168 
ORIGIN OF THE COPPER SANDS AND MARLS. 
The ascending section terminates, as is usual in all these districts, with red 
argillaceous marl, containing some small concretions of gypsum and courses of 
marlstone. The whole of the beds are perfectly horizontal. 
We could have wished that our time had permitted us to examine the range of 
the Permian deposits in all other parts of this district. By inspection of the Map, 
however, it will be seen, that they are covered to the south by secondary formations 
(Jurassic and Cretaceous), a fact which we ascertained by passing southwards to 
Simbirsk and Sysran. 
Origin of the Copper Sands and Marls . — It has been more than once stated in 
this chapter, and a reference to the Map on which the boundary is defined explains 
the fact, that the portion of the Permian strata which is cupriferous, extends for a 
certain distance only to the west of the Ural chain (on the average from 400 to 
500 versts) 1 . In all the Permian tracts more distant from these mountains, no trace 
of copper ore is to be found. These circumstances alone would naturally lead to 
the belief, that the Ural mountains had afforded the sources from whence the 
mineral matter proceeded. 
As we shall hereafter show that this chain was, in remote periods, the seat of 
processes of intense metamorphism, during which copper veins were abundantly 
formed in the older palaeozoic rocks, we are naturally led to suppose, that such 
operations may have had some connection with the deposit of the adjacent copper 
sands and marls. But in what manner were the latter rendered cupriferous ? Not 
certainly by the degradation of pre-existing copper lodes, and by the dissemination 
of their particles in the adjoining sea, for in no instance do we find such frag- 
ments ; the fact being, that beds composed of similar materials are so impregnated 
with the mineral in one spot and so void of it in a contiguous locality, as to ex- 
clude the hypothesis, that this locally saturated mineral condition can have resulted 
from the grinding down of the detritus of other cupriferous rocks. We are in- 
clined, therefore, to believe, that when the Permian deposits were accumulating 
in the adjacent sea, springs charged with salts of copper were flowing into it from 
the Ural chain, then undergoing a peculiar change of composition, and that such 
springs deposited the greater part of their metallic contents in those portions of 
the bottom of the sea which afforded to them the strongest points of attraction. 
1 In the marly, sandy and calcareous tracts forming the left bank of the Volga, copper ores were for- 
merly extracted at no great distance from that river. These deposits were, however, much less rich in 
ore than those nearer to the Ural chain, and they have been exhausted. Pallas alludes to copper ores on 
the river Kinel, not far to the east of Samara. 
