150 UNIVERSITY OF COLORADO STUDIES 



The next camp for paleontological purposes was about seven miles 

 south of Ft. Collins at Trilby Schoolhouse. At this point work was 

 done on Fossil Ridge, which extends north and south parallel with the 

 Colorado & Southern Railway. The ridge consists of a soft sandstone 

 in which are numerous concretions which contain fossils. This place 

 is the type locality for several species and abounds in individuals of other 

 species, particularly the large bivalve, Inoceramus ohlongus. It is not 

 uncommon to find a dozen or more of these shells six to eight inches in 

 length, in a single concretion two or three feet in diameter. An extensive 

 collection was obtained here. Some of the species obtained had not 

 been previously reported from Colorado. Excellent series of several 

 species were collected showing extremes of variation. Some of these 

 series will be useful for students as illustrating features of interest from 

 the standpoint of evolution. With these collections the University 

 museum now has more than twice as many species as have been recorded 

 for Fossil Ridge. 



Fossil Ridge is one of the most important localities in Colorado for 

 invertebrate fossils, yet it has received very meager treatment in the 

 literature of paleontology. With the material now in hand and with a 

 little more field-work to determine some questions of stratigraphy, it 

 will be possible to prepare a valuable report treating the locality with 

 the detail which it deserves. 



Along the blufifs of the Cache la Poudre River a short distance south- 

 east of Windsor several hundred specimens of a fossil bivalve, Veniella 

 humilis, were collected in an excellent state of preservation. Besides 

 these, there were two almost perfect specimens of another mollusk, 

 Pholodomya suhveniricosa. These were from beds which may be 

 assigned either to upper Pierre or to lower Fox Hills. Above, in 

 undoubted Fox Hills strata, were found a number of species in much 

 better condition than is usual in the friable sandstone of that group. 



West of Pawnee Buttes, in eastern Weld County, a general survey 

 of the field was made. Previous expeditions to this region had picked 

 up the most available material so that no extensive collections were 

 obtained. All fossils here are of vertebrate animals. A collection was 

 made consisting of a number of fossil jaw bones of various land forms. 



