392 S. F. Peckham — Origin of Bitumens. 



I took from a library shelf Prof. James Hall's report on The 

 Geology of New York, and glancing at the introduction, my 

 eye fell upon his clear description of the trend of the currents 

 in the Silurian ocean.* First came Newberry's Sargossa Sea, 

 which formed, when buried, one thousand feet of shale, so 

 filled with fucoids that where the shales outcrop at Erie, Pa., 

 it is impossible to obtain a piece of appreciable size that does 

 not contain a seaweed. On visiting Erie and talking the mat- 

 ter over, I found that, at the time the distillations of coal were 

 made in southern Ohio with which Dr. Newberry was familiar, 

 attempts had also been made to utilize the Erie shale as a 

 source of illuminating oil, and fifty gallons of distillate to the 

 ton had been obtained. 



The idea of metamorphism as a source of heat grew apace 

 — heat, steam and pressure and unlimited quantities — cubic 

 miles — of material on which to act. I had been familiar with 

 the anthracite of Rhode Island from boyhood, and with the 

 crystalline schists of eastern New England. I had been down 

 in the coal mine at Portsmouth on the island of Rhode Island, 

 and had seen the immense chambers from which the coal had 

 been mined. All traces of bedding had disappeared, and the 

 coal, almost graphite, had been seggregated into masses almost 

 spherical and connected only by a thread, by which the miners 

 traced the coal from one mass to another. 



At the Palisades the molten interior mass has punctured the 

 surface. Through eastern Pennsylvania the coal is meta- 

 morphosed into anthracite. At Saint Mary's, where the Phila- 

 delphia and Erie railroad crosses the summit of the Alleghames, 

 the coal is semi-anthracite. In the most easterly county of 

 Pennsylvania in which petroleum is obtained — McKean county 

 — the petroleum occurs at a depth of two thousand feet under 

 a pressure estimated at four thousand pounds to the square 

 inch and filled with paraffin e, just as it ought to be if produced 

 by metamorphism. Farther west, the petroleum becomes 

 lighter, until, at Smith's Ferry, it is almost burning oil in its 

 natural state. The products of distillation are all present in 

 proper sequence along the entire line from Point Gaspe to 

 Lookout Mt., and the porous sand bars and pebbly riffles, 

 formed by the' currents of the primeval ocean, are now filled 

 with the oil because they afford a receptacle adequate to receive 

 and store the vast accumulations of distillate. 



Now, while I have received many very pleasant and favor- 

 able comments upon the provisional hypothesis which I ven- 

 tured to propose in my Report, to the 10th Census, I have for 

 some time had a critic who seems to partly disagree with me.f 



* Nat. Hist. New York, Paleontology, iii, 45-60. 



f Rep. 10th Census U. S.. x, p. 59. This Journal, 1885 (?) 



