1818.] M. Deodat de Dolomieu. 167 



supplied laterally with a sufficient quantity of water, would 

 assume the character of a proper volcano, or burning mountain. 

 The secondary rocks, i. e. all those which either themselves 

 contain organic remains, or ai - e associated with those which do, 

 were deposited from solution or suspension in water. By the 

 deposition of these, and the increase by consolidation of the 

 primitive rocks, the thickness of the mass incumbent above the 

 central fluid is continually increasing ; and those causes which 

 anciently broke through the solid crust of the globe are now 

 rarely able to produce the same effect ; hence the greater mag- 

 nitude and frequency of volcanic eruptions in the earliest ages 

 of the earth ; for the same reason the elevation of large, moun- 

 tainous, or continental tracts above the general level no longer 

 takes place ; and thus the surface of the globe has become a 

 safe and proper habitation for man and other animals. If the 

 land animals were created as early as possible, that is, while the 

 great changes of the earth's surface above-mentioned were still 

 in progress, many of the most ancient traditions of deluges and 

 other catastrophes may be founded on fact. 



The fluidity of the central part of the globe, and its connexion 

 with the active volcanos, affords a plausible theory of earth- 

 quakes, and particularly accounts for the propagation of the 

 shock, with diminishing intensity, to great distances. 



The crystals of hornblende, 'of felspar, &c. which occur so 

 abundantly in most lavas are, according to this theory, not those 

 component ingredients of rocks which have resisted the heat 

 while the other substances associated with them have been 

 melted ; nor are they the result of the slow cooling of a vitreous 

 mass, but are produced by crystallization in the central fluid, 

 and are accumulated, on account of their inferior specific gravity, 

 about its surface, together with the peculiar inflammable matter 

 in which they float, whence they are disengaged during volcanic 

 eruptions. 



Article II. 



An Account of some Basaltic Columns at Pouck Hill, Stafford- 

 shire, with Prehuite, Zeolite, and Barytes. By J. Finch, Esq. 



(To the Editors of the Annals of Philosophy.) 

 GENTLEMEN, Birmingham, June I, 1818. 



Having perused, in the Geological Transactions, a valuable 

 paper, written by Arthur Aikin,' Esq. upon the greenstone 

 occurring at Birch-hill colliery, near Walsall, I was induced to 

 visit that spot. Having collected various specimens from the 

 mouth of the pit, I observed that the roads were repaired with a 



