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DESCRIPTIONS 
 
 OF 
 
 KEW SPECIES OF FOSSILS, 
 
 FROM THE 
 
 PALAEOZOIC ROCKS OF THE WESTERN STATES. 
 
 By J. H. McCHESNEY. 
 
 EXT. TRANS. CHICAGO ACADEMY OF SCIENCES, Vol. I. 
 

 VAN BENTIIUYSEN S PRINT, ALB,\NY. 
 
The following descriptions of new fossils, by J. H. 
 McChesney, of Springfield, Illinois, are part of those 
 noticed at a meeting of the Chicago Academy of Sciences, 
 on the eleventh of October of this year ; the remainder of 
 them will be distributed in connection with a reprint of 
 these, as soon as the engravings, illustrative of them, can 
 be completed. 
 
 These beautiful species, though a portion of them were 
 collected from other States, are all characteristic of rocks 
 which have their equivalents in Illinois. 
 
 17 '^ 5 82 
 
I' 
 
 - i 
 
 I 
 
CKINOIDEA. 
 
 Plalycsiims oriiogmiiulus (n. s.). 
 
 The calyx of this crinoid is a broad and shallow cup ; 
 its base of medium size, pentangular, and having the suture 
 lines barely visible ; entire surface flat; edges not beveled. 
 First radial plates wider than high, their lower margins 
 straight, sides rapidly spreading above ; superior lateral 
 angles from the edges of the cicatrices for the attachment 
 of the arms to their outer edges are short, the entire plate 
 having a general subquadrangular outline, its upper portion 
 slightly curved inward ; articulating scar shallow, sub- 
 semicircular in form, and occupies about one half the entire 
 width of the plate, edge but little raised above the general 
 surface of the plate. Second radials small, in some in- 
 stances scarcely filling the cicatrix of the first radial; 
 sustaining on each of their upper sloping edges small supra- 
 radials in double series. First bifurcation of the arms occurs 
 on the second supraradial plate, and again on the second 
 plate above on the inner branch, giving three arms to each 
 of the two main divisions of the ray, or thirty to the entire 
 individual. Arms composed of a double series of thin 
 j)lates, which are obtusely wedge-form at their interlock- 
 ing edges. Anal and interradial plates unknown. 
 
 Surface of the plates entirely and closely covered by 
 small spiniform granules, which on the base are directed 
 outward, and on the first radial plates downward. The 
 surface of the arm plates is traversed by very fine lon- 
 gitudinal lines or ridges which take their rise from the 
 
B 
 
 CRINOIDEA. 
 
 receding angles of the strife or notches of the articulating 
 faces of each plate, causing those of one plate to alternate 
 with those of the adjoining ones ; these can only be seen 
 by the aid of a lens. 
 
 Column round, of medium size ; central perforation 
 minute. 
 
 This species is closely allied to P. shumardanus (Geo. Rep. Towa, Vol. I, Part 
 2, PI. viii, fig. 5), from which it dilfers in several important particulars. The base 
 of that species is quite concave ; the upper part of the first radial much more 
 abruj)tly and distinctly curved inward ; the cicatrix, for the attachment of the 
 second to the first radial plate, is deeper and extends down farther on the plate, its 
 border is more elevated above the surface of the plate, and the edges of all the plates 
 o.' the cah'x are beveled. The basal and first radial plates of that species are 
 marked with a limited number of small but distinct nodes, arranged in lines, 
 instead of the thickly set granules of this species. 
 
 ? 
 
 Giological position and locality, Tn the Burlington division of the Carboniferous 
 limestone series, Burlington, Iowa 
 
 Body broad cup-shaped, moderately spreading from the 
 base upward. Basal plates unequal in size, very convex, 
 themselves forming a low shallow enp of abont one third 
 the entire height of the calyx ; upper margins somewhat 
 inflected. First radial plates much wider than high, 
 inereasing rapidly in width from below to their upper 
 margins, at which point they are slightly incurved, very 
 unequal in size, the anterior plate being one fourth larger 
 
 a 
 
 The accompan 3 nng diagram illustrates the form and propor- 
 tions of the basal and one of the first radial plates ; the size of 
 the articulating scar ; the small .second radial; and also the 
 form, relative size, and positions of the plates of the arms of 
 one ray to beyond the last bifurcation. 
 
 Platycrimis iiioritatiis (n. s.). 
 
CRINOIDEA. 
 
 7 
 
 than the postero-lateral one ; the articulating scar occupies 
 about one third the width, extending a little more than 
 one third the depth of the plate, and is a little protruding, 
 giving greater convexity to the j)late above than it pos- 
 sesses below. 
 
 Surface of plates destitute of ornaments or markings, 
 except a scarcely perceptible crescent-shaped depression 
 below the articular facet, and the channel along the line 
 of sutime bounding the radial plates, which are broad and 
 well defined. The divisions of the basal plates are not 
 grooved or channeled, but smooth. Summit and arms 
 unknown. 
 
 This species is most nearly related to P. pikiforinis of Hall, and P. planus of 
 Owen, from the former of which it is distinguished by its short wide radial plates, 
 which in a specimen of P. pihiformis, of the same diameter, are nearly twice the 
 height of those in this species; and the lines of suture in that are not channeled as 
 in this. The distinctions between this and P. planus are nearly the same as above. 
 
 The accompanying diagram gives the form and size of 
 the basal, and first radial plates ; as well as the extent of 
 the cicatrix for the attachment of the second radial. 
 
 Geological position and locality. In Burlington division of the Carboniferous 
 limestone, Monmouth (Illinois), Burlington (Iowa.) 
 
 Scaphioci’inus loiigldactylus (n. s.). 
 
 Body narrowly turbinate, slightly expanding toward the 
 top of the first radial plates ; base truncate. Basal plates 
 large for specimens of this genus, pentagonal in form, 
 height and width about equal, greatest width near the top 
 of the plate. Subradial plates nearly four times the size 
 of the basal plates, four of them hexagonal ; the fifth, 
 which is situated on the right side of the anal series, is 
 
8 
 
 CIUNOIUEA. 
 
 hoptagonal. First radial plates once and a half as wide as 
 liigh, pentagonal and having one of the upper lateral angles 
 very slightly truncated hy the corresponding angles of the 
 second radial plates. The second radial plate, situated on 
 the righthand side of the anal series, has the same num- 
 ber of angles with the other four, hut is of a different form 
 in consequence of its resting one side on the first anal 
 })late. The second radial plates are of the form peculiar to 
 this group of crinoids ; length of the base e(|ual to the 
 greatest width of the first radials ; they rapidly contract 
 up to the middle, where they are not more than half the 
 width of the base, above which they slightly expand again 
 to the base of the sloping angles which support the first 
 plates of the arms. The first arm plates are nearly as long 
 as two of the succeeding ones. 
 
 Arms, two from each ray, simple from their origin, and 
 composed above the first joints of short wedge-form plates, 
 of which there are about twenty to the inch ; their upper 
 edges are slightly reflected, giving a rough zigzag appear- 
 ance to the surface of the arms : the inside of these plates 
 are deeply grooved, and the tentacula are composed of 
 strong joints of about the length of the longest side of the 
 arm joints to which they are articulated. The number of 
 joints in the tentacula cannot be determined from the spe- 
 cimen from which the description is drawn. At about two 
 and a half inches from the base of the arms there are 
 several sijine-bearing plates visible, which appear to be 
 the summit plates of the proboscis ; if so, it would give a 
 proboscis of about two and a half inches in length. 
 
 Column, a small portion of which remains attached to 
 the specimen, is composed, near the body, of thin joints 
 beautifully sculptured on their articulating faces, pentan- 
 gular in form; central perforation pentalobate. 
 
CEINOIDEA. 
 
 9 
 
 Tlie accompanying diagram illustrates 
 the form, arrangement, and character of 
 the plates of the body, and a portion of 
 the arms of a nearly entire specimen of 
 this species. The extent of the incurving 
 of the sides of the radial plates is also 
 shown ; the remaining anal plates are hid- 
 den by the overlapping of the arms of the 
 postero-lateral rays. 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone, Kaskaskia, Illinois. 
 
 Zeacriims bifiircatus (n. s.). 
 
 Body and arms, when closed, of a somewhat cylindrical 
 form, the calyx alone forming a low cup, with the base 
 rather deeply impressed. The basal plates are small and 
 entirely concealed by the column, which is inserted in the 
 cavity of the base. Sub radial plates a little longer than 
 wide ; four of them hexagonal, and one heptagonal, by 
 the truncation of one of its lateral angles by the first anal 
 plate. First radial plates much wider than high, pentago- 
 nal or hexagonal. Second radials of about the same size as 
 the first, and obtusely wedge-formed above, except on the 
 anterior ray, where there are two additional radial 
 plates inserted between the first and third, or bifurcating 
 plate. These bifurcating plates give origin to two arms 
 each, which are composed of short quadrangular plates, 
 rather more than twice the width of their length. These 
 arms bifurcate again on the fourth or fifth plate above their 
 origin, and again several plates higher up : the jirecise 
 number cannot be determined from the specimen under 
 description. 
 
 2 
 
10 
 
 CllINOIDEA. 
 
 Anal plates small ; the first one hexagonal and elongated 
 below, resting upon the two adjoining subradials, and sup- 
 ported on the sides by the adjacent first radial ; on its 
 upper edges it supports the two small j^lates of the next 
 range ; the remaining anal plates have been broken away. 
 
 Column, where it joins the body, fills the cavity of the 
 base, and is composed of alternately thick and thinner 
 joints, which are coarsely notched at the outer margins of 
 their articulating surfaces. 
 
 This species differs from Z. maniformis of Shumard, in having compound arms 
 instead of simple, as well as in the proportionate size of the plates; from Z. mag- 
 noliaformis of Troost, in not having the subradial and radial plates elongated as 
 in that species, nor the cavity of the base so profound. Its nearest relations are 
 with Z. wortheni of Hall (Geo. Eep. Iowa, p. 683), from which it differs in the 
 depth of the basal cavity, in the less elongated subradial and first anal plates; also 
 in having but three radial plates in the anterior ray, instead of four as in that spe- 
 cies; and in the body being less robust, and the cup not so deep. 
 a 
 
 The accompanying figure illustrates the arrangement as 
 well as the form of the plates of the specimen as far as can 
 be traced, showing tho.se of the arm of the antero-lateral ray 
 to the third plate above the' second bifurcation The pecu- 
 liarity of possessing four radial plates in the anterior ray and 
 but two in each of the others, is a distinguishing feature of 
 this fo.ssil. 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone series, Kaskaskia, Illinois. 
 
 Zeacriiius iimcrosiiiims (n. s.). 
 
 Body forming a shallow cup, the centre of which is 
 deeply impressed, the impressed portion consisting of the 
 basal and lower half of the subradial plates. Basal plates 
 small, pentagonal, forming the bottom of the basal eavity, 
 and projecting beyond the circumference of the column. 
 Subradials elongate, height once and a half the width, 
 greatest diameter one third the length from the lower 
 margin ; in form, three hexagonal and two heptagonal : 
 the ujiper edges, which support the first radiaL, are more 
 
CRINOIDEA. 
 
 11 
 
 or less curved. First radial plates large, heptagonal, 
 pointed below ; faces slightly concave where they join the 
 subradials ; varying in height, the left postero-lateral one 
 being the shortest, and the anterior one equal to the long- 
 est ; in width they are nearly uniform, and wider than 
 high ; middle slightly protuberant a little below the supe- 
 rior margin, from which place they are flattened to the 
 top. The form of the second radial plates, if deprived of 
 the spine with which they are furnished and held in their 
 natural position, would be pentagonal, broad, and pointed 
 at the lower margins, narrowing rapidly upwards to the 
 base of the sloping edges, nearly twice as wide as high : 
 when perfect, the body of the plate is produced into a long 
 sharp spine, which, in the specimen from which this de- 
 scription is drawn, would measure seven eighths of an 
 inch in length. Each of these plates supports (upon a surface 
 which, in the separate spine, appears to be flat, ornamented 
 with elevated ridges) two plates of an irregular quadrangu- 
 lar form, the width of which is double the height. Above 
 these, and resting on the outer part of their articulating 
 surfaces, are two small wedge-formed plates, one above the 
 other. The next plate is irregular in form, and nearly as 
 large as the quadrangular plate, and resting partly upon 
 it and partly upon the small wedge-formed plates ; this is 
 a bifurcating plate, and supports a series of smaller plates 
 which are variable in size and shape, mostly wedge-form 
 and six in number, the last of which is also a bifurcating 
 plate, and gives support to two sets of small arm plates, 
 the number of which are not determinable in the specimen. 
 Anal plates (four of which are preserved) are arranged as 
 in Poteriocrinus ; the first pentangular, three times as long 
 as wide, the longest faces curved ; one convex, the other 
 concave, resting upon two subradials and against the first 
 radial of the left postero-lateral ; the others are elongate 
 hexagonal, and differing in size. 
 
12 
 
 CRINOIDEA. 
 
 Column, a part of which is preserved, is comparatively 
 small, elliptical in outline, and composed of thick and 
 thin joints alternately ; the thick ones projecting beyond 
 the others in a rounded rim ; the articulating faces of the 
 joints are deeply notched or striated. 
 
 The peculiarities of this singularly interesting crinoid consist, not only in the 
 spines of the second radial plates, hut also in the peculiar structure and arrange- 
 ment of the arms from this point upward to the place of the second bifurcation. 'J he 
 outer ends of the plates of each main division of each ray between these points are 
 articulating faces, and are joined to the corresponding portion of the adjacent ray; 
 and thereby arching over the interradial spaces by a structure composed of the half 
 of each ray, and forming by their union the base of one set of arms which are free 
 above. It is altogether probable that the portions of the postero-lateral rays which 
 are next the anal side are not articulated in this manner, but form of themselves 
 each a distinct and independent set of arms. The.se characters are quite sufficient 
 to distinguish this crinoid from any other heretofore described, when the spinose 
 plates or any portion of the arms are preserved ; and in their absence, the form of 
 the subradial plates will alone determine its character. . 
 
 The accompanying diagram illustrates the form and proportions of the plates and 
 structure of the body, and part of one arm of the anterior ray of this species. The 
 dotted lines on the first radial plates show the extent of the flattened portion of the 
 plate : a illustrates the second radial plate, as it would appear when in position 
 without the spine; h, the same with the spine perfect; c, the main division of one of 
 the rays from above the second radial plate, and extending as far as it can be traced 
 in the specimen; the right hand side of this part of the figure shows the articulating 
 faces which join those of the adjacent ray: d, the front of the arm, showing the 
 
CEINOIDEA. 
 
 13 
 
 manner in which the first hifiircation is produced. Fip:. 1 is the quadrangular plates 
 which rest upon the upper surfaces of the second radials; fig. 2, the first hifui cating 
 plate above the second radial; and fig. 3, the second, abovb which point the arms 
 are free and movable. 
 
 Geological position and localities. The specimen from which the de.scription is 
 drawn was found in rocks of the Coal measures at Cai linville, Macoupin county, 
 Illinois; but I have found spines and other fragments belonging to the same form at 
 the mouth of Rush creek, Indiana, and in Sangamon county, and other places in 
 Illinois. 
 
 Note. This remarkable Crinoid belongs more nearly to the genus Zeacrinus than to any 
 other established genus ; but if a sufficient number of specimens should be found, with spe- 
 cific differences, having the marked peculiarities of this specimen constant, they may become 
 of generic importance. 
 
 Actiiiocsinius asteiiiis (n. s.). 
 
 Body of medium size, rather robust, subturbinate, trun- 
 cate at the base. Arms proceeding from the base in strong 
 horizontal lobes, or branches, which commence at the third 
 radial plates, and give a remarkable pentalobate appear- 
 ance to the fossil. Basal plates comjiaratively large, thick- 
 ened at their lower margins, forming a transverse ridge or 
 node on each plate, giving a tripartite base ; excavated 
 beneath for the reception of the column. First radial plates 
 comparatively large, the height from the base of the calyx 
 to their upper margin equal to half that of the entire 
 calyx. Second radials very much smaller, hexagonal in 
 form, height equal to two thirds their width ; the upper 
 and lower lateral edges of the same size. Third radials 
 almost equaling the second in size, mostly heptagonal, 
 supporting upon each of their upper sloping edges a large 
 sized supraradial plate which is also a bifurcating plate, 
 and sustains on its outer sloping edge a series of brachial 
 plates, the second of which appears to be excavated for 
 the reception of the first of the arm plates ; on the inner 
 sloping edge, it supports other bifurcating supraradials ; 
 these in turn support on their inner edges brachials, and 
 on the outer supraradials, giving eight arms to the ray. 
 
14 
 
 CRINOIDEA. 
 
 This arranj^ement can only be traced on the postero-lateral 
 rays, the others being l)roken away just above the third 
 radial plates ; but from the comparative size of the open- 
 ings, it is probable that the antero-lateral rays have about 
 the same arrangement, while the anterior ray was proba- 
 bly smaller. The plates on the sides of the ray above the 
 second bifurcation are bent upward at their outer margins, 
 and unite with the plates forming the top of the ray. First 
 interradial plate somewhat regularly hexagonal, of nearly 
 the same diameter as the second radials, supporting two 
 smaller hexagonal plates in the second range, and live 
 irregularly formed plates in the third, the outermost of 
 which rest also upon the supraradials, and are united 
 above, as are the other three, with the plates of the crown. 
 Anal area large ; the first plate hexagonal, almost equal- 
 ing the first radials in size ; supporting two smaller plates 
 in the second range, one hexagonal, the other heptagonal, 
 and four still smaller in the third range, with a greater 
 number of narrow elongated ones in the fourth, which unite 
 above with the plates of the dome. 
 
