578 HISTORY OF GEOLOGY. 



alluvial soil, in caves, and in the beds of lakes and seas. _ This exposi- 

 tion is of the most instructive character, as a means of obtaining right 

 conclusions concerning the causes of geological phenomena. Indeed, 

 in many cases, the similarity of past effects with operations now going 

 on, is so complete, that they may be considered as identical ; and the 

 discussion of such cases belongs, at the same time, to Geological Dyna- 

 mics and to Physical Geology; just as the problem of the fall of 

 meteorolites may be considered as belonging alike to mechanics and 

 to physical astronomy. The growth of modern peat-mosses, for exam- 

 ple, fully explains the formation of the most ancient : objects are buried 

 in the same manner in the ejections of active and of extinct volcanoes; 

 within the limits of history, many estuaries have been filled up ; and in 

 the deposits which have occupied these places, are strata containing 

 shells, 17 as in the older formations. 



n Lyell, B. HI. c. xvii. p. 286. See also his Address to the Geological Society 

 in ISSY, for an account of the Researches of Mr. Stokes and of Professor Gop- 

 pert, on the lapidification of vegetables. 



