42 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA, [bull.106. 



For about 50 feet above the coal seams the following species are 

 found, the most of them iu abundance: 



Ostrea coalvillensis. Eulimella chrysallis. 



Anomia propatoris. Admetopsis. 



Corbula subtrigpnalisf Chemnitziaf 



Cyrena or Corbicula. Melania* 

 Avicula. 



Four feet below the highest band in which these species were found 

 there is a layer of sandstone containing plant remains. They were 

 very abundant and fairly well preserved at one small outcrop where a 

 collection was made. Plants also occur sparingly in other bands of 

 sandstone above this and in the massive sandstones of No. 8. The 

 plants have been examined by Mr. F. H. Knowlton, of the Geological 

 Survey, and in his notes on them he says: 



The matrix, a bard, fine-grained brownish sandstone, preserves the outlines and 

 coarse nervation of the plant remains very satisfactorily, but does not well retain 

 the fine nervation. A number of the species, however, are so characteristic that 

 there can be little doubt as to their determination. 



The collection consists of thirty-live specimens representing about twelve species, 

 the most important of which belong clearly to the Laramie group. They are as 

 follows : 



*Sequoia longifolia Lx. Ficns planicostata ? Lx. 



Sequoia reichenbachi Heer. *Ficus irregularis ? Lx. 



Glyptostrobus europaeus ? Heer. *Viburnum marginatum Lx. 



Salix elongata O. Web. Viburnum sp. 



Salix integra Gopp. *Cinnamonum affiue Lx. 



Salix sp. *Magnolia tenuinervis Lx. 

 Ficus lanceolata Heer. 



Those marked with an asterisk in the above list are, according to Mr. 

 Knowlton, u Laramie species about which there is little doubt as to 

 their correct determination." The others are u either fragmentary and 

 therefore of doubtful determination, or occurring in formations other 

 than the Laramie." Only one species in the list, Sequoia reichenbachi, 

 is known to occur below the Laramie and it has a wide range, being 

 found from the Jurassic or Lower Cretaceous to the Tertiary. 



If the evidence of these plants were considered alone there could be 

 no hesitation in referring the strata containing them to the Laramie. 

 Some of the invertebrates also from No. 7 are very closely related to 

 Laramie species if not identical with them, but unfortunately the most 

 of them are of types that have a great vertical range and therefore are 

 of little use in correlation. Ostrea coalvillensis is probably identical 

 with 0. glabra. Corbula subtrigonalis is a Laramie species, but closely 

 similar forms occur in the Colorado. Anomiapropatoris also is represented 

 in both of these formations by closely similar or identical forms. Mod- 

 iola multilinigera is a Colorado species and it has near relatives in the 

 Laramie. The form listed as Melania seems to be very close to Melania 

 ivyomingensis, a species that has been considered characteristic of the 