 Surface of the plates marked by strong angular ridges ; 
 those of the first radial, and anal plates, which join those 
 of the basal plates, are two or three in number, and meet 
 in the centre of the plate, forming prominent, slightly 
 transverse nodes ; while those above are single, and form 
 rounded tubercles where they meet in the centre of the 
 plate. The plates above the third radials are produced in 
 the middle, and form ramifying ridges, running along the 
 different divisions of the ray. 
 
 The dome, which is but little elevated, is terminated b}'- 
 a very strong central proboscis, and composed of rather 
 large polygonal plates, produced into elevated somewhat 
 rounded tubercles ; which character is also extended to 
 those forming the roof of the arm bases, or lobes. 
 
CRINOIDEA. 
 
 15 
 
 Tliis species is of the type of, and closely allied to A. lowei of Hall (Geo. Kept. 
 Iowa, pi. 15, fig. 5), but dilTers from it in the greater lieight in proportion to its 
 width, and in the mode of growth and arrangement of plates in the arm bases, this 
 species being destitute of the intervening plates, between the bifurcating ones, and 
 also in its not possessing inter-supraradials between the main divisions of the ray. 
 Both of- the last mentioned characters are marked peculiarities of that species, as 
 may be seen by the diagram accompanying the description. The proboscis is also 
 smaller, and the tubercles of the dome are neither so numerous nor strong as in that 
 species. 
 
 a 
 
 The accompanying diagram illustrates 
 the form, size, and relative positions of 
 the arms of the postcro-lateral rays, as 
 far as can be a.scertained from the spe- 
 cimen. The great number of six-sided 
 plates in the interradial and anal series 
 form a remarkable feature in this 
 species. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone, Monmouth, Illinois. 
 
 Actiiiocriluis teimisciilptus (n. s.). 
 
 Body below the arms distinctly turbinate ; base truncate, 
 and slightly concave for the insertion of the column. Basal 
 plates of medium size, slightly thickened at their lower 
 margins, and forming of themselves a very shallow cup. 
 First radial plates largest, hexagonal and heptagonal, a 
 little wider than high ; the upper and lower lateral angles 
 nearly equal. Second radials considerably smaller than 
 the first, hexagonal, width once and a half the height. 
 Third radials larger than the second, somewhat wider than 
 high, hexagonal and heptagonal, and supporting upon each 
 of their upper sloping edges a hexagonal supraradial plate 
 of large size, which sustains upon its outer sloping edge 
 
IG 
 
 CfllNOIDEA. 
 
 a .series of simple })raeliial plates ; while upon the inner 
 edge it gives support to another but smaller supraradial 
 plate, which again supports two series of brachial plates, 
 giving three arms to each main division ; and as all the 
 rays appear to he furnished with a like number (as far as 
 can be determined from the specimen), this arrangement 
 would give thirty arms to the entire individual. 
 
 The interradial series con.sists of seven or eight jolates 
 each, the first large, equaling in size the second radials, 
 but more regularly hexagonal, resting upon the upper 
 lateral angles of the first radials and against the lower 
 lateral angles of the second radials, while it supports upon 
 its upper angles two other smaller plates, one pentagonal 
 and the other hexagonal ; the.se support two still smaller 
 ones in the third range and two in the fourth, with some- 
 times a small narrow or elongated plate situated between 
 the brachial plates of the adjacent rays. There are also 
 two small elongated inter-supraradial plates situated be- 
 tween the two main divisions of each ray, the lower one 
 resting upon the inner edges of the first and between the 
 second supraradial plates ; the .second of these plates rest 
 upon the top of the first. Anal series composed of twelve 
 plates, the first hexagonal, little smaller than the radial 
 plates, supporting two heptagonal plates in the second 
 series, which are equal in size to the second radials ; the 
 third range consists of four plates, the fourth of three, 
 fifth of one, and one other still higher, which separates the 
 brachial plates of the outer arm of each postero-lateral 
 ray. Arms and summit unknown. 
 
 Column at its junction with the base large, round; cen- 
 tral perforation at this point large, pentalobate. 
 
 The surface of this beautiful crinoid is clal)orately sculptured, very similarly to 
 A. sculptus of Hall (Geo. Hep. Iowa, PI. x, fig. 11); but the markings are more 
 delicate, and the secondary set of ridges are broken so as to give them the appear- 
 ance of lines of beads, rendering it beautifully ornamental ; but in structure it is 
 more nearly related to y/. ornatus (figured on the same plate with that last men- 
 
CRINOIDEA. 
 
 17 
 
 tiono(l), and its congeners; but differs from all of them hitherto described in the 
 nature and strength of the surface markings, as well as in the form of the body at 
 the base of the arms, this species not having the interbrachial and interradial spaces 
 sunk into deep channels and grooves as in most of them. It differs from Jl. ornatus 
 and some others in the number of arms, and in the body being more regularly tur- 
 binate. 
 
 P 
 
 Geological position and locality. Burlington division of the Carboniferous lime- 
 stone series, Columbia, Missouri. 
 
 Body regularly and broadly turbinate below the arms, 
 above broadly conical, and terminating in a rather strong 
 central proboscis; base somewhat broadly truncated. 
 Basal plates proportionately large, much thickened, pro- 
 jecting below, and forming a trilobed rim around the top 
 of the column. First radial plates nearly as wide again as 
 high, hexagonal and heptagonal. Second radials forming 
 only a narrow line between the first and third radials, 
 quadrangular ; width full three times the height. Third 
 radials rather small, pentangular, and supporting upon 
 each of their ujiper sloping edges two broad short supra- 
 radials, the uppermost of which are bifurcating plates, 
 and sustain each two sets of braehial plates in double 
 series ; except in the anal portions of the postero-lateral 
 
 a 
 
 ^ The accompanying diagram illustrates 
 the form and arrangement of the plates 
 of the body to the bases of the arms of 
 a specimen of this species, and affords 
 a good opportunity for comparison with 
 its most closely allied species’. 
 
 Actmociliiiis subspqiialis (n. s.). 
 
 3 
 
18 
 
 CllINOIDEA. 
 
 rays, where on one side the second supra radial plate sup- 
 ports on its inner edge a double series of brachials, and on 
 the outer a single secondary supraradial, which gives sup- 
 port on one side to brachial plates, and on the other to two 
 still higher supraradials : the uppermost, being also a 
 bifurcating plate, gives origin to two more arms, making 
 six arms to the ray, four of which take their rise from one 
 main division, while the other main division has but two 
 arms. The other postero-lateral ray has but five arms, 
 possessing but one extra bifurcating plate : this arrange- 
 ment gives the following brachial formula = 23. This 
 is probably an unusual arrangement, and not the true one 
 of the species, which may be either 22 or 24. The interra- 
 dial plates are three in each series ; the first one compara- 
 tively large, ten-sided, supporting the other two, which 
 are quite small, uj)on its upper angles. Anal plates 
 seven or eight, irregularly arranged ; the first one nearly 
 as large as the first radial plates, heptagonal, and supports 
 three in the second range, the two outermost of which are 
 large, the central one small ; the other four are irregularly 
 placed above ; one of the middle ones large, situated 
 between the upper parts of the adjoining rays, and sup- 
 porting the last and outermost brachial plates upon its 
 upper sides. The surface of the basal and first radials are 
 elevated into prominent transverse nodes ; that of the third 
 radial, first interradial, and four of the anal plates, into 
 prominent rounded nodes ; and all of the other j)lates of 
 the calyx are more or less nodulose, except the second 
 radials. The plates of the dome and proboscis are highly 
 tuberculose ; they are irregular in size and form, and the 
 nodes are angular, the ridge being in the direction of the 
 longest diameter of the node. The articulating facet for 
 the attachment of the column is round, large, somewhat 
 deeply sunk into the cavity of the basal plate : central 
 perforation round, minute. Column and arms unknown. 
 
CRINOIDEA. 
 
 19 
 
 This species is somewhat closely related to A. (zqualis 
 of Hall (Geo. Hep. Iowa, PL xi, fig. 4), but is more ele- 
 vated in comparison with its diameter, the surface arrange- 
 ments differently disposed, the third radial and first bifur- 
 cating supraradial plates having distinct nodes, which that 
 species does not possess ; and the arrangement of the arms, 
 as well as the difterence in number, is entirely distinct, 
 the formula of that species being = 26 arms, while 
 this has probably not more than twenty-two. 
 
 a 
 
 The diagram illustrates the form, size and arrange- 
 ment of the plates of the body to the bases of the arms 
 of a specimen of this species. The very short second 
 radial plates form a peculiar feature. The additional arm 
 e on the right postero-lateral ray is probably due to 
 dent and not a specific character, the number being 
 twenty-two. 
 
 Geological position and localities. In the Burlington division of the Carboniferous 
 limestone series, Monmouth (Illinois), and Burlington (Iowa). 
 
 Actinocriims fosteri (n. s.). 
 
 The calyx of this species is broadly turbinate, expand- 
 ing rapidly from below upward to the base of the arms, 
 where the diameter is one third greater than the height ; 
 base truncate or concave. Basal plates quite low, slightly 
 thickened at their lower margin, so as to form a perpen- 
 dicular rim to the cup. First radials of medium size, rather 
 wider than high ; upper lateral angles large. Second radi- 
 als little more than half the size of the first, hexagonal, 
 except that in the right postero-lateral ray, which is 
 pentangular ; width greater than the height, irregular in 
 shape and size. Third radials hexagonal, being truncated 
 above by a large sized polygonal inter-supraradial plate. 
 Upon each of the lateral sloping angles of the third radials 
 rests a single supraradial plate of about two-thirds the 
 
20 
 
 CRINOIDEA. 
 
 size of the tliird radials, and sustaining upon its outer 
 sloping edges a series of brachial plates, two of which 
 remain on some of the rays in the specimen ; ujion its 
 inner sloping edges it supports a supraradial of the second 
 order, which in turn gives origin to two sets of brachial 
 plates, making three arms to each principal division or six 
 to each ray, equal to thirty to the entire individual. First 
 interradial jDlates hexagonal, size rather larger than that 
 of the second radials, supporting on its upper edges two 
 smaller plates, one of which is hexagonal, the other hep- 
 tagonal ; in each series above these there are five and 
 sometimes six smaller polygonal plates, irregularly placed, 
 the uppermost of which is a narrow elongated plate, and 
 situated high up between the upper brachial plates of the 
 adjacent rays dividing them, and is generally wider at the 
 top than below. 
 
 Anal series, in the specimen under examination, consists 
 of thirteen plates, the first of which is hexagonal, some- 
 what smaller than the first radial plates ; sides nearly 
 parallel : the two succeeding plates are, one hexagonal, the 
 other heptagonal, as large or larger than the second radials ; 
 the third range consists of four small plates, the outer arms 
 of which rest against the third radials ; in the fourth range 
 there are three plates only, and in the fifth but two ; a 
 single plate above and between them, which separates the 
 brachial plates of the postero-lateral rays. 
 
 The centres of all the plates are more or less convex, 
 and traversed by ridges which are compound on the 
 radial plates and single on the others; these ridges meet 
 at or near the centre of the plate, and form pointed angu- 
 lar nodes, increasing in comparative size as they reach the 
 upper portion of the calyx. The node on the plate situated 
 immediately above the third radial plate is remarkably 
 conspicuous. 
 
CRINOIDEA. 
 
 21 
 
 This species is related to A. multibrachiatus and A. proboscidialis of Hall (Geo. 
 Rep. Iowa, PI. x, figs. 10 and 13); but differs from any of that type heretofore 
 described, in the number and arrangement of the arms and rays, and also in the 
 form and proportions of the body. 
 a 
 
 The accompanying diagram is from a 
 specimen of this species, and illustrates the 
 form of the plates to the bases of the arms. 
 The very large inter-supraradial plates, which 
 truncate the top of the third radial plate, is a 
 distinguishing feature which is not possessed 
 by any other species of this group to such a 
 remarkable extent, as in this one. 
 
 P 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone series, Burlington, Iowa. 
 
 Actiiiociiims SMbveiitricosiis (n. s.). 
 
 The calyx of this crinoid is turbinate, with the sides 
 somewhat inflated ; summit depressed convex, rising 
 abruptly at the edges and flattened in the centre. Base 
 small ; basal plates being but little larger than the column 
 at the junction, and expand gradually to their superior 
 edges, at which point the inflation of the sides of the cup 
 commences. First radial plates largest, two heptagonal 
 and three hexagonal, the superior lateral angles being the 
 longest. Second radials hexagonal, higher than wide, great- 
 est width below the centre. Third radials as large as the 
 second, heptagonal in form, height equal or greater than 
 the width ; sustain upon their upper sloping angles siijira- 
 radials of medium size, which in shape are mostly hep- 
 tagonal. These plates support on their outer angles a series 
 of brachial plates, three of which are visible in the speci- 
 men ; on their inner angles they support supraradials of 
 
22 
 
 CRINOIDEA. 
 
 the second degree, very small in size, but which support 
 other series of plates on each of their upper sloping edges ; 
 on the one simple brachial plates, while on the other the 
 second is a bifurcating plate, and gives rise to two arms ; 
 which make four arms from each main division of each 
 ray, or eight arms to the entire ray. The interradial series 
 consists of nine, and in some instances ten plates, the first 
 of which is hexagonal, equaling in size the second radials, 
 resting upon the superior lateral angles of the first radials, 
 and flanked on its sides by the second radial, while upon 
 its upper edges it sustains two smaller plates in the second 
 range, two in the third, fourth, and fifth ranges each ; 
 which plates gradually decrease in size as they rise, the 
 highest being very small : the tenth plate, when it exists, 
 is minute, and situated high up between the brachial of 
 the adjacent arms. 
 
 Anal plates, but three remain in the specimen from 
 which the description is drawn, but in other specimens of 
 the species they are from thirteen to fifteen in number; 
 the first is hexagonal and of the size of the second radials, 
 and supports two in the second range : the other ranges 
 consist of three, three, three, two and one respectively. 
 These plates appear to be subject to some variation 
 both in number and arrangement, but are generally of an 
 hexagonal form, and decrease in size from below upward ; 
 the uppermost being very small, as in the case of the 
 interradials. 
 
 The surface of all of the plates of this crinoid, except 
 those of the summit, are tumid or highly convex, and tra- 
 versed by a number of ornamental ridges, which, on the 
 centre of the plates, are faint, but where they pass from 
 plate to plate they are very sharp and well defined, having 
 deep punctures between them, which in some weathered 
 specimens appear to pass into the interior of the test. 
 
CRINOIDEA. 
 
 23 
 
 Compared -with A. ventricosus of Hai.l (Iowa Rep. Vol I, PI. xi, fig. fi), which 
 it closely resembles, it is a more lofty form, caused by the several ranges of plates 
 being much higher in proportion to their width than in that species : the interradial 
 and anal series consist of one or two more ranges of plates; the basal plates are 
 also much longer. The dome of this species is not elevated as in that, being in most 
 instances nearly flat or but slightly convex, and is not cut up by such deep channels 
 as is that of A. ventricosus. On the summit of the dome, there is a small anal 
 opening situated subcentrically nearest to the anal side. Arms and column un- 
 known. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone series : Burlington, Iowa. 
 
 Actiiioeiiims iini?eforiHis ( n. s.). 
 
 Body, below the arms, narrowly turbinate ; the greatest 
 diameter, which is at the point of attachment of the arms, 
 is little more than once and a half the width of the base ; 
 the summit is a dome, surmounted by a sub-central pro- 
 boscis of comparatively large size. Base truncate. Basal 
 plates low, thickened at their lower margin, and forming 
 an expanding rim around the base of the cup. First radial 
 plates rather large in comparison with the other plates of 
 the body, height and width about equal ; and are, as are 
 also the first and second interradial plates, furnished with a 
 central tubercle or subspine, while the other plates of the 
 body are scarcely convex. Second radial plates minute, 
 quadrangular ; width nearly twice the height. Third radials 
 pentangular; but little wider than high; slightly larger 
 than the second radials, supporting on each of their supe- 
 rior sloping edges in the anterior and antero-lateral rays a 
 double series of brachial plates, and in the postero-lateral 
 ray brachials on one side and a single supraradial on the 
 side adjoining the anal area, which gives support to a sin- 
 gle brachial on each of its sloping edges, making the brachial 
 formula = 14 arms to the entire specimen. The inter- 
 radial series consists of but one octagonal plate in each 
 area, which is comparatively large, and a little higher than 
 wide, the general form being ovate. 
 
24 
 
 CRINOIDEA. 
 
 Anal series consists of seven plates, the first slightly 
 larger than the first radials, heptagonal, supporting three 
 in the second range and three in the third range, the cen- 
 tral one of which is placed between the brachial plates of 
 the adjacent arras and unites with the plates of the dome. 
 Dome composed of small polygonal plates. 
 
