Denton.] 306 



of large bones, most of wlilcli were solid, and turtles, some of which 

 were two feet in length, and perfect. I think the sandstone is proba- 

 bly of Miocene age. 



In the petroleum shale, underlying the sandstones, are innumerable 

 leaves of deciduous trees ; among them I think I recognized the wil- 

 low, the maple and the oak, but shall be able to speak more definitely, 

 when the specimens which I collected arrive. Dipterous insects, 

 resembling the musquito, and their larvae abounded ; they are in a 

 wonderful state of preservation. 



The story that these beds tell seems to be this. A large fresh-water 

 or brackish lake existed, covering a considerable portion of western 

 Colorado and eastern Utah. Streams carried down fine sediment 

 and free petroleum, from numerous springs in the surrounding coun- 

 try, for ages ; the petroleum increased in flow until the sediment of the 

 lake became thoroughly charged with it, and the cannelite was the re- 

 sult. A change in the level of the country and the course of the streams 

 is indicated by the overlying sandstones and conglomerates, nearly des- 

 titute of petroleum, and at least one thousand feet in thickness. Dur- 

 ino; the time that this immense amount of sediment was being depos- 

 ited, willows, maples, oaks, and many strange ti'ees grew on the land, 

 palaeotheres and turtles swam in the waters, and clouds of insects 

 sported over its surface. The bitumen seems to have flowed from the 

 shales as petroleum, after their upheaval, filling ci-evlces perhaps formed 

 by that upheaval, and to have hardened in time into its present form. 



Description and Analysis of a new kind of Bitumen. By 

 Aug. a. Hayes, M. D. 



Prof Wm. Denton, lately returned from a geological exploration 

 of parts of Utah and Colorado, placed in my hands for chemical analy- 

 sis some fragments of bitumen, discovered by him near the junction 

 of White and Green Rivers. The physical characters of this min- 

 eral connect it with the variety of cannel coal called Albertite ; a 

 fact which gives great interest to the discovery, apart from economi- 

 cal considerations. 



In chemical composition, relation to heat and solvents, it differs 

 from Albertite remarkably, and falls within the class of true bitumens, 

 of which it is an important member, well characterized. 



It may be viewed in another connection with some scientific inter- 

 est, and it is to this relation that I purpose to call attention. 



When the cannel coal of New Brunswick was discovered and de- 

 scribed, geologists and mineralogists were unAvilllng to class it with 

 known coals of the cannel kind, on account of its general resemblance 

 to some known bitumens. Jet, from the tertiary formation, seemed to 

 be its nearest relative, but so strong was the impression of its physical 



