d n Sj io t~^ co d cm' OS CM DODO* CO CO N ■* f 00 00 « n cs in od o o m r-I cd> eo ■* o" i-l i_ CO 00 Vh CO H 1*9 CO f. tH o eo iH g H O •* O CM ■*' CM O ^ H H ri B H t' lO* H O J, o o £ c §•2 c a »' g ~ *•< O CL> o 2 .O S- cu oj a s co 3 t> CM* iH O0 CM O 2 t- t- H M O M O W M owt* oo th Ed in* *' 00 CM 1—1 T— I in in cm 8 §8* o in cm" CM CO CO CO ^ CM* cs co o> oo' co ■*' CM in CM CM CO OS CD ©' co' t>" in in © in oo t-h 8 3 oo in © i-J os oo' in in cm co co co os os © os cm' in £ g a s s g i-" cm' N lO O0 N 0O OS CM* i-I i>- in CM* i-H "*. °. ^ CO CO CO* © cm oo i—i in in © t>* * iH* 00 oo in CO oo CO © -f * H N I 1 CS Tl" 00 cm' co in co -^ oo i-* d cm' h d M CO O H lO M Tji O* cm m co * © oo in* ©' CM* ©* CD in cm © oo © 00 00 CO CM CO © 00 NOTICE To be inserted between pages 66 and 67, Bulletin 23, Illinois State Geological Survey This paper is a reprint from the same plates e# the extract from Bulletin 23, published in November, 1913. The first publi- cation of the new species of fossils noted herein was in this ex- tract that was distributed in November, 1913. Earlier studies and interpretation of the strata 69 Stratigraphy 72 General stratigraphic relations 72 Thickness and formations of the series 73 Girardeau limestone 73 Occurrence and stratigraphic relations 73 Detailed section 73 Edgewood limestone 75 Occurrence and stratigraphic relations 75 Detailed sections 77 Channahon limestone member 84 Essex limestone 86 Occurrence and stratigraphic relations 86 Detailed section 86 Sexton Creek (Brassfield) limestone 87 Occurrence and stratigraphic relations 87 Detailed sections 88 General conclusions 91 Paleontology of the Girardeau and Edgewood limestones 95 Introductory statement 95 Descriptions of species from the Girardeau limestone 95 Descriptions of species from the Edgewood formation 113 Fossils from the Channahon limestone member 149 PLATES Fossils from the Alexandrian series 161 1 Part II of this series, dealing with the stratigraphy and paleontology of the Essex and Sexton Creek limestones, is in preparation. (67) STRATIGRAPHY AND PALEONTOLOGY OF THE ALEXANDRIAN SERIES IN ILLINOIS AND MISSOURI PART I 1 By T. E. Savage OUTLINE PAGE Introduction 68 Distribution of strata 69 Earlier studies and interpretation of the strata 69 Stratigraphy 72 General stratigraphic relations 72 Thickness and formations of the series 73 Girardeau limestone 73 Occurrence and stratigraphic relations 73 Detailed section 73 Edgewood limestone 75 Occurrence and stratigraphic relations 75 Detailed sections 77 Channahon limestone member 84 Essex limestone 86 Occurrence and stratigraphic relations 86 Detailed section 86 Sexton Creek (Brassfield) limestone 87 Occurrence and stratigraphic relations 87 Detailed sections 88 General conclusions 91 Paleontology of the Girardeau and Edgewood limestones 95 Introductory statement 95 Descriptions of species from the Girardeau limestone 95 Descriptions of species from the Edgewood formation 113 Fossils from the Channahon limestone member 149 PLATES Fossils from the Alexandrian series 161 1 Part II of this series, dealing with the stratigraphy and paleontology of the Essex and Sexton Creek limestones, is in preparation. (67) 68 BIENNIAL REPORT INTRODUCTION The name Alexandrian series 2 was proposed by the writer in 1908, in order to provide a place for the early Silurian strata occurring in Illi- nois and eastern Missouri which occupy a position above the top of the generally accepted Cincinnatian (Richmond) and below the Brassfield (Ohio Clinton) limestone. Regarding the stratigraphic position of the Brassfield, Professor Schuchert 3 states in his classic work on the paleogeography of North America that "in the Anticosti section it is seen that this so-called Clinton (Ohio Clinton) or Triplecia ortoni zone, is older than the true Clinton of the Appalachian region." It is now also known that the fauna of the Brassfield limestone is very closely allied to that of the earlier Silurian strata of Illinois and eastern Missouri, as shown in the similarity of sev- eral of the genera and species to those of the older Edgewood limestone. For this reason, the strata representing the Brassfield in Illinois and Mis- souri are here included in the Alexandrian series. As now defined, the Alexandrian series embraces all the strata in this region between the top of the Cincinnatian (Richmond) and the top of the Brassfield limestone. It includes strata that have been referred to in the literature under various formation names ; as the Girardeau lime- stone, Bowling Green limestone, Noix oolite, Edgewood limestone, Sexton Creek limestone, Channahon limestone, and Essex limestone. Some of these strata have been assigned to positions in the geologic column as widely separated as the Trenton division of the Ordovician, and the Onondaga of the Devonian system. In 1857 Billings proposed the name Middle Silurian — "Anticosti group" 4 — for the succession of strata exposed on the island of Anticosti, in the Gulf of St. Lawrence. In the lower part of his Anticosti group, Billings included the representatives of Ordovician strata to which the name Richmond has since been applied ; in the upper part were included strata equivalent to the entire Niagaran series of the New York section ; and in the middle portion were strata belonging to the interval between the Richmond below and the Niagaran (New York Clinton) above, to which has been given the name Alexandrian series. Since the Anticosti group, as defined by Billings, embraced at the base so important a part of the Cincinnatian series as the Richmond, and in the upper part the whole of the Niagaran series, this term is not considered appropriate or in any sense to have priority as a name for only that portion of the Anticosti SeC- ^avage, T. E., Am. Jour. Sci. 4th ser. vol 25, p. 434, 1908. ''Schuchert, Charles, Paleogeography of North America: Geol. Soc. America, vol. 20, p. 538, 1910. ■T.illings, E., Can. Geol. Survey: Report of progress, pp. 247-255, 1857. ALEXANDRIAN SERIES 69 tion belonging to the interval between the Richmond of the Ordovician and the New York Clinton of the Silurian to which the name Alexandrian series has been applied. DISTRIBUTION OF STRATA The rocks representing the Alexandrian series in Illinois and eastern Missouri appear at the surface in two general areas separated by a dis- tance of 200 miles. One area borders both sides of Mississippi River from about the mouth of Ohio River, north nearly to Hannibal, Missouri. Within this belt outcrops occur at intervals over a width of 25 to 40 miles. Good exposures have been studied in Alexander and Union coun- ties, Illinois, and in the vicinity of Cape Girardeau, Missouri. Xorth of the fault line that crosses the south end of Jersey and Calhoun counties, Illinois, and west into Lincoln County, Missouri, strata representing some part of this series outcrop at a number of places over the east part of Lincoln, Pike, and Ralls counties, Missouri, and in Jersey, Calhoun, and Pike counties, Illinois, within a distance of 12 to 20 miles from the Mississippi. The second area in which these early Silurian rocks are exposed in the upper Mississippi valley is in Will and Kankakee counties in north- eastern Illinois, where somewhat isolated outcrops of the Sexton Creek (Brassfield) limestone and earlier Silurian strata appear at a number of places in the vicinity of Kankakee and Desplaines rivers. It is proba- ble that the Alexandrian strata in the Mississippi River area and in northeast Illinois are more or less continuous, probably along the present basin of the Illinois River, but they are concealed beneath younger deposits in the intervening region. EARLIER STUDIES AXD INTERPRETATIONS OF THE STRATA In a report in 1855, Air. G. C. Swallow, 5 who was then State Geol- ogist of Missouri, noted the white oolite bed in the vicinity of Louisiana, Missouri, and referred it to the Onondaga of the Devonian. In the same report Shumard 6 described a limestone occurring near Cape Girardeau, Missouri, under the name Cape Girardeau limestone, and considered it the oldest Silurian formation in the State. In discussing the stratigraphic geology of Illinois in 1866, Worthen 7 " recognized the Girardeau limestone in the vicinity of Thebes, but referred it to the Ordovician in the upper part of the Cincinnati group. 5 Swallow, G. C, Mo. Geol. Survey: Reports 1 and 2, p. 107, 1855. °Shumard, B. F., Mo. Geol. Survey: Report 2, p. 154, 1855. 7 Worthen, A. H., Devonian and Silurian systems of Illinois: Geol. Survey of Illinois, vol. 1, p. 130, 1866. 70 BIENNIAL REPORT On a later page of this report Worthen correlated with the Niagara of northern Illinois, the gray limestone forming the lower part of the Mississippi River bluff in the southwest part of Pike and the northwest part of Calhoun counties in Illinois (now known to be of Sexton Creek or Brassfield age). On another page he assigned to the Lower Helderberg group the dark limestone and the overlying mottled red and gray limestone in the vicinity of Thebes, that represent respectively the Edgewood and the Sex- ton Creek limestone in that portion of the State. He says : "It would appear probable that no beds of undoubted Niagara age were ever laid down in southern Illinois, but in their places these siliceous limestones, representing in part the age of the Lower Helderberg limestones and in part the Oriskany sandstones of the New York series were deposited resting directly upon the Cincinnati group of the Lower Silurian." In a report on the geology of Alexander County, 8 Illinois, published in 1868, the Girardeau limestone is again assigned to the Cincinnati group, whereas the overlying gray limestone, containing Dalmanitcs danai and its associates, is referred to the Lower Helderberg. In a paper presented to the American Association for the Advance- ment of Science in 1870, Worthen 9 again discussed the limestones occur- ring between the Clear Creek (Oriskany) beds and Cape Girardeau lime- stone in southwest Illinois. He concluded that : "these limestones represent the same geological horizon as the Niagara dolomites in the northern part of the state; and that the difference in the specific character of the fossils is entirely due to the changes in the oceanic conditions under which they were deposited, and not to the different ages of the sediments themselves." In describing the geology of Calhoun and Pike counties, Illinois, in 1879, Worthen 10 considered the gray limestone (Sexton Creek or Brass- field) appearing in the lower part of the Mississippi River bluff, from near the town of Rockport south to Hamburg, as the equivalent of the Niagara limestone in the northern part of the State. He regarded as the basal member of the Niagara in this region, the gray oolite and the overlying buff, magnesian limestone, outcropping a few miles below Hamburg, that are now known to correspond to the Edgewood as developed near Louis- iana, Missouri. In his description of the geology of Will and Kankakee counties, in 1870, W T orthen did not distinguish the Alexandrian series from the Nia- gara limestone. 8 Worthen, A. H., Geology of Alexander County: Geol. Survey of Illinois, vol. 3, pp. 20-32, 1868. 9 Worthen, A. H., Am. Assoc. Adv. Sci., vol. 19, p. 172, 1870. : "Worthen, A. H., Geology of Calhoun and Pike counties: Geol. Survey of Illinois, vol. 4, pp. 6, 7, and 26, 1870. ALEXANDRIAN SERIES 71 In a report on the geology of Lincoln County, Missouri, published in 1873, Potter 11 referred the oolite, present in the ridges and knobs in the northeast part of this county, to the Onondaga of the Devonian. In a paper intitled, "A remarkable fauna at the base of the Burling- ton limestone in northern Missouri," in 1892, Dr. C. R. Keyes 12 distin- guished the white oolite bed and the overlying buff or brown limestone exposed near Louisiana, and correlated them with the Niagara limestone of Iowa. In describing the vertical range of fossils at Louisiana, Missouri, in 1897, Keyes and Rowley 13 again referred the oolite bed and the associated buff limestone in this region to the Niagara. In the following year Keyes 14 published a paper on "Some geological formations of the Cap an Gres uplift," in which the name Noix oolite was proposed for the white oolite bed in the vicinity of Louisiana, and the term Bowling Green limestone was given to the buff magnesian limestone near Bowling Green, Missouri. Of these formations Keyes writes : "The Noix oolite and the Bowling Green limestone together may be regarded approximately as equivalent to the so-called Niagara of the Upper Mississippi basin." In his report on the geology of Pike County, Missouri, in 1907, R. R. Rowley 15 says : "The Silurian is represented by a white oolitic and a brown limestone. The oolitic limestone attains a thickness of about seven feet, and from its fauna is thought to belong to the Clinton. The brown limestone overlies the white oolitic and attains a maximum thickness of 25 feet. This horizon is clearly Niagara." In a paper by the writer 16 in 1908, a bed of cherty and mottled lime- stone in southwestern Illinois was recognized as the equivalent of some part of the Brassfield limestone of Ohio. A distinct formation of early Silurian time was also shown to be present in this region below the Brass- held limestone and above the Girardeau, and separated from each by a sedimentary break. The Silurian aspect of the fauna of the Girardeau limestone was emphasized, and the name Alexandrian series was proposed to embrace these post-Cincinnatian and pre-Clinton beds represented by the Girardeau limestone and the succeeding strata lying below the equiva- lent of the Brassfield limestone. "Potter, W. B., Mo. Geol. Survey, p. 242, 1873. 12 Keyes, C. R., A remarkable fauna at the base of the Burlington limestone in north- eastern Missouri: Am. Jour. Sci., 3d series, vol. 44, p. 447, 1892. 13 Keyes and Rowley, Vertical range of fossils at Louisiana, Mo. : Iowa Acad. Sci., vol. 4, pp. 26-40, 1897. "Keyes, C. R., Some geological formations of the Cap-au-Gres uplift: Iowa Acad. Sci. vol. 5, pp. 58-63, 1898. "Rowley, R. R., Geology of Pike County: Mo. Bur. Geol. and Mines, vol. 8, second series, p. 20, 1907. 1,J Savage, T. E., Lower paleozoic stratigraphy of southwestern Illinois: Am. Jour. Sci., 4th series, vol. 25, pp. 431-443, 1908. 72 BIENNIAL REPORT The following year the name Sexton Creek limestone was defined 17 for the Silurian strata in Illinois that are equivalent to some part of the Brassfield. The term Edgewood limestone was at the same time applied to that part of the Alexandrian series in western Illinois and eastern Missouri lying between the Girardeau and the Sexton Creek limestones. In discussing the faunal succession and the correlation of the pre- Devonian formations of southern Illinois 18 in 1910, the significance of the Silurian types of fossils in the Girardeau limestone was pointed out ; and the Channahon limestone in Will County was regarded as the equiva- lent of some part of the Edgewood formation of southern Illinois and eastern Missouri. In a paper read at the 1911 meeting of the Illinois Academy of Science, the Essex limestone 19 in Kankakee County, was described and the formation was provisionally referred to the Alexandrian series above the Edgewood and below the Sexton Creek limestone. STRATIGRAPHY General Stratigraphic Relations The strata comprising the Alexandrian series in Illinois and Missouri are everywhere uncomformable upon some horizon of the Richmond, and they are separated by a similar sedimentary break from the rocks that lie above them. In the south part of the area, in Alexander and Union counties, Illi- nois, and in Cape Girardeau County, Missouri, these strata usually rest upon different levels of the Orchard Creek shale of Richmond age, and are followed by Helderbergian limestone having the faunal aspect of the New Scotland of New York. Farther north, in Jersey, Calhoun, and Pike counties, Illinois, and Lincoln, Pike, and Ralls counties, Missouri, the Alexandrian overlies a blue shale that in Illinois has been correlated with the Maquoketa, and in Missouri has been called Hudson River shale, and Buffalo Creek shale. The rocks that overlie the Alexandrian strata in Jersey County, Illinois, are of Niagaran age, and in the northern part of Calhoun County, Illinois, and across the river in the northeast part of Lincoln County, Missouri, they are Devonian limestones of Hamilton age belonging to the Iowa or northwest (Dakota) province. A few miles still farther north, in the vicinity of Pleasant Hill, Illinois, and Louisiana, Missouri, they are im- mediately succeeded by a bed of dark shale of upper Devonian age. In the northeastern Illinois area, the Alexandrian strata rest upon "Savage, T. E., Ordovician and Silurian formations in Alexander County, Illinois: Am. Jour. Sci., 4th series, vol. 28, pp. 509-519, 1909. 18 Savage, T. E., The faunal succession and the correlation of the pre-Devonian forma- tions of southern Illinois: 111. State Geol. Survey Bull. 16, pp. 302-341, 1910. "Savage, T. E., The Channahon and Essex limestones in Illinois: Trans. 111. Acad. Sci., vol. 4, pp. 97-103, 1912. ALEXANDRIAN SERIES 73 the Maquoketa shale and, where exposed beneath superjacent strata, are followed by dolomites of Niagaran age. Thickness and Formations of the Series The strata comprising the Alexandrian series, as defined above, have a maximum aggregate thickness of about 175 feet. The series is divisible into four formations which, with the possible exception of the Essex lime- stone, are unconformable among themselves, but their faunas are clearly related. The sequence of the formations from below upwards is as fol- lows : Girardeau limestone, Edgewood limestone, Essex limestone, and Sexton Creek (Brassfield) limestone. Girardeau Limestone occurrence and stratigraphic relations The name Cape Girardeau limestone w r as given to the formation by Shumard in 1855, from Cape Girardeau, Missouri, near which town the strata were well exposed. The shortened form of the name has been adopted for this limestone. The Girardeau limestone is present only in the south part of the area under consideration, and is not known further north than a few miles above Cape Girardeau, Missouri. It is well exposed in Illinois near the mouth of Orchard Creek about two miles south of Thebes, and in the bluff of Mississippi River and in some cuts along the new Cairo and Thebes Railroad for some distance further south. It also outcrops in the bank of Mississippi River and along the Chicago and Eastern Illinois Rail- road one and one-half miles north of Thebes. In Missouri these strata occur over a small area in Cape Girardeau County and are exposed at the type locality, about two miles north of Cape Girardeau. In some places the Girardeau limestone rests unconformably upon the Thebes sandstone (Richmond), and in other places it overlies differ- ent horizons of Orchard Creek shale. The rocks of this formation consist of dark, fine-grained, hard, brittle limestones in layers two to four inches thick. Thin lenses of hard calcareous shale occur between the layers of limestone ; both the limestone and shaly partings in places contain numer- ous fossils. The total thickness of the formation is 35 to 40 feet. detailed section A representative section of the Girardeau limestone, exposed in the east bank of Mississippi River, two and one-half miles south of Thebes, Illinois, is given below, beginning with ( 1 ) at the bottom : Section of strata two and one-half miles south of Thebes Sexton Creek (Brassfield) limestone — 5. Red or pink mottled, fine-grained, brittle limestone, in layers eight to 36 inches thick, containing many small fossils 8 feet, 10 inches 74 BIENNIAL REPORT Dalmanella eleganttila var. parva. Orthoceras unionensis Hebertella sp. Illaenus sp. Plectambonites transversalis var. ele- Phacops pulchellus gantula 4. Light gray, rather fine-grained limestone with blotches of green shaly material, containing many nodules of chert 1 foot, 9 inches Favosites favosus Plectambonites transversalis Halysites catenulatus Stricklandinia triplesiana Zaphrentis sp. Triplecia ortoni var. Clathrodictyon vesiculosum Illaenus cf. daytonensis Orthis cf. davidsoni 3. Chert bands, 2 to 4 inches thick, separated by 2 to 3-inch layers of hard, impure limestone without fossils 5 feet, 6 inches (Break in sedimentation) Girardeau limestone — 2. Dark colored, fine-grained, hard, brittle limestone, breaking with con- choidal fracture, similar in all respects to 1 15 feet Ptychocrinus splendens 20 Schuchertella missouriensis Tanaocrinus cf. typus Cornulites tenuistriata Archaeocrinus sp. Modiolpsis concinna n.sp. Nematopora alternata Conradella sp. Nematopora delicatula Diaphorostoma niagarensis var. im- Nematopora fragilis matura n.var. Nematopora retrorsa Acidaspis halli Camarotoechia? festinata n.sp. Calymene dubia n.sp. Protozeuga sulcocarinata n.sp. 21 Cyphaspis girardeauensis Rafinesquina? mesicosta Proetus princeps n.sp. Rafinesquina? delicatula n.sp. 1. Dark-colored, fine-grained, hard, brittle, limestone in layers 2 to 4 inches thick, separated by thin partings of calcareous shale, and furnishing the fossils listed below 18 feet Ptychocrinus splendens Rafinesquina? delicatula n.sp. Tanaocrinus sp. Rhynchotrema ? illinoisensis n.sp. Nematopora alternata Schuchertella missouriensis Nematopora delicatula Cornulites incurvus Nematopora fragilis Cornulites tenuistriata Nematopora retrorsa cf.Cyclonema cancellata Camarotoechia? festinata n.sp. Diaphorostoma niagarensis var. imma- Dalmanella modesta n.sp. tura n.var. Homoespira immatura n.sp. Pterinea ornata n.sp. Leptaena rhomboidalis Acidaspis halli Lingulops ovata n.sp. Calymene dubia n.sp. Protozeuga sulcocarinata n.sp. Cyphaspis girardeauensis Rafinesquina? mesicosta Encrinurus deltoideus 20 The crinoids collected from the Girardeau limestone were submitted to Mr. Frank Springer, who made the above identifications. The preservation of these was not sufficiently good for illustrations. 21 The name Protozeuga has been defined in manuscript by Dr. W. R. Twenhofel for an early Silurian genus of the brachiopods having the characteristics of Woldheima but with punctate shells. ALEXANDRIAN SERIES 75 In the foregoing section, the two lower members represent the Gir- ardeau limestone in its typical development, having at this place a thick- ness of S3 feet. The succeeding strata, members 3 to 5 inclusive, belong to the Sexton Creek (Brassfield) limestone, the two formations being separated by a sedimentary hiatus. The Edgewood strata which, north of Thebes, appear below the Sexton Creek limestone, are not present in this locality. The decidedly Silurian aspect of the fauna of the Girardeau lime- stone appears in the lists presented above. The post-Richmond age of the Girardeau limestone is shown by the total absence of a single char- acteristic Richmond species in the formation, and also by the presence of such Silurian genera as Schuchcrtclla, Homoeospira, Camarotoechia? Diaphorostoma, Protozcuga, and Proetus. The only species in the Gir- ardeau fauna that are listed by Cumings from the Richmond strata of Indiana, or that are known to occur in the Maquoketa (Richmond) strata of Iowa and Illinois, are Lcptaena rhomboidalis and Cornulites tciiuistriata, neither of which possesses any stratigraphic significance. It should be noted also that the most abundant and characteristic of the Girardeau species, as Schuchertclla missouricnsis, Rafinesquinaf mesicosta and Protozeuga side o car mat a, continue upward into the suc- ceeding Edgewood limestone. Regardless of whether the Richmond shall eventually be transferred from its present position in the Ordovician (where in the mind of the writer it should remain) to the Silurian system, the Girardeau limestone appears positively of post-Richmond age, and clearly represents the earliest deposits of the early Silurian sea that ad- vanced into this region from the south during this epoch of submergence which culminated in the Brassfield transgression. Edgewood Limestone occurrence and stratigraphic relations The name Edgewood limestone was proposed in 1909 22 for the strata occurring between the Girardeau limestone and the Sexton Creek (Brass- field) limestone in southwest Illinois and eastern Missouri. In 1898, C. R. Keyes 23 proposed the name Noix oolite for the white oolite bed outcropping along Noix Creek at Louisiana, Missouri ; and the name Bowling Green limestone for the brown magnesian limestone that is well exposed a few miles farther west, in the vicinity of Bowling Green. —Savage, T. E., Ordovician and Silurian formations in Alexander County, Illinois : Am. Jour. Sci., vol. 28, p. 517, 1909. 23 Keyes, C. R., Vertical range of fossils at Louisiana, Missouri : Proc. Iowa Acad. Sci., vol. 4, p. 27, 1897. 