 The ovarian apertures, situated on the outside of the 
 arm openings, are very large, and may he easily mistaken 
 for another set of arms, especially as the brachial plates 
 are slightly protruding, and have somewhat the appearance 
 of bifurcating plates. 
 
 This species has some resemhlance to, and has licretofore been confounded with, 
 //. vanumlii (Suumaiid), figured and described in the Missouri Geol. Report; but 
 it differs not only in form, but also in the number and disposition of the arms. 
 That species is described as having fourteen or fifteen arm-openings, which, in one 
 instance, would give three arms to each ray; and, in the other, two to the anterior 
 and three to each of the other rays. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone. Honey creek, Illinois. 
 
 ActiJiocrIjsiis hiirdiaims (n. s.). 
 
 Body beloAv the arms urnshaped, spreading abruptly 
 above the first supraradial, and truncate at the base, which 
 is not excavated for the reception of the column. Basal 
 plates very low, but little thickened. First radial plates 
 of medium size, wider than high, the greatest width being 
 about midway between the base and summit of the plate. 
 Second radials hexagonal, width one-half greater than 
 their height, a little more than half the size of the first 
 radials. Third radials hexagonal, larger than the second 
 radials, height as great or greater than the width, support- 
 ing on their superior sloping angles supraradial plates, 
 which are ecpial in size to the second radials ; these are 
 also hexagonal, and support on their outer sloping angles 
 a series of brachial plates, two of which appear to aid in 
 forming the body of the crinoid, while on their inner 
 
CRINOIDEA. 
 
 25 ' 
 
 angles they support a single supraradial plate of the second 
 order, which gives origin to tAVO arms from its upper angles, 
 making three arms to each division of each ray, or six to 
 each ray, equal to thirty arms to the entire specimen. The 
 interradial series consists of four hexagonal plates in each 
 of the postero-lateral areas ; Avhile those of the antero- 
 lateral areas are five in number, one of which is pentago- 
 nal. The first interradial plate is of the size of the third 
 radial. First anal plate hexagonal, higher but not so Avide 
 as the first radials : second range consists of two smaller 
 plates which are heptagonal, Avith five other small plates 
 irregularly scattered in above the brachial plates of the 
 adjacent rays, uniting above. The summit of the specimen 
 is high, dome-shaped, and terminates in a rather strong 
 central proboscis, Avhich is surrounded near the base by a 
 number of plates, some of Avhich bear short spines. The 
 remainder of the plates of the dome are mostly small, a 
 few larger ones scattered promiscuously amongst them, 
 most of which are tuberculose. The plates of the calyx are 
 tumid, and traversed by a series of sharp ridges, Avhich 
 meet in the centre of the plate and form stars, the num- 
 ber of the rays varying according to the position of the 
 plate. 
 
 This species is most nearly allied to Jl. proboscidialis of Hall (Geo. Rep. of 
 Iowa), but differs from it in having six arms to each ray instead of only four, and 
 in the form and proportion of the plates of the cal3fx, which is never so much in- 
 flated as in that species. The dome of this species is composed mostly of small 
 plates, while that has it built up of large ones. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone series : Burlington, Iowa. 
 
 Actinocriims iiequibracliiatus ( n. s. ). 
 
 Body, below the arms, broadly turbinate, expanding very 
 rapidly for the last half of its height; above, depressed 
 convex, or a very short and broad conical shape, termina- 
 ting in a medium-sized subcentral proboscis, excentric on 
 4 
 
C’RINOIDEA, 
 
 2G 
 
 the anal side. Base small, truncate, and slightly excavated 
 for the reception of the column. Basal plates low, not 
 tumid. First radials rather large comjiared with the other 
 plates, hexagonal and heptagonal ; breadth and height 
 about equal, the greatest width being near the upper mar- 
 gin ; superior lateral angles very small. Second radials 
 short; breadth once and a half that of the height. Third 
 radials as wide again as high, heptagonal except those 
 adjoining the anal series, where they are shortened- one 
 angle, making them hexagonal : they support, on each of 
 their upper sloping edges, broad supraradial plates, in 
 double series, the upper one of which is a bifurcating plate, 
 and supports two double series of brachials, giving origin 
 to four arms to each ray, or twenty to the entire individual. 
 
 The interradial series consist of nine plates in four ranges 
 of two plates each, above the first plate, which is large and 
 of an octagonal form, resting upon the upper lateral angles 
 of the first radials, and flanked on the sides by the second 
 and third radials. The other interradial plates are much 
 smaller, and of various forms ; the uppermost are smallest, 
 and situated between the highest brachial plates that con- 
 tribute to form the body of the crinoid, entirely separating 
 them, and forming a shallow sinus which reaches into the 
 summit of the specimen. 
 
 Anal series, in the specimen used for description, consists 
 of thirteen plates, the first heptagonal, smaller than the 
 first radials, and supports three smaller heptagonal plates 
 in the second range : the two next ranges form arches 
 above, the 'first of three and the second of four plates 
 respectively ; while above the second of these arches, or 
 the fourth range of plates, there are two small plates which 
 separate the brachial plates of the adjoining rays, com- 
 pleting the series of thirteen plates, and uniting with those 
 of the summit of the specimen. 
 
CRINOIDEA. 
 
 27 
 
 The surface of the plates of the calyx is slightly convex, 
 while the plates of the summit are elevated into rounded 
 tubercles, those near the base of the proboscis being large, 
 and decreasing in size as they approach the arm openings. 
 
 This species possesses the peculiarity of having the arm openings situated on the 
 summit, or opening upwards, and not on the periphery, as in most species of j^cti- 
 nocrinus. The only other species with which I am acquainted, possessing the same 
 character, is A. nashvillcB (Tkoost), figured in Hall’s Report on the Geology of 
 Iowa, Vol. 1, Part 2. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone series, Monmouth, Illinois. 
 
 Actiiiocrlnus aiidrewsiaiius ( n. s. ). 
 
 Body regularly turbinate below the arms ; above, highly 
 dome shaped, and surmounted by a sub-central proboscis of 
 medium size, the base alone remaining in the specimen 
 under description. Base very small, and deeply excavated 
 for the reception of a small column. Basal plates not thick- 
 ened. First radial plates of medium size, a little wider than 
 high. Second radials minute, as wide again as high, quad- 
 rangular. Third radials pentangular, except those on the 
 posterior rays, which are hexagonal, having an extra angle 
 on the side adjoining the interradial series : these third 
 radial plates support on each of their upper sloping edges> 
 except in the anterior ray, supraradial plates in double 
 series, the uppermost of which is a bifurcating plate, and 
 gives support on each of its sloping edges to a double series 
 of brachial plates, giving four arms to each of these rays. 
 The third radial of the anterior ray supports two double 
 series of brachial plates, giving rise to two, arms only, 
 making the brachial formula as follows : = 18 arms to 
 
 the entire specimen. 
 
 The interradial series consists of three plates in each 
 series, the first one two-thirds the size of the first radials : 
 those adjoining the anterior ray are ten-sided, while the 
 others are but nine. Each of these plates supports on its 
 
28 
 
 CRINOIDEA. 
 
 upper edges two smaller plates, which are five, six or 
 seven-sided, as the case requires, the brachial plates of the 
 adjacent rays resting upon their upper edges. 
 
 Anal series consists of but four plates, the first one higher 
 but not so wide as the first radial plates ; the other three 
 form an arch over the superior edge of this plate, and are 
 flanked on their outer and upper angles by the radial, supra- 
 radial and brachial plates of the adjacent rays : the first 
 brachial plates of these rays join each other on their lateral 
 angles, and enclose the anal series beneath them. 
 
 The surface of the plates of the lower part of the crinoid 
 is entirely smooth to the unassisted eye ; those of the 
 dome, which are comparatively large polygonal plates, are 
 slightly convex. 
 
 Column unknown ; but judging from the articulating 
 facit of the base of the cup, it has been very small, and 
 apparently round. 
 
 Arms entirely unknown, except in number, which is 
 eighteen. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone series, Burlington, Iowa. 
 
 AcdBiociimis Iiageri ( n. s.). 
 
 Body, below the arms, broadly sub-turbinate, having the 
 sides of the base somewhat broadly rounded ; more rapidly 
 spreading above the third radial plates than below, and 
 again contracting at the base of the arms. The upj:)er part 
 of the calyx is slightly pentalobate, caused by the depres- 
 sion of the interradial and anal series. Summit depressed, 
 convex most prominent over the anal area, where there is a 
 small but very prominent anal opening. Basal j^lates low, 
 of medium size. First radials very large, half as wide again 
 as high. Second radials quadrangular, three times as wide 
 as high. Third radials pentagonal or hexagonal, proportion- 
 ate width and heighth as in second radials, and sustaining 
 
CRINOIDEA. 
 
 92 
 
 upon each of the upper sloping edges two supraradial plates, 
 which are not so wide but much higher than the plate on 
 which they rest ; the upper one of these is wedge-formed 
 above, and gives supjiort to two short, broad brachial plates 
 on each side ; the upper one is excavated above for the 
 insertion of the arm plates. This arrangement gives four 
 arms to each ray, or twenty to the entire specimen. First 
 interradial plate octagonal, not very large, supporting two 
 smaller plates in the second range, and in the anterior 
 series another smaller one above and between these ; the 
 last three plates differ in the number of their angles, and 
 are of an elongate form. Anal series consists of from seven 
 to nine plates, the first one heptagonal, equal in size to the 
 first radials, sustaining three in the second range and three 
 in the third, Avhile the remainder are placed above and 
 between the brachial plates of the adjoining rays. 
 
 Surface of the plates of the entire body smooth. 
 
 The peculiarities of this fossil consist in the possession of an anal opening, which 
 is a feature seldom present in specimens of this t)^pe, and in the arm-openings 1 eing 
 situated on the edge of the dome similarly to those of A. nashvillce (Tuoost) Geo. 
 Rept., Iowa. 
 
 Geological position and locality . In the Burlington division of the Carboni'.erous 
 limestone, Burlington, Iowa. 
 
 Forhesiociiims |{ratteui ( n. s.). 
 
 Body very large and massive, subglobose and indistinctly 
 pentalobate, very broadly spreading from below upward to 
 above the fi-rst supraradial plates, above which point it is 
 again contracted. The plates of the body are very large, 
 most of them highly covex or tumid, and bearing in the 
 centre on abruptly elevated node or subspine, some of 
 which are about an eighth of an inch in length and nearly 
 the same in diameter ; giving rather a bristling appear- 
 ance to the specimen. The basal plates are unusually large 
 for a specimen of this genus, and, in this individual, are 
 
30 
 
 CRINOIDEA. 
 
 four in number, which is probably an accidental feature, 
 three being the usual number. The subradials are gene- 
 rally smaller than the radial plates proper, but vary much 
 in size and proportionate form among themselves ; most 
 of them are higher than wide. The radial plates are elon- 
 gate, hexagonal, three in number, except on one ray there 
 are only two below the first bifurcation ; and above they 
 are small and many sided, with inter-supraradials between 
 the branches of the ray. The interradial and anal areas 
 are large and composed of a large number of plates, differ- 
 ing much both in form and size ; the first is hexagonal, as 
 large as the first radials, and situated in the receding 
 angles of two subradials : the entire area is considerably 
 protruding beyond the plain of the radial series. 
 
 Entire surface granulose. 
 
 Articulating faset for the attachment of the column is 
 large. 
 
 This specimen is almost too imperfect for description; but as it has for some 
 years been a well known fossil in the Collection of the late IIknry Puatten, and 
 is an extremely interesting specimen and the only one known of its peculiar struc- 
 ture ; I have thought best to describe it so far as its condition will bear; and name 
 it in honor of him. ' 
 
 Note. It is possible that the above described species may not belong to the genus to which 
 we have referred it; but what remains of the specimen has all the characters of the genus 
 Forbesiocrinus, except the number of plates in the basal series. 
 
 G-ological posiiioti and locality. In the Carboniferous limestone series, precise 
 position not known, but probably not below the Warsaw division ; it was collected 
 in Alabama, but the exact locality is not given. 
 
BRACHIOPODA 
 
 Oi'tliis kaskaskieiisis ( n. s.). 
 
 Shell resupinate, semicircular in outline. Dorsal valve 
 regularly convex, most gibbous near the umbo; cardinal 
 extremities slightly elevated or recurved. Ventral valve 
 generally concave ; beak elevated, and in some specimens 
 the elevation extends back toward the middle, distorting 
 the shell. Area rather low; marked by fine, closely 
 arranged transverse strije, which are most distinct near 
 the edges of the foramen and becoming obsolete toward 
 the extremities ; extends to the extremities of the cardi- 
 nal line, which is equal in length to the greatest width of 
 the shell below. Foramen subtriangular, height greater 
 than the width, partially closed, the cardinal process of 
 the dorsal valve filling the opening. 
 
 Surface marked by fine, distinct, rounded, somewhat 
 distorted radiating striae, which are increased by implan- 
 tation and crossed by very fine undulating striae, which 
 give to the surface, when seen through a lens, a beauti- 
 fully cancellated structure, which character is very distinct 
 on a partially exfoliated surface. 
 
 This Orthis belongs to the group usually referred to Orlhis umbraculum, but 
 differs materially from all the species of that group hitherto described. It differs 
 from O. kaokiik and robusta (II all) in being a much smaller shell, the dorsal valve 
 being less convex, and the ventral valve more deeply’’ concave, giving a more pointed 
 appearance to the beak of the ventral valve; in the area being not more than half 
 the height, in comparison Avith the width of the shell, as that of robusta. The 
 beak of this species is often flattened and distorted, as if having been attached to 
 some foreign body during life. Its area is not more than one half the height of that 
 of 0. umbraculum, according to the figuresgiven by De Koninck; and the strim are 
 much more closely arranged in this species. 
 
 Geological position and localities. This Orthis appears to be peculiar to the Kas- 
 kaskia division of the Carboniferous limestone series, and is found at Kas-^ skia 
 and Chester, Illinois. 
 
32 
 
 BRACIIIOPODA. 
 
 Ortlsis liisalkiBSES (n.s ). 
 
 Shell subquadrate, widest below the middle ; sides 
 broadly rounded toward the front ; length one quarter less 
 than breadth. Dorsal valve depressed convex, and having 
 the appearance of a broad shallow sinus extending from 
 beak to base. General form of ventral valve flattened or 
 very depressed convex, becoming slightly gibbous toward 
 the hinge line ; beak pointed, and projecting beyond that 
 of the opposite valve ; area low, rapidly sloping from the 
 beak, and becoming linear toward the extremities; fora- 
 men narrow, triangular, higher than wide, closed except a 
 small space at the base ; callosity rounded. There is a 
 line, which in some specimens is quite distinct, crossing 
 the area from the beak to its base at a point midway from 
 the foramen to the cardinal extremities. 
 
 Surface marked by sharp rugose radiating striae, 
 increased by implantation, and crossed by much finer 
 concentric striae and indistinct lines of growth. 
 
 Geological posiiion and localities. In the Upper Coal measures, Lasallc, Illinois. 
 
 Oitlits riidiiiioiida ( n. s.). 
 
 Shell subquadrate ; length and breadth equal ; widest 
 below the middle. Dorsal valve depressed convex, slightly 
 flattened in the middle toward the front. Ventral valve 
 less convex than the dorsal ; greatest gibbosity near the 
 umbo, which is sometimes flattened by being attached 
 during life to some foreign body. Area large, straight or 
 slightly curved outward, receding backward from the 
 hinge ; height at the beak about one fourth its entire 
 length ; upper margin gradually sloping from the beak to 
 the extremities of the cardinal line. Foramen narroAver 
 than high, closed by a rounded deltidium, except a small 
 space at the base which is filled by the cardinal process 
 of the dorsal valve. 
 
BRACIIIOPODA. 
 
 33 
 
 Surface of both valves marked by distinct, somewhat 
 elevated, rounded stria? which are increased by implanta- 
 tion, the spaces between them being a little wider than 
 the strijB ; also by much finer concentric striae which cross 
 the radiating striae, giving them a somewhat rugose tex- 
 ture ; and by numerous strong imbricating concentric lines 
 of growth. 
 
 This species differs from the last in the proportions of the shell, which is much 
 more elongated than that; in the greater convexity of the valves; in the greater 
 height of the area, and in the radiating striae being finer and less rugose than in 
 that species, as well as in its strong imbricating lines of growth : it is also a thicker 
 shell, and the muscular scars of the interior of the valves are deep and more dis- 
 tinct; the dental lamella and central septum stronger. The central septum is a 
 peculiar character in these fossils. 
 
 Geological position and locality. In the Coal measures twelve miles northwest of 
 Richmond, Missouri. 
 
 Ortliis pratteiii ( n. s.). 
 
 Shell subquadrangular in outline, somewhat broader 
 than long : cardinal line much less than the greatest width 
 of the shell, which is about the middle of the dorsal valve, 
 not very gibbous. Dorsal valve very slightly convex, fullest 
 at the middle below the umbo, having a broad undefined 
 sinus on the front of the shell which does not extend 
 beyond its middle, and also one on each side reaching 
 from the beak to the side of the shell between the cardinal 
 line and the widest part of the shell, depressing the edge 
 of the valves, giving them when viewed edgewise a some- 
 what undulating curve. Ventral valve much larger than 
 the dorsal, strongly pointed at the beak, which is extended 
 above the hinge line from one fourth to one third the 
 whole length of the shell ; gradually sloping from beak to 
 front, without visible curve except by distortion. Arefi 
 high, triangular, the base of the triangle being but little 
 greater than the sides : foramen narrow, height four times 
 5 
 
34 
 
 BRACIIIOPOUA. 
 
 the breadtli ; closed, except a small space at the base, 
 which is filled by the cardinal process of the opposite 
 valve. Surface of the area marked by longitudinal striae, 
 indicating the stages of growth. 
 
