ON SURFACE GEOLOGY, 



ESPECIALLY THAT OF THE 



CONNECTICUT VALLEY IN NEW ENGLAND. 



Introductory Remarks. 



It has not unfrequently happened that those geological phenomena which lie 

 nearest and most open to observation, have been the last to engage attention. 

 The crystalline rocks were much earlier studied than the fossiliferous ; and of the 

 latter, the older and most deeply seated were well understood before Cuvier and 

 Brogniart turned the attention of geologists to the tertiary deposits. It was not 

 till a much later date, that the drift deposit, although so widely spread over the 

 surface in northern regions, received any careful examination. And the subject of 

 terraces and ancient beaches, is only at this late period beginning to call forth 

 careful and thorough investigations ; although these forms of gravel, sand, and 

 loam, present themselves along nearly all our rivers, around our lakes, and towards 

 the shores of the ocean. 



I do not mean that these terraces, &c, have been entirely unnoticed by geologi- 

 cal writers of the last quarter of a century. In the writings of Dr. Macculloch, 

 more than thirty years ago, may be found some most beautiful delineations of 

 these phenomena, and accurate descriptions of the very remarkable and peculiar 

 terraces, called the Parallel Roads of Glen Roy, or Lochaber, which have engaged 

 the attention of more subsequent writers than almost all other forms of the terrace. 

 In the year 1833, the writer of this paper, in his Report to the Government of 

 Massachusetts on its Geology, devoted some pages to a description of the river ter- 

 races ; and gave a theory of their formation, different from that usually received. 

 Rut no accurate details of facts accompanied these views. 



Some elementary treatises on geology have, within a few years past, presented 

 the subject of terraces and ancient beaches. This is especially the case in the 

 writings of Sir Charles Lyell. That gentleman, also, has given to the public, 

 through learned societies and journals, several detailed descriptions of these phe- 

 nomena in particular localities. 



The work, however, which seems to me to mark an era in this department of 

 science, both in its presentation of facts and ability in reasoning, is Charles Dar- 

 win's Geological Observations on South America. It must have required extraordi- 

 nary industry to collect the facts, and great familiarity with geological dynamics to 

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