76 , BIENNIAL REPORT Where the oolite is best developed, as at Louisiana, its fossils indicate that this bed is the equivalent of about the upper two-thirds of the Edge- wood limestone, as exposed in the vicinity of Thebes, Illinois, and of the corresponding part of the limestone present near the town of Edgewood, Missouri. It represents a local, shallow water phase of sedimentation in this region during only a part of Edgewood time. This was recognized by Keyes in the following statement : "The oolite (Noix) appears to be somewhat of a local phase, but is present not only in the vicinity of Louisiana, but all the way to Paynesville, a distance of 18 miles. The formation appears to be represented elsewhere in the vicinity by fossiliferous limestones that are not oolitic." The strata to which the name Bowling Green limestone was applied, consist of about thirty feet of brown somewhat massive limestone, the middle and upper parts of which contain few or no fossils, but the lower one or two feet carries a fauna similar to that found in the oolite at Louis- iana, and in the upper part of the fossiliferous portion of the Edgewood limestone in the vicinity of Edgewood, Missouri. Inasmuch as the succession of strata from the base of the Edgewood to the top of the Bowling Green limestone appears to be unbroken, it is desirable to include all of these strata under a single formation name. For this more comprehensive series of deposits the term Noix oolite is not appropriate, because the oolite phase is developed only over a small part of the area of distribution of these strata, nor does it anywhere in- clude the entire thickness. Neither is the name Bowling Green limestone desirable, for it was proposed for the limestone near Bowling Green, Mis- souri, which represents only the upper and mostly unfossiliferous portion of the Edgewood. On the other hand, the name Edgewood, as originally proposed, embraces all of the strata between the Girardeau limestone and the Sexton Creek (Brassfield) limestone in this region. The lower fossil- iferous portion of the formation and the overlying brown, unfossiliferous Bowling Green phase are both well developed in the vicinity of Edgewood, Missouri, whereas the lowest beds of the Edgewood are not known north of this locality. For these reasons the name Edgewood limestone is retained as the formation name that includes all the strata in Missouri and Illinois, be- tween the horizon of the Girardeau limestone and the top of the magnesian limestone near Bowling Green, and the top of the brown limestone over- lying the oolite in Lincoln, Pike, and Ralls counties, Missouri, and on the opposite side of the river in Illinois, and their equivalents elsewhere in the Mississippi valley. It will be convenient, however, to subdivide the Edgewood forma- tion into three members, as follows: (1) The Cyrene member, which ALEXANDRIAN SERIES 77 will include the lower, fossiliferous limestone phase of the formation, below the Bowling Green member, exposed one to two miles east of Cyrene and Edgewood in Pike County, Missouri, and about two miles north of Thebes in Alexander County, Illinois; (2) The Noix oolite member which will refer to the local oolite facies of the formation, which is the equivalent of a variable portion of the upper part of the Cyrene member; and (3) the Bowling Green member, which will embrace the buff or brown mostly nonfossiliferous limestone in the upper part of the formation, corresponding to the strata outcropping near Bowling Green, Missouri. The name Channahon limestone will be retained for easy reference to the strata seen only along Desplaines River one mile southeast of Chan- nahon in Will County, Illinois. This limestone is considered the equiva- lent of some part of the Edgewood formation, but it cannot yet be cor- related with any particular part of it because of the complete isolation of the area from other exposures of the Edgewood limestone, and the slight difference in its fauna from that of the typical Edgewood limestone in eastern Missouri and southwest Illinois. Strata representing parts of the Edgewood limestone are nearly coex- tensive with the distribution of the Alexandrian series in the states of Illinois and Missouri. The lower, fossiliferous layers of the formation (Cyrene member) are present near the river in Alexander County, Illi- nois ; and over a considerable area in the vicinity of Edgewood and Cyrene, in Pike County, Missouri, where they are in places overlain by the Bowling Green member. Farther north, near Bowling Green and McCune Station, the Cyrene member of the Edgewood is mostlv absent, and the overlying Bowling Green member makes up the greater part of the formation. DETAILED SECTIONS An excellent exposure of the lower strata of the Edgewood limestone appears in Illinois along the east bank of the Mississippi River, about one and one-half miles north of Thebes, where they occur in the bottom of a low syncline, and occupy an old channel eroded in the Girardeau lime- stone during the post-Girardeau pre-Edgewood land interval. The suc- cession of strata at this place is shown in the following detailed section : 78 BIENNIAL REPORT Section exposed along the river one and one-half miles north of Thebes Edgewood formation (Cyrene member) — 10. Heavy layer of gray, coarsely granular limestone, oolitic in the upper part, containing many fossils 3 feet, 6 inches Clathrodictyon vesiculosum Schuchertella propinqua Lyellia thebesensis Spirifer (Delthyris) sp. Zaphrentis stokesi Whitfieldella billingsana Atrypa putilla Pterina thebesensis Atrypa tubulistriata n.sp. Lophospira thebesensis n.sp. Clorinda? thebesensis, n.sp. Cyphaspis intermedia Leptaena rhomboidalis Metapolichas breviceps var. clintonensis Rhynchotreta thebesensis Proetus determinatus 9. Rather soft, gray shale, without fossils 1 foot, 2 inches 8. Dark-gray, argillaceous limestone or calcareous shale, in two layers, each about six inches thick, separated by a two-inch parting of softer shale. The calcareous layers contain the fossils listed below 1 foot, 6 inches Clorinda? thebesensis n.sp. Whitfieldella ovoides n.sp. Rafinesquina? mesicosta Bellerophon consimilis n.sp. Schuchertella propinqua Dalmanites danai 7. Rather soft, gray shale, without fossils 1 foot, 6 inches 6. Layer of somewhat fissile, fine-grained, argillaceous limestone, con- taining few fossils 1 foot, 6 inches 5. Layer of rather hard limestone, having a 2-inch band of chert at the top ; no fossils found 8 inches 4. Layer of conglomerate consisting of fragments of Girardeau lime- stone, from 2 to 12 inches in diameter, imbedded in a matrix of fine-grained limestone. In some places this member appears to be composed of calcareous concretions surrounded by softer, bluish- gray shale 2 feet, 6 inches (A break in deposition) Girardeau limestone — 3. Hard, fine-grained, brittle, dark-colored limestone, with fossils char- acteristic of the Girardeau formation 2 feet, 6 inches (A possible break in deposition) Orchard Creek shale — 2. Bluish-gray, calcareous shale, containing one to 2-inch bands of shaly, concretionary limestone, 4 to 6 inches apart 18 feet (A break in deposition) Thebes sandstone — 1. Brown- or chocolate-colored, rather fine-grained sandstone, which weathers into thin layers 40 feet In the above section, the members 4 to 10 inclusive, constitute the Edgewood beds, as that formation is seen at its best exposure in south- ALEXANDRIAN SERIES 79 west Illinois. At this place the Girardeau limestone was almost entirely cut out by erosion prior to the deposition of the Edgewood strata. A thickness of 13 or more feet of the Girardeau limestone outcrops in the river bluff a few rods north of the place where the section was made. The conglomerate at the base of the Edgewood, number 4 in the section, is composed largely of fragments of Girardeau limestone. Another instructive exposure of the Edgewood strata in this vicinity is in an abandoned quarry one-fourth mile southeast of the village of Gale, about two miles northeast of Thebes. This is in the northeast quar- ter of sec. 4. T. 15 S., R. 3 W., where the following section was made: Section in abandoned quarry one-fourth mile southeast of Gale 4. Sexton Creek (Brassfield) limestone- Hard, gray limestone, in layers 4 to 8 inches thick, which are separated one from another by 2 to 3-inch chert bands. .11 feet (A break in sedimentation) 3. Edgewood formation (Cyrene member) — Single layer of gray, somewhat oolitic limestone, containing small pebbles of chert, one-fourth inch to 4 inches in di- ameter 10 inches Calvinia edgewoodensis n.gen., n.sp. Dalmanella edgewoodensis n.sp. Lyellia thebesensis Hindella? ambigua n.sp. Zaphrentis stokesi Rhynchonella? janea Atrypa praemarginalis, n.sp. Rhynchotreta parva n.sp. Atrypa putilla Cyclonema daytonensis Camarotoechia? antiqua n.sp. Lophospira fasciata n.sp. Camarotoechia? concinna n.sp. Metapolichas breviceps var. clintonensis (A break in sedimentation) 2. . Orchard Creek shale — Bluish-gray calcareous shale, bearing 1 to 2-inch bands of impure, concretionary limestone, 4 to 6 inches apart 8 feet (A break in sedimentation) 1. Thebes sandstone — Brown, fine-grained, slightly shaly sandstone, at the top of which is a hard, deeply iron-stained zone 6 feet In the section given above, the single layer comprising the third member, represents the total thickness of the Edgewood formation at this place. It belongs probably to a level a little higher than that of the uppermost layer in the preceding section. Strata equivalent to those of the Edgewood limestone near Thebes, Illinois, are well developed in the vicinity of Edgewood, in Pike County, Missouri. Along the streams one to one and one-half miles east and northeast of this town the following strata are exposed: 80 BIENNIAL REPORT Section of strata one and one-half miles northeast of Edgezvood, Missouri Thickness Edgewood limestone — Feet 3. Brown to yellow limestone, with few or no fossils (Bowling Green limestone member) 22 2. Brown limestone, in layers two to six inches thick, with Schuch- ertella propinqua and Dalmanites danai, common in the lower part, and Atrypa praemarginalis, A. put ilia and Dalmanella edgeivoodensis abundant in the upper; contain- ing the greater number of the fossils indicated in column 2 of the following table (Cyrene member) 6-11 (A break in sedimentation) Maquoketa (Richmond) shale — 1. Bluish-gray shale, with Strophomena rugosa, Isotelus sp., and other fossils 9-14 In a few places in this vicinity, the limestone corresponding to the Cyrene member is light gray, but in most places its color is brown. The upper 1 or 2 feet of this limestone, immediately below the Bowling Green member, contains a somewhat different fauna in different localities. In some places, as southeast of Edgewood, south of Clarksville, and at Louisiana, the upper layer contains many corals, including Calapoecia favositoidca, Clathrodictyon vcsiculosum, Favosites subelongus, Lyellia thebesensis, Zaphrentis subregularis, the form of Platystrophia described by Foerste, as P. daytonensis, Whitfieldella ovoides and Cyclonema day- tonensis. In other places the corals are mostly absent from this layer and its fauna consists largely of species of Atrypa, Camarotoechia? and Dalmanella. A few miles north of Edgewood, between Bowling Green and Wat- son Station, and still farther north in the vicinity of McCune Station, the Edgewood limestone is represented by 25 to 35 feet of brown, nonfossil- iferous limestone (Bowling Green member) at the base of which is in places a band one and one-half to two feet thick, containing numerous shells of Atrypa praemarginalis, A. putilla, Camarotoechia? concinna and Dalmanella edgeivoodensis. This lower fossiliferous band corresponds to only the upper part of the Cyrene member in the section northeast of Edgewood. Deposition of the Bowling Green limestone member is thought to have been initiated by a slight uplift of the region bordering the west side of this basin in Lincoln, Pike, and Ralls counties, Missouri, accom- panied by a slight subsidence of the area east of the line of uplift, but sedimentation appears generally to have been uninterrupted from the top ALEXANDRIAN SERIES 81 of the fossiliferous part of the Edgewood into the Bowling Green mem- ber. This movement put a stop to oolite deposition and so quickened erosion of the land on the west as to increase the discharge of mechanical sediments into the basin. From 3 to 6 miles west of Mississippi River the limestone equivalent to the upper layers of the Cyrene member near Edgewood, passes with a gradual transition into a thin bed of gray oolite which thickens towards the east, attaining its maximum in the vicinity of Louisiana, Missouri. A variable thickness of brown Bowling Green limestone usually overlies the oolite, being thickest where the oolite is thinnest, and thinnest where the oolite is best developed. However, the oolite bed does not increase in thickness at the expense of the lower part of the Bowling Green lime- stone, but where the oolite is thickest there is represented a greater thick- ness of the upper part of the Cyrene limestone member. There is given below a section of the strata exposed in the south bank of Noix Creek, at Louisiana, Missouri, where the oolite bed has its greatest known development. Section along Noix Creek, at Louisiana, Missouri Thickness 3. Upper Devonian shale — Feet Dark colored, fissile shale, with few fossils 3 (A break in sedimentation) 2. Edgewood limestone (Noix oolite) — Light gray oolite, in three layers, containing the greater number of the fossils indicated in column 3 of the follow- ing table 8 (A break in sedimentation) 1. Maquoketa (Richmond) shale — Bluish to greenish-gray shale, with few or no fossils.... 9 The Bowling Green limestone is absent at the place where the above section was made, but 2 to 4 feet of this limestone is present above the oolite less than one mile west ; and 6 to 8 feet of the Bowling Green lime- stone overlies the oolite at the mouth of Buffalo Creek, one and one-hali miles southeast of Louisiana. As is common with oolite faunas most of the shells in the oolite at Louisiana are distinctly smaller than those of corresponding species from the limestone that is not oolitic. They are often so silicified that peifect specimens of even the smallest forms can be obtained by dissolving the limestone with weak acid. The fossils from the oolite at Louisiana are indicated by a cross to the right of the name, in the third column of the table given below. A cross opposite the name, in the second column of 82 BIENNIAL REPORT the table shows that the species was found in the Edgewood limestone, near Edgewood, Missouri ; and a cross opposite the name in the first column indicates the presence of that species in the Edgewood limestone near Thebes, Illinois. Comparative table of fossils from the Edgewood formation, near Thebes, Illinois; near Edgewood, Missouri; and the Noix oolite, near Louisiana, Missouri FOSSILS ^•2 3 2 »? o Calapoecia f avositoidea n.sp Calvinia edgewoodensis n.gen., n.sp Clathrodictyon vesiculosum Nicholson and Murie Favosites subelongns n.sp Halysites catenulatus Linnaeus Lyellia thebesensis Foerste Zaphrentis cf. ambigtia n.sp Zaphrentis subregularis n.sp Zaphrentis cf. stokesi Edwards and Haime Atrypa praemarginalis n.sp Atrypa putilla (Hall and Clarke) Atrypa tubulistriata n.sp Brachyprion stropheodontoides n.sp Brachyprion latisculptilis n.sp Camarotoechia ? antiqua n.sp Camarotoechia ? concinna n.sp Clorinda ? thebesensis n.sp Dalmanella edgewoodensis, n.sp Hindella ? ambigua n.sp Homoeospira fiscellostriata n.sp Homoeospira subcircularis n.sp Leptaena rhomboidalis (Wilckens) Orthis flabellites var. fissiplicata Foerste Pentamerus parvulus n.sp Platystrophia daytonensis Foerste Protozeuga sulcocarinata n.sp Rafinesquina? mesicosta (Shumard) Rafinesquina? mesicosta var. mesistria n.var Rhipidomella tenuilineata n.sp Rhynchonella ? janea Billings Rhynchotreta parva n.sp Rhynchotreta thebesensis Foerste Rhynchotreta thebesensis var. multistriata n.var.., Schuchertella cf. missouriensis (Shumard) Schuchertella missouriensis var. convexa n.var.., X X X ALEXANDRIAN SERIES 83 Comparative table of fossils from the Edgewood formation, near Thebes, Illinois near Edgewood, Missouri; and the Noix oolite, near Louisiana, Missouri — Concluded FOSSILS o be 3 y, o 3.2 3 O -> 3 S rt £ r mi. oun Bel mi. e Co sex. , Mo part o., 11 Kan E. o 6 « .U ■« . u c^ skO s= phMh^o; A break in sedimentation 4c. Light-gray, hard, thick-bedded limestone with Syringolites cf. hnronensis and Spirifer radi- atus, 10 feet, in Calhoun and Pike counties. Pink limestone, 23 feet, in Alexander County, Illinois 10 to 23 feet 4b. Light-gray, hard limestone, fossils numerous in certain layers. Rhinopora near verrucosa, Cam- arotoechia acinus var. convexa, Straplionella Mistriata, Stricklandinia triplesiana, Strickland- inia n.sp. and Triplecia cf. ortoni common about 10 feet below the top, about 34 feet 4a. Light-gray or Pcntamerella? brown limestone containing manniensis and. Pentamerns 1 foot, 6 inches A possible break in deposition 94 BIENNIAL REPORT Generalised section of the Alexandrian strata in Missouri and Illinois — Concluded a o Location of ex- e posures u o fe c „w t/J i-H a; r w k > " •+* ^« O £ re S^^.^5 re i- ^°u^ .. 1 f- H EfS c> ° -a Co . o-^ O O 3 rtrr, re - • SO rt c o OJ B 'Sdiljjd -a o 3Wl o inches; surface irregularly annulated by low transverse ridges of various sizes, in well preserved specimens numer- ous fine transverse striae are present, of which 10 or 12 occur in a distance of 1 millimeter, longitudinal or septal striae usually distinct. Calyx mod- erately deep, with thin walls. Septa alternately long and short, the latter but slightly developed, the former generally curved, about 36 to 44 in a calyx 1 inch in diameter, continuous vertically in the peripheral portion, but the continuity in the central portion broken by the tabulae, distinct for a distance of one-fourth to three-eighths of an inch, their inner ends often coalesced in sets of two or three towards the center, towards the top there is considerable space in the central portion that is occupied only by the tabulae which are close set and somewhat undulating, some of them incomplete or inosculating, concave in the middle portion and bent downward at the periphery. In external appearance this species resembles the figures of Strep- telasmaf geometricum Foerste, but in our form there is no pseudoco- lumella formed by the twisting together of the inner edges of the primary septa at the center, as in the genus Streptelasma. Foerste's description is too meagre to permit a satisfactory comparison to be made with that species. This coral is common in the Edgewood limestone in Pike County, Missouri, and coralla thought to represent the same species are also common in the Channahon limestone in Will County, Illinois. Zaphrentis cf. stokcsi. Milne-Edwards and Haime (Plate V, figure 4) 1851. Zaphrentis stokesi. Milne-Edwards and Haime, Polyp. Foss. des Terr. Palaeoz., p. 330, pi. 3, figure 9. 1852. fCanina bilateralis, Hall, Pal. New York, vol. 2, p. 41, pi. 17, figures 3a-3h, and p. 113, pi. 32, figures 3a-3c. 1852. fPolydilasma turbinatum. Hall, Ibid, p. 112, pi. 32, figure 2. 1866. Zaphrentis stokesi. Billings, Cat. Sil. Foss. of Anticosti, p. 34. 1875. Zaphrentis stokesi. Nicholson, Paleontology Ontario, pp. 43 and 58. 1876. Zaphrentis stokesi. Rominger, Fossil Corals, Mich. Geol. Survey, p. 145, pi. 51, three figures in lower row. 1901. Zaphrentis stokesi. Lambe, Contrib. to Can. Paleontology, vol. 4, pt. 2, p. 120, pi. 9, figures 1, la and 2. 114 BIENNIAL REPORT Rominger's description : "Symmetrically curved conical polyparia, sometimes elliptical in outline by a compression in a direction transverse to the curvature. Length of cones about twice the diameter of the calyces, which in middle-sized specimens is about four centimeters. Calyces moderately deep with erect margins and a spacious subconvex bottom, on which the lamellae unite in an irregularly twisted, interlacing manner as low carinae. Lamellae linear, stout ; sixty to sixty- five larger ones alternating with as many small rudimentary crests may be counted in the circumference of calyces four centimeters wide. A large septal fovea is situated in the median line of the convex side of the curved polyparia. Trans- verse diaphragms well developed ; the crests on the upper side do not connect into continuous vertical leaves with those of the succumbent cups ; the lower side of the diaphragms is generally smooth, not crested. The external walls of the specimens are rarely preserved in the silicified condition, and the excoriated sur- face is longitudinally ribbed by the exposed vertical plications. In some speci- mens, however, the superficial epithecal crust is perfectly preserved." Coralla resembling those of this species were found in the Edgewood formation in Alexander County, Illinois, and Pike County, Missouri. Zaphrentis ambigua n.sp. (Plate IX, figure 2) For the description of this species refer to descriptions of the fossils of the Channahon limestone member of the Edgewood formation. Coralla thought to belong to this species are common in the Edge- wood limestone near Edgewood, and in the Noix oolite member of the formation at Louisiana and south of Clarksville, Missouri. Favosites subelongus n.sp. (Plate V, figures 9 and 10) Coralla growing in elongate club-shaped masses, 4 or 5 inches in height, the height greater than the width, with long prismatic corallites which are of very different sizes in the same specimen, the larger ones having a width of 1.5 to 2 mm., and the smaller ones less than one-half that width ; no septal spines or ridges visible. The tabulae are strong, complete, and usually horizontal or slightly oblique, five to ten in a dis- tance of 10 mm. Mural pores very few, usually situated near or in the angles of the corallites. Epitheca not seen. In some characters this coral resembles Favosites aspera d'Orbigny. but may be distinguished from that species by its less expanded mode of growth, by the smaller corallites of different diameters in the same coral- lit m, by the stronger, and more distinct, complete tabulae, and by the absence of septal spines. This species occurs in the Edgewood limestone, a short distance below the Bowling Green member, near Edgewood, at Louisiana, and south of Clarksville, in Pike County, Missouri. ALEXANDRIAN SERIES 115 Calapoecia favosiloidea n.sp. (Plate V, figures 1, 2, and 3) This species is distinguished from the form described by Billings as Calapoecia anticostiensis in having the corallites in contact, and poly- gonal in cross section, and in the much smaller pores which are sub- circular in outline. It differs from the forms known as C. canadensis Billings and C. cribriformis Nicholson in the much smaller coralla and smaller corallites, more distant and stronger tabulae, and the very much smaller pores, which are less regular in arrangement, and never so large as to give the walls a cribriform appearance. The corallum is subglobular or irregularly rounded ; width 2 to 3 inches, and height usually about equalling the width. Corallites in con- tact, polygonal in cross section, 1.5 to 2.5 mm. in diameter, diverging from a basal point. Walls of corallites of moderate thickness, their inner surface having 12 to 24 longitudinal spiniform ridges separated one from another by a row of numerous small pores ; the spines are short and pointed, 2 to 6 between adjacent tabulae ; pores rather small, subcircular, disposed in somewhat irregular longitudinal and transverse rows ; tabulae usually complete and almost horizontal, .25 to 2 mm. apart ; epitheca not seen. In some places this species is common in the Edgewood limestone, a short distance below the Bowling Green member, near Edgewood and Louisiana and south of Clarksville, in Pike County, Missouri. Calvinia nov.gen. Corallum compound, in irregularly hemispherical to globular masses, 3 to 5 inches or more in diameter, composed of cylindrical corallites, 2 to 3 mm. distant from one another, which emerge at right angles to the surface, calyx with slightly exserted margin ; septa in the form of irregu- larly spinose ridges along the interior of the corallites, extending about one-third to one-half the distance to the center ; tabulae numerous, hori- zontal and complete, spaces between the corallites filled with vesicular tissue composed of convex plates, resting upon one another, through which occasional slender, cylindrical tubules extend parallel with the corallites ; tubules somewhat undulating, rather uniform in size, their walls taking no part in the formation of the vesicular tissue through which they pass. This genus resembles Lyellia in having true vesicular tissue present in the spaces between the corallites, but differs from that genus in that the tissue in the interstitial spaces of Lyellia is wholly vesicular while in this genus there are many slender, undulating, cylindrical tubules passing through the vesicular tissue in a direction parallel with the corallites. 