BITTER CREEK VALLEY — BLACK BUTTES. 



145 



The fossil plants of Black Buttes, ranging through the same strata as 

 the invertebrates and extending up a few feet higher to the bed just 

 above the principal coal, are as follows : 



Apeibopsis discolor, Lx. 

 Cissites lobato-crenata, Lx. 

 Cissites tricuspidata, Heer. 

 Ficus planicostata, Lx. 

 Ficus planicostata latifolia, Lx. 

 Grewiopsis saportanea, Lx. 

 Greiciopsis tenuifolia, Lx. 

 Myrica torreyi, Lx. 

 Ophegrapha antiqua, Lx. 

 Pisonia racemosa, Lx. 

 Podogonium americanum, Lx. 



Quercus viburnifolia, Lx.' 

 Rhamnus salicifolius, Lx. 

 Sapindus caudatus, Lx. 

 Sequoia acuminata, Lx. 

 Smilax grandifolia, Ung. 

 Viburnum marginatum, Lx. 

 Viburnum platanoides, Lx. 

 Viburnum rotundifolium, Lx. 

 Viburnum whymperi, Heer. 

 Zizyphus fibrillosus, Lx. 



The higher beds of the section are lithologically very much like these 

 fossiliferous coal-bearing strata near the base. They are exposed in the 

 valley of Bitter creek for several miles east and southeast of Black Buttes 

 before the recognized Eocene is reached. A careful estimate, based on 

 the dips and distance across the strike, gives a total thickness of about 

 2,000 feet above the basal sandstone. No identifiable animal remains 

 were found within this series above the horizon already discussed, but 

 plants were collected from three other horizons associated with thin coal 

 beds. One of these, which is at least 700 or 800 feet above the Corbicula 

 bed, contains well preserved plants in great numbers, though only a few 

 species are represented. Their affinities are closest with the Fort Union 

 flora, as may be seen from the following list of species, all of which are 

 confined to or found abundantly in the Fort Union : 



Glyptostrobus ungeri, Heer. 

 Quercus dentoni, Lx. 

 Sapindus obtusifolius, Lx. 

 Conus fosteri, Ward. 



Tetranthera prsecursoria, Lx. 



New species belonging to the genera 

 Anemia, Cyperacites, Ficus, Rhus, Mag- 

 nolia, Juglans, Cinnamomum, etcetera. 



The other two horizons are near each other, several hundred feet higher, 

 and not more than a couple of hundred feet below the apparent base of 

 the Wasatch. The plants, which seemed similar to those of the last list, 

 were unfortunately lost in transit. 



Still higher in the section, at a point about eight miles southeast of 

 Black Buttes, there are two calcareous beds, separated by 50 feet of 

 strata, both of which contain numerous specimens of Physa pleromatis, 

 White, with Planorbis militaris, White ; Helix (?) sp., Viviparus ivyoming- 

 ensis, Meek, and fragmentary remains of turtles. Similar beds bearing 

 the same invertebrate fossils occur near the base of the Wasatch in the 



