236 PALEONTOLOGY. 



as in the typical species of the genus, and appearing- as an umbilicus on a 

 sinistral shell, the depression rather narrow and abrupt; under side flattened, 

 without any depression or umbilicus. Volutions about two in number, 

 somewhat rapidly increasing in size with the increased grow^th of the shell; 

 flattened on the lower surface for more than one-half their diameter, but 

 very evenly and regularly rounded above; periphery rounded, a little less 

 so below than above the middle; aperture semi-ovate, or having the form 

 of a circle, with the lower third truncated. Surface of the shell not 

 observed. 



The specimens of this species which have been observed are all internal 

 casts, and occurin a coarsely crystalline and quite friable limestone. The sub- 

 stance of the shell has been quite thick, and, being also coarsely crystalline, 

 crumbles at once on attempting to remove the specimens from the surround- 

 ing rock, so that the surface-characters of the shell cannot be obtained. 

 The generic features of the specimens are so obvious that there can be no 

 doubt whatever of their right reference to Maclurea; and their small size, 

 together with the rounded upper surface of the volutions, which do not 

 show the least tendency to become angular at the edge of the spiral 

 depression or cavity, but is evenly and regularly rounded on the inner as 

 well as on the outer side, will serve, we think, to distinguish it from all 

 other described species of the genus. 



Formation and locality. — In limestone, probably of the age of the Chazy 

 limestone of New York, at Ute Peak, Wahsatch Range, Utah. Collected by 

 Arnold Hague. 



Genus FUSISPIRA Hall. 



FUSISPIRA COMPAOTA U. Sp. 

 Plate I, fig. 25. 



Shell elongate, turreted; spire elevated, forming considerably more 

 than half, probably two-thirds, of the entire length of the shell; composed 

 of six or more short, compact, rather rapidly-increasing volutions, which 

 are strongly rounded on the surface, and less than half as high as their 

 diameter. Aperture not definitely determined, but apparently elongated, 

 and probably attenuate below, judging from what can be seen of the lower 