 Surface of the shell marked by distinct, somewhat ele- 
 vated striae which are increased by implantation, the 
 intermediate spaces being smaller than the striae ; and by 
 very fine concentric striae which give a finely cancellated 
 appearance to the surface when under a lens, as well as 
 by strong somewhat distant imbricating lines of growth. 
 
 This shell is closely related to the two jireceding species, but differs from both of 
 them in the great height of the area and the narrowness of the deltidial plate : the 
 .strim are not so distant and not so rough as in either of them. In the proportionate 
 width of the shell it resembles Orthis lasallensis, but is easily distinguished by the 
 height of the area, which in that species is very small. From the last it differs in 
 being wider than long, the length and breadth of that species being nearly or quite 
 equal; and the proportionate height of the area is also very different. 
 
 Geological position and locality. In the Coal measures, Charbonier, Missouri, 
 
 Prodiictus asperus ( n. s.). 
 
 Shell of medium size, usually longer than wide ; hinge 
 line eqnal to four fifths the greatest width of the shell. 
 Cardinal extremities usually rounded or obtusely angular. 
 Ventral valve ventricose, moderately recurved and extend- 
 ing slightly beyond the hinge line ; usually divided by a 
 broad shallow undefined sinus extending from beak to 
 base ; front of the valve often somewhat flattened, rounded 
 on the sides to near the middle of the shell, from which 
 point they became flattened, and fall nearly perpendicular 
 upon the cardinal line ; auriculate extensions slightly pro- 
 duced and thickly set with spines. Dorsal valve moderately 
 concave to near the anterior prolongment, at Avhich place 
 it becomes abruptly deflected with that of the ventral 
 valve ; immediately beneath the beak of the ventral valve 
 it is marked with a shallow cavity, from which a Ioav unde- 
 fined, someAvhat angular ridge passes obliquely outAvard to 
 
BRACIIIOPODA. 
 
 35 
 
 the sides of the shell; and in specimens where the sinus 
 of the ventral valve is distinct, there is a third ridge pass- 
 ing to the front of the shell, less distinctly defined. 
 
 Surface of the ventral valve marked by a great number 
 of spines, the bases of which are elongated, or have the 
 shell elevated above them, giving to the surface the 
 ajipearance of being covered by irregularly broken, radi- 
 ating striae or ribs ; also by broad, low, rounded, concen- 
 tric bands, which become narrower and more closely 
 arranged toward the front of the shell. 
 
 The dorsal valve is also marked by concentric bands, 
 which are more closely arranged than those of the ventral, 
 and more thickly set with spines. The spines are more 
 perfectly preserved than those of the opposite valve, and 
 finer, and usually lay flat upon the surface, radiating from 
 the beak. The spaces between the spines are somewhat 
 dejaressed, giving the surface a punctured appearance. 
 
 Geological position and localities. In the Coal measures at Lasalle, Springfield, 
 and various other places in Illinois. 
 
 Productus syiHinetricus ( n. s.). 
 
 Shell of medium size, depressed, suborbicular ; length 
 and breadth about equal. Cardinal line considerably less 
 than the greatest width of the shell below; extremities 
 rounded ; auriculate extensions small, but distinct from 
 the vault of the shell, straight or slightly elevated. Ven- 
 tral valve quite regularly convex, expanding at the front, 
 and entirely destitute of a mesial sinus; front regularly 
 and broadly rounded ; beak large, little incurved, barely 
 passing beyond the hinge line. Dorsal valve regularly con- 
 cave, of moderate depth. 
 
 Surface marked much as in the preceding species ; but 
 the spines and broken rib-like striae of the ventral valve 
 are much finer and more thickly set, and the. concentric 
 
36 
 
 BRACIIIOPODA. 
 
 bands are narrower and more closely arranged, becoming 
 crowded on the front of the shell. 
 
 This shell, though closely related to the last described species, differs from it in 
 being a larger shell, less ventricose and always much broader, entirely destitute of 
 mesial sinus, less enrolled, beak not projecting so far beyond the hinge line; in its 
 dorsal valve being less concave, and nearly or quite destitute of the lateral ridges 
 which pass obliquel}’’ from the beak to the sides of the valves in that species. 
 
 Geological position and localities. In the Upper Coal measure limestone at 
 Lasalle and Springfield, Illinois. 
 
 Pi’oductiis Avillieramis (n. s.). 
 
 Shell above medium size, subquadrate in general form, 
 somewhat longer than wide, greatest width below the 
 middle of the shell ; hinge line entirely straight ; cardinal 
 extremities slightly rounded. Ventral valve regularly 
 arched from near the beak to the base of the shell, having 
 a broad, shallow, not well defined sinus extending from 
 beak to base ; front broadly rounded to the sides of the 
 valve, gradually rounded from the edges of the sinus to 
 the sides of the shell : beak small, pointed, projecting 
 slightly beyond the cardinal line. Dorsal valve flat over 
 the visceral portion, and moderately deflected in front. A 
 small depressed pit exists beneath the beak, from which 
 faintly defined ridges extend, one on each side to the outer 
 edge of the valve just below, and slightly diverging from 
 the cardinal line, and another to the front of the shell 
 corresponding to the mesial sinus of the ventral valve. 
 
 Surface of the ventral valve marked by coarse, much 
 broken, radiating striae or ribs ; and by broad concentric 
 bands, the surface of which are somewhat thickly set with 
 strong tubular spines, which are not usually preserved, 
 their bases only remaining. The spines are implanted on 
 the ribs, adding much to their broken appearance. The 
 surface structure of the dorsal valve is of a somewhat finer 
 texture than that of the other. The spines are smaller, the 
 ribs finer, and the concentric bands more closely arranged. 
 
BRACIIIOPODA. 
 
 37 
 
 The interior of both valves, in addition to the above char- 
 acters, is covered by very fine undulating concentric striae 
 crossing the radiating ribs. 
 
 This species has usually been referred to P. scabriculus (JIartin); but com- 
 pared with the figures of that species given by I)e Koxinck, it is not so rectaisgu- 
 lar, being considerably broadest near the base, and the cardinal line being not more 
 than two thirds the greatest width of the shell. The sides of the ventral valve of 
 P. scabriculus are nearly perpendicular to the plane of the dorsal valve, while in 
 this species they are regularly rounded from the edge of the sinus to the lateral 
 borders. The longitudinal ribs are more broken and less continuous than in that 
 species, and the spines are much more numerous and not regularly disposed. 'J’rans- 
 verse bands are a feature not possessed, or at most very indistinctly so, by P. 
 scabriculus, while in this they constitute a marked character. This shell has also 
 some resemblance to P. asperus, herein described, but is a much larger shell, 
 less conve.x, less enrolled, hinge line entirely straight, cardinal extremities not 
 rounded as in that, mesial sinus more distinct and the transverse bands much 
 larger. 
 
 Geological position and locality. In the Coal measures, Charbonier, Missouri. 
 
 Proliiictus tulm1o8{)iiiii8 ( n. s.). 
 
 Shell large, semiovate, longer than wide, gradually 
 expanding from the beak to near the front of the shell ; 
 front rounded. Ventral valve gibbous, highly arcuate, hav- 
 ing a shallow well defined sinus extending from near the 
 beak to the base, and in some specimens is somewhat angu- 
 lar ; cardinal line shorter than the width of the shell below ; 
 extremities rounded or obtusely angular ; auricular expan- 
 sions short, but distinct from the vault of the shell. Dorsal 
 valve concave, and having a broad low angular ridge ex- 
 tending from the cavity beneath the beak to the front of 
 the shell. 
 
 Surface marked by distinct, rounded, somewhat closely 
 arranged concentric bands which are covered with pustules 
 or spine bases, the spines themselves being rarely pre- 
 served ; but when they are seen, they are very fine, and 
 of considerable length, one of our specimens having them 
 preserved to nearly one half inch in length. These spines, 
 when broken, exhibit a tubular structure. 
 
38 
 
 BRACniOPODA. 
 
 Specimens of this species, when exfoliated, usually, 
 instead of the pustules or spine bases, show a deeply and 
 beautifully punctured surface. 
 
 Tliis -p <ies has, in this country, usually been reP-rred to P. punctatus (Mar- 
 Tri>i), hut possesses several reinaikahle differences, which have induced me to re- 
 gard it as a distinct species. Taking Dk Koninck’s figures and de.scriptions for the 
 characters of tiuit sj)coies, our shell is much more elongated than that, being longer 
 than wide, while that is wider than long. The auricular extensions arc much less 
 l)roduced or flattened than in that; the shell expands gradually from beak to near 
 the base, while that widens abruptly and is much more flattened on the top. De 
 Konin'cic, in his description, states that the spine bases on their shell are arranged 
 on the anterior margin of the bands; while in this shell they are scattered promis- 
 cuously over their surface. The hinge line is proportionately much shorter than in 
 Martin’s species, and the heak more incurved. Compared with P. vittatus 
 (II.ALi.’s Geo. Report of Iowa, page 037), it is more elongated; hinge line propor- 
 tionately shorter; beak less-elevated, and not so abruptly recurved. 
 
 G ologicul position and localitips. In the Coal measures throughout the Western 
 States. 
 
 FriMlllCtUS fiJSCk'lllutUS ( n. s.). 
 
 Shell rather below medium size, elongated; length of 
 the hinge line three-fourths the greatest width of the shell, 
 and auriculate. Ventral valve strongly arcuate, flattened 
 on the top, or marked by a broad shallow sinus; sides 
 nearly perpendicular, which, together with the flattened 
 top, gives it a somewhat angnlar appearance; auricles re- 
 curved, pointed, with the sides of the shell just in front of 
 them somewhat contracted ; beak small, jfointed, slightly 
 projecting beyond the hinge line. Dorsal valve profoundly 
 concave, slightly flattened over the visceral area, and pro- 
 longed in front and at the sides with the ventral valve, and 
 recurved at the cardinal extremities or auricles. 
 
 Surface of the ventral valve marked by medium-sized 
 rounded radiating ribs which are increased by bifurcation, 
 and toward the front of the shell several of them unite in 
 fascicles, which are not developed except in adult indi- 
 viduals, and are not seen when the prolonged portion of 
 the valve is broken away. The surface is also marked by 
 
BRACniOPODA. 
 
 39 
 
 very fine concentric striae and a few faint wrinkles of 
 growth on the upper part of the shell, and traces of spine 
 bases very sparingly scattered over the surface, except on 
 the sides immediately over the ears, where there is a clus- 
 ter of eight or ten. The cavity of the dorsal valve is also 
 marked by radiating ribs, finer than those of the ventral 
 valve, and frequently bifurcating, giving them a somewhat 
 contorted ajipearance. The concentric wrinkles of this 
 valve are more distinct than those of the other valve near 
 the cardinal lines, sometimes of equal strength with tlie 
 radiating ribs, and bending over upon the reflected portion 
 of the valve which forms the auricles. 
 
 Specimens of this species are usually found with the 
 prolonged portion of the valves broken away, entirely 
 changing the appearance of the shell from that presented 
 by perfect individuals. 
 
 The animal appears to throw a partition across from the 
 dorsal to the ventral valve, which appears, when the pro- 
 longment is broken away, to be the continuation of the 
 flattened portion of the valve over the visceral portion, 
 and nearly conforming to its concavity, though destitute 
 of its distinct ribs, the visceral portion being distinctly 
 limited by an imbricated ridge. 
 
 This species has usually been referred to P. flexistria of M‘Cor, from which it 
 differs in being much less inflated over the ears and toward the beak, and in the 
 striae uniting into fascicles toward the front. It is more nearly related to P. elegans 
 (N. and P., Journal Acad. Nat. Sciences of Philadelphia, Aug. 1854), than to the 
 last mentioned species; but is a much broader shell, is frequently marked by a dis- 
 tinct mesial sinus; more extended on the hinge line, much less marked by tubercles, 
 and having the fasciculate striae on ihe front of the ventral valve. 
 
 Geological position and localities. In the Kaskaskia division of the Carboniferous 
 limestone series, at Fountain Bluff, Kaskaskia and Chester, Illinois, and Leven- 
 worth, Indiana. 
 
40 
 
 BRACHIOPODA, 
 
 Pl iMlllCtllS illfhltllS ( n. s.). 
 
 Shell of medium size, extremely gibbous or inflated and 
 strongly enrolled ; cardinal line straight, equal to or greater 
 than the greatest width of the shell; broadly rounded in 
 front. Ventral valve extremely gibbous, geniculated above 
 the middle, divided by a strong, well defined, rounded sinus 
 extending from near the beak to the base; beak large, 
 rounded, and projecting a little beyond the hinge line ; 
 auricular extension somewhat inflated, divided from the 
 vault of the shell by a distinct depression extending from 
 near the beak to the sides of the shell at a point back of 
 the middle. Dorsal valve unknown. 
 
 Surface marked by regular, somewhat indistinctly round- 
 ed longitudinal ribs, increased by bifurcation, and, behind 
 the geniculation of the shell, by closely arranged concen- 
 tric bands or wrinkles ; the entire surface being marked by 
 very fine, slightly undulating, concentric striae, visible only 
 by the use of a magnifier; also a few faint traces of spine 
 bases are distributed over the surface and on the ears. 
 
 Tliis species has some resemblance to P. splendens (N. and P., Journal Acad. 
 Nat. Sciences, Philadelphia, 1854), but is more inflated, much more elongated, less 
 extended on the hinge line, strise finer, spine bases less numerous, beak and umbo 
 less flattened, finer ribs, and depressed between the vault of the shell and the 
 auricles. 
 
 GMlogical position and locality. Carboniferous limestone, Levenworth, Indiana. 
 
 Productiis pileifontiis ( n. s.). 
 
 Shell of medium size, slender, gradually expanding from 
 beak to base, very strongly enrolled and entirely desti- 
 tute of mesial sinus. Ventral valve strongly arcuate, very 
 gibbous, much produced in front and inflated at the sides; 
 cardinal line very short ; beak small, pointed and incurved. 
 Dorsal valve small, profoundly concave, and produced in 
 front and on the sides with the opposite valve. 
 
 Surface marked by numerous fine even thread-like radia- 
 ting striae, increased by implantation and often distorted 
 
BRACIIIOPODA. 
 
 41 
 
 slightly, and by transverse wrinkles Avhich are strong on 
 the sides of the valve but scarcely perceptible on the mid- 
 dle, except on the dorsal valve where they pass entirely 
 over ; body of the ventral valve also marked by a few 
 spine bases. 
 
 Thii^pecies bears considerable resemblance to P.cora (D’Orbignt); but differs 
 from it, when compared with specimens from the same localities as those mentioned 
 by him, in being a much more attenuated shell, in having a much smaller and more 
 pointed beak, shorter hinge line, more contracted at the edges of the ventral valve: 
 also more regularly arched from beak to base; that species having a broad depressed 
 beak, being a broader shell, and regularly curved to a little in front of the umbo or 
 near the middle of the shell; then produced in a right line to near the front of the 
 shell, which is often expanded.* 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone, Chester, Illinois. 
 
 Asilbocelia ^emimila ( n. s.). 
 
 Shell minute ; length and breadth nearly equal. Ven- 
 tral valve extremely gibbous and arcuate, having a slight 
 depres_sed sinus extending from beak to base ; sides and 
 front rounded ; beak comparatively large, strongly incurv- 
 ed, projecting considerably above the hinge line ; cardinal 
 area small, proportionately high, triangular, much shorter 
 than the width of the shell below; extremities rounded : 
 deltidium high triangular, extending nearly to the point 
 of the beak; width at the base about one-third the entire 
 length of the cardinal line. Dorsal valve very much 
 smaller than the opposite one, sub-semicircular ; length 
 very little more than the width, flat or slightly convex, 
 most gibbous at the beak ; hinge line straight. 
 
 Surface apparently smooth. 
 
 This species is very closely allied to Orthis umbonata of Conrad, but differs from 
 it in having the hinge line less than the width of the .shell below, and also in the 
 ventral valve being less gibbous, and the beak not so much incurved. 
 
 Geological position and localities. In the Coal measure slates and shales of 
 Peoria and Bureau counties, Illinois. 
 
 • The above comparisons are made with American specimens, for the reason that D'Orbignt’s 
 original specimens were from this country, while those figured by De Koninck in his monograph 
 are European specimens identified by D’Orbignv’s description. 
 
 6 
 
42 
 
 BRACHIOPODA. 
 
 Spirifer transversa ( n. s.)- 
 
 Shell small, varying from sub-semicircular to subtrian- 
 gular, gibbous; valves nearly equal; diameter equal to the 
 length of the shell ; cardinal extremities produced in mu- 
 cronate points. Ventral valve slightly the most gibbous; 
 mesial sinus deep and subangular, extending from beak to 
 base, narrow and having a small plication in the bottom ; 
 beak slightly incurved over the area, which is of medium 
 height, and reaches to the extremity of the cardinal line ; 
 foramen triangular, higher than wide, having a distinct 
 groove down each side for the insertion of the deltidial 
 plate. Dorsal valve most gibbous near the beak, from which 
 point it curves gently toward the front of the shell ; mesial 
 elevation of moderate height, narrow and having a de- 
 pressed line along the centre, corresponding to the eleva- 
 tion in the bottom of the sinus in the opposite valve. 
 
