JOURNAL . 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. VIII JULY 19, 1918 No. 13 



GEOLOGY. — New geological formations in western Wyoming.'^ 

 Eliot Blackwelder, Geological Survey. 



As a result of the writer's field work in the Owl Creek, Sho- 

 shone, Wind River, Gros Ventre, and Teton ranges of western 

 Wyoming, from 1910 to 1913, several new geologic formations 

 have been recognized and the names proposed for them have 

 been adopted by the U. S. Geological Survey. As the prepa- 

 ration of detailed reports on this region awaits the completion 

 of the field studies, which have themselves been deferred for 

 more urgent work elsewhere, several years may elapse before 

 the reports appear in print. It therefore seems advisable to 

 publish, in advance, definitions of these new formations, so 

 that the names may be available for general use. In fact, while 

 this paper was being considered and revised in manuscript, some 

 of the names have already been used in print by other writers.^ 



GROS VENTRE FORMATION 



In Peale's^ original description of the Threeforks (Montana) 

 section, the Cambrian was divided into the Flathead quartzite, 

 Flathead shale, and Gallatin limestone. Later, Hague and his 

 associates used the same terms, but restricted the Gallatin to 



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

 ■^ ToMLixsox, C. W., Journ. Geol. 25: 25.5-257. 1917. Condit, D. D., U. S. 

 Geol. Survey Prof. Paper 98-0. 1916. 



3 Peale, a. C, U. S. Geol. Survey, Bull. 110. 1893. 



417 



