THE 



JOURNAL OF GEOLOGY 



NOVEMBER-DECEMBER, igos 



THE MORRISON FORMATION AND ITS RELATIONS 



WITH THE COMANCHE SERIES AND THE 



DAKOTA FORMATION 1 



T. W. STANTON 



The beds now generally designated on U. S. Geological Survey 

 maps as the Morrison formation have been a subject of interest and 

 discussion since 1877, wnen abundant remains of dinosaurs were 

 found in them. The first extensive collections of the vertebrate 

 fauna were obtained in the neighborhood of Morrison near Denver, 

 in Garden Park, near Canyon City, Colorado, and at Como, or 

 Aurora, Wyoming. Since then the formation has been recognized 

 by means of its fossils, its lithologic features, and its stratigraphic 

 relations in the Black Hills, on the Laramie Plains, and elsewhere 

 in Wyoming, in Montana, in western Colorado, in southeastern 

 Colorado, and in adjacent parts of Oklahoma and New Mexico. 



Of the various names that have been applied to the formation 

 Atlantosaurus beds is, perhaps, most frequently seen in the literature, 

 but Como stage, Beulah shales, Morrison formation, and Gunnison 

 formation have been locally applied. In recent publications Darton 

 has used the term "Morrison formation" in all the areas mentioned. 



The formation is non-marine throughout, so far as known, and 

 consists of variegated marls and shales with irregular beds of sand- 

 stone and sometimes thinner layers and lenses of siliceous limestone. 



1 Published by permission of the Director of the U. S. Geological' Survey. 

 Vol. XIII, No. 8 657 



