CORRESPONDENCE WITH SCIENTIFIC MEN. 63 



visited Shropshire and Radnorshire, and was then con 

 vinced that there was a vast extent of what may be called 

 a transition country, that had never been noticed by Wer 

 ner and the wise ones of that time. Some of my obser 

 vations I communicated to Dr. Henry, Dr. Holland, and 

 Mr. Greenough,* and gave a short notice of the country 

 in the first edition of my " Geology" in 1813. The latter 

 observations were carped at or disputed by Conybeare, 

 and I have never since had the opportunity of reviewing 

 the country attentively, or even visiting the greater part 

 of it. Mr. Murchison's views confirm all my first conclu 

 sions. His work is entitled "The Silurian System," (a 

 name I do not much approve) ; it comprises the regions 

 occupied by the ancient Silures (a British nation). The 

 great basis of the country is " transition " between the coal 

 and the most ancient slate rocks, comprising also several 

 coal-fields and insulated portions of secondary formations. 

 This country is singularly broken by the protrusion of 

 remarkable igneous or volcanic rocks of whose nature I had 

 little doubt ; but Dr. Holland, whom I showed specimens 

 to in 1811, although he was just returned from Iceland, 

 declined to give an opinion. I had then never seen a re 

 cent or acknowledged volcanic rock in situ. Mr. Murchison 

 has kindly presented me with a copy of his work, and if 

 my health and strength permit, I will send a review of it for 

 your Journal (which will probably be the last labor of mine 



in geology) I don't know whether Dr. M. has 



enclosed you a little tract of Horace Smith in favor of 

 railroads. In the conclusion, he says we have been all 

 travelling upon a fine locomotive system, from the clay of 

 our birth, 68,000 miles per hour ; the comparison with rail 

 road speed is striking, yet how few think about it ! Mr. 

 Hazlitt said, justly, the discoveries in astronomy have com 

 pelled bigots to lengthen Jacob's ladder. Indeed, such 



* Greenough set off immediately to Radnorshire, but brought back nothing 

 but doubts and puzzles. 