116 BIENNIAL REPORT It differs from Plasmopora in that in the latter genus the spaces be- tween the corallites are entirely filled with tubules within which convex plates (tabulae) have interfered with the regular development of the walls, resulting in their irregularly zig-zag mode of growth. It is distinguished from Heliolitcs by the fact that in the latter genus the spaces between the corallites are occupied entirely with numerous intimately united, polygonal tubules having thin, regular walls. The type of the genus is Calvinia edgewoodensis n.sp described below : Calvinia edgewoodensis n.sp. (Plate IV, figures 15, 16, and 17) Corallum compound, massive, subspherical to discoid in shape, the larger specimens 5 to 6 inches in diameter ; corallites circular in section, subequal in size, about 25 millimeters in diameter, separated one from another by an average distance a little less than the diameter of the tubes, walls of the corallites marked on the exterior and interior by alter- nating longitudinal ridges and furrows ; septa represented by about 12 low, interrupted vertical ridges or striae of unequal size, which bear short spinose projections at irregular intervals. Tabulae generally com- plete and almost horizontal, situated at unequal distances, averaging about 5 in a distance of 5 millimeters. Sometimes the adjacent tabulae are less than .5 millimeters apart and at other times they are more than 2 millimeters. The coenenchyma is made up of true vesicular tissue through which numerous, more or less undulating cylindrical tubules ex- tend parallel with the corallites, and at irregular distances, usually less than 1 millimeter, apart; upper surface of corallum made granulose by the upper ends of the tubules. This species occurs in the Edgewood formation one-fourth mile southeast of Gale, in Alexander County, Illinois. Lyellia thebesensis Foerste (Plate V, figures 6 and 7) 1909. Lyellia thebesensis. Foerste, Bull. Sci. Lab. Denison Univ., April, 1909, p. 95, pi. 4, figures 69A, 69B. Foerste's description : "Forming massive coralla with the walls of neighbor- ing corallites almost in contact with each other, leaving very small inter-spaces for the coenenchyma. The tabulae average about 8 or 9 in a length of 5 millimeters and the plates in the intermediate spaces are more numerous, but not distinctly vesicular. The diameter of the corallites is slightly more than 1 millimeter. The walls of the corallites are slightly crenulated, and are slightly striated lengthwise No septa are visible." ALEXANDRIAN SERIES 117 In some of our specimens of this species the convex plates which compose the coenenchyma are arranged one above another in such regular order that their overlapping edges form irregular zig-zag lines which extend in a vertical direction and resemble the walls of the tubules in the related genus Plasmopora. This species is common in the upper part of the Edgewood formation, near Thebes, Illinois, and in the vicinity of Edgewood, Louisiana and Clarksville, in Pike County, Missouri. Hydrozoa Stromatoporoidea Clathrodictyon vcsiculosum Xicholson and Murie (Plate V, figure 8) 878. Clathrodictyon vesiculosa m. Nicholson and Murie, Jour. Linn. Soc. Zool., vol. 14, p. 220, pi. 2, figures 11-13. 880. Clathrodictyon vcsiculosum. Nicholson and Etheridge, Mon. Sil. Foss. Girvan, p. 238, pi. 19, figure 2. 882. Stromatopora conccntrica. Spencer Bull. Mus. Univ. Missouri, vol. 1, No. 1, p. 45. 886. Stromatopora minuta. Rominger, Proc. Acad. Nat. Sci., Philadelphia, p. 49. 887. Clathrodictyon vcsiculosum. Nicholson, Annals. Nat. Hist. ser. 5, vol. 19, p. 1, figures 1-3. 892. Clathrodictyon vcsiculosum. Nicholson, Mon. Brit. Stromatoporoids, p. 147, pi. 17, figures 10-13, and pi. 18, figure 12. 896. Clathrodictyon vcsiculosum. Whiteaves, Can. Rec. Sci., vol. 7, p. 134. 908. Clathrodictyon vcsiculosum. Parks, Univ. of Toronto Studies, Geol. Ser., No. 5, p. 14, pi. 7, figures 1 and 6 and pi. 8, figures 3, 4 and 5. Nicholson and Etheridge's description: "Skeleton in the form of cake-like expansions, from about an inch to a foot in diameter, and from half an inch to two inches in thickness in the center, but thinning out towards the circumference. Young specimens sometimes encrusting foreign bodies, but the unattached portions of the under surface being otherwise covered with a concentrically striated epitheca. Upper surface irregularly undulating and exfoliating concentrically round the ele- vated points. Surface smooth, not tuberculated. Internal structure of exceedingly fine and close-set horizontal or slightly undulating lamina, of which about twenty occupy the space of one-tenth of an inch (counting in the interlaminar spaces as well). The horizontal laminae are undulated and inflected at short intervals, so as to divide the interlaminar spaces into a series of minute lenticular vesicles or cells which often communicate laterally by imperfection of their boundaries." Concerning the horizon of this form in America Parks says : "This species occurs at the very base of the Silurian, in the Lower Niagara, Clinton, and in certain 'passage beds' between the Clinton and the Medina." It is not rare in the Edgewood strata, in Alexander County, Illinois, and at almost all of the fossil localities in Pike County, Missouri. It also occurs in the Sexton Creek limestone in the Illinois basin. 118 BIENNIAL REPORT Molluscoidea 28 Brachiopoda Rafinesquinaf mesicosta (Shumard) (Plate III, figure 10) For synonymy and description of this species see a previous page of this paper, under the fossils of the Girardeau limestone. Shells of this species occur in the Edgewood limestone near Thebes, Illinois, and near Edgewood and at Louisiana in Pike County, Missouri. Rafinesquinaf mesicosta var. mesistria n.var (Plate VI, figure 6) Shells differ from those of the normal species in their somewhat larger size and more elongate outline, and especially in the much less prominent alternating character of the striae. Near the margins of the shells of R. (Brachyprion?) mesicosta every alternate stria from the median costa is distinctly larger and longer than the ones adjacent, and usually every fourth stria from the median costa is much stronger than the three (sometimes five) intervening ones. In the new variety, the median costa of the ventral valve is also more prominent than any of the others, and every alternate stria is smaller and shorter than the adja- cent one on each side, but the further grouping of the striae with three to five weaker ones between any two adjacent much stronger ones, so conspicuous in the shells of the species, is rarely present. The dimensions are: length, about 16 mm.; greatest width, about 18 mm. The shells of this variety are not rare in the oolite member of the Edgewood limestone at Louisiana, and near the mouth of Buffalo Creek, in Pike County, Missouri ; and below Hamburg in Calhoun County, Illi- nois. Brachyprion latisculptilis n.sp. (Plate VI, figure 5) This species resembles Rafinesquina (Brachyprion?) mesicosta (Shumard) in general outline, and in having the median costa of the ventral valve more prominent than those on the sides. It differs from Shumard 's species in having only about one-half as many striae, in the much less conspicuous alternating character of the striae, and in having* the median costa of the ventral valve relatively much less prominent. It 28 A number of poorly preserved bryozoa were collected from the Edgewood strata near Thebes, Illinois, and at Louisiana, Missouri. These were submitted to Dr. E. R. Cummings- for study, who has furnished the following preliminary statement concerning them: "None of your bryozoa are identical with described species. They appear to belong to the genera Lioclema, Orbignyclla, Diamcsopora, and Monotrypa. If you have other evidence that these came from Silurian rocks older than early Niagaran, the bryozoa can not be considered as out of accord with such a conclusion." ALEXANDRIAN SERIES 119 appears to have been derived from Shumard's species by the weaker development of the middle one of the group of three weak costae and the suppression of the smaller striae, leaving relatively broader flat spaces between those that remain. The shells are semi-elliptical in outline, a little wider than long, the hinge line straight and equaling the greatest width of the shell, forming almost right angles with the lateral margins. Ventral valve very slightly convex, most prominent along the median portion, the convexity greatest in the umbonal region, the surface sloping to the cardinal extremities with a concave curvature and with a gently convex curvature to the lateral and anterior margins. Beak pointed and extending very slightly beyond the cardinal margin. Dorsal valve slightly concave or almost plane. Surface of both valves marked by low radiating striae, about one-fourth of which extend to the beak. The median one on the ventral valve slightly stronger than the others. The striae are low. about one-half as numerous as in R. (Brachy prion?) mesicosta, about two occurring in the space of 1 mm., with rather broad, flat spaces between them. Besides the radiating striae there are traces of numerous fine concentric lines which give to the surface between the striae a some- what fluctuose appearance. The dimensions are : length, 8 to 9 mm. ; width, about 1 1 mm. This species occurs in the oolite member of the Edgewood limestone at Louisiana, Missouri, and south of Hamburg, Illinois. Brachyprion strophcodontoidcs n.sp. (Plate VI, figure 4) This species is closely related to Rafincsqiiina (Brachyprion?) mesi- costo var. mcsistria, from which it is chiefly distinguished by the absence of a prominent median costa on the ventral valve. The shells are con- cavo-convex, semi-elliptical in outline, length of different specimens 15 to 20 mm., width about equaling or slightly exceeding the length, greatest at or near the hinge line ; the lateral margins almost straight, rounding gradually to the regularly convex anterior margin. Ventral valve rather strongly convex in the median portion, most prominent in the umbonal region, the surface sloping rather steeply, with a concave curvature to the cardinal extremities, and with a gently convex curve to the lateral and anterior margins. Cardinal area narrow, beak low, scarcely project- ing over the cardinal margin. Dorsal valve gently and rather uniformly concave, the concavity distinctly less than the convexity of the ventral valve, beak low, not projecting. Surface of both valves marked by very numerous fine radiating striae, some of which are somewhat alternating in size, of which four or five occupy the space of 1 mm., only a few extending to the beak. Occasionally indistinct lines of growth are some- times present, and in some shells the ventral surface is gently undulating. 120 BIENNIAL REPORT This species is common in the oolite member of the Edgewood lime- stone at Louisiana, and near the mouth of Buffalo Creek, in Pike County, Missouri, and south of Hamburg, in Calhoun County, Illinois. Leptaena rhomboidalis (Wilckens) (Plate VI, figure 3; and Plate III, figure 11) For synonymy, and description of this species see a previous page of this paper, under the fossils of the Girardeau limestone. This form is rather rare in the thick layers of gray limestone in the upper part of the Edgewood formation, in Illinois and in corresponding strata near Edgewood and at Louisiana, Missouri. Schuchcrtella propinqua (Meek and Worthen) (Plate VI, figure 1) 1868. Hemipronites sub planus? Meek and Worthen, 111. Geol. Survey, vol. 3, p. 349. 1868. Hemipronites propinquus. Meek and Worthen, 111. Geol. Survey, vol. 3, p. 351. Meek and Worthen's description : "Shell semi-oval, or more than semi- circular in outline, compressed, resupinate, subequivalve, approaching plano- convex ; hinge line about equaling the greatest breadth of the valves at any point farther forward ; front and anterior lateral margins forming a regular semi- circular curve. Ventral valve nearly flat, or a little convex at the umbo, and slightly concave towards the front ; beak not projecting beyond, nor very distinct from, the cardinal margin; cardinal area (mainly hidden in the matrix in our specimens) apparently of moderate breadth, inclined backwards, and extending to the extremities of the hinge. Dorsal valve slightly and rather evenly convex ; beak not distinct from the cardinal margin. Surface of both valves ornamented with distinct, abruptly raised, radiating striae, with flat intervening depressions, in which there are generally from one to three or four smaller and shorter striae, one of which is sometimes nearly as large at the border as the principal ones but soon becomes smaller, and generally dies out near the middle of the valves, while the smallest ones are still shorter; crossing all of these, there are numerous extremely fine, regular, closely arranged concentric striae. "Breadth of one of the largest specimens, 1.30 inches ; length, 1.05 inches ; convexity, 0.18 inch. "Locality and Position : Dark gray limestone at Thebes, Alexander County, Illinois ; apparently of the age of the Niagara division of the Upper Silurian." The authors note that this species differs from 5". sub plana (Conrad) in being less extended along the hinge line in proportion to the length of the valves ; in the greater difference in the size of the primary and the smaller striae ; in the wider and more flattened spaces between the radiat- ing striae ; and in the slightly finer and more crowded concentric striae. This species is very abundant in the dark, shaly limestone zone near the middle of the Edgewood formation, in Illinois, and in a corresponding horizon in Pike County, Missouri. ALEXANDRIAN SERIES 121 Schuchertella cf. missouriensis (Shumard) (Plate III, figures 12 and 13) Shells closely resembling this species occur rarely in the Edgewood limestone near Edgewood, and in the Noix oolite member at Louisiana, Missouri. Schuchertella missouriensis var. convexa n.var. (Plate VI, figure 2) Shells resemble those of Schuchertella propinqua in the character of their surface markings, but differing from the latter in the much smaller size and much greater convexity of the ventral valve. They are much like those of 5. missouriensis (Shumard) in size and general pro- portions, but are distinguished from that species by having every alternate one of the radiating striae smaller and shorter than the others, and not extending one-half the distance from the margins to the beak. In the shells of 5\ missouriensis (Shumard) and those of the nearly related species 5\ curvistriata, there is a group of 3 (sometimes 5) very slender striae between any two adjacent stronger and larger ones. Schuchertella propinqua and S. missouriensis var. convexa appear to have been derived from the Girardeau species 5. missouriensis by the stronger development of the middle one of the group of 3 slender striae and the suppression of the smaller one on either side of it. In some of the shells of 5". missouriensis, this tendency towards the greater develop- ment of the middle one of the group of three fine radiating striae than of the adjacent one on each side can be seen, and occasionally in the shells of the variety convexa, and 5. propinqua, traces of a fine stria on each side of the smaller ones can be distinguished. In adult shells of S. missouriensis var. convexa the ventral valve is quite strongly convex (convexity usually greater than is indicated in the figure), most promi- nent in the umbonal region, from which the surface slopes rather abruptly to the cardinal margin, and with a gentle curvature in the lateral and anterior portions. Dorsal valve nearly flat. The dimensions are: length, about 8 mm.; width, about 13 mm.; thickness of ventral valve, 2.5 to 3 mm. This variety is common in the Noix oolite member of the Edge- wood limestone at Louisiana and near the mouth of Buffalo Creek, in Pike County, Missouri, and south of Hamburg in Calhoun County, Illinois. 122 BIENNIAL REPORT Or this flabellites var. fissiplicata Foerste. (Plate VI, figure 7) 1895. Orthis (Dinorthis) calligramma var. fissiplicata, Foerste, Ohio Geol. Survey, vol. 7, pp. 572 and 573, pi. 37a, figures 20a and b. Shells differ from those of Orthis flabellites in the more strongly con- vex dorsal valve, and the much more numerous radiating striae. From Foerste's species Hebertella daytonensis and H. faitsta, these shells differ in the flatter, less sharp and more rounded character of the radiating striae, and the absence of concentric markings. The ventral valve is moderately convex in the umbonal region from which the surface slopes rather steeply to the cardinal and cardino-lateral margins, and much more gently to the sides and front. Beak promi- nent, somewhat elevated, but not much incurved. Cardinal area of mod- erate width. Dorsal valve about as convex as the ventral, with a shallow undefined sinus extending from near the beak to the anterior margin. The slope of the surface rather uniformly curving from a short distance in front of the umbonal region in all directions. Beak small and incurved, cardinal area narrow. Surface of both valves marked with rather flat radiating striae which divide once or twice between the beaks and the margins where from 55 to 70 may be counted on large shells. No con- centric markings are visible. The dimensions are: length, about 18 mm.; width, about equaling the length ; thickness, 5 to 6 mm. Shells of this variety occur in the oolite member of the Edgewood limestone at Louisiana, and near the mouth of Buffalo Creek in Pike County, Missouri, and south of Hamburg, in Calhoun County, Illinois. Platystrophia daytonensis Foerste (Plate VI, figure 8) 1885. Orthis biforata var. lynx forma daytoncsis. Foerste, Bull. Sci. Lab. Denison Univ., vol. 1, p. 82, pi. 13, figure 8. Foerste's description : "Shell of small size, wider than long, with a subquad- rate outline, hinge line usually shorter than or equaling the breadth of the valves, in one specimen exceeding it in size. The shells have their outline distinctly pre- served and are found only as simple valves showing their exterior surface. "Ventral and dorsal valves with the sinus and fold rounded, the plications also more rounded than those of the Lower Silurian formations, simple. "These specimens could perhaps be considered as the young of the forma "revcrsata" were it not for the simple plications on both fold and sinus, which remain simple while on the corresponding places of the other form there would be several additional plications intercalated. Length of medium sized specimen, 12 mm. ; breadth, 18 mm. ; convexity, as well as can be determined by a comparison of different single valves, 9 mm.; breadth of largest specimen, 24 mm. Locality and position, Soldiers Home, Clinton Group." ALEXANDRIAN SERIES 123 This species closely resembles the form figured by Hall under the name Delthyris brachynota 29 , but not described. It occurs near the top of the fossiliferous part of the Edgewood limestone, near Edgewood, and south of Clarksville, in Pike County, Missouri. Dalmanella edgewoodensis n.sp. (Plate VI, figures 11, 12, and 13) Shells of this species are readily distinguished from those of D. elegantula (Dalman) in having the dorsal valve distinctly more convex than in the typical shells of the latter species ; the ventral valve is less highly arched in the umbonal region ; the radiating striae are uni- formly coarser and fewer in number ; and the cardinal area of the dorsal valve is wider in proportion to the width of that of the ventral valve by more than one-half. Our shells are subelliptical in outline, the ventral valve quite strongly convex, most prominent in the median portion which is not elevated in a distinct fold, beak pointed, elevated but not greatly incurved ; delthyrium nearly twice as high as wide, cardinal area arched quite strongly upward, about twice as wide as that of the dorsal valve which extends nearly in the plane of the valves. Dorsal valve slightly convex, with a slight median depression extending from the beak to the front, beak not projecting. Surface of both valves marked by prominent radiating striae which divide 2 to 4 times between the beak and the margins where two to three occur in the distance of 1 mm., curving upward over the lateral slopes. Shells of this species are common in the Edgewood strata, in Mis- souri, and occur more sparingly in the upper part of the Edgewood forma- tion near Thebes, Illinois. Rhipidomella tenuilineata n.sp (Plate VI, figures 9 and 10) Shell small, subcircular to transversely subelliptical in outline, as wide or a little wider than long, the greatest width near the middle, length about 7 mm., width 7 to 8 mm., thickness 2.5 mm., hinge line short, about one-half the greatest width of the shell. Ventral valve rather strongly convex, most prominent in the umbonal region, the surface sloping rather abruptly to the cardinal margin and with a moderately convex curvature to the front and lateral margins, the median portion most prominent but scarcely elevated into a well-defined fold. Dorsal valve much less convex than the ventral, the curvature nearly uniform, the slope to the cardinal margin a little steeper than over the lateral and front portions, the middle 'Geology of New York, Report of fourth district, p. 70, fig. 6, 1843. Oi 124 BIENNIAL REPORT part of the valve flattened or depressed in a broad, shallow sinus which extends nearly to the beak. Surface of both valves marked by numerous very fine radiating striae which divide three or four times in passing from the beaks to the margins ; a number of concentric lines of growth are also visible under a lens. These shells differ from those of other known species of the genus, except R. saffordi Foerste, in their small size, the very numerous, exceed- ingly fine, radiating striae, and the broad, flattened or depressed median portion of the dorsal valve. From Foerste's species they may be dis- tinguished by the greater width near the hinge line, which gives to the shells a more circular or elliptical outline, and the much finer and more numerous radiating striae. They occur in the oolite member of the Edgewood limestone at Louisiana, and near the mouth of Buffalo Creek in Pike County, Missouri. Pentamerus parvulus n.sp. (Plate VII, figures 18, 19, 20, and 21) Shell biconvex, subovate in outline, sides rather straight and front rounded, width equaling or a little less than the length, widest anterior to the middle, apical angle 60 to 75 degrees, valves subequally convex. Ventral valve moderately convex, most arcuate in the umbonal region, beak prominent, acuminate, not much incurved, cardinal and lateral slopes steep, anterior portion of shell moderately convex, median portion of the valve depressed in a rather shallow sinus which extends more than three-fourths of the distance from the front to the beak, broad in the anterior portion where, in occasional shells, there is a slight tendency towards the development of a low indistinct ridge in the bottom. Beneath the beak is a prominent spondylium, longitudinally three lobed, and sup- ported in the posterior portion by a very short median septum. Dorsal valve slightly more convex than the ventral, most prominent along the median line which is somewhat elevated from near the beak to the front in a poorly defined mesial fold, (the illustration of this valve makes it appear a little too broad in proportion to its length) cardinal and lateral slopes rather steep, surface more gently convex in the anterior portion, beak pointed but not much incurved, spondylium narrower on the bottom than that of the ventral valve, not longitudinally lobed, and supported for the greater portion of its length by a rather strong median septum. Surface of each valve marked by a number of concentric lines of unequal strength. This species differs from Clorindaf thebesensis in its smaller size, narrower outline, more acuminate beaks, and absence of radiating striae. Associated with it are a few shells of somewhat similar proportions, but ALEXANDRIAN SERIES 125 showing three to five faint rounded radiating plications on the anterior half of the shell, which are thought to represent Clorinda? thebesensis. This species occurs in the Noix oolite member of the Edgewood limestone in the vicinity of Louisiana and Clarksville, Missouri, and below Ham- burg in Calhoun County, Illinois. Clorinda f thebesensis n.sp. (Plate VII, figures 7 and 8) Shells of medium or small size, biconvex, more or less subquadrate to subovate in outline, about as wide as long, the greatest width near the middle of the shell. Ventral valve rather strongly convex, most prom- inent in the umbonal region ; median area becoming depressed in a broad shallow sinus which widens towards the front, and bears