 Surface marked by nine to twelve strong, somewhat 
 angular plications on each side of the mesial fold and sinus, 
 crossed by fine sharp closely arranged concentric striae, 
 arching abruptly up or back, both on the plications and 
 mesial fold. The surface of the cardinal area, and the por- 
 tion of the shell bounding it, is covered by fine but clearly 
 distinct granules. 
 
 This species belongs to the group of which S. mucronatus of the Hamilton rocks 
 of New-York may be considered the type; from which species it differs in being a 
 much smaller shell, much more ventricose, having much more closely arranged con- 
 centric lines, and in having more distinct plications, which are not directed toward 
 the beak as in that shell. It differs from S. submucronatus of Hall (Geo. of Iowa, 
 PI. 4, fig. 4), in being a shorter shell, and in the form of the mesial elevation, which 
 in that species is single and much broader than in this; in having a less number of 
 plications, area not so high, and more gradually sloped from the beak toward the 
 cardinal line, instead of carrying its breadth for some distance, then terminating 
 abruptly as in his fig. 46. This is also a much more rotund species than any spe- 
 cimens of that. It differs from S. kentuckensis of Shumard, in having a greater 
 number of plications, which arc, proportionately to the size of the shell, much more 
 slender and more closely arranged ; and the mesial fold of that species has no cen- 
 tral depression, nor the sinus an elevation. 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone at Buzzard’s Roost, Alabama. 
 
BRACHIOPODA. 
 
 43 
 
 Spirifer siibelliptica (n. s.)- 
 
 Shell transversely subelliptical, gibbous ; hinge line 
 less than the greatest width of the shell ; cardinal extre- 
 mities regularly and strongly rounded ; beaks distant and 
 slightly incurved. Mesial sinus of the ventral valve broad 
 and shallow, not angular, somewhat broadly expanded 
 toward the front of the shell ; area moderately high, 
 rapidly sloping from the beak downward, and not reach- 
 ing the extremities of the cardinal line ; foramen narrow, 
 height double the width, distinctly grooved at the sides. 
 Dorsal valve less gibbous than the ventral ; mesial eleva- 
 tion broadly rounded and simple. 
 
 Surface marked by from five to seven simj)le rounded 
 plications, which are distinct on the front of the shell, but 
 gradually die out as they approach the cardinal line, and 
 crossed by fine closely arranged concentric lamellae which 
 arch abruptly upward as they cross the plications and 
 mesial fold. The lower edges of the lamellae are orna- 
 mented by very fine closely arranged hair-like spine bases. 
 
 This differs from the foregoing species by being a larger shell, much less rotund 
 and much longer in proportion to i s width, and in its simple mesial fold and sinus, 
 as well as in other respects. It differs from S. kentuckensis in being a much larger 
 shell, i» its hinge line being less than the greatest width of the shell, and its cardi- 
 nal extremities rounded. Specimens of this species are usually found flattened, from 
 which we infer that the substance of the shell is very thin. 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone, Buttonmould Knob, Kentucky. 
 
 Spirifer perplexa ( n. s.). 
 
 Shell small, varying in form from suborbicular to trans- 
 versely subelliptical, globose ; widest in the centre, and 
 having the cardinal extremities strongly rounded. Ventral 
 valve much the largest, convex, most gibbous near the 
 beak, destitute of sinus (except a faint depressed line in 
 rare instances) ; beak prominent, and strongly recurved 
 over the area ; hinge line much less than the greatest 
 
'44 
 
 BRACIIIOPODA. 
 
 width of the shell ; area triangular, little wider than high, 
 not well defined ; triangular foramen comparatively large, 
 higher than wide, occupying nearly one half the entire 
 length of the area. Dorsal valve generally depressed con- 
 vex, sometimes quite gibbous, and most so near the beak, 
 which is slightly incurved ; transversely elliptical, with 
 the upjier side of the ellipse flattened. 
 
 Surface marked by numerous fine closely arranged con- 
 centric bands, the lower margin of which sometimes 
 shows a very fine fimbriate structure, giving, when well 
 preserved, the appearance of fine radiating strim which 
 can only be seen with a magnifier. 
 
 This species is one of the group usually referred to S. lineatus of Martin; but 
 according to their figures, it is a very distinct shell. The difference of size in adult 
 individuals is alone of specific importance. Our shell seldom attains a breadth of 
 more than five eighths of an inch, while theirs is sometimes two inches; the lamella 
 of S. lineatus is also much more conspicuous, giving a more rugose surface than in 
 this species. 
 
 Geological position and locality. In the Upper Coal measures in almost every 
 part of the country where rocks of that age exist. 
 
 ^pirifer su!>\ eiitiicosa (n. s.). 
 
 Shell of medium size, transverse, subelliptical, width 
 one fourth greater than the length ; cardinal line slightly 
 less than the greatest Avidth of the shell below ; extremi- 
 ties rounded ; valves about equal, and regularly rounded 
 in front and on the sides. Ventral Amlve gibbous and regu- 
 larly arcuate, having a shallow, well defined, regularly 
 rounded sinus extending from beak to base ; beak small, 
 incur\md ; area low, extending to the extremities of the 
 cardinal line, coarsely striated transversely, edges or 
 boundary rounded. Dorsal valve of equal thickness with 
 the other, but more angular in its convexity, elevated in 
 the centre into a prominent mesial ridge Avhich is sharply 
 angular in the middle ; beak rather large, gibbous, and 
 someAvhat incurved. 
 
BRACHIOPODA. 
 
 45 
 
 Surface of each valve marked by from sixteen to twenty 
 low rounded plications on each side of the mesial fold and 
 sinus, and from seven to nine on the mesial fold. Some of 
 the plications bifurcate, while others are simple on the 
 same specimen. Also marked by fine concentric strim, 
 which slightly undulate as they cross the plications. 
 
 This shell is closely allied to S. ivcrebescens of Hall (Geo. Rep. Iowa, PI. 27, 
 fig. 6), but differs considerably in detail. The length of the hinge line is less than 
 the width of the shell below; extremities rounded; plications often bifurcating. In 
 that species the length of the hinge fine is equal to or greater than the width of the 
 shell below; extremities salient or submucronate; plications stronger, and usually 
 simple; mesial prominence less elevated, less angular, and po.sscssing a less number 
 of plications. 
 
 Geological position and locality. In Coal measures. Big Creek, Indiana; near 
 New-llarmony. 
 
 Rofzia (n. s.). 
 
 Shell small, subglobose, length and breadth equal. Ven- 
 tral valve regularly arched from beak to base ; scarcely 
 sinuate except by the smaller size of the two central plica- 
 tions ; beak small, projecting considerably beyond that of 
 the opposite valve, slightly incurved, truncated by a small 
 rounded foramen; cardinal area very small, triangular, the 
 base little more than one fifth the Avidth of the shell, dis- 
 tinctly defined, longitudinally striate ; deltidium compara- 
 tively large, Avith the sides subparallel: the centre is 
 depressed, giving it a bilobed appearance, base more than 
 one-third the width of the cardinal line, Avhile the upper 
 end is the full breadth of the foramen. Dorsal valve more 
 convex than the ventral, fullest near the beak. 
 
 Surface marked by from nine to sixteen simple sharply 
 rounded plications, Avhich extend from beak to base : the 
 two outermost on each side are rather indistinct; the tAvo 
 central ones on the ventral valve, and one on the dorsal, 
 are somewhat finer than the others, which feature gives 
 the shell the appearance of being slightly sinuous on each 
 valve. Shell structure highly punctate under a strong lens. 
 
64 
 
 BRACHIOPODA. 
 
 This species more closely resembles R. punctulifera of Shumard (Trans. Acad. 
 Sci. St. Louis, Vol. I, No. 2), but is a smaller shell, not so much elongated, more 
 globose, has normally a less number of plications and proportionately a smaller 
 area. 
 
 His species is described as having a moderately wide shallow sinus extending from 
 the front nearly to the beak; a feature not possessed by this shell, there being no 
 proper sinus, and only the appearance of one near the front. 
 
 Geological position and localities. In limestone of the Upper Coal measures in 
 Menard, Mason, Fulton, Peoria, Tazewell, Knox, Marshall, and many other coun- 
 ties in Illinois. 
 
 Atlijriis si)iriferoides ( n. s.). 
 
 Shell transversely serai-elliptical ; hinge line straight ; 
 width double the length. Dorsal valve gibbous, having a 
 strong double mesial elevation which extends from beatc to 
 base; beak incurved. Ventral valve most gibbous toward 
 the beak ; mesial sinus deep, slightly emarginate in front, 
 corresponding to the depression in the mesial elevation of 
 the opposite valve ; beak closely incurved over that of the 
 opposite valve ; foramen very broad, and entirely filled by 
 the beak of the opposite valve. Both valves thickened on 
 the cardinal line, giving it almost the appearance of a 
 linear area. 
 
 Surface traversed by somewhat closely arranged trans- 
 verse lamellose bands, indicating the stages of growth, and 
 slightly arching upward on the mesial fold and sinus ; and 
 also by very fine intermediate strim, and, in well pre- 
 served specimens, it also exhibits fine radiating strise. 
 
 This species is closely allied to Af. phalaena of Phillips, which is the only species 
 of this form I know of having been described; but is, proportionately with the 
 length of the shell, much less extended on the hinge line; the concentric lamellae 
 are more distant, and the mesial sinus more profound. It differs from any species 
 of this group hitherto described from our rocks, in its strong resemblance to speci- 
 mens of the Genus Spirifer. 
 
 Geological position and locality. In Kaskaskia division of the Carboniferous 
 limestone series. Fountain Bluff, Illinois. 
 
BRACHIOPODA. 
 
 47 
 
 Atliyrus orbicularis (n. s.)- 
 
 Shell sub-circular, or varying from transversely sub- 
 elliptical to subovately elongate, moderately gibbous. Dor- 
 sal valve less than the ventral, depressed convex, rarely 
 slightly elevated in front; beak closing the foramen of the 
 opposite valve. Ventral valve convex, strongly gibbous 
 toward the beak; front sometimes flattened, but without 
 true sinus ; beak prominent, slightly incurved, and ver- 
 tically or somewhat obliquely truncated by a circular 
 foramen. 
 
 Surface distinctly marked by concentric lamellose bands 
 of growth. 
 
 This species is closely allied to A. sublamcllosa of Hall (Geo. Kept. Iowa, p. 702), 
 from which it is easily distinguished by having a larger ventral than dorsal valve, 
 while in that the dorsal valve is much the largest; and by the much greater eleva- 
 tion or thickening of the ventral valve toward the beak. 
 
 It has sometimes been referred to Tercbratula plano-sulcata of Phillips, from 
 which it differs in being a less rotund shell, and in the much less gibbosity or infla- 
 tion of its ventral valve toward the front of the shell, as well as in other respects. 
 
 Geological position and localities. In Coal measures, particularly the upper por- 
 tion, extensively distributed in the Western States. 
 
 Atliyrus differeiitiiis ( n. s.). 
 
 Shell varying in form from subcircular to subelliptical, 
 and sometimes subquadrate ; greatest width about the 
 middle. Dorsal valve quite regularly convex, slightly ele- 
 vated in front into a broad mesial prominence ; beak 
 incurved beneath that of the opposite valve, and partially 
 closing the foramen. Ventral valve more gibbous than the 
 dorsal, having a narrow and generally well defined sinus 
 extending from near the beak to the base, widening more 
 or less in different specimens as it approaches the front 
 of the shell, though usually well defined along its centre 
 by a somewhat sharply rounded depression, and inflated 
 along the sides ; front is produced ; beak slightly incurved, 
 and truncated vertically by a round foramen of medium 
 
 size. 
 
V 
 
 48 BRACmOPODA. 
 
 Surface marked by fine concentric stricc, and also by 
 stronger lamelliB marking the stages of growth. Partially 
 exfoliated specimens sometimes show radiating striae, 
 Avhich are not visible on perfect shells. 
 
 This species differs fi oin yithyrus su'>quadruta of IIai.i. (Geo. Rep. Iowa, PI. 27, 
 fig. 2), in the more regular convexity of its valves, in the elevated front being 
 broader and lower. The ventral valve of yJ. sabquadrata is nearly straight from the 
 centre of the shell to the outer edge of the mesial sinus, while that of this species 
 is regularly convex. It differs from Terrehratala suhtillta o( Hall in being much 
 wider proportionately to its length, in its more circular out ine, and in its sinus 
 being more distinctly defined much nearer the beak, and more sharply defined 
 along its centre on the front half of the shell. 
 
 This is one of our American forms which has been referred to Terebratula 
 royssii (Leveii.le); but according to De Koninck’s descriptions and figures, it 
 possesses differences which are clearly of specific importance. He states in his de- 
 scription that the principal character of T. royssii consists in a sort of epidermis 
 composed of a great number of thin, narrow, concentric lamellge, formed by the 
 union of a great number of small spines implanted upon the outer edge of the con- 
 centric lines of growth, a character never possessed by specimens of our shell. The 
 sinus of the European specimens is broader, more profound, and becomes obsolete 
 near the middle of the shell, and is regularly concave : in this it extends to near 
 the beak, and is abruptly rounded (approaching an angle) at the bottom, and usu- 
 ally somewhat inflated at the sides. 
 
 Geological position and localities. In Coal measures at Lasalle, Springfield, 
 Belleville, and Sparta (Illinois), and near Richmond and at Charbonier (Missouri). 
 
 Terebratula iuoruata (n s.). 
 
 Shell elongate, ovate, length once and a half the 
 breadth, widest below the middle, front rounded. Ventral 
 valve but slightly convex, fullest near the beak, flattened 
 or slightly concave in front ; beak large, projecting con- 
 siderably beyond that of the dorsal valve, and incurved; 
 size and form of the foramen indeterminable from the 
 broken condition of the specimens : sides of the valve 
 near the beak abruptly inflected to meet those of the oppo- 
 site one. Dorsal valve more gibbous than the other, very 
 convex near the beak, spreading toward the sides and 
 front, with the centre sharply rounded. 
 
 Surface marked by a few distant lines of growth some- 
 
BRACHIOPODA. 
 
 49 
 
 what elevated, by fine concentric striae, and is finely but 
 
 closely and beautifully punctate. 
 
 Geological position and locality. In Coal measure limestones in Sangaman county, 
 Illinois. It is also found in the Carboniferous limestone series as low down as the 
 Keokuk division. 
 
 RliyiichoiielLi eatonisetbrmis ( n.s.). 
 
 Shell very gibbous, subtriangular ; greatest width near 
 the front, which is truncate ; sides regularly rounded to 
 near the beak, which is small and slightly protruded be- 
 yond the curve ; valves unequal. Ventral valve convex 
 near the beak and at the sides, having the centre depressed 
 into a very profound rounded sinus, which is almost as 
 broad as the greatest width of the valve, and prolonged in 
 front into a linguliform extension which conforms to the 
 elevated front of the opposite valve ; beak slightly in- 
 curved over that of the opposite one. Dorsal valve pro- 
 foundly gibbous and highly elevated in front, regularly 
 arched from beak to base, and rapidly sloping from the 
 edge of the elevation to the sides of the shell ; slope 
 nearly straight at the front of the shell, and convex toward 
 the middle. The mesial and front elevations are marked 
 by from three to five strong angular plications, while the 
 remaining portion of the shell is plain, with the exception 
 of very fine concentric striae which appear to conform to 
 the shape of the shell at its different stages of growth. 
 
 I know of no other species in the rocks of this age, with which this can easily be 
 confounded. It has much the general form of the Genus Eatonia as given by Hall, 
 but is very clearly a true lihynchonella. This species bears considerable resemblance 
 to R. missouriensis (Shumard, Geological Report of Missouri, PI. fig. 5), but is 
 less angular than that species, not so broad on the top of the elevation, and the 
 plications are not so large. Perfect specimens of R. missouriensis show very fine 
 longitudinal strite, which are not mentioned in Shumard’s descriptions; which fea- 
 ture this species never possesses. There are also other difierences. 
 
 Geological position and localities. In Coal measure shales at Graysville, Illinois; 
 and in the Big Creek limestone, Indiana. 
 
 7 
 
50 
 
 BllACIIIOPODA. 
 
 Uliynelioiiella c.\])laiiata ( n. s.)- 
 
 Shell small, sub-triangular, very gibbous ; beak small 
 and pointed, straight. Ventral valve nearly or slightly con- 
 vex to the middle, from which point it is abruptly curved 
 upwards, forming a broad and well defined sinus, having 
 one large, low plication in its bottom occupying one-half 
 the entire breadth of the sinus ; sides of the extension 
 nearly parallel. Dorsal valve extremely ventricose, greatest 
 elevation in front, gradually curving back to the beak, 
 which is small and closely incurved beneath that of the 
 opposite valve ; the sides of the front slope rapidly from 
 the edges of the elevated plications to about two-thirds the 
 depth of the valve, where they come in contact with the 
 next plication, which stands out abruptly in a stair-like 
 projection, from which the sides are perpendicular to the 
 lower edges of the valve. 
 
