MOOK, STUDY OF THE MORRISON FORMATION 



127 



Unio toxonotus White, On the Fresh-Water Invertebrates of the jSTorth 

 American Jurassic. U. S. Geol. Surv., Bull. Fo. 29, p. 17, pi. 2, figs. 

 1, 2, 1886. 



Unio macro pisth us White, On the Fresh-Water Invertebrates of the 

 North American Jurassic. U. S. Geol. Surv., Bull. No. 29, p. 17, pi. 2, 

 fig. 7, 1886. 



Unio iridoides White, On the Fresh-Water Invertebrates of the North 



Fig. 91. — Calcareous arkosic sandstone, from the Morrison formation near Canon City. 



The clear round grains are quartz and feldspar ; the interstitial banded grains are 

 calcite ; and the large grain at the left, with the dark grain above it, is replaced volcanic 

 ash. About 28 X. ^ 



American Jurassic. U. S. Geol. Surv., Bull. No. 29, p. 17, pi. 2, figs. 

 3, 4, 1886. 



Unio lapilloides White, On the Fresh- Water Invertebrates of the North 

 American Jurassic. II. S. Geol. Surv., Bull. No. 29, p. 18, pi. 2, figs. 

 5, 6, 1886. 



Unio stewardi White, Eeport on the Geology of the Eastern Portion of 

 the Uinta Mountains and a Region of Country Adjacent Thereto, by J. W. 