a broad, very slightly raised elevation. The front margin somewhat extended, fitting into a corresponding median notch at the front of the dorsal valve ; beak pointed, much elevated and incurved, the sides sloping away at an angle of about 100 degrees. Dorsal valve convex, with an indistinct median fold appearing anterior to the umbo and widening to the front, which is notched for the reception of the extension of the ventral valve. On some shells traces of three to five low rounded plications appear on the anterior half of the shell, but generally these are absent ; beak pointed and strongly incurved beneath that of the ventral valve. Surface of both valves showing fine concentric lines which are more numerous near the surface. The dimensions are: length, 12 to 15 mm.; width, about equaling the length ; thickness, 8 to 10 mm. In some respects this species resembles C. ventricosa (Hall), of the Niagara, from which it differs in its much less ventricose form, in the relatively smaller convexity of the ventral valve, and in its shorter median prolongation at the front. It is also disinguished from C. forni- eata (Hall) by its less ventricose and more subquadrate form, by the less prominent umbo of the ventral valve, and the relatively greater con- vexity of the dorsal valve. The species is common in the thick limestone layer in the upper part of the Edgewood formation near Thebes, Illinois, where it is associated with Whit field ell a billingsana and Lophospira thebesensis. Shells thought to represent the same species occur also in the Noix oolite member at Louisiana and near Clarksville, in Pike County, Missouri. Rhynchotreta parva n.sp. (Plate VII, figures 9 and 10) Shell subtriangular or cuneiform in outline, the valves moderately and about equally convex. The width about two-thirds of the length, 126 BIENNIAL REPORT greatest in the anterior portion ; the largest specimens measure 13 mm. long, about 9.5 mm. wide, and 4.5 mm. thick. Much smaller specimens, 3.5 to 4 mm. in length, are common in the oolite. The apical angle is about 46 degrees. The sides are nearly straight from the beak for about two-thirds of the length, whence they round off to the front margin which is gently convex. The lateral slopes are steep, forming nearly right angles with the plane of the valves. The ventral valve has a prominent, erect beak, the greatest convexity in the umbonal region, the surface sloping abruptly to the lateral margins and very gently in the anterior portion. No distinct fold or sinus is present. The dorsal valve is most convex in the posterior region, the median portion slightly depressed towards the beak which is small and incurved. The posterior slopes gently convex. The surface of each valve is marked by 14 to 16 simple plications which extend to the beak and are about equal in width to the intervening furrows. No distinct concentric markings are visible. This species most nearly resembles Rhynchotreta simplex Foerste, from which it is distinguished by its smaller size and narrower outline, by the greater length in proportion to the width, the more nearly trun- cate anterior margin and the greater number of plications. Shells of this species are common in the oolite member of the Edgewood limestone at Louisiana, Missouri, and south of Hamburg, Illinois. Rhynchotreta thebesensis Foerste (Plate VI, figures 19 and 20) 1909. Rhynchotreta thebesensis. Foerste, Bull. Sci. Lab. Denison Univ., April, 1909, p. 94, figures 66a-66c. Foerste's description: "Shell cuneiform, with long flat sides diverging at an angle of 60 to 70 degrees, with an acuminate beak. The anterior outline is rounded, and the depth of the shell is considerable for one of this type. In a shell having a width of 14.5 mm., the depth was 10.5 mm., the length of the brachial valve was 14.5 mm., and the length of the pedicle valve was estimated at slightly over 15.5 mm. Near the beak of the brachial valve a few specimens show a slight median concavity. The two medium plications are slightly raised anteriorly above the general convexity of this part of the shell. On each side of these median plica- tions there are four distinct and one indistinct plication, reduced sometimes to 3 distinct and 1 indistinct one. On the pedicle valve there is a median plication with 4 distinct and 1 indistinct plication on each side. This median plication, in some specimens, terminates in a slight depression anteriorly, in others the plication on each side of the median plication also is involved so that there is a broad flattening or slight depression, without the appearance of a sinus. There is no evidence of a deltidium partly closing the delthyrium. "Strata of uncertain age, but evidently lower Niagaran. Thebes, Illinois." This species is clearly related to the Clinton form, R. robnsta Hall, but differs from it in the much less pronounced fold and sinus, which are usually only slightly developed or wanting, in the Edgewood species. ALEXANDRIAN SERIES 127 Rhynchotreta thcbcsensis var. multistriata n.var. (Plate VI, figures 21 and 22) Associated with the shells of Rhynchotreta thebcsensis in the Edge- wood limestone near Thebes, Illinois, are a number which differ from those of the typical species, figured and described by Foerste in the less sharply acuminate ventral beak and more symmetrical outline, and in the finer and more numerous regular radiating plications, two of which are slightly elevated at the front in the mesial portion of the dorsal valve, and one or two of the central plications of the ventral valve are slightly depressed near the anterior margin. Entire surface marked by 14 to 17 simple radiating plications, about two of which on the extreme lateral margins are smaller than those on the other portions of the shell. The dimensions are: length, 18 to 20 mm.; greatest width, 17 to 18 mm. ; thickness, 8 to 10 mm. This variety is not rare in the Edge wood limestone near Thebes, Illinois. Camar otocchia? concinna n.sp (Plate VII, figures 4 and 5) This species differs from Camar otoechia indianensis (Hall), which it resembles in some respects, in having fewer plications in the sinus and on the fold of the ventral and dorsal valve respectively, and usually a smaller number on the lateral slopes. Shell small, subtriangular to broadly ovate in outline, length and width about equal, valves subequally convex ; front margin truncate or very gently rounded. Ventral valve convex in the umbonal region, the median portion depressed into a sinus which begins on the umbo and deepens toward the front, where it is not much produced ; beak small, acuminate, incurved. Dorsal valve most convex in the median portion, with a prominent fold extending about two-thirds of the length of the valve, and increasing in height from the umbo to the front ; beak small, incurved beneath that of the ventral valve. Surface of each valve marked by simple, sub-angular, radiating plications, two of which occupy the sinus, three are elevated on the fold, and four, with sometimes a trace of a fifth, occur on each of the lateral slopes. Around the front and lateral margins there are a few prominent, sub- imbricating concentric striae. The grooves between the plications are produced at the front and sides into acutely angular serrations which fit into corresponding angular notches beneath the plications of the opposite valve. The dimensions are : length, about 6 mm. ; width, about equal to the length ; thickness, 4 to 5 mm. Shells of this species were found in the Edgewood strata in Pike County, Missouri, and near Thebes, Illinois. 128 BIENNIAL REPORT Camarotoechia? antiqua n.sp. (Plate VII, figures 1 and 2) Shells in some respects resembling those of Rhynchonella? janea Billings, with which they are associated, but are distinguished from that species in having a more sharply defined fold and sinus, each of which bears one more plication than in R.f janea. Our species also has fewer plications on the lateral slopes of each valve, and the front margin appears more distinctly truncate. Shell subovate to pentangular in outline ; apical angle about 90 degrees ; valves about equally convex, length and width subequal, the greatest width near the middle. Ventral valve with the greatest convexity in the umbonal region, the median portion depressed into a sinus which begins about one-fourth the distance from the beak to the front, and becomes prominent towards the anterior margin, where it is occupied by four angular plications ; beak acute, elevated and incurved over the hinge line. Dorsal valve with mesial fold distinct for about two-thirds of its length and bearing 5 angular plications, the exterior one on either side being slightly smaller than the others ; beak incurved beneath that of the opposite valve. Surface marked by 4 angular plications on each side of the fold and sinus, and sometimes with trace of a fifth ; a few fine concentric lines and an occasional more prominent line of growth are also present. The dimensions are : length about 12 mm. ; width about equal to the length ; thickness about 7 mm. Shells of this species occur in the upper part of the Edgewood forma- tion in Alexander County, Illinois, and near Edgewood, Missouri. Rhynchonella? janea Billings (Plate VII, figure 3) 1866. Rhynchonella janea. Billings, Catalogue Silurian Fossils of Anticosti, p. 43. 1890. Rhynchonella janea. Foerste, Proc. Boston Soc. Nat. Hist., vol. 24, p. 316, pi. 5, figures 23 and 24. 1895. Rhynchonella janea. Foerste, Ohio Geol. Survey, vol. 7, pi. 30, figures 23 and 24. Billings' description: "Subovate, apical angle about 80 degrees; sides some- what straight in the upper half, rounded in the lower half; about one-half of the front margin truncated or nearly straight. Ventral valve moderately convex ; sinus deep and concave at the front, one-third the whole width, dying out near the umbo ; sides of the sinus with one or two prominent ribs from which there is a somewhat flat slope to the margin ; umbo prominent but narrow ; beak elevated about half a line above the hinge and moderately incurved ; there appears to be a circular for- amen beneath it. Dorsal valve more uniformly convex than the ventral; mesial fold dying out at about two-thirds the length. There are four angular ribs on the ALEXANDRIAN SERIES 129 fold and three on the sinus ; from six to eight on each side or from sixteen to twenty in all on each valve. Length 6 or 7 lines ; greatest width about the same. "This species differs from R. anticosticnsis in having the beak more incurved." Shells that cannot be distinguished with certainty from the above species were found in the Edgewood formation in Alexander County, Illinois, and near Edgewood in Pike County, Missouri. Protozeuga sulcocarinata n.sp. (Plate VII, figure 6) For description of this species refer to the description of fossils from the Girardeau limestone. Shells that are thought to be identical with this common species of the Girardeau limestone are not rare in the Noix oolite member of the Edgewood formation at Louisiana, Missouri. A try pa praemarginalis n.sp. (Plate VI, figures 14, 15, and 16) Shells resemble A try pa marginalis (Dalman) in some of their char- acters, but differ from that species in the less flattened and expanded shape, the shorter hinge line, and more circular outline, in the more strongly convex ventral valve which is not so reflexed at the lateral and front margins, and in the absence of such numerous equi-distant fine concentric lines. The shells are subcircular in outline, length and width about equal, hinge line rather short and valves subequally convex. Ven- tral valve strongly convex along the median portion, the greatest depth a little posterior to the middle. The surface sloping rather abruptly to the cardinal margin, almost straight from the convex median portion to the lateral margins, and gently convex in the anterior portion, the mesial part of the valve occupied by a rather deep sinus extending to the beak, narrower in the posterior half of the shell than in the anterior portion, and slightly produced in front, bordered on each side by a prom- inent ridge. Beak prominent, pointed, and somewhat incurved over the hinge line. Dorsal valve about the same convexity as the ventral, the deepest in the umbonal region, from which the surface curves rather steeply to the cardinal margin, and is gently convex in the lateral and anterior portions, with a prominent mesial fold which is narrow for about one-half the distance from the beak, becoming wider in the anterior portion, somewhat flattened along the middle, and separated from the lateral portions of the shell by a deep groove ; beak pointed and incurved closely beneath that of the ventral valve. Surface of both valves marked by radiating costae, about three on each side of the fold and sinus, which extend to the beak, and bifurcate two or three times before reaching the margins so that they appear to be clustered in three bundles on each side 130 15IKNNIAL REPORT of the fold and sinus, about six present on the fold apparently arising from a single one at the beak ; two or three costae occupy each side of the mesial sinus, arising from the bifurcations of the strong ridges that border the sinus. Sometimes there is also a central costa occupying the bottom of the sinus. There are occasional lines of growth, especially near the margins, but the fine regular concentric lines, so characteristic in A. marginalis, are not present. The dimensions are: length, 12 to 15 mm.; width, 12 to 15 mm.; thickness, about 7 mm. This species is common in the Edgewood limestone, immediately below the Bowling Green member, in the vicinity of Edgewood and Watson Station, and at other places in Pike County, Missouri, and is found also near Thebes, Illinois. Atrypa putilla (Hall and Clarke) (Plate VI, figure 25) 1893. Zygospira putilla. Hall and Clarke, Paleontology New York, vol. 8, pt. 2, p. 365, pi. 54, figures 35-37 ; pi. 83, figures 29 and 30. Hall and Clarke's description : "Shell small, elongate-suboval in outline. Pedicle valve the more convex ; umbo narrowed, apex acute, delthyrium unclosed. Medially this valve is elevated by a strong double plication, the parts of which diverge anteriorly, leaving a flat, low depression between them, and in this lies a single faint plication. The lateral slopes are considerably depressed, and each bears from four to seven coarse, often irregular plications, only a part of them reaching the beak. "The brachial valve is depressed-convex, with a conspicuous median fold, grooved longitudinally and bounded by deep marginal depressions. The lateral slopes are more convex than on the other valve, but are similarly plicated. Surface of the valves usually without concentric growth lines. "An average example has a length of 8 mm., and a greatest width of 7 mm. "Hudson River group. Near Edgewood, Pike County, Missouri." The form of this species that is found near Thebes, Illinois, is slightly larger than the average size of the shells occuring near Edgewood, Mis- souri. The shape and surface markings of the shells in the two localities are similar, and some of the larger individuals from Missouri are similar in size to the normal Illinois specimens. Among a large number of shells of this species are found some in which all of the radiating striae are entirely simple ; others in which only one or two of the striae on either side show traces of division ; and still others in which nearly all of the striae divide between the beak and the margins, and the shells approach A. pracmarginalis in general appearance. This species is also common in the Noix oolite member at Louisiana, Missouri. ALEXANDRIAN SERIES 131 Atrypa tuhulistriata n.sp. (Plate VII, figures 23 and 24) Shells suborbicular in outline, the length and width nearly equal, the hinge line in old shells about three-fourths the greatest width, cardinal extremities rounded. Ventral valve moderately convex, most prominent in the umbonal region, beak pointed and somewhat incurved, the cardinal slopes steep, lateral and anterior slopes more gently convex, mesial part of the valve depressed into a prominent sinus that extends nearly to the beak, becoming deeper and broader towards the anterior margin where it is produced into a short lingual extension, marked by about four or five plications which appear to be formed by the bifurcation of the lateral bounding plications. Dorsal valve more convex than the ventral, rather strongly arched in the umbonal region, beak small and closely incurved, the cardinal slopes very steep, lateral and anterior slopes moderately convex, mesial fold extending nearly to the beak, prominently elevated on the anterior half of the shell, marked by four to six plications wdiich arise by the bifurcation, once or twice, of the two longest ones. The lateral slopes of both valves are each marked near the margin by six to twelve somewhat irregular radiating plications which arise from the bifurcation, once or twice, of about three original ones, the longest not extending quite to the beak. Surface of both valves with prominent concentric ridges or lamellae, 1 to 1.5 mm. apart, which are slightly inflated where they cross the plications. The dimensions are : length of different shells, 12 to 17 mm. ; width, about equal to length ; thickness, 5 to 10 mm. In appearance this species somewhat resembles Atrypa nodostriata Hall, from which it differs in the relatively deeper dorsal valve, in the fold and sinus extending more nearly to the beak, and with more sharply defined borders, and in the radiating striae not extending quite to the beak. These shells are common in the Noix oolite member of the Edge- wood formation at Louisiana, and near the mouth of Buffalo Creek, in Pike County, Missouri, and south of Hamburg in Calhoun County, Illinois. Spirifer (Delthyris) sp. (Plate VII, figure 22) This small species of Spirifer, which is represented by only a single ventral valve, resembles Delthyris sulcata Hisinger in some respects, but lacks the imbricating concentric lamellae of that genus. The valve is moderately convex, length and width subequal, about 5 millimeters, with a fairly well defined mesial sinus, on either side of which are four plica- tions and a trace of a fifth. 132 BIENNIAL REPORT This species is rare in the upper part of the Edgewood formation, near Thebes, Illinois. Homocospira fiscellostriata n.sp. (Plate VI, figures 23 and 24) Shell biconvex, subovate in outline, somewhat longer than wide. Ventral valve more convex than the dorsal, the greatest convexity in the umbonal region from which the surface slopes rather steeply to the cardinal and cardino-lateral margins, and more gently to the sides and front ; the mesial portion of the valve somewhat elevated, with a prom- inent stria on each side of the median line; in the furrow between these striae is a rounded ridge which extends nearly three-fourths of the dis- tance from the front to the beak. The beak is prominent and pointed, but not much incurved over the hinge line. Dorsal valve moderately convex, the greatest depth a little posterior to the middle, from which the surface slopes with a rather uniform curvature to the cardinal, lateral and anterior margins ; the mesial portion of the valve bears a slight depression which is occupied by a low ridge extending nearly to the beak and is divided by a shallow furrow in the anterior half of its length, with a trace of an additional division near the front margin. The beak is small and closely incurved beneath that of the ventral valve. Surface of both valves marked by radiating striae of which about four on each side of the median line of the valves extend to the beaks ; of these, the two adjacent to the median line on each valve usually divide twice, while some of the others divide once and others divide twice between the beak and the margin. No distinct concentric lines of growth are visible. The dimensions are : length, 7 to 8 mm. ; width, about 6 mm. ; thick- ness, 2 to 2.5 mm. This species more nearly resembles Homoeospira sub circular is, with which it is associated in the Edgewood limestone, than any other known species, but differs from that form in the somewhat smaller size, and the more numerous and irregular divisions of the radiating striae. The latter character will also serve to distinguish this species from all other known species of the genus. Shells of H. fiscellostriata occur in the Noix oolite phase of the Edgewood limestone at Louisiana, Missouri. Homoeospira subcircularis n.sp. (Plate VI, figures 26 and 27) Shells moderately biconvex, sub-circular in outline ; ventral valve most prominent in the median portion, the surface curving strongly from the umbonal region to the cardinal margin and a little more gently to the sides and front; mesial sinus narrow in the posterior portion, extending ALEXANDRIAN SERIES 133 to the beak, bordered on each side by a prominent angular ridge, the bottom occupied by a simple elevation in the anterior half of the shell, beak prominent and rather strongly incurved. Dorsal valve a little less convex than the ventral, deepest near the center, from which portion the surface slopes with about equal convexity to the cardinal, lateral and anterior margins ; mesial fold not much elevated above the sides, extending to the beak, much wider in the anterior half of the shell, somewhat flattened on top, and divided in the anterior portion by a furrow which extends more than one-half the distance from the front to the beak, the latter rather small and closely incurved beneath that of the ventral valve. Surface of both valves marked by seven or eight subangular costae on each side of the fold and sinus, of which the two nearest the fold and sinus on each side divide once on the posterior one-third of the shell. No concentric lines are visible. The dimensions are : length, 8 to 9 mm. ; width, about equaling the length ; thickness, 4 to 4.5 mm. This species is more closely related to Homoeospira fisccllostriata than to any other known species, but differs from it in the fewer striae that divide, and the less numerous divisions of the radiating striae. It also somewhat resembles H. beecheri Foerste, from which it may be distinguished by the bifurcation of the two striae nearest and on each side of the median fold and sinus. Shells of this species are common in the Xoix oolite member of the Edgewood limestone in the vicinity of Louisiana, Missouri. Hindella? ambigua n.sp. (Plate VI, figures 17 and 18) Shells somewhat resembling Hindella umbonata (Billings), from which they differ in the relatively greater width in proportion to the length, especially posterior to the middle, in the lower ventral beak, and in the less deep excavation bordering the hinge line. They differ from Hindella prinstana (Billings) in the more elongate form of the shell, the relatively shorter hinge line, and the more prominent ventral beak. The shells of this species show some variation in shape and size, but are bi-convex, subovate in outline, the greatest width at or slightly posterior to the middle. Ventral valve most convex in the umbonal region, the surface curving steeply to the cardino-lateral margins, and sloping more gently toward the sides and front. In some shells a faint depression appears in the median line for a short distance from the front margin, in others no sinus is discernible ; beak rather small, pointed, and strongly incurved over that of the dorsal valve, with the umbonal surface of which it is not quite in contact. Dorsal valve less convex than 134 BIENNIAL REPORT the ventral, the greatest convexity in the umbonal portion, sloping quite steeply towards the cardinal regions and rather evenly towards the front and lateral margins; beak incurved, and concealed beneath that of the ventral valve. Surface of both valves marked by rather fine concentric lines which are most conspicuous near the margins. The dimensions are: length, 15 to 20 mm.; width, 13 to 18 mm.; thickness, 9 to 14 mm. Shells of this species are not rare in the Edgewood strata near Edgewood, in Pike County, Missouri. Fragments of shells thought to represent the same species were also found in the upper part of the Edgewood formation in Alexander County, Illinois. Whit field ell a billing sana (Meek and Worthen) (Plate VII, figures 11 and 12) 1868. Ccntronclla billingsana. Meek and Worthen, 111. Geol. Survey, vol. 3, p. 352, figures a, b, c ; pi. 6, figures 5a-5c. Meek and Worthen's description : "Shell attaining a moderately large size, subovate in form ; valves nearly equally convex, the ventral being a little more gibbous than the other, particularly in the umbonal region ; greatest breadth near the middle, or slightly in advance of it; posterior lateral slopes nearly straight, or sometimes a little concave in outline, and converging to the beaks at various angles of from 70 to 80 degrees ; front usually rather narrowly rounded, faintly subtrun- cate, or very slightly