112 PECKHAM — THE GENESIS OF BITUMENS. [April 1, 



how fully his conclusions, based almost wholly on theoretical con- 

 siderations, have been confirmed by the experiments of Daubree, 

 who was led to investigate this subject, from observing that the 

 action of the alkaline, thermal waters of the spring at Plombieres, 

 at a temperature of 6o°-7o° C, had in the course of centuries given 

 rise to the formation of zeolites and other silicated minerals among 

 the bricks and cement. of the old Roman baths/ He further shows 

 that at a temperature of loo'^ C. silicates are produced from a reaction 

 between alkaline silicates and carbonates of lime, magnesia and 

 iron. He says further, " Now the supposed mode of formation of 

 the primitive molten crust of the earth would naturally exclude all 

 combined or intermingled water, while all the sedimentary rocks 

 are necessarily pervaded by this liquid, and are consequently in a 

 condition to be rendered semifluid by the application of heat. 

 .... If now, we admit that all igneous rocks, ancient plutonic 

 masses as well as molten lavas, have their origin in the liquefaction 

 of sedimentary strata we at once explain the diversities of their 



composition The presence of fossil plants in the melting 



strata would generate carburetted hydrogen gases, whose reducing 

 action would convert the sulphurous acid into suphuretted hydro- 

 gen ; or the reducing agency of the carbonaceous matter might give 

 rise to sulphuret of calcium, which would be, in its turn, decom- 

 posed by the carbonic acid or otherwise The carbu- 

 retted hydrogen and bitumen evolved from mud volcanoes, like 

 those of the Crimea and Baku, and the carbonized remains in the 

 moya of Quito, and in the volcanic matters of the island of Ascen- 

 sion, not less than the infusorial remains found by Ehrenberg in 

 the ejected matters of most volcanoes, all go to show that fossili- 

 ferous sediments are very generally implicated in volcanic phe- 

 nomena."^ Again, he states, that in a letter to Sir Charles 

 Lyell, dated February 20, 1836, Sir John F. W. Herschel main- 

 tains that with the accumulation of sediments the isothermal lines 

 of the earth's crust must rise, so that strata buried deep enough will 

 be crystallized and metamorphosed, and eventually be raised with 

 their included water to the melting point." Again Dr. Hunt says, 

 *' We conceive that the earth's solid crust of anhydrous and primi- 

 tive rock is everywhere deeply concealed beneath its own ruins, which 



1 Etudes et experiences syjitJiHique sitr le vietamorphisnie, par M. A. Daubree, 

 Paris, 1859, p. 98; Ann. des Mines (5), xiii, 227. 



2 Essays, p. 8. 



