II. THE FAUNA OF THE UPPER DEVONIAN IN MONTANA. 



Part 2. The Stratigraphy and the Brachiopoda. 



By W. p. Haynes. 



(Plates III-VIII.) 



A number of years ago Dr. P. E. Raymond undertook the description 

 of the fauna of the Upper Devonian in Montana, basing his work upon 

 collections made by Mr. Earl Douglass and himself for the Carnegie 

 Museum. The first part, containing a description of the Cephalopoda 

 and a few other fossils from the " Red shales," appeared in 1909 in 

 these Annals. 



In this, the second contribution to the subject, the writer describes 

 the Brachiopoda, based on the material in the Carnegie Museum, 

 supplemented by collections, which he has himself made for the 

 Museum of Comparative Zoology, and describes the stratigraphy of 

 the formation. 



The writer is indebted to Dr. Raymond for many suggestions in the 

 preparation of this work for publication. 



Stratigraphy. 

 The writer has made a study of the Three Forks Formation at it? 

 type-locality at Three Forks, Montana, and also throughout the 

 Three Forks quadrangle and the neighboring region along the Missouri 

 river in the Fort Logan quadrangle (See Plate III). In this report 

 the distribution and stratigraphy of the formation will first be con- 

 sidered, and then the fauna will be discussed, with a detailed de- 

 scription of the brachiopods of the limestone and green shale members 

 of the formation. 



Three Forks Formation. 



General Description. — Lying in apparent conformity upon the Jef- 

 ferson limestone is a series of shales and limestones, which have been 

 named by the late Dr. A. C. Peale the Three Forks Shales.^ He 

 described the formation in some detail, which may be briefly summar- 

 ized by the following columnar section. 



1 Peale, A. C. Bull. U. S. G. S., No. no, pp. 29-30, 1893. 



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