sinuous. Dorsal valve regularly convex, and without any traces of a sinus or mesial ridge ; beak rather gibbous and distinctly incurved. Ventral valve with a shallow, rather narrow mesial sinus, generally moderately well defined at the front, and extending to the central region, where it gradually becomes obsolete ; beak moderately prominent, rather pointed, somewhat arched, with apparently a very small perforation at the extremity, connected when the del- tidium is removed, with a comparatively large triangular opening extending to the incurved beak of the opposite valve. Surface of both valves marked with obscure concentric striae of growth. "Length of the largest specimen in the collection, 0.63 inch ; breadth, 0.50 inch ; convexity, 0.34 inch. "Locality and Position: Alexander County, Illinois, in a thin local bed of gray limestone ; apparently near the horizon of the Niagara division of the Upper Silurian." This species is very common in the thick layers of gray limestone in the upper part of the Edgewood strata, and is one of the characteristic fossils of this formation in Illinois. Whitfieldella ovoides n.sp. (Plate VII, figures 13, 14, and 15) 1868. Mcristclla? sp. Meek and Worthen, 111. Geol. Survey, vol. 3, p. 354, pi. 6, figures 4a and 4b. Shells differ from Whitfieldella billingsana (Meek and Worthen) in the larger size and greater convexity of the valves, the more elliptical ALEXANDRIAN SERIES 135 outline, less acuminate beaks, the ventral beak much more strongly incurved over that of the dorsal valve, and in the sinus of the ventral valve extending from the front nearly to the beak. The characters men- tioned above will also serve to distinguish this species from IV hit field ella acuminata, described on a later page, and from IV. intermedia Hall. The shells are biconvex, subelliptical in outline, the greatest width near the middle, the anterior margin truncate or somewhat produced. Ventral valve rather strongly arched, most convex in the umbonal region from which the surface slopes abruptly to the cardinal margins, and more gently to the sides and front ; median portion of the shell depressed in a narrow shallow sinus which is deepest at the front margin, from which it extends two-thirds or more of the distance to the beak; the beak of the ventral valve is prominent, and strongly incurved over and upon that of the dorsal valve. Dorsal valve slightly less convex than the ventral ; highest along the median line, especially on the posterior half of the shell, from which the cardinal slopes are steeper than those over the lateral and antero-lateral portions ; no well defined mesial fold is present but the median portion of the valve is the most prominent from the front to near the beak, which is concealed beneath that of the ventral valve. Surface of both valves marked by lines of growth and by numer- ous very fine concentric striae, which appear only under a lens. The dimensions are: length, 18 to 22 mm.; width, 15 to 17 mm.; thickness, 8 to 9 mm. This species gecurs in the Edgewood limestone near Thebes, Illinois, and Edgewood, Missouri. It is common in the upper layer of the oolite at Louisiana, and at a corresponding level between Clarksville and Kissen- ger, in Pike County, Missouri ; and is also common in the Channahon limestone, in Will County, Illinois. W hit field ella f speciosa n.sp. (Plate VII, figures 16 and 17) Shell biconvex, broadly subovate in outline, the length and width about equal, the greatest width a little anterior to the middle ; valves subequally convex. Ventral valve moderately convex, most prominent a little posterior to the middle, the beak pointed, not much incurved ; the lateral margins meeting at the beak at an angle of 80 to 100 degrees, the cardinal slopes abrupt, lateral slopes somewhat less steep, and the anter- ior slopes more gentle ; the mesial portion of the valve depressed in a rounded sinus extending nearly to the beak, widest in the anterior por- tion where it is slightly produced. Dorsal valve with the convexity and surface slopes much as those in the ventral valve, the beak pointed 136 BIENNIAL REPORT but not much incurved, the median portion elevated in a fold which is rather flat on top and extends nearly to the beak, most prominent in the anterior portion, where in some shells it is rather definitely bounded. Surface marked by numerous very fine concentric striae and a few stronger concentric lines of growth, which are usually confined to the marginal portions of the shells. The dimensions are: length 10 to 11 mm.; width, about equaling the length ; thickness, 4 to 5 mm. This species is common in the Noix oolite member of the Edge- wood limestone in the vicinity of Louisiana and south of Clarksville, Missouri, and below Hamburg in Calhoun County, Illinois. Mollusca Pelecypoda Ctenodonta subelliptica n.sp. (Plate VII, figure 25) Shell somewhat resembles Ctenodonta elliptica Hall in general outline, but differs from that species in the much smaller size, in the steeper anterior slope, and in the more narrowly rounded posterior extremity. The shells are subelliptical in outline, the greatest convex- ity above and posterior to the center, slightly flattened in the umbonal regions, the anterior margin slightly concave from the beak to the mid- dle of the front, thence rounding somewhat sharply to the ventral mar- gin, which is rather uniformly and broadly convex, to the posterior, where it curves most strongly upward around the posterior margin to the hinge ; the slope from the beak to the posterior extremity is nearly straight. The beaks are situated slightly anterior to the middle, mod- erately prominent, pointed forward, and slightly incurved. Surface marked by fine concentric lines of growth which are more numerous near the margins. The dimensions are: length, about 13 mm.; width, 7.5 mm.; and thickness, about 3 mm. This species is very common in the lower part of the Edgewood limestone near Edgewood, Missouri. Ptcrinca tlicbcscnsis Meek and Worthen (Plate VII, figure 28) 1868. Pterinea thebesensis. Meek and Worthen, 111. Geol. Survey, vol. 3, p. 354, pi. 6, figure 3. Meek and Worthen' s description: "Shell (left valve) obliquely rhombicoval, longer than high, moderately convex in the central and umbonal regions ; cardinal margin less than the greatest length, bordered behind by an obscure marginal ridge, and ranging very obliquely to the umbonal axis, or nearly parallel to the greater ALEXANDRIAN SERIES 137 diameter of the valve; basal margin forming a broad semicircular curve; anterior side truncated, sometimes obliquely and sometimes nearly vertically, a little rounded at its rectangular connection with the hinge above, rather distinctly gaping (unless the margin of the other valve is warped inwards) ; posterior margin most prom- inent, and narrowly rounded below the wing ; posterior wing abruptly flattened from the swell of the umbo, rectangular at the extremity, and considerably shorter than the margin below, from which it is separated by a faint oblique sinuosity; anterior wing a very short inconspicuous, round, rather convex lobe, obscurely denned by a faint, oblique concavity, extending down from the anterior side of the beak, which is moderately convex, depressed, and placed about half way between the middle and the anterior extremity. Surface marked by fine concentric striae, and near the anterior truncated (gaping?) margin, by rather distinct subimbricating marks of growth. "Length 0.80 inch; height, 0.50 inch; convexity (of left valve), 0.20 inch. "Locality and Position : Alexander County, Illinois, in a thin local bed of gray limestone ; apparently near the horizon of the Niagara division of the Upper Silurian." This species is common in the Edgewood strata of Alexander County, Illinois, in which rocks the type specimen was found. In some respects it resembles the species of Pterinea occurring in the limestone near Channahon, but differs from it in the shorter and less pointed pos- terior wing, and in the less abruptly truncate anterior margin. Colpomya abrupta n.sp. (Plate VII, figure 27) Shells so unlike any other known species that comparison would be of little value. They are subrhomboidal to subquadrate in outline, moderately convex, the greatest convexity a little above the middle ; hinge line straight, two-thirds the length of the shell ; beaks somewhat elevated, compressed and incurved over the hinge line, situated near the anterior end which is narrower than the posterior, and is short and rounded ; the ventral margin gently convex, slightly indented a little anterior to the middle by a shallow depression which extends over the slightly flattened umbones obliquely from the beaks to the ventral mar- gin ; the ventral margin rounding to the posterior end which is obliquely truncated, forming an angle of about 112 degrees with the hinge; cardinal slope somewhat compressed and alate posteriorly. Surface marked by moderately strong unequal concentric lines of growth. The dimensions are : length about 21 mm. ; width about 12 mm. ; and thickness 5 to 6 mm. This species occurs in the lower part of the Edgewood limestone near Edgewood, Missouri. 138 BIENNIAL REPORT Cypricardinia subqnadrata n.sp. (Plate VII, figure 26) Shell somewhat resembles Cypricardinia arata Hall, from which it differs in the greater width in proportion to its length, and the more truncate posterior end which meets the hinge line at a much smaller angle. It is also readily distinguished from C. undulostriata Hall by the relatively greater width, more nearly vertical posterior extremity, and the absence of fine undulating concentric striae. The shells are subquadrate in outline, hinge line straight, more than two-thirds of the greatest length. Beak situated near the anterior margin, directed for- ward, moderately prominent and incurved ; the anterior end short, con- cave immediately below the beaks, rounding to the basal margin which is gently convex, and slightly indented near the middle. The postero- ventral extremity rounded, above which the margin is truncate, meet- ing the hinge line at an angle of about 102 degrees. The surface is most convex in the antero-dorsal portion where it rounds rather steeply to the front; a shallow depression extends obliquely over the somewhat flattened umbones from near the beak to the middle of the basal margin. In the posterior portion, the cardinal slope becomes very gently convex or somewhat compressed, and alate. Surface marked by prominent concentric lamellae, of which three to five occupy the space of 1 mm. The dimensions of the type are : length, about 13 mm. ; width, 7.25 mm. This species occurs in the oolite member of the Edgewood limestone near Louisiana, Missouri. Liospira cf. affine (Foerste) (Plate VIII, figure 5) 1885. Raphistoma affinis. Foerste, Bull. Sci. Lab. Denison Univ., p. 95, pi. 19, figure 18. 1893. Raphistoma affine. Foerste, Ohio Geol. Survey, vol. 7, p. 550, pi. 26, figure 18; and pi. 37a, figures la, b and c. Foerste' s description: "Shell lenticular; breadth a little more than twice the height ; convexity moderate above, equally so below ; volutions varying from two and a half to three and a half, with a moderate slope above, coincident with that of the spire ; the last volution sharply carinate around the periphery, convex below, being more so at the umbilicus into which the slope is abrupt; suture distinct, forming a small groove between the volutions; umbilicus as wide as the outer volution ; the last volution becoming transversely rhomboidal, the aperture itself not being preserved, the breadth about three times the height. Surface apparently smooth. "This species is almost in every respect identical with forms of Raphistoma lenticularis as known to me from the Lower Silurian formations. It is however a much smaller shell, with less numerous volutions, and apparently a distinct form. ALEXANDRIAN SERIES 139 "Breadth of largest specimen, 7 mm.; height, 3 mm.; breadth of the end of the last volution, 3 mm. ; height, 1.2 mm. ; aperture not preserved." In volume VII of the Geological Survey of Ohio the following addition is made to the description of this species : "The transverse striae are close and fine ; from the junction of each whorl with the preceding one, the striae bend back strongly towards the quite sharp angle, which is formed at the middle of each whorl, laterally. In a general way the striae form an angle of forty-five degrees with the latter. In the larger shells there is commonly a very shallow depression on the upper surface of the last coil, a short distance from its edge, which causes an apparent slight thickening of the shell along the edge, especially towards the aperture. The mouth is oblique, facing diagonally downwards (if the apical end of the spiral be placed at the top). The largest specimen so far found has a greatest diameter of 20 mm." Shells referred to this species are not rare in the oolite phase of the Edgewood in Pike County, Missouri, and Calhoun County, Illinois. Hormotoma tcnera n.sp. (Plate VIII, figure 9) Shell small, elongate, consisting of about seven volutions which enlarge very gradually from the apex, the last one not expanding much more rapidly than the preceding; the height about 13 mm.; greatest width about 5 mm. Volutions rather evenly convex, without any trace of a peripheral angulation or band. The suture is moderately deep and only slightly oblique ; the aperture apparently ovate, higher than wide. The shell is so exfoliated that no traces of surface markings of any kind are preserved. The shells of this species somewhat resemble those of Hormotoma? subulata (Conrad), from which they differ in the much smaller size, fewer and less oblique whorls, and the more shallow sutures. The same characters will serve to distinguish them from Hormotoma gracilis Hall, of the Ordovician strata. Shells of this species are rather common in the Edgewood limestone near Edgewood, and in the oolite at Louisiana, Missouri. Lophospira fasciata n.sp. (Plate VIII, figures 7 and 8) Shell rather small, conical, a little higher than the width at the base ; volutions about four or five, but slightly overlapping grad- ually increasing in size from the apex, cross section about as high as wide, the outer volution enlarging more rapidly than the preceding; aperture subcircular, not much expanded ; periphery rounded except as the carinae impart to it a subangular appearance, with somewhat flat- tened intercarinal spaces; revolving carinae three, about equidistant 140 BIENNIAL REPORT apart, the middle one slightly stronger than the outer ones. Base of the shell rounding into a small umbilicus. Surface marked by numer- ous fine transverse lines of growth which are not much deflected in passing over the carinae. The dimensions are: height of spire, 12 to 15 mm.; width at the base, about 10 mm. This species is not rare in the Edgewood strata in Pike County, Missouri. It belongs to the Bicincta section of Lophospira, as defined by Ulrich 30 and resembles L. bicincta Hall in the number of carinae on the volutions and in the almost vertical direction of the transverse striae. It is distinguished from Hall's species by the shorter spire, and the absence of a sharp elevated line bordering either side of the central carina, from which it is separated by a shallow furrow. Lophospira thebesensis n.sp. (Plate VII, figure 31) This species belongs to the Robusta section of Lophospira, as de- fined by Ulrich, 30 and seems to be distantly related to L. Virata Ulrich, from the Cincinnatian beds of Ohio, which it somewhat resembles in size and in the larger surface features. It differs from that species in having only three or four volutions, which are more angular along the peripheral band than in that form. In our species the peripheral band is prominent and median in position. Upper slope of the volutions, between the band and the suture, divided near the middle by a low ridge on either side of which the surface is flattened or concave. A more distinct revolving ridge occurs about the same distance below the band, the intervening spaces also being flattened ; suture moderately deep, aperture and umbilicus not well exposed. Transverse lines of growth fine and numerous. The dimensions are : height, 22 to 30 mm. ; width, about equaling the height. This species is common in the thick limestone layer of the Edge- wood formation near Thebes, where it is associated with IV hit field ella billing sana and Ly cilia thebesensis. Similar shells were also found in the Edgewood beds, near Edgewood and at Louisiana, Missouri. Bellerophon consimilis n.sp. (Plate VIII, figure 2) Shell differing from Bellerophon exiguus, with which it is asso- ciated, in the generally larger size, the narrower volutions, and the sharper and higher dorsal carina. The two latter characters also dis- 'Ulrich, E. 0., Geol. Survey of Minn., vol. 3, part 2, p. 963. ALEXANDRIAN SERIES 141 tinguish this form from Bcllerophon umbilicus with which it seems to be rather closely related. In our shells only the outer volution is visible. This increases rather rapidly in size, in somewhat triangular in cross section, not much expanded at the aperture, and bears throughout its length a sharp prom- inent dorsal carina, away from which the shell slopes quite steeply, the sides rounding below into the small umbilicus. Surface markings not known, as the shells are all in the form of casts ; the surface of the casts are smooth, preserving no trace of the lines of growth. The dimensions are : greatest diameter, 18 to 22 mm. ; greatest diameter of outer volution, about 12 mm. Shells of the above species occur in the Edgewood strata in the Missouri locality, and imperfect shells of Bellerophon, thought to rep- resent the same species, were also found in the Edgewood formation in Alexander County, Illinois, where they were associated with Schucher- tella propinqua and Dalmanites danai. Bellerophon exiguus Foerste (Plate VIII, figure 6) 1855. Bucania exigua. Foerste, Bull. Sci. Lab. Denison Univ., vol. 1, p. 99, pi. 13, figures 18a, b, c, d. 1889. Bellerophon (Bucania) exigua. Foerste, Proc. Boston Soc. Nat. Hist., vol. 24, p. 288, pi. 6, figure 3. 1893. Bcllerophon (Bucania) exiguus. Foerste, Ohio, Geol. Survey, vol. 7, p. 548, pi. 25, figures 18a, b; pi. 31, figures 18a, b; pi. 31, figure 3; pi. 37a, fig- ures 2a, b, c. Foerste's description : "Number of volutions not known, the last alone vis- ible, increasing rapidly in size, and expanding at the aperture ; the exact character of the aperture not known from want of preservation, but is presumed to be sim- ilar to that of B. bilobatus. The outer volution rounded on the dorsum at its origin, a mesial carina gradually developing towards the aperture near which it becomes quite distinct, in some individuals decidedly so. From this carina, the sides slope evenly to the umbilicus, which they enter with a sudden curve, form- ing a low, indistinct lateral carina, by the increase of curvature. Umbilicus ap- parently closed, the last volution alone being visible in the specimens examined. Surface of the cast smooth, traces of the original shell, however, seem to remain in a few spots, indicating a system of striae curving from the mesial carina ob- liquely backwards, these apparently crossed by the other striations. The usual form of the cast, however, is smooth, the shell being entirely removed. "Measurements, on account of the imperfect preservation of the shell towards the aperture, are of little value, still the following will serve to give a general idea of the proportions of the shell. Greatest diameter of the typical specimen (PI. 13, figs, a, b), 9 mm.; diameter at right angles to this, 6.2 mm.; diameter of the last volution at the point where it becomes visible, 3.5 mm. ; broadest part of volution preserved, 7 mm. From this they vary in size from the specimens which become almost minute to some having a greatest diameter of 22 mm." 142 BIENNIAL REPORT In size, shape of whorls, and general appearance, our shells resem- ble those of Foerste's species described above. However, neither the aperture nor the umbilicus are well exposed, and so the certain identifi- cation is not possible. Imperfect casts are not rare in the Edgewood strata, in Pike County, Missouri. Straparollus pumilis n.sp. (Plate VII, figure 29) Shell very small, depressed, consisting of about four and one-half, rather gradually enlarging volutions, the last one of which comprises a little more than one-half the width of the shell ; the diameter is 4 to 4.5 mm.; and the height 1.5 to 2 mm.; spire very low, less than one- half of the height of the shell, the suture is rather shallow; umbilicus narrow and deep. The body volution is sub-elliptical in cross section, rounded in the peripheral portion, above which the surface is rather uniformly convex to the suture, and shows a corresponding curvature below the periphery to the edge of the umbilicus, into which the slope is more abrupt. No surface markings of any kind preserved. This species resembles Straparollus (cf. Oriostoma) incarinatum Foerste, from which it is distinguished by its much smaller size, lower spire, and narrower umbilicus. Shells of this species are not rare in the lower layers of the Edge- wood limestone, near Edgewood, Missouri. Cyclonema daytoncnsis Foerste (Plate VIII, figure 4) 1893. Cyclonema bilix Foerste, Ohio Geol. Survey, vol. 7, p. 551, pi. 30, figure 15. Foerste's description : "The outer lip of the aperture is sharp. The inner lip is strongly broadened, thus increasing a little the size of the aperture. This broadened flange of the lip meets the lower surface of the shell with a concave curvature, which is strongest towards its inner end of attachment to the previous whorl ; here it forms often a strong though rounded groove with the slightly raised margin of the shell. In other respects the shell is very variable. In the ordinary form the whorls are rounded. Very distinct fine close sharp striae of growth traverse the shell transversely, indicating the outlines of the aperture at various stages of development. In addition to these striae, transverse wrinkles of moderate distinctness and having the same general direction, also are frequently present. The longitudinal revolving striae are much less closely placed, and at more or less regular intervals certain of these striae are very strong and sharply elevated, forming the most prominent lines in the exterior ornamentation of the shell." This shell was submitted to Dr. Foerste who kindly compared it with the type specimen, and stated : "It can not be distinguished, and is sufficiently typical to serve as the type of the species itself." It occurs in the Noix oolite bed at Louisiana, and in the Edgewood strata near Edgewood, Missouri, and near Thebes, Illinois. ALEXANDRIAN SERIES 143 Poleumita bellasculptilis n.sp. (Plate VIII, figure 3) Shells somewhat resembling Pleurotomaria cyclonemoides described by Meek and Worthen from the Niagara limestone, but distinguished from that species by their much smaller size, and more angular volutions, which are marked by relatively fewer revolving lines. They also re- semble Trochonema pauper Hall, from which they differ in the more angular volutions, which are more flattened on the upper surface, in the smaller umbilicus, and the more angular aperture. The shell is small, about 12 mm. in height, the greatest w T idth of the body whorl about one-half the height of the shell. Spire conical, apical angle about 90 degrees, whorls four to five, scarcely overlapping; the first one or two small, the succeeding ones, especially the last, rather rapidly increasing in size. An angular carina separates the upper slope from the median and basal portion of the whorls. The upper slope of the body whorl, between the suture and the carina, is nearly flat, becoming gradually more convex in the higher whorls which are nearly circular in section. Below the carina the surface is flat or gradually rounded, down to the gently convex basal portion of the whorls. The upper slope of the volutions is marked by three revolving ridges, of which the middle one is the largest, and is the only one that persists in the two uppermost whorls. Below the carina there are twelve to fifteen revolving ridges and furrows on the body whorl, only five or six of which are visible on this portion of the second volution, the num- ber becoming gradually fewer from the aperture toward the apex. No transverse lines of growth preserved ; aperture apparently subovate, not expanded. Shells of this species occur in the Edgewood strata in Pike County, Missouri. Holopea minuta n.sp. (Plate VII, figure 30) Shell readily distinguished from any known species by its very small size. The height is about 2.5 mm., the width about equal to the height. It consists of about four and one-half, rather rapidly enlarging, strongly convex volutions, which are nearly circular in cross section, the last one not very ventricose. The umbilicus is very small; the suture rather deep, the aperture apparently almost circular, with a thin, reflexed inner lip. Surface with no distinct transverse markings preserved. This species occurs in the lower part of the Edgewood limestone, near Edgewood, Missouri. 