74 FORESTRY IN EASTERN RUSSIA. 



Roderick and his companions were enabled to establish a 

 clear succession of carboniferous, devonian, and silurian 

 deposits. True granite is of very rare occurrence along 

 the axis of the chain, and has at a comparatively recent 

 period burst through the eastern dislocations. The 

 periods of dislocation, the change of relative level of land 

 and water, and of the protusion of igneous rocks, appear 

 to have been phenomena repeated at different geological 

 epochs. From the occurrence of cupriferous minerals 

 diffused throughout the Permian strata, Sir Roderick 

 infers that anterior to the deposition of those beds, 

 metallic veins must have existed in the Ural mountains ; 

 and from the abundance of the remains of terrestrial 

 plants in the same deposits, that the chain must have been 

 raised to a certain extent above the level of the then existing 

 ocean. Subsequent periods of disruption are proved by 

 the lines of disturbance in the Permian series on the 

 immediate flank of the Ural range, and connected 

 with dislocations which have affected them. The patches 

 of Jurassic rocks at the north and south extremities of 

 the range, are considered to have been subsequently 

 desiccated, and the absence of strata of that age through- 

 out the great mass of the chain, or for 12 of latitude, to 

 prove that it was constantly above the level of the sea 

 during the Jurassic epoch. Between that period and the 

 accumulation of the gold alluvia, there are no signs of 

 any great changes in the physical structure of the Ural 

 range, and the only deposits assignable to that interval 

 are certain trachytic grits and beds of lignite, which, it is 

 conceived, may have been formed in lakes. On the west 

 side of the chain the order of the metalliferous rocks is 

 best developed ; but it is on the east igneous slopes that 

 the miner is best repaid by ores. Sir Roderick concludes 

 that " the widely-spread cupriferous deposits of Permia, 

 which occupy all the low country to the west of these 

 mountains, have been derived from pre-existing eastern 

 lands, upon which the plants and vegetables enclosed in 

 the Permian conglomerates must have grown. Judging 



