GEOLOGICAL RESULTS OF THE PETCHORA SURVEY. 
419 
whilst they differ materially from synchronous rocks of the Ural. This fact has 
led us naturally to connect the Timan with the subsoil of the vast low Muscovite 
countries, of which it forms the north-eastern girdle, and to separate it from the 
Ural, which in our language, has already assumed the Siberian type. Even the 
eruptive rocks of the Timan are, as we have shown, very different from those ot 
the Ural, and much more accordant with those of Scandinavia, with the eastern 
flanks of which country the range seems to be in intimate connection. 
The survey of the Petchora has further determined the exact north-eastern 
limits of the enormous basin of Permian deposits, whilst an examination ot the 
flanks of the Ural or the Timan have equally shown us, that though pertaining to 
the same series of paleozoic life, the Permian strata must unquestionably be 
distinguished from the old and altered rocks of the Ural, out ot which they have, 
indeed, been formed, and to which they are usually unconformable. In that 
phenomenon alone then we see the proof, that certain groups of animals have not 
always been obliterated by the powerful local changes, which have separated one 
deposit from another. 