 Surface marked by eight simple angular plications, which 
 do not extend quite to the beak; two of which are very 
 strong, and elevated on the dorsal valve into a mesial 
 prominence, with two corresponding depressions in the 
 sinus of the other valve ; the plications on each side of the 
 prominence, except the first, are indistinct, particularly 
 the outer ones, which are scarcely perceptible. There are 
 also traces of very fine concentric striae crossing the plica- 
 tions, and having a zigzag direction, which are visible only 
 on the front of the shell. 
 
 This species bears some resemblance to JR. woriheni of Hall, described in a pam- 
 phlet entitled “Descriptions of New Species of Fossils from the Carboniferous 
 limestone of Indiana and Illinois;” but is considerably more elevated in front, not 
 so angular in outline, and H. wortheni does not possess any plications except the 
 two which are elevated into the mesial prominence. 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone. I have also a specimen, doubtfully labeled, from the Coal measures near 
 New-IIarmony, Indiana. 
 
BRACIIIOPODA. 
 
 51 
 
 Kliyiiciioiiclla carboiiaria ( n. s.). 
 
 Shell transversely subelliptical in outline, when viewed 
 from above, with a small sharp beak projecting beyond the 
 general outline ; and when seen in front, of a somewhat 
 quadrangular form, having the gides rounded. Ventral valve 
 very shallow, slightly convex near the beak and on the 
 sides, with the center depressed and prolonged into a quad- 
 rate extension, which fits into the sinus in the border of 
 the opposite valve. Dorsal valve very much elevated, espe- 
 cially in front, from which point it gradually slopes with 
 but little curve to the beak; the lateral slopes rounded 
 down to the sides of the front. 
 
 Surface marked by about thirty simple plications, which 
 are rounded or subangular in the sinus and on the mesial 
 elevation, and flattened on the sides of the shell : ten of 
 these plications are elevated on the dorsal valve and a cor- 
 responding number depressed on the ventral, which depres- 
 sion and elevation do not extend past the middle of the 
 shell ; the cardinal areas of the dorsal valve are somewhat 
 depressed. 
 
 This species may be compared with /?. cooperensis of Shumard (Geologica^ 
 Eept. Missouri), which it somewhat resembles in general outline, but is more trans- 
 versely elongate, and has a greater number and smaller plications. The geological 
 position is also very different, his being found in rocks of the age of the Chemung 
 of New-York, this being from the Upper Coal measure rocks. 
 
 Geological position and locality. In the Upper Coal measure limestone, near 
 Farmington, Illinois. 
 
 Itliyiiclioiiella algeri ( n. s.). 
 
 Shell small, varying from suborbicular to transversely 
 subelliptical, and sometimes subovate, usually gibbous, some- 
 times in young specimens depressed convex ; beak straight 
 and pointed. Ventral valve shallow, depressed convex near 
 the beak, and becoming broadly sinuate and prolonged into 
 a broad subquadrangular extension in front. Dorsal valve 
 ventricose, somewhat regularly convex, elevated in front ; 
 beak incurved beneath that of the opposite valve. 
 
52 
 
 BRACHIOPODA. 
 
 Surface marked by from nine to fourteen simple sub- 
 angular plications, which are distinct in front, but become 
 obsolete near the middle of the shell, from three to four of 
 which are elevated on the front of the dorsal valve, and a 
 corresponding number depressed in the opposite valve ; and 
 also by very fine undulating concentric striae, and a few 
 zigzag lines of growth on the front of the shell, most dis- 
 tinct on the elevation and in the sinus. 
 
 The only species with which this can possibly be confounded is R. nucleata of 
 Hall (Geological Report of Iowa, PI. 23, fig. 2); but it is not triangular, and the 
 plications are larger, fewer in number, and do not extend to the beak as in that 
 species. The geological position is also different, the above cited occurring in the 
 middle of the Carboniferous limestone series. 
 
 Geological position and locality. In coal measures at Big creek, near New Har- 
 mony, Indiana. 
 
 LAMELLIBRANCHI ATA . 
 
 Leda oweiii ( n. s. ). 
 
 Shell somewhat above the medium size, rather more 
 than twice as long as wide, very gibbous and inflated ante- 
 riorly, rapidly tapering and attenuate posteriorly ; beaks 
 somewhat prominent, incurved and closely approximate, 
 situated near the anterior extremity of the shell and point- 
 ing anteriorly ; anterior extremity rapidly sloping from 
 the beak downward, and rounded below. Ventral margin 
 broadly curved, and, a little anterior to the middle, some- 
 what projecting ; posterior extremity narrowly rounded ; 
 hinge line posterior of the beaks straight, or very slightly 
 arched ; hinge with ten teeth on the anterior side of the 
 beak, some of which are comparatively large, and about 
 forty-one or two on the posterior side ; those beneath the 
 
LAMELLIBRANCHIATA. 
 
 53 
 
 beak extremely small, but gradually increasing in size as 
 they approach the posterior extremity, except two or three 
 of the terminal ones, which are smaller. Exterior of the 
 shell marked by a slight depression, which extends from 
 the beak to the lower side of the posterior extremity, and 
 by strong irregular concentric bands or folds which become 
 finer and less distinct as they approach the cardinal line. 
 
 Geological position and locality. In the Coal measures : mouth of Rush creek, 
 Indiana, five miles below New-Harmony. 
 
 Leda gibbosa (n. s. ). 
 
 Shell of medium size, once and a half as long as wide, 
 ovoid anteriorly, elongate and moderately attenuate poste- 
 riorly ; beaks elevated and slightly anterior of the middle 
 of the shell, incurved and pointing posteriorly ; cardinal 
 line curved, and on the posterior side sharply elevated, with 
 a distinct depression between it and the umbonal slope. 
 Ventral margin regularly curved; escutcheon, broad and 
 faintly depressed. 
 
 Surface marked by fine but distinctly elevated concen- 
 tric striae. 
 
 This species differs from Leda bellastriata of Stevens (Am. Journal of Science, 
 Vol. XXV., P. 261), in being much shorter in proportion to its width, much less 
 contracted and attenuate posterioily, and more ventricose. 
 
 Geological position and locality. In Coal measures on the Wabash river, five miles 
 below New-Harmony, Indiana. 
 
 Leda polita (n. s.). 
 
 Shell small, somewhat elongated posteriorly, about 
 twice as long as wide, broadly subovate, widest anterior 
 of the middle : beaks very small, pointed towards the 
 shortest end, incurved and closely approximate, situated 
 about one third the entire length of the shell from the an- 
 terior extremity, which is sharply rounded ; the curve of 
 the ventral margin is a very perfect semi-oval, rounded 
 
54 
 
 LAMELLIBRANCHIATA. 
 
 abruptly at the posterior end ; hinge line on the posterior 
 side of the beak straight, or slightly depressed. Surface of 
 the shell appearing smooth to the unassisted eye, but 
 under a magnifier, of ordinary power, it is covered with 
 very fine concentric strim which are recurved as they ap- 
 proach the cardinal line of the posterior ; and also by one 
 or more faintly depressed lines along the posterior umbo- 
 nal slope ; teeth unknown. 
 
 This species is allied to L. bellastriata (Stephens, Am. Jour, of Science, Vol. 
 xxv), but is not so much prolonged at the posterior end, the cardinal line is not 
 so much depres.sed, and it does not possess the beautiful distinct concentric striae 
 which is so marked a character of that species. 
 
 Geological position and locality In the Coal measures at Dr. E. Hall’s mill. Pope 
 creek, Knox county, Illinois. 
 
 ^iiciila parva (n. s.). 
 
 Shell minute, subtriangular, somewhat gibbous at the 
 beaks, which are small, incurved, approximate, pointing 
 toward and terminating the anterior extremity ; cardinal 
 line straight to near the beaks, where it is slightly curved 
 downward ; cardinal line and anterior slope are at right 
 angles to each other. Ventral margin beautifully and 
 gradually curving upward to the posterior, which is sharply 
 rounded. Interior of the hinge unknown. 
 
 Surface marked by comparatively coarse, regular, sharp, 
 concentric strim. 
 
 This shell has the general appearance of N. shumardana of Hall. (Trans. Albany 
 Inst., Vol. iv, Nov. 185G), but differs from it entirely in the surface structure; that 
 species being only finely striated, as are alt shells of this class, when destitute of 
 ornamental surface structure ; while the makings of this species are of an orna- 
 mental nature, sufficiently strong to be considered of specific importance. 
 
 Geological position and locality. In the Coal measures at Danville, Illinois. 
 
 ^'ucula cylmdriciis (n. s. ). 
 
 Shell small, about twice as long as wide, subcylindrical 
 in form ; valves most ventricose a little anterior to the mid- 
 
LAMELLIBRANCHIATA. 
 
 die, from which point they slope abruptly to the posterior 
 extremity, and but slightly to the anterior : beaks short, 
 obtuse, almost anterior, and pointing forward ; depression 
 beneath them extremely small : hinge lines, posterior to the 
 beaks, straight or slightly arching, and nearly at right 
 angles to the anterior slope. Teeth unknown. 
 
 Surface smooth and polished, except fine concentric 
 lines of growth, which are verj^ indistinct. 
 
 Geological position and locality. In Coal measures, Carnahan’s Coal mine, 
 Mercer county, Illinois. 
 
 Astaitella varica (n. s.). 
 
 Shell subcircular, only moderately gibbous but most so 
 on the umbones, beaks anterior to the centre of the shell, 
 approximate, sharp and pointing forward ; anterior end 
 deeply concave under the beak and rounded below. An 
 oblique ridge extends from the beak in the direction of the 
 posterior basal margin, becoming faint or imperceptible 
 before reaching the front; ligamental area deeply marked. 
 
 Surface marked by very strong, somewhat distant con- 
 centric ridges, which, when perfect, are raised into thin, 
 sharp expansions, their number on the specimen under 
 description, which is about half an inch wide, is ten. The 
 spaces between them are regularly rounded. 
 
 Geological position and locality. In Coal measures, Springfield, Illinois. 
 
 Ediiioiidia conceiitrica ( n. s.). 
 
 Shell longeT than high, subelliptical, ventricose on the 
 umbones ; beaks about one fourth distant from the anterior 
 to the posterior of the shell, prominent, slightly incurved 
 and pointing to the anterior ; margins quite regularly 
 curved, except the dorsal, which is nearly straight. 
 
 Surface marked by concentric wrinkles or folds, irregu- 
 
56 
 
 LAMELLIBRANCHIATA. 
 
 lar in their distance from each other, sometimes two or 
 three appear to be crowded upon each other. Minute sur- 
 face markings unknown. 
 
 Geological position and localities. In the Coal measures, Carnahan’s Coalmine, 
 Mercer county (Illinois), Big Creek (Indiana), Charbonier (Missouri). 
 
 All<»risiiia clavata ( n. s.). 
 
 Shell of medium size, elongated posteriorly, broad and 
 gibbous at the beaks, rapidly sloping from the umbones to 
 the anterior extremity, and gradually decreasing in width 
 and thickness, as it approaches the posterior ; beaks approx- 
 imate and incurved, situated one-fifth of the entire length 
 of the shell from the anterior extremity ; anterior margin 
 rapidly sloping from the beaks to the point of greatest 
 length, which is situated below the middle of the shell and 
 regularly rounded below to the ventral margin, which is 
 straight or slightly sinuate a little anterior of the center of 
 the shell, and regularly curving upward as it approaches 
 the posterior extremity ; posterior extremity sharply 
 rounded ; cardinal margin concave or slightly depressed in 
 the middle. On the surface of the shell, between the ante- 
 rior and posterior umbonal ridges, there is a flattened or 
 slightly concave space extending like a sinus from the beak 
 to the base or ventral margin of the shell. 
 
 The surface of the shell is marked by strong concentric 
 ridges which mark the different stages of growth, most dis- 
 tinct on the middle of the shell. 
 
 Geological position and locality. In the Kaskaskia division of the Carboniferous 
 limestone series, Chester, Illinois. 
 
 Allorisma simiata (n. s.). 
 
 Shell below medium size, prolonged posteriorly, thick, 
 and extremely gibbous along the posterior umbonal slope ; 
 beaks prominent, projecting considerably above the cardi- 
 
LAMELLIBRANCHIATA. 
 
 67 
 
 nal line, closely approximate and incurved, situated a little 
 more than one-third the entire length of the shell from the 
 anterior extremity. Anterior margin rapidly sloping from 
 the beaks to the extremity, and sharply rounded below. 
 Ventral margin strongly sinuate, the sinus being situated 
 anterior to the middle, and gradually rounded to the pos- 
 terior extremity, which is narrow ; cardinal line straight 
 from the beaks to the posterior extremity. 
 
 The surface of each valve is marked by a broad shallow, 
 but distinctly defined depression extending from the beak 
 to the base or ventral margin of the shell between the an- 
 terior and posterior umbonal slopes. 
 
 Surface marked by strong concentric ridges parallel 
 with the borders of the shell. 
 
 This species differs from the last one described, in being 
 a shorter shell in proportion to its depth, in its more pro- 
 minent beaks and in the strong sinus marking the centre 
 of the valves, and in being much more gibbous, especially 
 along the umbonal slope. 
 
 Geological position and localities. In the Kaskaskia division of the Carboniferous 
 limestone, Kaskaskia and Chester, Illinois. 
 
 Myaliiia swallovi (n. s.). 
 
 Shell small subtriangular, height once and a half the 
 length, somewhat gibbous on the umbones ; cardinal border 
 oblique and slightly arched ; posterior margin subparallel 
 with the umbonal ridge, and forming with the cardinal 
 line an angle of 130® ; ventral margin strongly rounded ; 
 distance across the ventral extremity of the shell some- 
 what less than the width above ; anterior extremity pro- 
 jecting a little beyond the point of the beak, and somewhat 
 swollen or inflated between the beak and the margin of the 
 valve, with a shallow sinus or depression between it and 
 the umbonal ridge, running from the beak to the centre or 
 8 
 
58 
 
 LAMELLIBRANCHIATA. 
 
 middle of the buccal border: buccal border straight or 
 very slightly concave ; umbonal ridge prominent, slightly 
 angular, and declining with a gradual slope to the posterior 
 margin ; anterior slope very abrupt, nearly at right angles 
 with the plane of the shell. The umbonal ridge is curved 
 in the upper part of the shell toward the posterior extre- 
 mity, but afterward reflected, and terminating on the 
 anterior side of the ventral portion of the shell. The 
 surface of the shell is marked with extremely fine concen- 
 tric striae, which are bent abruptly as they cross the 
 umbonal ridge ; also with a few concentric lines of growth. 
 
 This is a very pretty species, and is somewhat closely related to M. recta of 
 Shumard (Ext. from Trans. Acad. Science, St. Louis, Vol. I, No. 2, if we have 
 succeeded in rightl_) referring that species); but it differs in having the beaks not 
 quite terminal and less acute, the cardinal margin more arched, and the umbonal 
 ridge not so angular; the ventral portion or base of the shell is not so wide as in 
 his species, in comparison with the width from the posterior end of the cardinal 
 line to the middle of the buccal border. 
 
 Geological position and locality. In the Coal measures at Charbonier, and 12 
 miles northwest of Richmond, Missouri. 
 
 GASTEROPODA.' 
 
 Bellerophoii ellipticus ( n. s.). 
 
 Shell large, very thin and fragile ; inner volutions 
 small, and but little expanding ; outer volution large, 
 broadly expanded, almost flattened ; aperture very trans- 
 verse elliptical, as wide again as long ; lip sharp, outer 
 portion notched ; posterior portion deeply sinuate, where 
 it passes over the preceding volution, and forms a callus 
 of equal thickness with the other portion of the lip. Dor- 
 sum marked in the earlier stages by a very shallow, 
 narrow groove, which becomes broader, and has the centre 
 
GASTEROPODA. 
 
 59 
 
 elevated as it approaches the front of the last volution, 
 into a somewhat sharper and prominent carina, which 
 terminates in the notch in front. Umbilicus open, and of 
 moderate size. 
 
 Surface of the shell covered with very fine longitudinal 
 strim, which terminate abruptly at about the middle of the 
 expanded portion of the last volution, the remainder of 
 which is marked by broad transverse undulations, or 
 wrinkles, and also by concentric or transverse striae, much 
 finer than the longitudinal striae, giving a finely cancellated 
 structure to the shell where the two sets cross each other. 
 The concentric striae and the wrinkles are bent abruptly 
 backward, as they cross the carina in front, and but 
 slightly over the groove in the earlier stages of growth. 
 
 Specimens of this species, when found in limestones or 
 very compact shales, are usually in the state of casts, 
 owing to the thinness of the shell and the ornamented 
 structure of the exterior, which adheres more firmly to 
 the matrix than to the smooth interior ; and in this state 
 the impression of the striae appear like low distant plica- 
 tions, which is owing to some of the striae being stronger 
 than others, and making a deeper impression. 
 
 Geological position and localities. In the Coal measures, at Dr. E. Hall’s Mill, 
 Pope Creek, Knox Co.; Carnahan’s Mine, Mercer Co.; and Mr. Fisher’s Mine, 
 near Lacon, Illinois. 
 
 Belleroplion vittatns ( n. s.). 
 