144 BIENNIAL REPORT Diaphorostoma niagarensis Hall (Plate VIII, figure 1) 1852. Platyostoma niagarensis. Hall, Paleontology New York, vol. 2, p. 287, pi. 60, figures la-v. 1879. Platyostoma niagarensis. Hall, 28th Rept. N. Y. State Mus, p. 175, pi. 28, figures 1-12; pi. 29, figures 1-15. 1881. Platyostoma niagarensis. Hall, 11th Ann. Rept. Indiana Geol. and Nat. Hist., pi. 29, figures 1-12, and pi. 30, figures 1-15. 1889. Platyostoma niagarensis. Nettelroth, Ky. Fossil Shells: Mem. Ky. Geol. Survey, p. 185, pi. 33, figure 30. Hall's description : "Globose ; volutions 3 or 4 ; body whorl large ; inflated towards the aperture which was dilated; sutures deep; spire depressed (rarely elevated); shell thin; surface striated across the volutions, and in well preserved specimens longitudinally marked by filiform undulating striae. The spire appears to be depressed often when the shell retains its natural proportions, and at other times from pressure; in a few examples it is consid- erably elevated. The fine undulating longitudinal striae do not always appear, and sometimes only upon a portion of the surface, even where there is no appearance of abrasion. In other examples, they have evidently been worn off, leaving the transverse striae well preserved." In the specimens from the Edgewood formation, both in Missouri and Illinois, the transverse striae are well preserved, but there is little, if any, trace of longitudinal markings. The species occurs near Thebes, Illinois, and near Edgewood, Missouri. Arthropoda Trilobita Isotelus longaevus n.sp. (Plate VIII, figure 15) This species of Isotelus is especially interesting because it is one of the few representatives of the genus that lingered for a time after the close of the Ordovician period. It differs from the common Richmond species Isotelus maximus Locke and /. gigas De Kay in the proportion- ately much shorter and wider cephalon. It most closely resembles Isotelus susae Whitfield in its general proportions, but is distinguished from that species by its relatively broader and shorter cephalon, by the greater constriction of the glabella between the eyes, which are not sit- uated so far backward as in /. susae. The facial sutures behind the eyes extend much farther outward, reaching the posterior border much nearer the genal angle than in Whitfield's species. The cephalon is short, subcrescentiform in outline, the length along the median line about 12 mm., equaling nearly one-half the greatest width ; the genal angles obtusely rounded. The surface is convex over ALEXANDRIAN SERIES 145 the middle portion, with a rather abrupt slope nearer the front and lat- eral margins. The glabella not distinctly defined. The eyes are sep- arated by a distance of about one-half the length of the cephalon, situ- ated a little posterior to the middle of the head. Anterior to the eyes the facial sutures round outward to near the margin which is reached in front of the median line of the eyes, the sutures from opposite sides are then continuous around the anterior extremity of the cephalon to their junction at the middle of the front margin. Posterior to the eyes the sutures are directed backward and outward, cutting the posterior border a little more than one-half the distance from a point in the pos- terior border directly behind the inner margin of the eyes to the genal angles. The free cheeks are broad, gently convex, longer than wide, the widest part being opposite the posterior border of the eyes ; the outer border, behind the point where the facial suture reaches the anterior margin, is nearly straight to the obtusely rounded genal angles. This species occurs in the lower part of the Edgewood limestone near Edgewood. Illinois, where it is associated with Dalmanitcs danai and Schuchertella propinqua. Pvoctus determinatus Foerste (Plate VIII, figures 10 and 11) 1885. Bathyurus. Foerste, Bull. Sci. Lab. Denison Univ., vol. 1, p. 103, pi. 14, figure 5. 1887. Proetus determinatus. Foerste, Bull. Sci. Lab. Denison Univ., vol. 2. p. 91, pi. 8, figures 2, 3, 3a. 1895. Proetus determinatus. Foerste, Ohio Geol. Survey, vol. 7, p. 523, pi. 26, fig. 5 ; pi. 27, figures 2, 3, 3a. Foerste's description : "Glabella conical, convex, sharply defined from the remaining portions of the head by a distinct furrow ; obscurely marked by three pairs of grooves; the posterior pair being inclined at an angle of forty-five de- grees to the axis of the glabella, cutting off the postero-lateral corners; the mid- dle pair, although shorter and less inclined, are still fairly distinct ; the anterior pair are very indistinct, quite short, and but slightly inclined ; in addition three very indistinct pairs of pits may be seen, the two anterior pairs are at the ends of the two anterior pairs of grooves, the posterior pair are opposite the middle of the posterior grooves. In the distinct occipital furrow beneath the postero- lateral corners of the glabella are two almost triangular tubercles which add to the conical appearance of the glabella. The occipital ring, broad at the middle, narrow at the ends, is supplied with a distinct granule near the center. "The anterior margin of the head is curved downwards, giving this portion of the head a distinctly convex appearance ; the edge is narrow, but plainly ele- vated at an angle of perhaps forty degrees with those parts of the anterior mar- gin immediately adjacent. The palpebral lobes are rounded, and are situated opposite the anterior half of the posterior furrows. The facial sutures anterior to the palpebral lobes curve slowly outward toward the anterior edge, then sud- denly inward again, cutting the edge beyond a line passing through the lateral edge of the tubercles. 146 BIENNIAL REPORT "In this genus the facial sutures behind the eyes are parallel for a short dis- tance, then curve outward and reach the posterior border of the head, usually at a point half way between the glabella and the postero-lateral margin of the head. In Cyphaspis the posterior furrows become deep grooves, dividing the glabella into three distinct lobes, of which the central lobe is obovate in form. The middle and anterior furrows are usually wanting. The tubercles found in the Ohio species have not this signification, but are caused by the bifurcation of the occipital furrow. "Length of smaller specimen, glabella, 3.5 mm.; including anterior margin, 5 mm. Breadth of glabella 3.1 mm. ; including palpebral lobes, 4.5 mm. ; width measured between the antero-lateral margins of the area anterior to the glabella, 4.5 mm. Length of the larger specimen, glabella, 7 mm. ; including occipital ring, 8.2 mm. ; including also anterior margin, 10 mm. Width of glabella just above the tubercles, 7 mm. "Locality and Position : Soldiers Home, near Dayton, Ohio, Clinton Group." This is a common species in the gray limestone in the upper part of the Edgewood formation, in Illinois, and in equivalent layers near Edgewood and at Louisiana, Missouri. Cyphaspis intermedia (Weller) (Plate VIII, figure 12; and Plate IX, figure 26) For the description of this species refer to descriptions of fossils of the Channahon limestone. Cranidia of a trilobite that can not be distinguished from the above species are not rare in the Edgewood strata near Thebes, Illinois, and in Pike County, Missouri. Metapolichas breviceps var. clintonensis (Foerste) (Plate VIII, figures 13 and 14) 1895. Lichas breviceps var. clintonensis. Foerste, Ohio Geol. Survey, vol. 7, p. 529„ pi. 25, figures 26a-26e ; pi. 27, figures 18, 19. Foerste's description : "This species occurs in the Ohio Clinton limestone at Brown's Quarry, common (glabella sometimes 22 mm. long) ; Soldier's Home, rare ; Fauver's Quarry, a glabella ; in the 'Orthoceras block' from Huffman's Quarry ; upper shaly courses at Huffman's Quarry, several specimens ; Fair Haven,, a glabella; Hanover, Indiana, rare. A careful study of the head of the typical forms of Lichas breviceps from the Niagara of Waldron, Indiana, was prepared for the Bulletin of Denison University vol. 3, pi. 13, figure 21. An entire head was found in the above mentioned 'Orthoceras block'. It presents all the features of the Waldron head with one exception. In the occipital furrow — between the postero-lateral lobes of the glabella, the occipital segment, and the area posterior to the eye — lies, in the case of this as well as all other Clinton specimens, a trans- versely oblong, very distinct, and fairly large lobe, represented in the case of the Waldron specimens only by a very slight ridge. When it is desired to distinguish this Clinton form from its Niagara descendant the varietal name clintonensis may be used. The Clinton pygidia show no distinctions. The hypostoma is frequent at Brown's Quarry." ALEXANDRIAN SERIES 147 In the cranidium of this trilobite there is present, in the occipital furrow beneath each one of the lateral lobes, a distinct oblong lobe which is characteristic of Foerste's variety clintonensis of this species. This is a common fossil in the heavy layer of gray limestone in the upper part of the Edgewood formation, in Illinois. It is also found in corresponding strata near Edgewood and in the Noix oolite member at Louisiana* Missouri. Dalmanitcs danai Meek and Worthen (Plate VIII, figures 16 and 17) 1865. Dalmania danae. Meek and Worthen, Proc. Acad. Nat. Sci., Philad., p. 264. 1868. Dalmanites danae. Meek and Worthen, 111. Geol. Survey, vol. 3, p. 363, pi. 6, figures la-lf. Meek and Worthen's description : "Attaining a large size, entire outline ovate. Cephalic shield rather compressed, nearly semicircular, about twice as wide as long, rounded in front, and nearly straight or slightly concave in outline behind, with posterior lateral angles produced into mucronate spines extending backwards to the fourth or fifth thoracic segment. Glabella composing rather more than one-third the entire area of the shield, and slightly more convex than the cheeks, including the neck segment, as long as its greatest anterior breadth, and about twice as wide (exclusive of the alae, or fixed cheeks) in front as behind; separated from the cheeks on each side by a well defined furrow ; anterior lobe composing about half its entire area, transversely elliptical, and a little less than twice as wide as long, usually showing in internal casts a shallow pit near the middle of its posterior side ; lateral furrows well defined — anterior one oblique, the other two transverse, and not always strongly defined quite out to the lateral margins ; anterior lateral lobe longer, more oblique, and, at its outer end, wider than either of the other two. Occipital segment widest and most prominent in the middle, scarcely equaling the transverse diameter of the posterior extremity of the glabella; neck furrow well defined, but deepest on each side, and arching a little forward in the middle ; its continuations across the posterior sides of the cheeks broad, deep, and straighter than the posterior margin — extending nearly to the lateral margins of the cheeks, where they curve a little backwards. Cheeks sloping slightly around the outer side to a broad, shallow undefined marginal de- pression, outside of which there is a moderately thick, somewhat rounded border, which does not extend entirely around the front of the glabella, but continues back into the posterior lateral spines. Eyes reniform, not oblique, nearly half as long as the antero-posterior diameter of the front lobe of the glabella, and sit- uated slightly more than their own length in advance of the posterior margin of the cheeks, with (in casts) a moderately distinct marginal furrow around their outer bases; (height and other details unknown) ; palpebral lobes semicircular and depressed. Facial sutures cutting the lateral margins of the cheeks nearly oppo- site the posterior extremities of the eyes, and passing around the antero-lateral and front margins of the glabella so near the anterior border as scarcely to leave any perceptible band connecting the movable cheeks around the front. "Hypostoma obscurely subtrigonal, about one-eighth wider anteriorly than its length, moderately convex ; anterior margin forming a broad, regular, con- vex curve ; lateral margins contracted behind the anterior lateral angles, and 148 BIENNIAL REPORT converging a little posteriorly for about two-thirds the entire length, thence more abruptly to the posterior extremity, which is transversely truncated, and provided on each side with a minute, slightly projecting point, while still farther forward, on each lateral margin, there appears to be traces of another minute slightly pro- jecting irregularity of outline. Around the posterior and lateral margins there is a more or less distinct sulcus, behind which the posterior margin is flattened. Within this marginal sulcus there is, on each side, a little behind the middle, an oblique eye-like depression. "Thorax wider than long, the length being to the breadth as 21 to 28, nearly once and a half as long as the cephalic shield; mesial lobe as wide anteriorly as the posterior extremity of the glabella, and very slightly broader near the middle, where it is about three-fourths as wide as the lateral lobes, from which it is only separated by narrow, rather shallow furrows — most convex along the middle and flattened on each side ; segments not clearly seen in the specimens ex- amined. Lateral lobes somewhat more depressed than the mesial one, and sloping very gradually to the lateral margins. Segments equaling the antero-posterior diameter of the posterior lateral lobes of the glabella; each curving abruptly back- wards at the outer extremity and terminating in a flat, sharply pointed, or lanceo- late projection, most produced in the posterior ones; provided with a deep, well defined, longitudinal furrow, which starts from the anterior side of the inner end, and curves at first a little obliquely outward, and then passes straight out- ward, slightly nearer the posterior than the anterior margin, to the middle of the flattened scythe-shaped outer ends, where they usually curve a little backwards and become obsolete. "Pygidium nearly semielliptic, or subtrigonal, the anterior lateral angles be- ing somewhat rounded, and the lateral margins converging to the more or less pointed posterior extremity, with a broad convex curve ; slightly longer than the cephalic shield, and rather more than two-thirds as wide ; mesial lobe somewhat more convex than the lateral lobes, and two-thirds as wide, gently rounded, and tapering gradually to the posterior extremity where it is apparently continued into an abruptly projecting caudal appendage; segments 12 to 13, straight, well defined (except near the termination) by distinct furrows, which are deeper on each side than at the middle. Lateral lobes with eight or nine well defined arched segments, which become more oblique posteriorly, and are defined to near the edge of the smooth margin ; each divided by a furrow deeper than those between, and like in those of the pleurae, the anterior division being slightly narrower than the other at the inner end. "Surface (of cast) smooth, except traces of small scattering tubercles on the anterior lobe of the glabella. "Length of the largest specimen seen, exclusive of the little caudal append- age (the length of which is unknown), 4.93 inches. Length of pygidium, 1.50 inches ; breadth of same, 2 inches ; breadth of its axillary lobe, 0.55 inch. Length of thorax, 2.05 inches; breadth of same, 3 inches; breadth of its mesial lobe, 0.80 inch. Length of cephalic shield, 1.44 inches; breadth of same, 3 inches; length of posterior lateral spines, near 1.10 inches; length of glabella, exclusive of neck segment, 1.30 inches ; anterior breadth of same, 1.35 inches ; posterior breadth of same, 0.84 inch. Length of eyes, 0.39 inch ; distance of same from posterior margin of cheeks, 0.42 inch. ALEXANDRIAN SERIES 149 "Locality and position : Two miles above Thebes, Alexander County, Illi- nois. Apparently at or near the horizon of the Niagara division of the Upper Silurian." This trilobite is very abundant in a narrow, somewhat shaly zone in the lower part of the Edgewood beds, near Thebes, Illinois, and in the lower layers of this formation near Edgewood, Missouri. It resem- bles D. limulurus (Green), in some respects, but may be distinguished from that species in its larger size, its more obtusely rounded anterior margin of the cephalon, the more convex outline of the lateral margins of pygidium, the fewer number of annulations in the axis of the pygid- ium, and in the shorter and more slender caudal spine. Fossils. from Channahon Limestone Members Coelenterata Anthozoa Zaphrentis ambigua n.sp. (Plate IX, figure 2) Corallum resembling Z. subregularis in having the longitudinal (septal) striae distinctly visible on the exterior, and crossed by very fine transverse lines ; in the alternating curved septa which do not reach the center, and are united at their inner ends into sets of twos and threes. It differs from that species in the longer, more slender and gently taper- ing, and variously flexed mode of growth, and in having the surface marked with frequent prominent transverse ridges and constrictions throughout its length. Septa alternating in size, primary septa forty to fifty, undulating, fasciculate, the inner edges of the bundles extend- ing more than half way to the center, secondary septa very short, dis- tinct only in the calyx, tabulae somewhat irregular, nearly horizontal for about one-third of the diameter of the corallum. Calyx of individ- uals of average size, about 12 to 15 mm. deep, with thin walls and steep slope; diameter about 11 mm. when the length of the corallum is 40 mm. Surface marked by distinct longitudinal septal striae and by numerous ridges and furrows of unequal size, which are covered by numerous very fine transverse lines. The dimensions are: length, 25 to 80 mm.; diameter, 8 to 13 mm. This species is common in the lower part of the Channahon lime- stone in Will County, Illinois, where it is associated with Zaphrentis subregularis, Schuchcrtella curvistriata, Metapoliclias ferrisi and other fossils of this limestone. Coralla thought to represent this species are also common in the Edgewood limestone near Edgewood, and in the Noix oolite member of this formation at Louisiana, near the mouth of Buffalo Creek, and south of Clarksville, Missouri. 150 BIENNIAL REPORT Zaphrcntis subregidaris n.sp. (Plate IX, figure 1) For the description of this species see a previous page of this paper. Coralla referred to this species are numerous in the Channahon limestone in Will County, Illinois. Molluscoidea Brachiopoda Lingulops illinoisensis n.sp. (Plate IX, figures 3 and 4) Shells resemble Lingulops granti Hall and Clarke, of the Niagaran in their subelliptical to obovate outline, in the platform-like muscular area of the valves, in the absence of the median septum in the ventral valve, and in the broad margin of contact around the peripheral portion of the shells, which is grooved for the passage of the pedicle. They differ from L. granti in their uniformly much smaller size, more obovate outline (some of the shells are more strongly obovate than those fig- ured), and the more tapering anterior portion. The posterior extrem- ity is slightly less acuminate than in L. granti; the peripheral margin of contact is broader than in that species, and has not its greatest width beneath the beak of the ventral valve. The muscular platform in the ventral valve is somewhat wider and presents a more distinctly lobate appearance than in shells of the above named Niagaran species, appar- ently consisting of two median lobes extending nearly one-half the dis- tance to the anterior margin, on each side of these are two or three lateral lobes the outer ones of which are successively shorter. The exterior surface of the valves was not seen. The dimensions are : length, 2.5 to 3 mm. ; width, about 2 mm. Shells of this species are common in the Channahon limestone in Will County, Illinois, where they are associated with Cyphaspis inter- media, Proctus channahonensis and other species characteristic of this limestone. Pholidops sub elliptic a n.sp. (Plate IX, figure 5) Shell somewhat resembles the Niagaran species, Pholidops squami- formis Hall, from which it is distinguished by its less quadrate, and more elliptical to ovate outline, and by the absence of any trace of radiating striae. It also differs from P. ovalis Hall in the relatively narrower posterior portion, and in having the apex situated nearer the posterior margin. The shell of P. snbclliptica is depressed convex or almost flat, sub- ovate to subelliptical in outline, about three-fourths as wide as long, ALEXANDRIAN SERIES 151 widest at or anterior to the middle ; the apex pointed and situated about .5 mm. from the posterior margin. Surface marked by strong concen- tric lamellae, with no trace of radiating markings. The dimensions are : length, about 4.5 mm. ; and width, about 3.5 mm. This species is rare in the Channahon limestone in Will County, Illinois, where it is associated with Lingulops illinoisensis, Rhynchotreta intermedia and other Channahon forms. Schuchcrtella curvistriata n.sp. (Plate IX, figure 6) This species was probably derived from 5. missouriensis Shumard, of the Girardeau limestone, which it resembles in the nearly flat shell; in the unequal and somewhat fasciculate character of the radiating striae ; in the distinct upward curving of the striae in the cardino-lateral re- gions ; and in the numerous, very fine concentric markings which are somewhat undulating as they cross the wide, flat spaces between the larger radiating striae. It differs from that species in the larger size, and the greater length in proportion to the width of the shell. The primary radiating striae extend to the beak and are twelve to sixteen in number; between any two of these there are usually intercalated three rather coarse lines, the longest one of which extends nearly to the beak, the one of intermediate length reaches considerably posterior to the middle of the valve, while the shortest one is not conspicuous more than one-third of the distance from the margins. This species also somewhat resembles S. propiuqua of the Edge- wood strata, in size and general appearance, but can be distinguished from it by the upward curving of the radiating striae in the cardino- lateral regions, and in the generally shorter hinge line in proportion to the greatest width of the shell, giving it a more circular outline. The dimensions are: length, 15 to 22 mm.; width, 22 to 28 mm. Shells of this species are very abundant in the limestone exposed near Channahon, in Will County, where they are associated with Mcta- polichas ferrisi, Pterinca elegans and Zaphrentis ambigua. Dalmanella cf. edgewoodensis n.sp. (Plate IX, figure 9; and Plate VI, figures 11, 12, and 13) For description refer to the descriptions of the fossils of the Edge- wood formation. The shells of Dalmanella from the Channahon limestone are slightly more arcuate, and have somewhat more angular plications than those referred to this species from the Edgewood strata of Missouri. They are common in the Channahon limestone in Will County, Illinois. 152 BIENNIAL REPORT Rhipidomella hybrida (Sowerby) (Plate IX, figure 10) 1839. Orthis hybrida. Sowerby, Murchison's Silurian System, p. 360, pi. 13, figure 11. 1843. Orthis hybrida, Hall, Geol. of N. Y., Rept. Fourth Dist., p. 105, figure 7. 1852. Orthis hybrida. Hall, Pal. N. Y., vol. 2, p. 253, pi. 52, figure 4. 1860. Orthis hybrida. Roemer. Die Silurische Fauna des West. Tenn., p. 63, pi. 5, figure 6. 1868. Orthis hybrida. Meek and Worthen, 111. Geol. Survey, p. 371, pi. 7, figure 7. 1889. Orthis hybrida. Nettelroth, Kentucky Fossil Shells: Mem. Ky. Geol. Surv., p. 39, pi. 32, figures 32-35. 1892. Rhipidomella hybrida. Hall and Clarke, Pal. N. Y. vol. 8, pt. 1, pp. 210, 224, pi. 6, figures 1-5. 