On the so-called Land Plants from the Lower Silurian of Ohio. 335 



ciniiati Group (Lower Silurian), S. tenuistriata the upper part, and S. 

 rhomboidalis in the Upper Silui-ian (Niagara Group). 



The material I have at hand from the Niagara Group of Indiana 

 shows a still more marked difference between S. rhomboidalis and *S. 

 gibhosd and tenuistriata, than between the two latter, in almost every 

 feature, but more especially the internal structure. 



Strophomena squamula — (James), 



S. squamula — James. Catalogue of Lower Silurian F<)s.«ils, Sept. 1S71. 



Shell small, thin, semi- oval in outline, broader than long ; hinge line 

 varying from a little more to a little less than the greatest breadth of 

 the shell farther forward. 



Dorsal valve slightly concave or nearly flat ; cardinal line straight ; 

 cardinal area linear ; a slight depression immediately forward of the 

 beak. Surface covered, with fine, rounded, radiating strife of nearly 

 uniform size, increased toward the free margins by bifurcation. 



Ventral valve slightly convex ; beak and hinge line slightly project- 

 ing ; cardinal area narrow, a little the widest in the middle ; foramen 

 triangular and nearly closed by the cardinal process of the other valve ; 

 a strong mesial rib extending from the beak to the front ; surfiice 

 covered by fine, rounded, radiating strife, which bifurcate once or twice 

 before reaching the free r:iargins ; the striae starting at and near the 

 beak more prominent than the branching ones ; crossed by very fine 

 concentric lines, visible only under a good magnifier, and even then 

 in some cases quite obscure. Visceral space very little, the valves 

 being so closely drawn together, translucent. Interior not observed. 



Breadth of a full sized specimen, f ths of an inch ; length, i an inch. 



Position and locality : Cincinnati Group, about 350 feet above low" 

 water-mark of the Ohio river, at Cincinnati. 



Collected by U. P. James. 



On the so-called Land Plants from the Lower Silurian of Ohio; by J. S. 

 Newberry. [From the American Journal of Science and Arts, 

 August, 1874.] 



In the January number of this Journal [republished in the January 

 number of this Journal, page 43], ^Ir. Leo Lesquereux describes 

 two fossils found in the upper portion of the Cincinnati Group, near 

 Lebanon, Ohio. These he considers as the remains of land plants, and 



