6o8 TRANS. ST. LOUIS ACAD. SClEKCt:. 



direction nearly direct from the marginal angle on one side to the 

 medial depression, and thence (slighly bending) to the angular 

 margin of the shell on the other ; transverse ridges crossed by fine 

 closely arranged longitudinal ridges, producing fine rectangular 

 papillae Exterior portions of shell smoother than the interior, with 

 the striations less conspicuous. In some places, the striae are more 

 crowded together than in others, but this may arise from com- 

 pression in the rock. 



This species differs from Conularla tiiagarensis in that it is 

 very much larger ; and both the longitudinal and transverse striae 

 are relatively very much smaller, more numerous, and less curved ; 

 the medial depression is less distinct ; th*e longitudinal grooves are 

 deeper though not so broad ; and, in particular, the grooves of the 

 inner surface are not marked by conspicuous punctures. 



The entire length of the shell is twenty -one centimetres with 

 the apex broken off", but, if it were angular in place of rounded, 

 the shell would measure three centimetres longer. At the broad- 

 est end, the extreme width of the side is thirteen centimetres, with 

 portions of two adjacent sides crushed There are from 20 to 

 30 transverse striae in the length of a centimetre, and from 30 to 

 40 longitudinal grooves in the same distance. 



Formation and Locality. — Of this species only two larger spe- 

 cimens have been found (and one or two fragments). These were 

 obtained from the "chert-bed" at the Jolly-cut road at Hamilton, 

 Ontario, in 1872, by Mr. Yeomans, the superintendent of the 

 quarries. One of these specimens now belongs to the Museum of 

 McGiil University and the other is in my own collection. 



Of this species I published a notice in the Canadian Naturalist of Mon- 

 treal in 1879, but the fuller description has been delayed to the present. 

 Since finding these specimens in 1S72, I have never seen any that have 

 been subsequently obtained, although Col. Grant has observed one or two 

 fragments. Although this species is so rare, Cornularia tiiagarensis is not 

 uncommon, and of this latter species even large specimens have been 

 found, one of which, comparatively large, and many smaller, have been in 

 my possession. 



CONULARIA RUGOSA, nOV. Sp. 

 PJates 8 & 9. Fig. 2; 2a is surface enlarged. 



.Shell large, and broad, pyramidal ; medial depression on side 

 scarcely apparent, but producing an abrupt bending of the striae. 

 Surface of shell removed, showing only the internal cast. Broad, 

 flattened, transverse ridges, separated by narrow deep channels, 



