« 



in Massachusetts. 



71 



# 



and at about the same depth (a few feet) beneath the 

 ocean^ it would seem as if the same cause had produced 

 them all. But geologists have not discovered any cause 

 which elevates or depresses either land or sea so uni- 

 formly as this effect seems to require. The draining of 

 a swamp on the coast, by the bursting of its sandy bar- 

 rier, whereby the loose materials settle down into a more 

 compact state, will explain some cases of this kind. 

 Earthquakes, also, do sometimes cause the land to sub- 

 side. But no such agency has been known to produce 

 a submarine forest. Nor is there any decisive evidence 

 that the waters of the ocean are subject to a slow eleva- 

 tion. So that, upon the whole, although we can ex- 

 plain the origin of submarine forests in particular places, 

 it seems difficult to account for the great similarity of 

 circumstances under which they occur all over the globe. 



ACTION or ATMOSPHERIC AGENTS UPON HARD Q,UARTZ 



ROCK. 



Those numerous rounded and smoothed boulders of 

 quartz, so common in the western part of Massachusetts, 

 appear to have bid defiance to all decomposing agencies 

 in past ages, and to be destined to endure unchanged for 

 ages to come. But I examined lately a curious and 

 instructive example of these boulders, in the fruit-tree 

 nursery of Mr. Tracy, in Norwich, which seems to indi- 

 cate that decomposition may be going on where we 

 scarcely suspect it. This boulder was several feet in 

 diameter ; and though not as smooth as some boulders of 

 this rock, yet I should not have suspected that It had 

 suffered the least waste, were it not for an inscription 

 upon its surface. The name of John Gilpin is marked 



