216 PALJSONTOLOQY OF NEW YORE. 



abruptly bent forward in the centre, but absolutely continuous, though more 

 frequently alternating and interlocking, while often there is no visible departure 

 from a regular curving line. 



The ornamentation upon the crests of the striae and the upper half of the 

 interstriate spaces is precisely the same as already described ; but the striae are 

 stronger. The specimen has a much coarser and stronger aspect than any 

 other one observed, and the pyramid is more abruptly expanded from the 

 apex. The single specimen known does not afford satisfactory evidence of 

 specific distinction, and I have therefore recorded it as a variety of the form 

 with which it preserves many characters in common. 



Formation and locality. In the coarse arnenaceous shales of the Hamilton 

 group in Schoharie county, N. Y. 



The conditions of preservation in nearly all the species of Conularia are such 

 as to preclude any satisfactory determination of the angle subtended by the 

 sides of the pyramid. The specimens have, in nearly every case, been more 

 or less distorted by pressure, and more frequently completely flattened, so 

 that the original form is never fully preserved. In these conditions the 

 measurement of the apical angle is attended with difficulty, and the results are 

 far from satisfactory. 



The following species have been carefully measured, and the angle given is 

 the sum of the angles of two adjacent faces — the result corresponding to the 

 angle inclosed between the edges of a flattened specimen. By this mode of 

 measurement C. undulata, in several individuals, gives a range of 21° to 30°, 

 and an average of 25°; C. crebristriata, 20° to 29°, and an average of 24 \° 

 in two individuals ; C. Cayuga gives an angle of 28° ; C. continent ranges from 

 28° to 41°, and in four measurements gives an average of 35°; C. congregata, 

 in four measurements, gives a range of 22° to 29°, and an average of 26°. 

 These variations of the included angle are probably due, in a great degree, to 

 the varying direction of the pressure which has flattened the shell ; it rarely 

 happening that this force is exerted in a vertical direction upon the face or 

 upon the angle of the shell, but upon some intermediate point or in an oblique 

 direction. 



