1897.] NATURE AND ORIGIN OF PETROLEUM. 107 



at low temperatures from fats alone by the combined action of 

 pressure and heat. 



Steam is left out of this formula and it is therefore inadequate. 

 There is no evidence whatever that any portion of the crust of the 

 earth has ever been subjected to the combined action of heat and 

 pressure without the presence of steam or hot water, and in my 

 judgment the steam has been a very potent factor in determining 

 not only the formation but the transference of bitumens. 



I have been many times told that the Turrellite of Texas consists 

 of a mass of loose shells cemented together with bitumen. As it 

 had that appearance, I never questioned the statement, until lately 

 I had occasion to examine a specimen of this mineral. I pulver- 

 ized some of it and proceeded to analyze it by solvents. I found 

 that a portion of the mineral matter passed through fine filter paper. 

 I then digested a piece of it in successive portions of chloroform, 

 until the chloroform was no longer colored. There remained a 

 white shell-rock, or coquina, quite firm and strong, very light in 

 weight, with the cavities of some of the shells partly filled with 

 crystallized rhomb-spar; together with fragments of shells and 

 dust. Under the microscope some of the dust was only one twenty 

 thousandth of an inch in thickness. The shells had been subjected 

 to the action of hot water after all traces of the soft parts of the 

 animals had disappeared and a part of the lime had been dissolved 

 and redeposited in the cavities of the shells and between them, 

 thus cementing them together ; and this anterior to the entrance 

 of the bitumen, which must have filled the shell-limestone as a 

 vapor or in a fluid or semi-fluid condition. When separated from 

 the shells the bitumen is very pure and uniform in its composition, 

 containing many times the amount of carbon that existed in the 

 soft parts of the animals that made the shells > their home. The 

 porous shell-rock simply aff'orded an adequate receptacle for the 

 bitumen that was distilled or sublimed into it. 



I have lately examined California petroleums more closely than I 

 ever had before. I have distilled off the lightest portion from some 

 Wheeler's Canon green oil that I took from the Canon in 1866. I 

 also distilled about fifty per cent. — the lightest portion — from some 

 Pico Canon oil that I got from there two years ago. While in Cali- 

 fornia in the fall of 1894, I distilled from several samples of black 

 oil, taken from wells in the Sespe and Torrey Canons and near Bards- 

 dale, about twenty-three per cent, of the lightest portion. The distil- 



