﻿in Paleontology 33 



has not been observed by the writer in the latter formation. 

 Peale 34 reports it in the uppermost part of the Jefferson limestone 

 at Logan, but it is probable that the form listed by Peale is the 

 variety since distinguished as animasensis . 



Locality. — Paradise P. O., Utah, Manson Sta., Idaho. 



Martinia maia (Bill) 

 PI. IV figs. i-ig. 



The rather large collection of specimens from the Logan 

 Canyon section show considerable variation with respect to 

 outline of shell, gibbosity, and height of area. The narrow 

 elongate type is represented by shells in which the length ex- 

 ceeds the width, whereas in some of the broad types the width 

 is equal to i^- times the length. An incurved ventral beak, a 

 gibbous umbonal region, a short hinge line, and rounded cardinal 

 angles generally characterize the elongate type of shell. The 

 broad shell shows a slightly incurved ventral beak, a less gibbous 

 umbonal region, and a long hinge line. A slightly incurved 

 ventral beak and high area characterize some shells of the long, 

 narrow type. 



These specimens exhibit about the same kind and amount of 

 variation as shown by specimens from Nevada. None of the 

 Utah specimens, however, attain the large size shown by a few of 

 the Nevada specimens. Although the outer surface of the shell 

 is smooth, exfoliated specimens show fine striae which character- 

 ize the inner surface of the shell, as shown in the illustrations. 



Locality. — Logan, Utah; Rock Greek, Montana. 



PELECYPODA 



Pterinopecten sp. 



PI. IV fig. 5. 



Shell small, subrhomboidal, regularly rounded. Left valve 



moderately convex. Posterior ear rounded and rather flat. 



Anterior ear unknown. Surface marked with s_trong radiating 



j' 



"Bull. U. S. Geol. Survey No. no, 1893, p. 29. 