 Shell of medium size, subglobose, somewhat rapidly 
 expanding at the sides. Aperture semilunate, broadly 
 transverse, but rather shallow : outer lip very thin, and 
 expanding at the sides into sharply rounded, ear-like exten- 
 sions, very broadly and deeply sinuate ; and when the 
 specimen is held with the plane of the mouth horizontal 
 with the axis of the shell, the sinus extends nearly its 
 entire width : notch shallow, rounded at the bottom, and 
 
60 
 
 GASTEKOPODA. 
 
 about an eighth of an inch wide in adult specimens. The 
 inner side of the mouth is formed entirely by the preced- 
 ing volution, without thickening or callosity. Axis of the 
 shell imperforate. 
 
 Surface, except the outer half of the last volution, 
 marked by about twenty-four sharp, revolving, nearly 
 parallel bands, some of which, on the sides of the shell, are 
 interrupted, forming broken striae or elongated nodes. 
 
 This species has usually been referred to B. urii, of Fleming, and has been 
 figured as such by Messrs. Norwood and Pratten in the Transactions of the 
 Academy of Sciences of Philadelphia, June 1855; but on careful comparison with 
 figures and descriptions by De Koninck, Phillips and others, it proves to be a 
 very distinct and well marked species. B. urii is characterized by from 36 to 38 
 keels, or revolving bands; while this species, by an examination of a large number 
 of specimens before us, presents no more than 26, and rarely more than 22. The 
 principal points of separation, however, consist in the nature of the axis, and in 
 the form of the sides of the mouth. In B. urii the sides of the mouth are connected 
 by a callosity to the preceding volution in front of the axis of the shell, while in 
 this species they are free, and stand out somewhat distant from the volution. 
 
 B. urii has the structure of an umbilicate shell, except the perforation being 
 filled by callosity, leaving only a slight depression on the sides of the shell, expressed 
 as follows by De Koninck; “ Z^s ombilices sont remplacSs par des petites fassettes 
 arrondies et peu profondes.” In our shell the volutions do not pass around the cen- 
 tre, but their inner edges form the axis. This peculiarity is not only of specific 
 importance, but actually places the shell in a different subdivision of the genus. 
 
 Geological position and localities. In Coal measures at the mouth of Rush Creek 
 (Indiana), Graysville (Illinois). 
 
 Belleroplioii blaiiyanus ( n. s.). 
 
 Shell small, subglobose, rapidly expanding on the sides 
 in front. Aperture broadly transverse, semilunate, deeply 
 impressed by the preceding volution ; outer lip thin; sides 
 attached by a slight callosity to the preceding volution in 
 front of the axis of the shell. 
 
 This shell is umbilicate in form, though imperforate, 
 the cavity being filled by callosity, except a small circular 
 indentation. 
 
 Surface marked, except the front or last half of the outer 
 volution, by about sixteen sharp, nearly parallel, longitu- 
 
GASTEROPODA. 
 
 61 
 
 dilial or revolving bands, which are not always continuous ; 
 and on the sides, around the axis, by a few rows of elon- 
 gated nodes, which appear to be broken or undeveloped 
 revolving bands, which extend much farther upon the front 
 of the shell than the other bands ; the portion of the front 
 not thus covered is smooth, except some very fine con- 
 centric striae, and a double carina along the dorsum, which 
 is sometimes very faintly visible. 
 
 This shell is most nearly related to B. urii of Europe, but differs from it in hav- 
 ing not more than half the number of revolving bands, and in the sides of the front 
 half of the outer volution being covered by broken ribs or nodules. 
 
 Geological position and localities. In Coal measures in Saline and Peoria coun- 
 ties, and at Danville and Graysville, Illinois. 
 
 Belleroplioii steveiisianiis ( n. s.). 
 
 Shell small, slightly elongate, gradually expanding 
 toward the front. Aperture transverse, sub-semilunate, 
 sometimes triangular, modified by the preceding volution : 
 outer lip thin, sides very much thickened by an overlap- 
 ping callosity ; dorsum furnished with a rib-like band, 
 bounded on each side by a sharp narrow depression. 
 
 Surface beautifully ornamented by concentric strim or 
 lines of growth, which curve forward on the sides of the 
 volution and slightly back on the central band. 
 
 Geological position and locality. In Coal measure shales in the vicinity of Spring- 
 field, Illinois. 
 
 Pleurotomaiiii beckwUliaiia (n. s.). 
 
 Shell small ; whorls four to five, rounded both above 
 and below, rapidly and regularly expanding except at the 
 aperture below where the shell is deflected or more abruptly 
 widened ; mouth subcircular ; outer lip thin, and broken 
 away in the specimen under description ; columella lip but 
 slightly thickened. 
 
 Surface beautifully ornamented by fine but very dis- 
 
62 
 
 GASTEROPODA. 
 
 tinct longitudinal or revolving striae, and by folds or 
 wrinkles extending back obliquely from the suture line 
 over the upper part of the whorls. 
 
 From the centre of the outer lip there is a narrow flat- 
 tened, scarcely elevated band, extending longitudinally 
 over the whorl, the lower edge of which is most prominent. 
 
 This species has the general form of P. carbonaria (N. and P.), but is a much 
 less shell, and is finely striated, while that is marked by strong bands or revolving 
 ribs. 
 
 Geological position and locality. So far as I am aware, this beautiful shell has 
 only been found in the Coal measure shales over the upper coal seam at Danville, 
 Illinois. 
 
 ^atica slmmardi (n. s.). 
 
 Shell much elongated or subfusiform, smooth except 
 several strong irregular lines of growth ; substance of the 
 shell rather thick. Spire produced ; number of whorls 
 unknown ; suture impressed ; whorls flattened above, and 
 sharply rounded below. Columella thickened above, and 
 covered on the upper side of the aperture by a heavy cal- 
 lus, which entirely conceals the umbilicus. Aperture 
 subova te, nearly two-thirds the length of the last volution ; 
 greatest diameter in the direction of the axis of the shell : 
 outer lip sharp. 
 
 This shell differs from N. ventrica (N. and P., Journal Acad. Nat. Sci., Jan. 
 1855) = N. magister (Stevens, Amer. Journal of Science, Vol. xxv), in being a 
 much more elongate shell ; the comparative length being, in a specimen of the same 
 diameter, as two to one; in not possessing the radiating lines running from the 
 suture into the body of the whorl, and in the possession of the very massive 
 callosity. 
 
 Geological position and locality. In Coal measures, Lasalle, Illinois. 
 
 Platyostoiiia peorieiisis ( n. s.) 
 
 Shell of iHedium size, somewhat elongated subglobose, 
 composed of about two volutions, which are contiguous, 
 expanding quite rapidly, the outer one much inflated near 
 the aperture, which is longitudinally ovate, widest below ; 
 
GASTEROPODA. 
 
 63 
 
 spire usually depressed (sometimes a little elevated) ; 
 sutures deep and distinct : substance of the shell very thin. 
 
 Surface entirely destitute of plications or folds, and 
 marked only by very fine concentric lines, apparently of 
 growth. 
 
 This species possesses the characters common to all the 
 species of this genus ; but we know of no shell from rocks 
 of this age, hitherto described, with which it can be con- 
 founded, or with which it is necessary to draw comparisons. 
 
 Geological position and localities. In the Upper Coal measure limestone, Peoria, 
 Fulton, and many other counties in Illinois. 
 
 ]\autilus forbesiaiius^ ( n. s.). 
 
 Shell subglobose, convolute, not embracing, moderately 
 increasing in width and regularly convex on the back, 
 sharply rounded on the sides and sloping rapidly into the 
 umbilicus, which is large and deep, disclosing all of the 
 preceding volutions. Aperture transversely subelliptical, 
 twice as wide as high, but slightly modified by the dorsal 
 convexity of the preceding volution. Septa moderately 
 distant ; relative distance somewhat less than one fourth 
 the breadth of the shell at the same place, somewhat 
 deeply concave, and presenting a moderately shallow 
 receding curve on the back of adult specimens, but much 
 deeper in young individuals. Siphuncle rather large, ven- 
 trally situated, causing in the septa a funnel-shaped 
 depression. 
 
 Surface ornamented on each side by a line of large, 
 rounded, somewhat distant nodes, which form a very con- 
 spicuous feature of the fossil. Surface of the shell unknown. 
 
 This species has a slight resemblance to iV. ferratus of Cox (Geo. Report Ken- 
 tucky, Vol. iii), but differs in being less globose, increasing less rapidly in the 
 diameter of the voUtions, and more particularly in possessing the large nodes on 
 each side of the shell. 
 
 Geological position and locality. In Coal measures, Carnahan’s mine, Mercer 
 county, Illinois. 
 
 • Named in honor of P. S. Forbes, Esq., of New-York City, late Consul to Pekin, 
 
G4 
 
 GASTEROPODA. 
 
 \iuitiliis illhioieii$LS ( n. s.). 
 
 Shell very large ; the greater diameter, of a specimen 
 possessing a little less than three volutions, measuring full 
 nine inches, and nearly four in the greatest breadth of the 
 volution, which is still septate, the outer chamber having 
 been broken away ; convolute whorls joining, but not em- 
 bracing. Form of the volutions subquadrate, transverse ; 
 dorsum flat (in the younger stages of growth appears to 
 be slightly convex, becoming slightly concave in large indi- 
 viduals), sides inflated, greatest Avidth a little to the ven- 
 tral side of the centre ; edges of the periphery ornamented 
 by a row of very broad nodes, Avhich present a series of 
 regular undulations when viewed across the angle of the 
 shell ; umbilicus very broad, of moderate depth, the sides 
 regularly rounded on to the successive volutions. Septa 
 rather distant ; at a point Avhere the volution measures two 
 inches from the ventral to the dorsal side, their dorsal 
 edges are distant five eighths of an inch, and increase in 
 distance with the groAvth of the shell, somcAvliat deeply 
 concave, recurving rather strongly on the dorsum and but 
 moderately on the sides. Position of the siphuncle un- 
 known. 
 
 Surface of the shell marked by strong transverse lines 
 of growth. 
 
 This species is somewhat closely allied to iV. planovolvus of Siiumard (Trans. 
 Acad, of Sci. St. Lous, Vol. i, No. 2), but differs in being a much larger shell, in 
 having more distant septa, and in the large strong nodes on the edges of the dor 
 sum ; his species not being described as a nodose shell. 
 
 Geological position and locality. Upper Coal measure limestone, Lasalle, Illinois. 
 
 Note. — F or a description of the Genus Ambocelia, recently established by Prof. James 
 HalLj see Regents' Report of the State of New-York for the present year. 
 
CEPHALOPODA. 
 
 65 
 
 IVautiliis qiiadiaiigiilus ( n. s.). 
 
 Shell of medium size, somewhat discoid, convolute, 
 slightly embracing. Volutions increasing in size but mode- 
 rately, the increase being more in the dorso-ventral than 
 in the lateral diameter ; volutions quadrate in form ; in 
 young specimens the transverse diameter is proportionately 
 greater, becoming more equal in older specimens, and in 
 some instances the dorso-ventral diameter becomes con- 
 siderably greater than the lateral ; sides of the volutions 
 flat, slightly rounded in front. Volutions, in a specimen 
 of two and a half inches in greatest diameter, little 
 more than two in number, and ornamented by a line of 
 prominent lanceolate nodes on each of the outer angles ; 
 and another line on each side of the centre of the dorsum 
 in old and medium-sized specimens, which are not deve- 
 loped in young individuals, though in adults they become 
 more prominent than the marginal lines, and leave a deep 
 rounded channel between them : they are also arranged in 
 transverse lines across the back of the shell ; and still 
 another indistinctly developed line of nodes along the 
 outer edge of the umbilicus, most prominent in young- 
 individuals. Umbilicus broad, exposing almost the entire 
 breadth of the different volutions; the slope from the 
 inner line of nodes to the j>receding volution precipitous. 
 Septa moderately distant ; the distance in a well pre- 
 served specimen being about one third the transverse 
 diameter of the shell, forming on the back of the shell, 
 when exposed, a rather deep, and on the sides a moderately 
 recurved sinus, which is owing to the quadrangular form 
 of the volutions. The exact position of the siphon is not 
 determined, but it is apparently situated on the ventral 
 margin. 
 
 Surface of the shell, in well preserved specimens, is 
 marked by very fine transverse striae, which form on the 
 back of the shell a deep receding curve. 
 
 9 
 
66 
 
 CEPHALOPODA. 
 
 This is quite an abundant species in the rocks of the Coal measures, and espe- 
 cially so at Graysville, Illinois, though usually in fragments : the specifie characters 
 are, however, so marked as to render them easily recognized. 
 
 ^luUihts iimloc’iiiiiiatus (n. s.). 
 
 Associated with the above species there is another quite 
 distinct, though allied species, of which we have but a 
 fragment. Its characters are so marked that we deem it 
 entirely safe to draw from it the following description. 
 
 Shell of medium size, convolute, very rapidly increas- 
 ing in transverse diameter. Volutions quadrangular, the 
 lateral diameter being nearly twice that of the dorso- 
 ventral, slightly rounded on the back, and ornamented 
 as in the preceding species by four rows of nodes ; the 
 outer ones large and lanceolate ; the inner rows small, 
 rounded and i^uch more closely arranged than the 
 others, there being eight of these in the space occuj^ied by 
 five of the others. The nodes of the inner rows are not 
 planted opposite each other, but alternate ; there is also 
 a line of small indistinct nodes arranged along the angular 
 edge of the umbilicus, but these do not form a conspicuous 
 feature. The siphuncle of this species is very small, and 
 lies close upon the back of the preceding volution. 
 
 This species increases much more rapidly in width than the last : the nodes on 
 the outer angles of the volutions are larger, while the central nodes are much the 
 smallest and more closely arranged than those of the other species ; and they do 
 not appear ever to attain an equal size with those of the outer lines, while those of 
 the last species become the most prominent, and are all arranged opposite each 
 other - 
 
 Geological position and locality. In Coal measures, Graysville, Illinois. 
 
 Goiiiatites Isatlmwayasia* ( n. s.). 
 
 Shell moderately small, discoidal, much compressed. 
 Volutions two to three, strongly embracing, and concealing 
 about two-thirds of the inner volutions ; umbilicus com- 
 paratively wide and shallow. Dorsum extremely narrow, 
 having a linear depression along its centre; sides of the 
 volutions very slightly and regularly convex to the slope 
 
 * In honorem Dominse Mary Hathaway. 
 
CEPHxVLOPODA. 
 
 67 
 
 into tlie umbilicus which is more sharply curved. Aperture 
 very narrow and much elongated. Septa on the sides of 
 the volutions strongly sigmoidal, with the curves or lobes 
 which stand back toward the apex -much more sharply 
 turned than those pointing in the opposite direction. Outer 
 shell entirely wanting. 
 
 This species somewhat resembles in form, G. polihis of Shumard (extract Trans. 
 Acad, of Sciences of St. Louis, 1858), but is not rounded on the dorsum; nor does 
 the outer volution embrace so as to entirely conceal the inner ones, as in that. 
 
 Geological position and locality. The specimen from which the above description 
 is taken, was found in the shales over the lower coal seam, more than three hun- 
 dred feet below the surface, at Lasalle, Illinois ; but from its polished appearance, it 
 possibly may have been drifted from some other geological formation before being 
 imbedded. 
 
 tyitoceras* giginsteuiii (n. s.). 
 
 Shell very large, discoidal or nearly so. Volutions two, 
 contiguous, and sometimes the ventral side slightly com- 
 pressed by the dorsum of the preceding volution, rapidly 
 expanding; section strongly elliptical, the dorso-ventral 
 diameter being much greater than the lateral ; septa 
 convex, distant one inch measured on the side near the 
 outer chamber ; umbilicus broad and shallow : the spire in 
 some specimens appears to be slightly more depressed 
 on one side than on the other; siphuncle comparatively 
 small and nearly central. The outer or produced portion 
 of the last volution is nearly straight, and, when perfect, is 
 extended so as to render the form of the shell somewhat 
 elongate ; mouth unknown. 
 
 Surface, of perfect specimens, beautifully ornamented 
 by low, rounded, transverse, rib-like strife, which curve 
 back on the dorsum, and measure eight or nine to the inch 
 on the middle of the outer volution ; and by fine revolving 
 strife, four or five of which measure a line. 
 
 The greatest diameter of the specimen under descrip- 
 tion is about twelve inches, and the diameter at right 
 angles to it, ten inches. 
 
 ♦ S»e note on page 76. 
 
68 
 
 CEPHALOPODA. 
 
 This shell (lifTers from Ci/roceras (^/Jtaites') magnijicum of Bii.lings (Canada 
 Geological Survey), in the much greater distance of the septa from each other, and 
 in the dorsum being strongly convex, while it is flat in that. It differs from Phrag- 
 moceras maximum, of the Devoniaji rocks of New-York, in the less convexity of 
 the septa and in their greater distance from each other. 
 
 Geological position aad locality. In the Niagara division of the Upper Silurian 
 rocks, Joliet, Illinois. 
 
 TroclioeiTiis despliuiaeiisis (n.s.). 
 