1895. Orthis (Rhipidomella) hybrida. Foerste, Geol. Ohio, vol. 7, p. 584, pi. 25, figure 10. Shell subcircular in outline, slightly wider than long, hinge line less than two-thirds as long as the greatest width of the shell, valves sub- equally convex. Ventral valve moderately convex, the greatest depth in the umbonal region which slopes rather steeply to the sides ; beak elevated, somewhat arched but not incurved beyond the hinge line, cardi- nal area narrow, triangular. Dorsal valve a little less convex than the ventral, most prominent in the umbonal region which is flat or with a slight depression in the middle portion ; cardinal area narrower, and beak lower and less arched than in the ventral valve. Surface of both valves marked by rather fine radiating striae which divide two or three times between the beak and the margins, and arch upward on the pos- tero-lateral slopes. Sometimes a few rather prominent concentric lines are also present. The dimensions are: length, 7.5 to 11 mm.; width, 9 to 12 mm.; thickness, 1.5 to 3 mm. The surface characters of this species resemble those of Dalman- ella elegantula (Dalman), but the shell is distinguished by the nearly equal size and convexity of the valves, and the absence of a well defined sinus in the dorsal valve. It occurs in the Channahon limestone, in Will County, Illinois. Rhynchotreta lepida n.sp. (Plate IX, figures 16 and 17) Shell small, triangular in outline, valves subequally convex, the greatest width near the front. Ventral valve rather strongly convex in the umbonal region, becoming very gently sloping in front, without fold or sinus ; beak large, elevated, not much incurved. Dorsal valve ALEXANDRIAN SERIES 153 highest near the umbo, the slope becoming gentle in the anterior por- tion, flattened or very slightly depressed in the median umbonal area, the depression sometimes continuing as an undefined sinus from the beak to the front; beak strong, much incurved beneath that of the ventral valve. Surface of each valve marked by about fifteen simple, rounded plications, having rather wide, flat or gently rounded furrows between them ; numerous delicate concentric markings and occasional stronger lines of growth are usually present. The dimensions are : length, 6 mm. ; width, 5.5 mm. ; thickness, 2.5 mm. This species resembles Rhynchotrcta parva of the Edgewood lime- stone in its small size, but differs from that form in the smaller size of the adult shells, the larger apical angle, the more rounded plications and the presence of numerous fine concentric markings. From R. simplex Foerste it may be distinguished by its smaller size, the greater number of plications, and the less flaring and more truncate anterior margin. Shells of this species are not rare in the Channahon limestone in Will County, Illinois. RJiynchotreta intermedia n.sp. (Plate IX, figures 14 and 15) Shells differing from RJiynchotreta thebesensis Foerste in the smaller size, more transverse shape, more prominent fold and sinus and less elevated ventral beak. It is subtriangular in outline, as wide or wider than long, with apical angle about ninety degrees. Ventral valve depressed convex in the umbonal region, with a rather broad, shallow sinus, which widens toward the front, occupying the median portion throughout the anterior two-thirds of the length. The lateral surface on either side of the sinus is almost flat. Beak acute, elevated, little or not at all incurved. Dorsal valve rather evenly convex, with steep cardino-lateral slopes on either side of the beak, somewhat flattened in the medium portion, an ill-defined, almost imperceptible fold is present on the anterior half of the median portion of the shell ; beak acuminate and incurved. Surface of each valve marked by about fourteen simple, subangular, radiating plications, and occasional prominent concentric lines of growth. The dimensions are: length, 13 mm.; width, 14 mm.; greatest thickness, 6 mm. This species is rare in the Channahon limestone in Will County, Illinois. 154 BIENNIAL REPORT A try pat sp. (Plate IX, figures 7 and 8) Separated valves of shells thought to belong to a species of Atrypa occur in the Channahon limestone member of the Edge wood near Chan- nahon, in Will County, Illinois. Whit field ella acuminata n.sp. (Plate IX, figures 11 and 12) Shells resembling Whit field ell a billingsana in the subovate form, and erect, pointed beaks, but distinguished from that species in the larger size and much less strong convexity, and in the produced anterior mar- gin. The new species is somewhat ovate in outline, greatest width near the middle, valves almost equally convex, posterior end acuminate, apical angle of larger shells nearly ninety degrees. Ventral valve mod- erately convex, most prominent in the umbonal region, the postero-lateral slopes abrupt, the convexity over the other portions of the valve nearly uniform, a poorly defined mesial sinus is present for a short distance from the anterior margin where the shell is slightly extended; beak acute, elevated and considerably incurved. Dorsal valve slightly less convex than the ventral, greatest convexity along the median portion where a low indistinct fold appears towards the front margin ; beak acute, incurved beneath that of the ventral valve. Surface without radiating ornamentation ; but marked by numerous concentric lines which are most prominent near the margins. The dimensions are : length, about 20 mm. ; width, about 14 mm. ; thickness, 8 to 9 mm. This species is not rare in the Channahon limestone, in Will County, Illinois, where it is associated with Zaphrentis ambigua, Schnchertella cnrvistriata and Pterinea elegans. Whitfieldella ovoidcs n.sp. (Plate IX, figure 13, and Plate VII, figures 13, 14, and 15) This species is described on an earlier page. It is rather common in the Channahon limestone in Will County, Illinois. Mollusca Pelecypoda Pterinea elegans n.sp. (Plate IX, figure 18) This species resembles P. tJiebesensis Meek and Worthen in size and absence of radiating markings, but differs from that form in its less oblique shape, in the absence of a marginal ridge bordering the ALEXANDRIAN SERIES 155 posterior cardinal margin, and in the shorter and less narrowly rounded extension below the posterior wing. The straight hinge line is a little longer than the greatest width of the shell below, prolonged posteriorly into a mucronate point ; below this the nearly straight posterior margin of the wing rounds gently into the broadly curved basal margin. Anter- ior side somewhat obliquely truncated, a little rounded to the hinge above and slightly gaping. Posterior wing less abruptly flattened from the swell of the umbo than in P. thcbesensis, and separated from the margin below by only a trace of a sinuosity, which is present only in the right valve. Anterior wing short and convex and somewhat rounded as in P. thebcsensis, obscurely defined by a faint furrow extending along the anterior side of the moderately convex beak which is placed about half way between the middle and the anterior extremity. Surface marked by fine and coarser concentric lines. The dimensions are : length, 12 to 17 mm. ; height, 7 to 12 mm. ; convexity, 4 to 6 mm. This species is abundant in the Channahon limestone in Will County, where it is associated with Schuchertella curvistriata and Meta- polichas ferrisi. Callonema pristina n.sp. (Plate IX, figure 20) Shell turbinate, wider than high, consisting of about four volutions which increases rather rapidly in size. The height is about 11 mm., and the width about 14 mm. The whorls are contiguous so that each extends about one-half of its height above the preceding one. They are sub- circular in cross section, w T ith a very slight peripheral angulation or carina, above which the volutions are very slightly flattened. The body whorl comprises more than one-half of the height and is about twice the width of the spire above. It has a faint angulation along the per- iphery, above which the slope is a little less convex than that from the periphery to the umbilical region. The suture is rather deep. The aperture is nearly circular, slightly wider than high. The umbilicus is very small or closed by the inner lip of the aperture. Surface with numerous simple, regular, prominent transverse striae, numbering about six in a distance of 1 mm., which extend slightly backward from the suture and are scarcely deflected in passing over the periphery of the volutions, below which they are equally strong as above, and continue obliquely backward to the umbilical region. No revolving lines are vis- ible. This shell resembles no other known Silurian species of gastropods with which it should be compared. It differs from Isonemia in the less 156 BIENNIAL REPORT strong peripheral carina, and in having the transverse striae equally strong below the peripheral angulation as above. This species occurs in the Channahon limestone member of the Edgewood formation, near Channahon, in Will County, Illinois. Cyclonema daytoncnsis Foerste (Plate IX, figure 21) For the description of this species see an earlier page. This species occurs in the upper part of the Channahon limestone, in Will County, Illinois, and in the Edgewood limestone in Pike County, Missouri, and Alexander County, Illinois. Diaphorostoma UUnoisensis n.sp. (Plate IX, figure 19) Shell small, 5 to 7 mm. high, the width about equaling the height. The spire rising one-third of its height above the outer volution, con- sisting of about three whorls which expand quite rapidly. The volutions subelliptical to subcircular in cross section, the vertical diameter slightly greater than the transverse, narrowly rounded above so as to form a deeply impressed suture, and almost as abruptly rounded on the lower side. Aperture not expanded, only slightly oblique, complete, sub-ellip- tical in outline. Entire surface marked by fine transverse lines, and occasional coarser striae, which pass straight across the volutions in an almost vertical direction. The dimensions are : height of spire, 5 to 7 mm. ; greatest diameter of shell, 5 to 7 mm. This species is not rare in the Channahon limestone in Will County, Illinois. It resembles D. niagarensis var. immatura in its small size and general appearance, but differs from that form in the more nearly equal width and height of the spire, and the more nearly circular cross section of the volutions. Cephalopoda Dawsonoceras tenuilineatum n.sp. (Plate IX, figure 22) This species differs from Dawsonoceras annulatum Sowerby, of the Niagaran limestone, in having the slopes of the annulations subequal, and the furrows or interspaces symmetrical, and in having the surface marked with very fine, somewhat undulating longitudinal striae (about ten in a width of 1 mm.) crossing the ridges and furrows. Shell moderately large, gradually expanding, with prominent an- nulations, of which five occur in a distance of 25 mm. where the largest diameter of the shell is one inch. The ridges and intervening furrows ALEXANDRIAN SERIES 157 are symmetrical, marked by unequal transverse striae some of which are subimbricating. Very fine undulating, longitudinal lines cover the entire surface. This species is common in the Channahon limestone, in Will County, Illinois, and specimens that are thought to represent this species were also found in the Edgewood strata in Pike County, Missouri. Arthropoda Trilobita Proetus channahonensis Weller (Plate IX, figure 25) 1907. Proetus channahonensis. Weller. Bull. Chicago Acad, of Sci., No. 4, pt. 2, p. 228, pi. 20, figures 6, 7. Weller's description : "Head moderately convex, semi-circular in outline, the length of the genal spines not determined. Glabella semi-elliptical in outline, de- pressed convex, defined by distinct but not deep dorsal furrows ; first and second lateral furrows obsolete or faint, nearly transverse in direction and not contin- uous across the median portion of the glabella, posterior furrows not deeply im- pressed but always present, they originate at the dorsal furrows opposite the eyes and extend obliquely inward and backward with a slight convex curve nearly to the occipital furrow, their posterior extremities dividing the glabella into three nearly equal parts. Occipital furrow narrow, well defined, including a pair of small subovate occipital lobes back of the postero-lateral angles of the glabella. Occipital segment rather narrow, its surface somewhat depressed below the gla- bella. Surface of the cheeks sloping with an even convex curve from the dorsal furrows laterally and anteriorly to within about one millimeter of the margin, outside this convex slope is an even, flattened, continuous marginal border which continues around the anterior margin of the head ; along the posterior margin of each cheek is a strong posterior cheek furrow which is continuous from the dorsal furrow opposite the occipital furrow to the inner side of the marginal border. The anterior extremity of the glabella is separated from the marginal border by a narrow band which is continuous with the convex portion of the cheeks on either side. The fixed cheeks are narrow with the palpebral lobes rising directly from the dorsal furrows. Free cheeks broad, the eyes of moderate size, their surface describing about a semi-circle, their anterior extremities at about the mid-length of the glabella. "Pygidium semi-elliptical in outline, the axis strongly convex, bordered by the sharp dorsal furrows, occupying nearly one-third the entire width of the pygidium at the anterior margin, tapering posteriorly and terminating in a bluntly rounded extremity lying within the marginal border, divided into ten or eleven rounded annulations which become faint posteriorly. Surface of the pleura slightly flattened adjacent to the dorsal furrows and then becoming moderately convex to the lateral margins, the thickened marginal border narrow and scarcely differentiated from the general surface, becoming a little wider posteriorly ; each slope is divided into nine segments which become faint posteriorly, the last two being scarcely recognizable, the anterior-most segments extend entirely to the 158 BIENNIAL REPORT lateral margin but the posterior ones terminate within the margin, in some speci- mens the broader segments are faintly grooved but in others no grooves can be detected. "The surface of both head and pygidium are smooth. "The dimensions of a nearly complete head with the exception of the genal spines and occipital segment are : width 15 :5 mm. ; length, along median line 9 mm. ; width of glabella at occipital furrow 6.5 mm. The dimensions of a very perfect pygidium are : width 10 mm. ; length 6.5 mm. ; width of axis at anterior margin 3 mm. ; length of axis 5.5 mm. "Location : Channahon, Will County, Illinois." This species closely resembles P. determinatus Foerste, but differs from that form in the slightly more prominent glabella and deeper glabellar furrows. It is very common in the limestone near Channahon, Illinois. Cyphaspis intermedia Weller ( Plate IX, figure 26) 1907. Cyphaspis intermedia. Weller, Bull. Chicago Acad, of Sci., No. 4, pt. 2, p. 231, pi. 20, figures 3-5. Weller's description : "Glabella semi-elliptical in outline, about three- fourths the length of the head, rounded in front and truncate behind, strongly convex longitudinally and transversely, surrounded laterally and anteriorly by a narrow but well defined dorsal furrow, the bottom of which is a little impressed below the inner margin of the cheeks ; at the base of the glabella are a pair of small but well-defined lateral lobes which extend about half way up the sides of the glabella, they are separated from the main portion of the glabella by the posterior glabellar furrows which originate at the dorsal furrows about two-thirds the distance from the anterior extremity of the glabella to the occipital furrow, they describe a slight curve obliquely backward and inward, meeting the occipital furrow about half way between its middle point and the dorsal furrows ; a sec- ond pair of lateral furrows are slightly impressed in the sides of the glabella just above the dorsal furrows, just in front of the mid-length of the glabella. The occipital furrow is narrow and shallow. The occipital segment is narrow and flat, its surface being considerably depressed below the glabella. The fixed cheeks extend nearly horizontally from the dorsal furrows into the palpebral lobes which lie opposite the outer extremities of the posterior glabellar furrows; in front and back of the palpebral lobes the surface slopes away rather abruptly from the dorsal 'furrows and is continuous around the anterior extremity of the gla- bella as a rather broad, slightly convex, sloping area between the dorsal furrow and the marginal border. Marginal border sharply defined and rather broad. Free cheeks not preserved in any of the species observed. Thorax and pygidium unknown. Entire surface of the cranidium covered with fine papillae which are more crowded upon the cheeks, being nearly obsolete upon the marginal border, "The dimensions of the best preserved specimen, a cranidium, are : length 5 mm. ; width between the margins of the palpebral lobes, approximately 5.7 mm. ; length of glabella and occipital segment 4.25 mm.; convexity of glabella 1.2 mm. "Locality : Channahon, Will County, Illinois. ALEXANDRIAN SERIES 159 Glabellae of this species are common in the limestone near Chan- nahon, in Will County, Illinois. This form differs from C. clintonensis Foerste, mainly in the proportionately shorter glabella. Metapolichas ferrisi Weller (Plate IX, figures 23 and 24) 1907. Metapolichas ferrisi. Weller, Bull. Chicago Acad.' of Sci., No. 4, pt. 2, p. 224, pi. 22, figures 12, 13. Weller's description : "Entire body sub-elliptical in outline. Cranidium sub- triangular in outline, broadly rounded or sub-truncate in front. Glabella depressed- convex, about as wide as long, bordered laterally by shallow but well-defined dorsal furrows, narrowest a little back of a line joining the eyes, a little broader at the occipital segment than in front; median lobe occupying the entire width of the glabella in front, rapidly becoming narrower posteriorly until in line with the eyes it occupies only one-third the width of the glabella, posteriorly it is nearly confluent with the third lateral lobes externally ; first lateral furrows strong and well defined, curving from just back of the antero-lateral extremities of the median lobe, backward and inward, nearly parallel with the dorsal furrows to a point just back of the line joining the eyes, where they are continuous with the third lateral furrows, making a sharp turn outward and forward around the posterior extremities of the anterior lateral lobes, this inner well-defined portion of the third lateral furrows is short, being continued obliquely forward to the dorsal furrows as slight depressions which are sometimes almost obsolete ; second lateral furrows represented by slight indentations of the anterior furrows into the inner sides of the anterior lateral lobes at about the middle of their length ; anterior lateral lobes compound, sub-elliptical in outline, the longer axis a little more than twice the shorter, directed outward and forward, confluent posteriorly towards the dorsal furrow with the third lateral lobes; third lateral lobes much smaller than the anterior ones, ill-defined, separated from the median lobe by slight depressions only, which may sometimes be almost obsolete, from the anterior lateral lobes they are sharply separated within but laterally towards the dorsal furrows they are almost wholly confluent. Occipital furrow shallow, rather broad and ill-defined in the center, becoming more strongly defined laterally where it divides, the two divisions on each side surrounding a small, sub-ovate or slightly sub-rhombic occipital lobe. Occipital segment rather broad and flattened in the middle, a little narrower and more convex laterally. Fixed cheeks very narrow in front of the eyes, connected anteriorly around the front of the glabella by a narrow, flat, marginal border, back of the eyes they are much broader and are produced laterally, they are crossed near the posterior margin by the well-de- fined posterior cheek furrows, between the eyes and the posterior cheek fur- rows the surface is gently convex and slopes laterally and posteriorly. Palpebral lobes small, free cheeks unknown. "The thorax is represented in the specimens studied only by detached and broken segments. The axis is apparently broad and depressed-convex. "Pygidium depressed-convex, semi-elliptical in outline ; the axis depressed, but little elevated above the surface of the pleura, occupying more than one-third of the entire width of the pygidium anteriorly, crossed anteriorly by two transverse furrows, the first of which is much better defined and continuous across the entire width of the axis, the second one is less sharply defined, and is not con- 160 BIENNIAL REPORT tinuous across the median portion of the axis, each of the two lateral portions curving backward toward their inner extremities ; posteriorly the axis is produced into a depressed post-axial region, the dorsal furrows converge posteriorly to about the middle of the pygidium where the axial region is about one-half its width at the anterior margin, from here the dorsal furrows diverge posteriorly, the axial region again becoming broader, the furrows do not reach the posterior margin of the pygidium so that the axial region is coalescent posteriorly with the pleural segments on either side. The pleura are divided into three pairs of broad grooved segments, the posterior-lateral angles of the two anterior pairs project slightly beyond the border of the pygidium as posteriorly projecting free points, between the free points of the second pleural segments the border is continuous. "The entire surface of the head, pygidium and thoracic segments is covered with small, more or less irregular, rounded papillae. "The dimensions of the best preserved cranidium observed are : length 17.5 mm. ; approximate width between the eyes 18.5 mm. ; width at posterior margin 30 mm. ; width of median lobe of glabella in front 13 mm. The best preserved pygidium has the following dimensions : length 16 mm. ; width 24 mm. ; width of axis at anterior -margin 9 mm.; width of axial region at narrowest point 4 mm. "Locality : Near Channahon, Will County, Illinois." This species is very closely allied to M. breviceps var. clintonensis in the lobation of the glabella, which shows a small, oblong lobe in the occipital furrow beneath each of the lateral lobes, and in the presence of a third pair of lateral glabellar lobes. It is very abundant in the limestone near Channahon, in Will County, Illinois. Ostracoda Lepcrditia illinoisensis n.sp. (Plate IX, figure 27) Shell differing from Lepcrditia faba Hall, of the Niagaran, in being shorter and more nearly circular in outline, and in having the greatest convexity near the middle. The valves are subequally convex, and over- lapping; hinge line central, 1 mm. long; about one-half the greatest length of the shell. Width of the valve, 1.25 mm.; length about 2 mm. The anterior and posterior ends subequally convex and the base reg- where it is associated with Dalmanella cf. edgewoodensis, Proetus chan- nalwncnsis, and Cyphaspis intermedia. ularly rounded, surface smooth. This species occurs in the upper layers of the Channahon limestone, where it is associated with Dalmanella cf. edgewoodensis, Proetus chan- nahonensis, and Cyphaspis intermedia. PLATES Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Figs. 7 Fig. 9. PLATE III Fossils from the Girardeau Limestone Ptychcrifius splendens (S. A. Miller), page 95 View of the type specimen, X 2 (after Wachsmuth and Springer). Cyclocystoides illinoiscnsis Miller and Gurley, page 96. Outer rim of specimen, and a fragment of the outer rim of another speci- men, (after M. and G.) Nematopora fragilis Ulrich, page 99. A fragment showing mode of branching, X 6. Nematopora dclicatula Ulrich, page 98. A portion of a branch, X 6. Nematopora rctrorsa Ulrich, page 99. A fragment of a branch, X 6. Nematopora alternata Ulrich, page 98. A portion of a branch, X 6. Lingulops oiata n. sp., page 100. 7 and 8. View of a complete ventral valve, X 4. Rafinesquina? dclicatula n. sp., page 100. View of the type specimen, ventral valve, X 2. Rafinesquina f mcsicosta (Shumard), page 101. Fig. 10. View of an entire ventral valve, X l 1 /^. Lcptccna rhomboidalis (Wilckens), page 101. Fig. 11. View of an incomplete ventral valve, X l/ 2 . Schuchcrtella missouricnsis (Shumard), page 102. Fig. 12. Ventral view of a nearly complete shell. Fig. 13. Dorsal view of another specimen, both X \y 2 . Dalmanclla modcsta n. sp., page 102. Fig. 14. View of dorsal valve, X 2. Fig. 15. View of type specimen, ventral valve, X 2. Homocspira immatura n. sp., page 105. Fig. 16. View of ventral valve, X \]/ 2 . Fig. 17. View of another (imperfect) ventral valve, X \y 2 . Fig. 18. View of typical specimen, dorsal valve, X 2. Protozcuga siilcocarinata n. sp., page 105. Fig. 19. View of type specimen, dorsal valve. Fig. 20. Lateral view of the same shell. Fig. 21. The same, ventral valve, all X 6. Rhynchotrcma? illinoiscnsis n. sp., page 103. Ventral view of the type specimen. Dorsal view of same, X \]/ 2 . Camarotccchiaf festinata n. sp., page 104. Dorsal view of the type specimen. Anterior view of the same shell, all X l/ 2 . Fig. 26. Ventral view of the same specimen. Fig. 22. Fig. 23. Fig. 24. Fig. 25. