De Verneuil. 281 
isolated parts of the region. ‘Traveling by different routes, 
and meeting from time to time to compare their observations, 
the three savants gave a very wide range to the field of their 
operations. The nearly horizontal position of all the forma- 
tions beyond the chain of the Urals is in marked contrast with 
the manner in which the same groups are upturned and broken 
in Western Europe; and the great extent of the beds favors a 
rapid acquaintance with them. The work upon Russia in Ku- 
rope and the Ural Mountains, accompanied as is well known by 
geological maps representing each of those countries, appeared 
in 1845. It isa monument raised to the knowledge of the im- 
mense region to which it relates, and at the same time to the 
fundamental principles of geology. The introduction of the 
ermian system into science was one of the great results of 
this exploration. 
n. When it is possible to follow deposits from one country 
to another without interruption, it is easy to trace out corres- 
ii ndances among them; but this cannot be done between two 
Continents separated by 3,000 miles. : ; 
In the spring of 1846, the publication relating to Russia 
M. de V 
eae 
out and compare for the two continents the sedimentary 
Strata, from the lowest fossiliferous beds up to the coal. Such 
Was the task laid down for himself by this intrepid pioneer 12 
