PREFACE. 
xii 
of the palaeozoic systems, and explained the classification implied 
thereby, in a letter addressed to the venerable Dr. Fischer de Waldheim. 
Subsequently at St. Petersburgh he presented, in the name of his friends 
and himself, a report upon the whole survey to His Excellency the 
Count de Cancrine. This report, with an improved map and a general 
section across Russia from south to north (those which in an improved 
state now appear in PI. VI.), was shortly after laid before the Emperor, 
when His Imperial Majesty not only received the travellers with his ac- 
customed kindness, honouring them with his warmest thanks and special 
marks of his favour 1 , but further assured them that he considered their 
labours to be of great importance to his country. 
And here the authors must observe, that their efforts could have had 
no such result, if the wishes of the Emperor had not been admirably put 
into execution under the directions of his enlightened minister the Count 
de Cancrine, and by the excellent arrangements made by General Tcheff- 
kine in his department of the Imperial Corps of Mines. Nor can they 
omit to notice their obligations to Colonel Helmersen for his good advice 
concerning the Ural Mountains, with which he had rendered himself so 
familiar. To these and numerous other kind friends, both in the Russian 
metropolis and in the provinces, particularly to many officers of the 
Imperial Corps of Mines, as well as to various authors who have assisted 
them in different auxiliary departments of science, they will, in the course 
of this work, have other opportunities of expressing their obligations. 
Having thus arrived at more definite conclusions, the authors explained 
their matured general views to the Geological Society of London in the 
subsequent winter, and soon afterwards commenced the preparation of 
the present work, which in the summer of 1842 was brought into a 
systematic plan, during a visit which Count Keyserling and M. de Ver- 
* This survey having been carried out under the special orders and protection of the Emperor, the foreign 
geologists who were fully accredited to the governors and chief officers of the provinces, were substan- 
tially and virtually “pro hdc vice” in the Russian service; and for such gratuitous service they were 
honoured by marks of His Imperial Majesty’s satisfaction. 
