FOSSILS OF THE BUCK PEAK BEDS 373 



Dr F. E. Wright kindly examined the vein material for me, and found it 

 composed chiefly of laumontite with a small amount of quartz. 



FOSSILS OF THE PLANT BEDS 



On Thompson creek and the eastern slope of Buck peak, a complete 

 collection of plants was made at various times by Will Q. Brown, Pro- 

 fessor Lester F. Ward, James Storrs, and the writer, and the flora has 

 been thoroughly worked i;p and published by Professors Ward and Fon- 

 taine in the reports of the U. S. Geological Survey. The flora as described 

 consists of about 77 species, listed in Monograph XLVIII, page 140, 

 and no other forms have since been discovered in the original localities. 

 Their conclusion with reference to geologic age is that, "so far as they 

 throw any light on the question of age, they indicate that it is Jurassic." 



Shells are of exceptional occurrence in the leaf beds. Though care- 

 fully sought for, they have rarely been found, but on accoimt of their 

 bearing on the age of the deposit all the evidence should be recorded. A 

 doubtful fragment found with the plant fossils on Thompson creek was 

 referred to Doctor Stanton, who reports that "the fragment seems to be 

 part of a shell and is probably an Aucella, though there is not enough of 

 it for positive identification." 



RELATION TO THE "MYRTLE FORMATION" OF BUCK PEAK 



The summit of Buck peak is conglomerate and sandstone containing 

 the characteristic "Myrtle" (Knoxville) forms, Aucella piochi and A. 

 crassicolUs. Twelve hundred feet below the summit, on the northeastern 

 slope, at the "Todd locality," the plant beds shown in figure 3 occur, 

 dipping westward conformabl}', beneath a conglomerate containing many 

 indefinite vegetable fragments as well as good specimens of Aucella 

 piochi. These plant-bearing beds surely belong to the "Myrtle." 



In the upper 200 feet of plant beds exposed at that place there are half 

 a dozen beds of fine conglomerate, ranging from 2 to 10 feet in thickness, 

 like the immediately overlying aucella-b earing conglomerate, suggesting 

 continuous sedimentation, and that the plant beds belong to the "Myrtle 

 formation." 



Eecognizing this probability, at Buck peak we have taken every oppor- 

 tunity afforded in the region to examine the basal beds of the "Myrtle" 

 for plants, and traces of plants have been found at a number of localities, 

 but at only one place have we found a determinable species. Three miles 

 northeast of Piddles, in a gap of the ridge in southeast quarter of sec- 

 tion 8, with good specimens of Aucella piochi, a fossil plant was found 



