VEETEBEATES. 279 



tion represented by C. Springer!, of the earliest member of the Lower 

 Carboniferous. 



Position and locality: Limestone above coal No. 9, at Carlinville, 

 Illinois. 



Cladodtjs cakinatus, St. J. and W. 



PI. IV, Fig. 6, 7. 



Teeth very small, lateral diameter about equal to the greatest Light, 

 generally robust. Base relatively massive, sub-elliptical in outline, 

 gently arched vertically, broadly and regularly rounded behind, rather 

 deeply sinuate in front and abruptly rounded into the more or less 

 acutely rounded extremities, anterior basal angles occupied by promi- 

 nent anteriorly produced protuberauces which are connected by a low 

 marginal ridge, inferior surface moderately excavated, pitted, postero- 

 superior surface unknown. Crown more or less produced and constricted 

 basally in front, and deeply excavated in the median region, median 

 cone strong, sub-circular or sub-lenticular in transverse section with 

 delicate cutting edges, rapidly tapering to an acute point, erect or later- 

 ally deflected and nearly vertical to the horizontal plane of the base ; 

 lateral denticles normally four on either side, alternating in size, the 

 exterior pair relatively very large, more or less strongly divergent and 

 recurved, in form similar to the principal cusp ; the anterior face of the 

 median cone is marked with sharp-crested, more or less regular and 

 crowded cost re, which appear stronger in the lateral denticles and 

 less crowded, and obsolete in the swollen basal region, ornamentation 

 of posterior face not known. A medium-sized tooth measures .17 inch 

 in lateral diameter of base, hight .15 inch. 



Only two authentic examples of the present form have come to our 

 notice — one obtained by Mr. Fxjllee, from the horizon of coal No. 5, 

 and the other from bed No. 30 of the general section of the Middle Coal 

 Measures of Iowa. Both specimens being derived from nearly the same 

 stratigraphic position at localities distant from each other, much interest 

 attaches to their discovery on account of the evidence they furnish rela- 

 tive to the value of these remains in the identification of strata asso. 

 ciated with particular coal horizons at remote localities. 



The Iowa specimen is still smaller than that measured, and presents 

 an interesting feature of individual variation. The median cone is 

 eccentric, or to one side of the median line, and the short extremity 

 exhibits only two long, slender denticles, while the opposite end possesses 

 the full complement in its armature. Otherwise, in the form, disposi- 

 tion and ornamentation of the coronal cusps, as also the basal region, 

 the characters possessed in common indicate the most intimate relation- 



