220 



Scudder — Fossil Insects of North America, 



roots of plants, and would not be likely to occur in such a deposit as 

 that in wliich these remains were found. 



The only specimens of insects from the Tertiaries of North America 

 were discovered, in 18G5, by Professor William Denton, in the valley 

 of the White Eiver, Colorado, near the confines of Utah.^ This 

 valley lies just west of the main chain of the Kocky Mountains, and, 

 according to Professor Denton, the rocks all belong to the Tertiary 

 age. The country in which they occur is a most remarkable one ; 

 the whole surface is bare rock, eroded by water into ravines and 

 canons, gorges and valleys, a thousand feet in depth.^ 



The following table gives Professor Denton's view of the super- 

 position of the rocks ; the thickness of the several deposits is only 

 estimated. The upper beds are found near the junction of the White 

 and Green Eivers in Utah ; the lower ones, near the Parahlamoosh 

 Kange, where they are covered by immense beds of lava. 



1 



Eed and white sandstones 



Seen, but not examined 



2000 ft. 



2 



Brown sandstones, passing occasionally 

 into conglomerate and alternating 

 with thin beds of blueish and cream- 

 coloured shales, all dipping to the 

 w€st at an angle of about 20*. Pro- 

 bably of Miocene age. 



Turtles; fragments of large 

 bones and teeth of mam- 

 mals ; fossil wood of de- 

 ciduous trees. Perpendi- 

 cular veins of petroleum 

 coal. In the lower shales 

 Insects and leaves of de- 

 ciduous trees. 



1200 ft. 



3 



Petroleum shales, varying in tint from 

 a light-cream to inky blackness. One 

 bed, 20 feet thick, resembles cannel 

 coal. 



Innumerable remains of 

 Insects and leaves of de- 

 ciduous trees. 



1000 ft. 



4 



"White or light-brown sandstones. 

 White shales, on which are ripple 

 marks. Brown shales and shaiy 

 sandstones. 





800 ft. 



5 



Thick white sandstones and brown 

 shales. Thick brown sandstones. 



Brown sandstones, wea- 

 thered into cavities. 



1000 ft. 



6 



7 



Sandstone, limestone, shales, blue, 

 brown, and black underclays. Beds 

 of coal or lignite. Brown sandstones 

 and shales, very soft. Coal in se- 

 veral beds, with underclays. "White 

 sandstones, with alternating blue 

 shales. 



Limestone contains conchs 

 and small gasteropods. 

 Two wide expansions of 

 White Biver Valley have 

 been made where the soft 

 shales occur. 



2700 ft. 



Compact red sandstones. Wliite sand- 

 stones. Red sandstones, shaly and 

 micaceous. Thin fetid limestones. 



Fragments of shell in the 

 limestone. 



1400 ft. 



8 



Yellow soft sandstone 





300 ft. 



9 



Gypsum 





200 ft. 



1 Proc. Bost. Soc. Nat. History, vol. x., pp. 305-6, vol. xi., pp. 117-8 ; American 

 Naturalist, vol. i., p. 56 ; HoUister; The Mines of Colorado, pp. 378-87, 12rao. 

 Springfield, 1867. a Hollister, Mines of Colorado, p. 383. 



