INTRODUCTION. 5 1 



composed of the crystalline massive rocks, on either side a \ 

 succession of uptilted and upheaved strata covered in their 

 turn by younger, slightly tilted, or horizontal deposits 1 

 composing the neighbouring plains. Michell, however, did 

 not draw any general conclusions. Pallas was enabled from 

 his wide experience to fill in the details of Michell's skeleton 

 plan of a mountain-system. 



According to Pallas, granite forms the core of all great 

 mountain-systems. It is covered by unfossiliferous schistose 

 rocks of various kinds, serpentine, porphyry, etc. These rest 

 against the granite in highly-tilted or vertical positions, and 

 are themselves succeeded by argillaceous schists and shales, 

 and by thick masses of limestone containing marine fossils. 

 The shales and limestones have highly-tilted positions where 

 they occur in the inner parts of a mountain-system, but 

 become less tilted and horizontal in the outer portions, the 

 number and variety of the fossils at the same time increasing. 

 The low hills and plains are composed either of sandstone, marls, 

 and red clay with stems of trees and twigs of land plants, or 

 of loose material, with the bones of large land mammals. 

 Pallas examined the mammalian remains with great care. 

 He proved the astonishing frequency in the occurrence of 

 mammoth, rhinoceros, and bison in the Siberian plains, and 

 described a rhinoceros corpse with hide and hair complete, 

 imbedded in the sand and pebbles on the bank of the Willui 

 river. He also stated that great accumulations of sand 

 and sulphur occur in the schistose zone of rocks, and that 

 the decomposition of those materials gives origin to volcanic 

 disturbances, which however affect only the rocks above the 

 schistose zone and the granite. 



The primeval ocean of the globe, in his opinion, never stood 

 more than 100 fathoms above the present sea-level, so that 

 the granite core of the mountain-chains could not have been 

 covered by it. All mountain-ranges composed of schists, lime- 

 stone, and younger formations, or, as Pallas called them, the\ 

 mountains of the second and third order, owed their upheaval | 

 to volcanic force. The schist mountains had originated before 

 the creation of living creatures ; then the limestone ranges 

 rose above the primeval ocean, and some of these, such as the 

 Alps, in relatively recent periods. The mountains of the third 

 order were due to the last volcanic eruptions. The upheaval 

 of mountain-chains was always accompanied by violent ground- 



