570 Geological Society. Anniversary Address, 18^2. 



tions to illustrate tlie memoir on tiie Rhenish provinces by Professor 

 Sedgwick and myself. You must not, however, Gentlemen, judge 

 of the very high merits of the original from the reduced skeleton 

 map which we publish, and I beg you to consult the former as one 

 of the most valuable documents of this nature yet offered to the 

 public, particularly in the elaborate delineation of every variety of 

 igneous, metalliferous, aud metamorphic rocks, in a region so stri- 

 kingly replete with them. Silesia has also occupied much of the time 

 of 5l. von Dechen, in some districts of which he has marked the 

 existence of bands of carboniferous limestone as distinguished from 

 the Devonian, Silurian, and older members of the paleozoic series. 

 Oeynhausen, the old associate of Von Dechen, and so well remem- 

 bered by many of us, has recently bored in search of salt springs 

 through upwards of 1000 feet of lias near Pyrmont, a fact whicli 

 ought to teach us great caution in estimating what may be the 

 maximum thickness of deposits. In our own country, the accu- 

 rate method which INIr. De la Beche employs to test the thick- 

 ness of deposits, will eventually give us, I trust, close approxima- 

 tions to the facts ; and I learn from him that some of the ancient 

 strata (the carboniferous for example) which have been accumu- 

 lated in basins are enormously more thick than we had supposed, 

 whilst others extending, like the Old Red Sandstone, over wide 

 areas in lofty escarpments, will not prove to have those dimensions 

 we had assigned to them. When, indeed, we consider that all 

 shales, sandstones, &c. were once nothing more than the blue and 

 black, and red mud, or sand which occupied the bottom of seas in 

 former epochs, it seems as difficult to decide from general observa- 

 tions on the maximum thickness of any great deposit, as it would 

 be to insist on the utmost depth of the ocean without the survey of 

 the hydrographer. The borer and the field engineer must therefore 

 combine to enable us to speak with precision on the vertical dimen- 

 sions of strata. 



RUSSIAN AND NORTHERN SCHOOL. 



Not having yet personally visited Sweden, Norway, and Den- 

 mark, I am not prepared to say what progress our science has re- 

 cently made in these states, but I may remark, that the beautiful map 

 of Norway by Keilhau has scarcely received the attention which it 

 merits ; and we may be sure that the countries of so good geolo- 

 gists as himself and our associate Forchhammer, cannot be lagging 

 behind in the general onward movement. 



In regard, however, to Russia, I am enabled to speak with some 

 confidence, after the two visits which I have paid to that country. 

 Gratified as we were, not only by the most hospitable reception, but 

 also the kind assistance afforded us by every Russian, from the Em- 

 peror to his humblest subject, it M-as a real source of delight to my 

 associates and myself in our first visit to trace throughout the north- 

 ern regions of that vast empire, the same palaeozoic divisions which 

 have been proposed as types in the British Isles. During the last 

 summer we extended our researches to the distant Ural, the Siberian 

 plains, aud the steppes of the south ; aud afterwards terminated the 



