MODERN SCIENCE. 165 



SYSTEM ; made an immense survey of the geological features 

 of RUSSIA (where he traced the history of the Permian rocks), 

 the Ural mountains, THE HIMALAYAS, THE CAPE, Spain, 

 Brittany, Chili, and some Pacific groups. A few details may 

 show the practical nature of his work. In Italy and Sicily he 

 studied the action of the Vesuvius and the Etna, and showed 

 the rocks these volcanoes had been building. He accounted 

 for the vast masses of lava and basalt, found in all parts of 

 the earth, by recalling to his readers' mind that the eruption 

 of the Skaptar (Iceland), in 1783, had produced a stream of 

 lava 90 miles long, 8, 10, 15 miles broad, and 500 or 600 feet 

 thick the mass poured out on that occasion equalling the 

 bulk of Mont Blanc. He studied also the present formation 

 of limestone beds in the Mediterranean, their enormous 

 thickness, and their uprise of some 3,000 feet above the 

 sea level ; he pointed out the subsidence of part of the 

 English coast-line and the gradual crumbling of the cliffs far 

 beyond the old site of towns which have been moved further 

 inland. All these facts and many others were the materials out 

 of which Lyell was able to demonstrate his geological laws. 



1797 1858. Scrope made a special study of VOLCANOES ; 

 showed their multifarious action in all parts of the globe ; ex- 

 haustively surveyed the Auvergne volcano system, one of the 

 most instructive areas in the world : his work done for all time, 

 so beautifully is it carried out. His two chief books are mines 

 of geological knowledge. 



1797 1875. Lyell classified the stratification of the crust, 

 and established some of the GEOLOGICAL LAWS, especially that 

 of uniform, continuous, and permanent action of forces the 

 one great discovery which made him the master of the science. 

 William Smith had already taught that strata were laid 

 successively; but it was Lyell who formally introduced 



geologist who definitively demonstrated the fact (1883). He proved the 

 Upper Gneisses which overtop the sandstones, conglomerates, and Durness 

 limestones to be identical with the Lower Gneisses the primeval crust 

 of the earth and that the Upper Gneisses, therefore, were not of recent 

 formation as Murchison had taught, but as ancient as the earliest stage of 

 the earth's crust \ so that the order of succession of rocks in the Highlands 

 is apparent only, and not real. 