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 23, PLATE III PLATE IV. Fossils from the Girardeau Limestone Pterinea formosa n. sp., page 106 Fig. 1. View of left valve of type specimen, X 2. Modiolopsis concinna n. sp., page 107. Fig. 2. View of left valve of type specimen, X 2. DiapJwrostoma niagarensis var. immatura n. var., page 108. Dorso-lateral view of type specimen. cf. Cyclonema canccllata Hall, page 108. Lateral view of a nearly complete specimen. Conradella sp., page 107. Dorsal view of an imperfect specimen, X 3^4. Comulites tenuistriatus (Meek and Worthen), page 97. Lateral view of the type specimen. Comulites incurvus (Shumard), page 97. Lateral view of a small specimen, with a portion enlarged, X 5 (after Shu- mard). Calymene dubia n. sp., page 112. Dorsal view of an entire pygidium. Dorsal view of an incomplete cranidium of the typical specimen. Encrintirus dcltoideus Shumard, page 111. Fig. 10. Dorsal view of a pygidium, X 2. Acidaspis halli Shumard, page 110. Fig. 11. Dorsal view of a cranidium, slightly enlarged. Fig. 12. Ventral view of an almost entire individual, X 2. Cyphaspis girardeauensis Shumard, page 109. Fig. 13. Dorsal view of a cranidium, X 4 (after Shumard). Proetus princeps n. sp., page 108. Fig. 14. Dorsal view of the almost entire cranidium, of type specimen, X 3. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 9. Fossils from the Edgewood Limestone Calvinia edgewoodcnsis n. gen. n. sp., page 116. Fig. 15. View of the upper surface of the corallum of type specimen, natural size. Fig. 16. Longitudinal section of a portion of another corallum, X 2. Fig. 17. Transverse section of a portion of the same corallum, X 4. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 23, PLATE IV / t \ 10 j 4 l / 2 . Transverse section of a few corallites of same, X 3. Zaphrentis cf. stoke si Milne-Edwards and Haime, page 113. Lateral view of a corallum. Zaphrentis subregularis n. sp., page 113. Lateral view of the type specimen. Lyellia thebesensis Foerste, page 116. Longitudinal section of a portion of a corallum, X 4. View of the surface of a corallum of usual size. Clathrodictyon vesiculosum Nicholson and Murie, page 117. Fig. 8. Vertical section, X 9. Favositcs subelongus n. sp., page 114. Fig. 9. View of the upper surface of a corallum, natural size. Fig. 10. Longitudinal section of the corallum of the type specimen, natural size. Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 23, PLATE V V 4 .>._,.^^' Fig. 1. Fig. 2, Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PLATE VI Fossils from the Edgewood Limestone Schuchertella propinqua (Meek and Worthen), page 120. Ventral view of an exfoliated shell. Schuchtertella missouriensis var. convcxa n. var., page 121. View of the ventral valve of the type specimen, X l/ 2 . LcptcB rhomboidalis (Wilckens), page 101. Ventral view of an incomplete shell. Brachyprion stropheodontoides n. sp., page 119. View of the ventral valve of the type specimen, and a profile view showing the convexity of the same, X 1^. Brachypvion latisculptilis n. sp., page 118. View of the ventral valve of the typical specimen, X 2. Rafinesquina? mcsicosta var. mcsistria n. var., page 118. View of the ventral valve of type, X 1^. Orthis flabcllites var. fissiplicata Foerste, page 122. Ventral view of an entire valve, X 1^. Platystrophia daytoiiensis Foerste, page 122. Fig. 8. Dorsal view of a complete shell. Rhipidomella tenuilineata n. sp., page 123. Fig. 9. View of the dorsal valve of the type specimen, X 2. Fig. 10. Ventral view of another shell, X 2. Dahnanella cdgewoodensis n. sp., page 123. Fig. 11. Lateral view of the type specimen. Fig. 12. View of dorsal valve of same shell. Fig. 13. Ventral view of the same shell. Atrypa prccmarginalis n. sp., page 129. Fig. 14. View of dorsal valve of the type specimen, X \ 1 /t,. Fig. 15. Ventral view of same, X \y$. Fig. 16. View of ventral valve of another shell, X V/3. Hindella? ambigua n. sp., page 133. Fig. 17. Lateral view of the type shell. Fig. 18. Dorsal view of the same. Rhyuchotreta thebesensis Foerste, page 126. Fig. 19. Ventral view of a specimen of average size. Fig. 20. Dorsal view of the same shell. Rhynchotrcta thebesensis var. multistriata n. var., page 127. Fig. 21. Ventral view of the type specimen. Fig. 22. View of the dorsal valve of the same shell. Homocospira jiscello striata n. sp., page 132. Fig. 23. View of the ventral valve of the type specimen, X 2. Fig. 24. View of the dorsal valve of the same shell, X 2. Atrypa putilla (Hall and Clarke), page 130. Fig. 25. Dorsal view of an entire shell, X 2. Homocospira subcircularis n. sp., page 132. Fig. 26. Dorsal view of the type specimen, X 2. Fig. 27. View of the ventral valve of the same shell, X 2. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 23, PLATE VI PLATE VII Fossils from the Edgewood Limestone Camarotocchia? antiqua n. sp., page 128. Fig. 1. Ventral view of the type specimen. Fig. 2. Dorsal view of the same shell. cf. Rhynchonellaf janea Billings, page 128. Fig. 3. Dorsal view of an almost complete shell. Camarotocchia? concinna n. sp., page 127. Fig. 4. Dorsal view of the type specimen, X 2. Fig. 5. Ventral view of the same shell, X 2. Protozeuga sulcocarinata n. sp., page 105. Fig. 6. Dorsal view of complete shell, X 9. Clorindaf thebesensis n. sp., page 125. View of the ventral valve of the type specimen. View of the dorsal valve of another individual. Rhynchotreta parva n. sp., page 125. Ventral view of the type specimen, X l/ 2 . Dorsal view of the same shell, X l/ 2 . Whitficldclla? billingsana (Meek and Worthen), page 134. Dorsal view of the type specimen. Ventral view of another specimen. Whitfieldella ovoides n. sp., page 134. Ventral view of the type specimen. Dorsal view of another typical shell. Lateral view of the same shell. Whitficldclla speciosa n. sp., page 135. View of dorsal valve of the typical specimen. View of ventral valve of the type, both X \ l / 2 . Pcntamcrus parvulus n. sp., page 124. View of the ventral valve of the type specimen, X 2. View of the interior of the same, showing the spondylium, X 2. View of the dorsal valve of another shell, X 2. View of the interior of same showing the septum and spondylium, X Spirifcr (Dclthyris) sp., page 131. Fig. 22. View of an incomplete ventral valve, X 2. Atrypa tubulistriata n. sp., page 131. Fig. 23. View of ventral valve of the type specimen. Fig. 24. View of the dorsal valve of the type, both X 1*4. Ctcnodonta subelliptica n. sp., page 136. Fig. 25. View of the left valve of the type specimen, X l/ 2 . Cypricardinia siibquadrata n. sp., page 138. Fig. 26. View of the right valve of the type. Colpomya abrupta n. sp., page 137. Fig. 27. View of the left valve of the type specimen, X H. Ptcrinea thebesensis M. and W., page 136. Fig. 28. View of the left valve of the type specimen. Straparollus pumilis 11. sp., page 142. Fig. 29. Lateral view of the type specimen, X 5. Holopca 111 inn ta n. sp., page 143. Fig. 30. Lateral view showing aperture, type specimen, X 6. Lophospira thebesensis n. sp., page 140. Fig. 31. Lateral view of the type specimen. Fig. 7. Fig. 8. Fig. 9. Fig. 10. Fig. 11. Fig. 12. Fig. 13. Fig. 14. Fig. 15. Fig. 16. Fig. 17. Fig. 18. Fig. 19. Fig. 20. Fig. 21. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 2$, PLATE VII Odd 10 a 4> 4> 11 12 16 13 0*0 14 iy 18 # 22 15 *4> 21 23 20 24 <2 C ^ :>> 27 25 26 28 29 a 30 31 PLATE VIII Pii Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig- Fig Fig Fig Fig- Fig Fig- Fig Fig Fossils from the Edgewood Limestone Diaphorostoma niagarensis (Hall), page 144. Lateral view of a somewhat imperfect cast, X 2. Bellerophon consimilis n. sp., page 140. Dorsal view of the cast of the type specimen. Poleumita bellasculptilis n. sp., page 143. Lateral view of the type specimen, X 2. Cycloncma daytonensis Foerste, page 142. View of a shell of normal size. Liospira cf. affinc (Foerste), page 138. Lateral view of a specimen of about the average size, X 1J. Bellerophon cf. exiguus Foerste, page 141. Dorsad view of a cast of shell. Lophospira faseiato n. sp., page 139. Lateral view of the type specimen. Lateral view of the upper portion of the spire. Hormotoma tenera n. sp., page 139. 9. View of the type specimen, X 2. Proctus determinatus Foerste, page 145. 10. Dorsal view of an incomplete cranidium, X 2>4. 11. Dorsal view of an almost entire pygidium, X \ 2 /^. Cyphaspis intermedia Weller, page 158. 12. Dorsal view of an almost complete cranidium, X iy 2 . Metapolichas breviceps var. elintonensis (Foerste), page 146. 13. Dorsal view of an imperfect cranidium, X 2 l / 2 . 14. Dorsal view of an almost perfect pygidium. Isotelus longcevus n. sp. page 144. 15. Dorsal view of cranidium of the type specimen, X 2. Dalmanites danai Meek and Worthen, page 147. 16. Dorsal view of a cephalon of a little above the average size. 17. Dorsal view of a complete pygidium of another individual. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 23, PLATE VIII «■• » Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 9. Fig. 10. Fig. 11. Fig. 12. PLATE IX Fossils from the Channahon Limestone Zaphrentis subregularis n. sp., page 113. Lateral view of a specimen of moderate size. Zaphrentis ambigua n. sp., page 149. View of the type specimen. Lingulops iUinoisensis n. sp., page 150. View of the cast of the interior of ventral valve, X 7. View of the interior of the ventral valve of the type specimen, X 7. Pholidops subelliptica n. sp., page 150. View of surface of ventral valve of type specimen, X A]/ 2 . Schuchertella curvistriata n. sp., page 151. View of the dorsal valve of the type specimen. Atrypa? sp., page 154. View of the ventral valve of a specimen of average size, X 4^4. View of a dorsal valve of another individual, X 3^2. Dalmanella edyewoodcnsis n. sp., page 123. View of a complete ventral valve, X l/ 2 . Rhipidomella hybrid a (Sowerby), page 152. View of the ventral valve of an average specimen. IVhitficIdclla acuminata n. sp., page 154. View of the dorsal valve of the type specimen. Ventral view of the same shell. IVhitficIdclla oroides n. sp., page 134. Fig. 13. View of a nearly complete ventral valve. Rhynchotreta intermedia n. sp., page 153. Ventral view of the type specimen. Dorsal view of the same shell. Rhynchotreta lepida n. sp., page 152. View of the ventral valve of the type specimen, X 2. Dorsal view of the same shell, X 2. Ptcrinca elegans n. sp., page 154. View of the left valve of the type specimen, X 1^. Diaphorostoma iUinoisensis n. sp., page 156. Lateral view of the type specimen, X \ l / 2 . Calloncma pristina n. sp.. page 155. Lateral view of the type specimen, X 1 T 4- Cycloncma daytonensis Foerste, page 142. View of a nearly- complete individual of moderate size. Dawsonoccras tcnuilincatum n. sp., page 156. Longitudinal view of a portion of the type, at about one-half the greatest diameter. MetapolichaS fcrrisi Weller, page 159. Dorsal view of a nearly complete cranidium, X l 2 /^. Dorsal view of an entire pygidinm. Proetus channahonensis Weller, page 157. Dorsal view of a nearly complete cranidium, X \ 2 /$. Cyphaspis intermedia Weller, page 158. Dorsal view of an almost entire cranidium, X 2. Lcperditia iUinoisensis n. sp., page 160. View of the left valve of the type specimen. Fig. 14. Fig. 15. Fig. 16. Fig. 17. Fig. 18. Fig. 19. Fig. 20. Fig. 21. Fig. 22. Fig. 23. Fig. 24. Fig. 25. Fig. 26. Fig. 27. ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN NO. 2$, PLATE IX INDEX Page Acidaspis halli Shumard 110 Alexander County, Alexandrian series in 69, 72 Sexton Creek limestone in 87 silica from 42 Alexandrian series, Channahon limestone of 84-86, 149-160 definition of 68 distribution of 69 Edgewood limestone of. .75-86, 113-160 Essex limestone of 86-87 Girardeau limestone of. . .73-75, 95-112 Sexton Creek limestone of .. .68, 87-91 stratigraphy of 72-94 Analyses of : artesian water 64 coal No. 2 62 Illinois coals 14 Annulosa in Girardeau limestone. 97-98 Anthozoa in : Channahon limestone 149-150 Edgewood formation 113-117 Artesian water, occurrence of 63-65 Artesian wells in La Salle-Henne- pin quadrangles 58, 64, 65 Arthropoda in : Channahon limestone 157-160 Edgewood formation 144-149 Girardeau limestone 108-112 Atrypa? sp. 154 praemarginalis n.sp 129 putilla (Hall and Clarke) 130 tubulistriata n.sp 131 Bartow, Edward, work of 12 Bellerophon consimilis n.sp 140 exiguus Foerste 141 Big Muddy Valley, maps of 16 Birmingham, drilling near 49 Black Hollow, clays from 62 Blatchley, R. S., work of 12,15 Bleininger, A. V., work of 12 Bowling Green limestone 77 Brachiopoda in : Channahon limestone 150-154 Edgewood formation 118-136 Girardeau limestone 100-106 Brachyprion latisculptilis n.sp 118 stropheodontoides n.sp 119 Brassfield limestone, see Sexton Creek limestone. Page Bryozoa in : Edgewood formation 118 Girardeau limestone 98-99 Bureau, artesian wells at 65 sand and gravel from 61 Bureau County, see Hennepin quad- rangle. C Cady, G. H, work of 12,16 Calhoun County, Alexandrian series in . 69 Essex limestone in 86 Callonema pristina n.sp 155 Calopoecia favositoidea n.sp 115 Calrinia nov.gen 115 edgewoodensis n.sp 116 Calymene dubia n.sp 112 Camarotoechia? antiqua n.sp 128 concinna n.sp 127 festinata n.sp 104 Carbondale formation in western Illinois 46 Carlinville, oil and gas near 15, 33 Carlyle oil field 15,33 Cedar Point, artesian wells at 65 Cement, production of 41 Centralia-Sandoval oil field 33 Cephalopoda in Channahon lime- stone 156-157 Channahon, section of limestone near 84 Channahon limestone 84 description of fossils from 149-160 Carbondale formation in western Illinois 46 Chester formation, studies of 14, 48 Clathrodictyon vesiculosum Nichol- son & Murie 117 Clay, in Hennepin and La Salle quadrangles 62 production of 38 studies of 15, 16 Clay products, production of 38 Clorinda? thebesensis n.sp 125 Coelenterata from : Channahon limestone 149-450 Edgewood formation 113-117 Coal, in Hennepin-La Salle quad- rangles 62 production of 29 production by counties 30-31 production in Illinois since 1853.. 28 studies of 14-16 INDEX— Continued Page "Coal Measures," in Hennepin-La Salle quadrangles 60-61 sandstone from 39 Coal Mining Investigations, estab- lishment of 12 Coal No. 1 in western Illinois 47 Coal No. 2, analyses of, from Hen- nepin-La Salle quadrangles ... 62 in Colchester-Macomb quad- rangles 46, 48 Coke, production of 32 Colchester, formations near 46, 47 Colchester-Macomb qu a d r a n g 1 e s , geology of 45-50 Collins well No. 1, log of 52-53 Cook County, clay products in 38 Cooperation with : Department of Applied Chemis- try 14, 15 Department of Ceramic Engineer- ing ; 15 Mining Engineering Department. 14 U. S. Bureau of Mines 14 U. S. Geological Survey 14, 26, 55 University of Illinois 14 Cooperative Coal Mining Investiga- tions, establishment of 12 Colpomya abrupta n.sp 137 Conradella sp 107 Cormilitcs incurvus (Shumard) .... 97 tenuistriatus (Meek & Worthen) . 97 Crawford County, natural-gas gaso- line from 37 oil wells drilled in 34 Crinoidea in Girardeau limestone. .95-96 Ctenodonta subeUiptica n.sp 136 Cumberland County, overflowed lands in 17 Custer Park, Sexton Creek lime- stone near 89 Cycloncma cancellata Hall 108 daytoncnsis Foerste 142, 156 Cyclocvstoidcs illiuoiscnsis (Miller & Gurley) 96 Cyphaspis intermedia (Weller) . 146, 158 girardeauensis Shumard 109 Cypricardinia subquadrata n.sp 138 Cyrene limestone member 76,78-79 D Dalmanella edgewoodensis n.sp 123 cf. edgewoodensis n.sp 151 modesta n.sp 102 Dahnanites danai Meek & Worthen 147 Dawsonoceras tenuilineatum n.sp... 156 Deep borings, studies of 21 Page Deep drilling near Birmingham.... 49 Deer Park, artesian wells at 64 clays from 62 Depue, artesian wells at 65 sand and gravel from 61 Devonian formation, artesian water from 65 limestone from 40 silica from 42 Diaphorostoma illinoisensis n.sp 156 niagarensis Hall 144 niagarensis var. immattira n.var. . 108 Drainage surveys and maps. ... 16, 18-20 E Early Wisconsin drift 61 Echinodermata in Girardeau lime- stone 95-96 Edgewood limestone : Bowling Green member of 77 Channahon limestone of 84 Cyrene member of 76 Noix oolite of 77 occurrence and stratigraphy of . . . 75 paleontology of 113-160 section of, at or near : Edgewood, Missouri 81 Gale 79 Louisiana, Missouri 81 Thebes 78 Educational bulletins 16 Embarrass Valley, reclamation in.. 16 Encrinurus deltoidcus Shumard.... Ill Essex, section of limestone near. ... 86 Essex limestone, occurrence and stratigraphy of 86 paleontology of 87 Expenditures by Survey 22-23 F Farosites snbelongus n.sp 114 Financial statistics of Survey 22-23 Fluorspar, production of 41 Fossils, comparative tables of.. 82, 83, 85 descriptions of species from : Channahon limestone 149-160 Girardeau limestone 95-112 Edgewood formation 113-149 in Edgewood limestone 78, 79 in Essex limestone 87 in Girardeau limestone 74 in Sexton Creek limestone 90-91 Franklin County, coal in 29 Fulton County, overflowed lands in 17 G Gale, section of Edgewood forma- tion near 79 INDEX— Continued Page Gallatin County, overflowed lands in 17 Galena dolomite, lead and zinc in. . . 43 Galena region, bulletin on 21 Galena-Trenton limestone, water from 65 in H e n n e p i n-L a S a 1 1 e quad- rangles 60 Gas in surface deposits 48 Gas, see Oil and gas. Gasoline, production from natural gas 37 Gastropoda in Girardeau lime- • stone 107-108 Geological Survey, organization of. 11 expenditures of 22-23 Girardeau limestone, occurrence and stratigraphy of 73 paleontology of 95-149 Glacial deposits in Hennepin-La Salle quadrangles 59, 61 Glass sand 41, 63 Grant, U. S., work of 12 Gravel, see Sand and gravel. Griggsby well Xo. 1, log of 53 H Hancock County 45 Hamburg, Sexton Creek limestone near 88 Hardin County, fluorspar from.... 42 lead and zinc in 43 overflowed lands in 17 Hardinville quadrangle, investiga- tion of 15 Hennepin, artesian wells at 65 Hennepin quadrangle, see La Salle- Hennepin quadrangles. Hindella ambigua n.sp 133 Hoing well No. 1, description of. . .51, 52 Holopea niinuta n.sp 143 Homeospira fiscellostriata n.sp 132 immature! n.sp 105 subcircularis n.sp 132 Honnotoma tencra n.sp 139 Hydrozoa in Edgewood formation. 117 I Illinois, mineral products of 26, 27 Illinois River valley 59 Illinois State Museum, fossils loaned by 95 Isotelus longaei'us n.sp 144 Page J Jasper County, overflowed lands in. 17 Tersey County, Alexandrian series in 69 Essex limestone in 88 Joliet, production of coke at 32 K Kankakee County, Alexandrian series in 69 Essex limestone in 86 Kaskaskia Valley, maps of 16 Kay, F. H., work of 12 Kirkwood sand 33 La Salle, artesian wells at 65 glass sand at 41, 63 sand and gravel from 61 La Salle anticline, oil in 33 in La Salle-Hennepin quadrangles 60 La Salle County : natural cement from 41 Portland cement rock in 63 La Salle-Hennepin quadrangles, investigations in 55-63 Lawrence County, natural-gas gaso- line from 37 petroleum in 33 Lead, zinc, and silver production of 43 Leperditia illinoisensis n.sp 160 Lcptaena rhomboidalis (Wilckens) . 101,120 Lime, production of 40 Limestone, from upper Illinois Val- ley 41,61,63 production of , 39 Lindgren, J. M., work of 12, 16 Lingulops illinoisensis n.sp 150 oi ata n.sp 100 Liospira cf. affine (Foerste) 138 Logs of Collins, Hoing, Griggsby wells 52,53 Lophospira fasciata n.sp 139 thebesensis n.sp 140 Lowell, clays from 62 Lower Magnesian limestone in : La Salle and Hennepin quad- rangles 61, 63 La Salle County 41 Lxcllia thebesensis Foerste 116 M Macomb quadrangle, see Colches- ter-Macomb quadrangles. INDEX— Continue d Page McClosky sand in Lawrence County 33 McDonough County 45 McFarland, D. F., work of 12 McLeansboro limestone for flux... 40 Metapolichas breviceps var. clinton- cnsis (Foerste) 146 ferrisi Weller 159 Mineral, paint 44 products of Illinois 27 resources in Illinois in 1911 and 1912 26-44 statistics 26 water, production of 42 Mining Engineering Department, cooperation with 14 Mississippian brachiopods 21 Mississippian series, near Colches- ter . . 47 Keokuk limestone of 48 limestone quarries in 40 oil in 33 St. Louis limestone of 47 Modiolopsis concinna n.sp 107 Mollusca in : Channahon limestone 154-157 Edgewood formation 136-144 Girardeau limestone 106-108 Molluscoidea in : Channahon limestone 150-154 Edgewood formation 118-136 Girardeau limestone 98-106 Murphysboro coal in Western Illi- nois 46,48 N Natural gas, as source of gasoline. 37 production and uses of 36,37,46 Natural cement 41, 63 Ncmatopora alternata Ulrich 98 delicatula Ulrich 98 fragilis Ulrich 99 retrorsa Ulrich 99 Niagaran limestone 65 Noix oolite 77 O Oil and gas, conditions for accumu- lation of 49 in western Illinois 45-50, 51 Wabash County 33 Carlinville 33 studies of 14, 15 wells in Illinois by counties, 1910- 1912 35 Ordovician formations, limestone from 40 sandstone from 39 Oregon, glass sand at 41 Page Orthis fiabcllitcs var. fissiplicata Foerste 122 Ostracoda in Channahon limestone. 160 Ottawa, glass sand at 41, 63 Overflowed lands, studies of 16, 17 P Paleontology of Alexandrian series 67-160 Parr, S. W., work of 12 Pelecypoda in : Channahon limestone 154-156 Edgewood formation 136-144 Girardeau limestone 106-107 Pennsylvanian series in western Illi- _ nois 46 limestone from, for fluxing 40 Pentamerus parvulus n.sp 124 Petroleum, production and prices of 33,34 Pholidops subclliptica n.sp 150 Pig iron, production of 32 Platteville limestone, lead and zinc in 43 Platystrophia daytoncnsis Foerste.. 122 Pleasant Hill, Sexton Creek lime- stone near 89 Plymouth oil field 51-53 Poleumita bellasculptis n.sp 143 Pope County, fluorspar from 42 lead and zinc from 43 Portland, artesian wells at. 65 Portland cement rock 63 Pottsville formation in western Illi- nois 46 Princeton, artesian wells at 65 Proetus channahonensis Weller 157 dcterminatus Foerste 145 princcps n.sp 108 Protozeuga sulcocarinata n.sp. 105, 129 Pterinea elegans n.sp 154 formosa n.sp 106 thebesensis Meek and Worthen.. 136 Putnam County, see La Salle-Hennepin quadrangles. Pyrite, production of 43 Ptychocrinus splcndens (S. A. Mil- ' ler) 95 R Rafinesquina? delicatula n.sp 100 ? mesicosta (Shumard) 101, 118 ? mesicosta var. mesistria n.var. . . 118 Reclamation of overflowed lands.. 16, 17 Rhipidomella hybrida (Sowerby).. 152 tenuilineata n.sp 123 INDEX— Concluded Page Rhynchonella ? janea Billings 128 Rhynchotrema ? illinoisensis n.sp.. 103 Rhyncotreta intermedia n.sp 153 lepida n.sp 152 parva n.sp 125 thebesensis Foerste 126 thebesensis var. multistriata n.var. 127 S St. Louis limestone in western Illi- nois 47 St. Peter sandstone, artesian water from 65 glass sand from 41 in La Salle-Hennepin quadrangles 60 Saline County, overflowed lands in. 16, 17 Salisbury, R. D., work of 12, 16 Sauer, C. O., work of 12, 16 Savage, T. E., work of 12 Sand and gravel, in La Salle-Hen- nepin quadrangles 61 production of 41 Sandstone, production of 39 Schuchertella curvistriata n.sp 151 cf. missouricnsis (Shumard).... 121 missouriensis (Shumard) 102 missouriensis var. convexa n.var. 121 propinqua (Meek and Worthen) . 120 Schuyler County 45 Sexton Creek limestone, fossils from 90,91 occurrence and stratigraphy of.. 87, 89 Shaw, E. W., work of 21 Shockel, B. H., work of 21 Silica, production and uses of 42 Silurian formation, limestone from 40 Silver, see Lead, zinc, and silver. South Chicago, production of' coke at 32 Spirifcr (Dethyris) sp 131 Spoon River, maps of 16 Spring Valley, sand and gravel from 61 Starved Rock State Park 65 Stone, production of 39-40 Straparollus pumilis n.sp 142 Stratigraphic studies in various quadrangles 14 Stratigraphy of Alexandrian se- ries 67-160 Stromatoporidea in Edgewood for- mation 117 Stull, R. T, work of 12 Sulphuric acid 43 Sumner quadrangle, investigation of 15 Page T Thebes, sections near 73, 78 Topographic surveys 17 Tracey sand in Lawrence County. . 33 Trilobita in Channahon lime- stone 157-160 in Edgewood formation 144-149 in Girardeau limestone 108-112 Tripoli, see Silica. Triumph, sand and gravel at 65 Trowbridge, A. C, work of 21 U Udden, J. A., work of 12 Union County, Alexandrian series in 69 silica from 42 U. S. Bureau of Mines, coopera- tion with 14 work of 12,37 U. S. Geological Survev, coopera- tion with 14, 26, 55 University of Chicago, fossils loaned by 95 University of Illinois, cooperation with 14,15 Utica, artesian wells at 64 clays from 62 natural-cement plant at 41 V Vermes in Girardeau limestone. .. .97-98 Vermilion County, pyrite in 43 W Wabash County, oil in 33 Waters, mineral, production of.... 42 Waukegan, production of coke at.. 32 Weller, Stuart, work of 12 Wells, studies of 14, 64, 65 oil, see Oil and gas and Log. West Virginia, coking coal from... 32 White, K. D., work of 12 Whitfieldella acuminata n.sp 154 billingsana (Meek and Worthen) 134 ovoidcs n.sp 134, 154 ? speciosa n.sp 135 Williamson County, coal in 29 overflowed lands in 17 Will County, Alexandrian series in. 69 Z Zaphrentis ambigua n.sp 114, 149 cf. stokesi Milne-Edwards and Haime 113 subrcgularis n. sp 113, 150 Zinc, see Lead, zinc, and silver.