viii 



THE GEOLCGIST. 



lithological characters are fugitive, and the red, green^ and 

 yellow sands of the north^ are found even in our islands, as in 

 Devonshire and the adjacent tracts^ to be replaced by black 

 schist and limestones. But, here again geology enables us to 

 interpret the language of nature, for it was by seeing the letters 

 of the alphabet spread out before him in a cabinet, and, 

 without even having visited the country, that Mr. Lonsdale was 

 led to conceive that a large portion of this tract, though very 

 dissimilar in mineral aspect^, would prove to be of the same 

 age as the Old Red Sandstone/^ 



The proceedings of the Geological Society of London 

 during the past year^ evidence the distribution of Silurian 

 rocks and the associate types in Russia in Europe, and 

 Asia ; to which results^ Mr. Murchison adds his ovv^n opi- 

 nion, that these may yet be traced in the Altai mountains 

 (from fossils which he has inspected from that locality) and 

 China. That North America abounds in similar ty2:)es^ is 

 proved by the communications of Professor James Hall,* and 

 W. E. Logan,t and Mr. A. GesnerJ They extend doubt- 

 less much further, but as yet nothing more determinate has 

 been ascertained ; suffice it to say, that the more extended the 

 examination has been, the more general has the distribution 

 of Silurian types been found, and the more numerous conse- 

 quently are the arguments that the title is erroneous, although 

 sanctioned by leading Geologists of the day, and the adoption 

 of the term by foreign authors in their works. We may sum 

 up the investigations in this department of geology, by using 

 the words of the author before alluded to, stating ^' the results 

 in each mstance^ as leadiJig to the vieiv of the paleozoic rocks^ 

 as a great tripartite series composed of the Carboniferous, Devo- 

 nian, and Silurian sy stems,'' 



The Glacial Theorij — The close of last year found Geo- 

 logists divided in their opinions upon this subject ; their 



* Proc. Geol. Soc, Vol. III. p. 416. f Geologist Vol. I. p. 169- 



X Geologist. Vol. L, p. 301. 