 Shell very slightly trochiform, suhorbicular in outline; 
 spire not elevated; volutions about three, expanding very 
 moderately with the growth of the shell, contiguous; sec- 
 tion sub-elliptical, dorso-ventral diameter greater than the 
 lateral ; dorsum strongly convex, ventral side slightly 
 flattened or impressed by the convexity of the preceding 
 volution ; septa convex, distant from each other in the 
 middle of the outer volution on the dorsum about three 
 lines ; umbilicus broad and shallow ; siphuncle not dis- 
 tinctly seen. 
 
 Surface . marked by numerous strong, obliquely trans- 
 verse angular or sharply rounded ridges, strongly arching 
 back on the dorsum, and increasing in distance from each 
 other with the age of the shell : the spaces intervening 
 those ridges are regularly concave ; minute surface 
 character unknown. 
 
 This beautiful shell is found in the Niagara division of the Upper Silurian rocks 
 of Joliet, and on the Kankakee river, Illinois. 
 
 <)rthoceras riislieiisis { n. s.). 
 
 Shell small, elongo-conical, tapering gradually, slightly 
 sometimes almost imperceptibly flattened on one side ; 
 septa subelliptical or nearly circular, convex, distant from 
 each other from one-sixth to one-third their diameter ; si- 
 phuncle cylindrical, central or nearly so ; shell marked by 
 shallow annulations about equally distant with the septa, 
 and. separated by shallow rounded depressions. 
 
 This species differs from both O. aculeatum and O. accidentale of Swallow in the 
 siphuncle being nearly central, and from the former in tlie siphuncle not being 
 formed of a succession of hollow spheres; but no surface character of those species 
 being given, it is difficult to make any further comparisons. 
 
CEPHALOPODA. 
 
 69 
 
 I have a specimen from Coal measure slate in Ky., which T take to be the same 
 with the above; and if so, the siphuncle is irregularly cylindrical through the cham- 
 bers and strongly constricted in the septa. 
 
 Geological position and locality. In Coal measures at Ru.sh creek, five miles down 
 the Wabash river; from New-IIarmony, Indiana, and in various localities in Illinois. 
 
 Ortlioceras kiioxeiisis ( n. s.). 
 
 Shell very small, elongate conical, increasing but 
 slightly in diameter in proportion to its length; septa cir- 
 cular, convex, distant from each other about one-third of 
 their diameter; siphuncle minute, round and situated cen- 
 trally. 
 
 Surface destitute of ornament, sometimes polished. 
 
 The only perfect specimen of this species in my possession, is a very small one, 
 and probably a young individual; but I have fragments from various localities of 
 much larger specimens, apparently of the same species, which have the septa vary- 
 ing in distance from each other from one-sixth to one-fourth their diameter; from 
 which it is probable that the chambers increase more in diameter than in length 
 with their age. 
 
 This species differs from O. moniliformis of Swallow, in having a small siphuncle 
 instead of a large one, and still more distinctly in being destitute of the annulations 
 which, according to the description, constitute such a distinct feature in that species. 
 
 Geological position and locality. In Coal measures at Danville, Springfield, Peoria, 
 and Dr. E. Hall’s Mill, Knox county, Illinois. 
 
 GASTEROPODA. 
 
 Biicailia cliicagoeiisis ( n. s.). 
 
 Shell moderately large, convolute, strongly trumpet- 
 shaped. Volutions about five, transversely sub-elliptical, 
 slightly impressed on the ventral sides by the convexity 
 of the preceding volution, increasing very moderately in 
 size with the age of the shell ; the inner volutions increas- 
 ing somewhat more rapidly than the outer ones; outer part 
 of the last volution broadly and rapidly expanding into a 
 large funnel-shaped circular aperture, much thickened as 
 it approaches the margin. Diameter of the mouth nearly 
 
70 
 
 Gasteropoda. 
 
 doul)le the greatest or transverse diameter of the volution 
 two inches back. 
 
 Umbilicus broad and shallow. Surface character un* 
 known. Specimen a cast. 
 
 This species is most nearlr .-illied to B. expansa of Hall, Vol. I. Palaeontology 
 of N. Y. 1*1. 40, f. 7; from which it differs in having ntore volutions, a circular 
 aperture instead of a lunate one, and in being destitute of the carina possessed by 
 that species. 
 
 Geological position and locality. In the Niagara group at Thornton, Cook county, 
 Illinois, and in the quarries near Chicago. 
 
 Fleiiiotoisiaiia Jiodomargiiiata (n s.). 
 
 Shell rather small ; spire elevated conical, composed of 
 from three to four volutions ; length of the shell equal to 
 once and a half its greatest diameter. Volutions some- 
 what angular, flattened above and rounded below, having 
 the periphery marked by a narrow flattened or slightly 
 concave spiral band: outer volutions joining onto the 
 preceding ones just below the band; suture well marked, 
 scarcely canaliculated. C.oluniella straight, produced be- 
 low, which makes the distance below the spiral band at the 
 commencement of the last volution considerably more than 
 half the entire length of the specimen. Border of the lips 
 thin, gently receding toward the middle ; notch shallow, 
 axis solid. 
 
 Surface marked by coarse transverse strife, of equal 
 strength above and below the band, and which are gently 
 recurved towards the notch, conforming to the border of 
 the lip, and more abruptly on the spiral band. These 
 strife, when seen through a lens, present somewhat the 
 appearance of projecting lamellm. At the upper edge of 
 the volution every alternate stria is elevated, forming a 
 sort of elongate node, which are sometimes elevated so as 
 to present the appearance of a band of nodes ; the strife 
 between die out at the commencement of the nodes. 
 
 This shell is of the same type of P. sulcomarginata of Conrad, from the Hamil- 
 ton rocks of New-York, but is a much longer shell, the surface markings are pro* 
 
GASTEROPODA. 
 
 71 
 
 portionately coarser, the nodes near the upper margin of the volution are very much 
 larger and commence at the earliest ages of the shell, while those of the other species 
 are not developed until the shell is nearly half grown. It is also destitute of the 
 second row of small nodes a little above .the revolving band, which forms a conspi- 
 cuous feature in P. sulcomarginata. 
 
 Geological position and locality. In shales of the age of the Hamilton group of 
 New-York, near Batesville, Arkansas. 
 
 Platyceras cyitolites ( n. s.). 
 
 Shell small, slender, composed of little more than one 
 volution ; beak small, pointed, enrolled, but joining on to 
 the outer part of the volution ; dorsal line angular, be- 
 coming distinctly carinate on the outer part of the shell, 
 with a flattened space each side, which gives it the ap- 
 pearance of having a slight carina on each side of the 
 shell. On the short side of the shell there is one or two 
 small incipient plications, which are not developed till 
 the shell is nearly full grown. Aperture angularly ovate. 
 
 The direction of the strias or lines of growth Avould in- 
 dicate the existence of a broad shallow sinus on each side 
 of the dorsal carina ; curvature of the beak in a plane 
 with the short side of the shell. 
 
 The slender form and dorsal carina of this shell give it somewhat the appearance 
 of the Genus Cyrtolites. 
 
 It is somewhat related to Platyceras ( Capulus) acutirostris of Hall, but dif- 
 fers from it in the curvature of the shell, in the existence of the carina, and in the 
 enrollment of the beak. 
 
 Geological position and locality. In the Burlington division of the Carboniferous 
 limestone series in Calhoun county, Illinois. 
 
 BRACHIOPODA. 
 
 Trematospira matliewsoiii ( n. s.). 
 
 Shell small, varying from subcircular to suhquadrate in 
 outline, length usually a little greater than the width ; 
 cardinal line broadly rounded onto the sides of the shell; 
 shell somewhat ventricose, valves nearly equal in con- 
 
72 
 
 BRACHIOPODA. 
 
 vexity. Ventral valve the larger, somewhat regularly 
 convex, and having a hroad shallow medial depression, 
 which apparently extends from near the beak to the base, 
 where the front of the valve is prolonged into a rounded 
 extension which corresponds to the elevation in the oppo- 
 site valve ; Imak small, incurved over that of the opposite 
 valve, perforation small. Dorsal valve convex, regularly 
 rounded, except in front, where it is elevated into a promi- 
 nent mesial elevation, which appears to become obsolete 
 a little in front of the beak. 
 
 Surface marked, at the front, by from eight to ten small 
 rounded plications on each side of the mesial prominence, 
 which bifurcate near the umbo, but are usually simple the 
 remainder of their length; and by seven or eight on the 
 elevation which are fasciculate, apparently rising from 
 one strong plication at the beak. 
 
 This shell is allied to T. hudsonica of Hall, Palaeontology of New-York, Vol. 
 iii; but differs from it in being more elongate in proportion to the width, that spe- 
 cies being usually much wider than long; and also in having the cardinal extremity 
 more sharply rounded, finer striae and a proportionately narrower mesial fold and 
 sinus. 
 
 The above characters are taken from the casts of several specimens ; and it is pos- 
 sible that in the perfect specimens the character may vary slightly, but not essen- 
 tially, as tho.se given are sharply and distinctly defined. 
 
 Geological position and locality. In Niagara limestone, Chicago (Bridgeport), 
 Illinois. I have also two specimens doubtfully labeled from near Madison, Indiana. 
 
 IMsciiia capuliforma ( n. s.). 
 
 Shell large for specimens of this genus, circular in out- 
 line, largest valve broadly subconical or approaching dome 
 shape ; apex prominent, situated a little one side of the 
 center ; shell slightly inflated on the long side, and most 
 prominent just back of the apex, and contracted below 
 the apex on the short side, giving it the appearance of a 
 slightly incurved beak. Smaller valve rather deeply con- 
 cave, having the nucleus abruptly impressed, not perfo- 
 rate, but with a linear depression extending from the 
 
BRACIIIOPODA. 
 
 73 
 
 center of the depression to the border of the valve on the 
 short side ; this depression forms, on the inside of the shell, 
 a narrow ridge without any appearance of a slit. 
 
 " Surface marked by fine irregular concentric lines, ap- 
 parently of growth ; no radiating strife visible. 
 
 The specimens are usually found in an exfoliated condition; but u hen the shell is 
 preserved, it consists of a thick epidermis of corneous texture externally, while the 
 inner portion is formed of a great number of very thin lamina. 
 
 Geological position and locality. In Coal measures near Springfield, Illinois, and 
 12 miles northwest of Richmond, Missouri. 
 
 LAMELLIBRANCHIATA. 
 
 ^hiciilites vaseyaiia ( n. s ). 
 
 Shell small, nearly twice as long as wide, moderately 
 compressed, most gibbous on the umbones, broadly rounded 
 at the anterior end, rapidly tapering from the beaks to- 
 ward the posterior extremity, which is narrow and sharply 
 rounded ; beaks situated about one-third the length of the 
 shell from the anterior extremity, very small, closely ap- 
 proximate, pointing posteriorly; cardinal line, posterior 
 of the beak, elevated into a sharp ridge, ventral margin 
 gently and regularly curving; hinge with from twelve to 
 sixteen comparatively strong teeth, about equally distri- 
 buted on the anterior and posterior sides of the beak. 
 
 Surface marked by very fine elevated concentric striae, 
 which conform to the border of the shell. Interior of the 
 shell (as shown by the depression on casts) has a some- 
 what strong and elevated ridge rising from beneath the 
 beak and passing obliquely downward, reaching the edge 
 at about the centre of the ventral margin ; which charac- 
 ter places it under the Genus Nuculites of Conrad. 
 
 This shell is very much the form of Lsda polita (nobis), but the concentric striae 
 are coarser, and the shell is not so ventricose; but the internal structure at once 
 separates it from that, as well as from all other species of Leda. 
 
 Geological position and locality. lu shales of the age of the Hamilton rocks of N. 
 York, Batesville, Arkansas. 
 
 10 
 
74 
 
 LAMELLIDRANCIIIATA. 
 
 ^'iiciila reetkUJj^ulii ( n. s.). 
 
 Shell small, subtriangular in outline, somewhat com- 
 pressed; ventral margin very broadly rounded, sometimes 
 almost straight, posterior margin sharjily rounded ; cardinal 
 line and anterior slope nearly at right angles to each other, 
 the former of which is straight, and the latter slightly 
 curved; beaks small, incurved, approximate, pointing to- 
 ward and almost terminating the anterior extremity. Hinge 
 line, on the posterior side of the beak, marked by about 
 eight comparatively strong teeth, and on the anterior side 
 by four or five teeth not quite so prominent. 
 
 Surface marked by fine concentric strim, and by some 
 stronger lines of growth, 
 
 . Geological position and locality. In dark colored .shales of the age of the Hamilton 
 rocks of New York, near Batesvilte, .Arkansas. 
 
 Note. — Dr. Owen, in his Preliminary Geological Report of Arkansas, described some dark 
 shales near Batesville, as belonging to the lower Carboniferous rocks; and the two above spe- 
 cies and the Pleurotomaria nodomarginata (nobis) may belong to that formation, as I 
 have only these and one or two other fossils from which to determine the geological age of the 
 rocks : they appear, however, to be of Devonian type. 
 
 Pinna atlainsi ( n. s.). 
 
 Shell thin, moderately large, conico-triangular in form, 
 regularly widening from the beak to the posterior end; 
 valves strongly ventricose, the greatest gibbosity being 
 nearer to the ventral margin than to the hinge line, regu- 
 larly rounded to the former, but slightly flattened as they 
 approach the latter. 
 
 Surface marked by distinct lines of growth which start 
 at right angles with the hinge line, and soon begin to sloj^e 
 forward toward the beak, and become so strongly curved 
 as to strike the ventral margin at a very acute angle ; these 
 lines indicate a strongly rounded posterior margin. 
 
 This species differs from P. peracuta of Siiumaud, in the greatest gihhositj' of 
 the valves being nearer the ventral margin than to the hinge line, vdiilc in that it is 
 the reverse; and in the flattening of the valves being toward the hinge line, and not 
 below as in that species. 
 
 Geological position and locality. In Coal measure rocks at Lasalle, Illinois. 
 
CORALS. 
 
 75 
 
 S) iiii«’opora inultatteiiiiata ( n. s.) 
 
 This species grows in large clusters of long, slender, 
 more or less flexuous, circular or subcircular corallites, 
 which are unequally approximate on account of the flexu- 
 osity; at some points in contact firmly grown together, 
 while at others they are distant one, two or even three 
 times their diameter. Tubes of connection irregularly dis- 
 tant, moderately slender, and either at right angles or 
 slightly oblique. 
 
 Surface marked by frequent shallow annulations indi- 
 cating the stages of growth. Diameter of the corallites 
 less than a line. 
 
 This species, in the size of the corallites, rcsemhles S. tabulata of Van Clevk, Ext. 
 du Tome V des Archives du Museum d’llistoire naturelle, Paris; but differs from it 
 in the corallites being flexuous, while in that they are perfectly straight, and in being 
 connected by tubes at unequal intervals, while that is united at regular distances by 
 tubes which expand and unite with each other, forming a wall-like partition. 
 
 It still more nearly resembles S. perelegans of Billings, Geological Survey of 
 Canada; from which it differs in the corallites being not quite so large, the flexuosi- 
 ties more irregular, and the annulations much less distinct. 
 
 Geological position and locality. In Coal measures eight miles south of Springfield, 
 Illinois. 
 
 Cyathaxoiia piolifera (n.s. ). 
 
 .Coral pointed below, gradually widening to the top in 
 the form of a reversed cone, bent in a horn-like curve, 
 sometimes nearly straight ; calyx circular, cavity mode- 
 rately profound; radiating lamellae often more or less dis- 
 torted, numbering at the margin from thirty -five to fifty 
 according to the size of the individual; often every alter- 
 nate one only extends a short distance from the margin. 
 
 Columella or axis comparatively large, lenticular in out- 
 line in its free portion, the greater diameter being in the 
 direction of the curvature, and sometimes becoming al- 
 most or entirely cylindrical below. 
 
 Surface marked by distinct, narrow, rounded longitudi- 
 nal ribs, crossed by bands or wrinkles of growth of irregu- 
 
76 
 
 CORALS. 
 
 lar width, which in an occasional specimen present a few 
 short spines or tubes. 
 
 The usual height is from one-half to an inch: diameter 
 of the calyx very variable. . 
 
 Tliis species is somewhat closely allied to Tarhmolia cynodon of Rafinesque et 
 Clifford, Ann. Gener. de Phys. de Bruxelles, t. v, p. 234, 1820. See Cyathaxona 
 cynodon, MM. Milne-Edwauds et IIaime, Monographie des Polypiers fossiles. It 
 differs from that species in not being properly a spinose coral; and in the rare in- 
 stances where it does possess a few spines, they are not arranged as in that on the 
 alternate ribs; and in the form and size of the columella, which in that species is 
 round and proportionately much smaller than in this. 
 
 Geological position and locality. In Coal measures, very widely distributed in the 
 Western States. 
 
 Note. — An examination of more perfect specimens of the shell described on page 67, as 
 belonging to the Genus Cyrtoceras, may require it to he classed under the Genus Lituites. 
 The departure from an exact plane in the eurve of the hest specimen in my possession may 
 be occasioned by accident, and I have no specimens which reveal the true character of the 
 mouth. 
 
 ERRATA. 
 
 Pages 46 and 47, for Athyrus, read Athyris. 
 
 Page 63, insert Cephalopoda over the words Nautilus forbesianus; in twelfth 
 line from bottom, for ventrally read centrally; and for Pekin, at the bottom of the 
 page, read Canton. 
 
 Page 64, at the top, for Gasteropoda, read Cephalopoda. 
 

 
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