102 FORMS OF MODIFIED DEIFT. 



of Lake Superior. In Vermont, the map of Washington county shows an example in a 

 branch of the Winooski River, called Kingsbury Branch, uniting with the Winooski at 

 Montpelier. If we follow up Kingsbury Branch to Sabin Pond, in Woodbury, and then 

 pass up the left hand stream from this to its source, we shall pass through eight ponds. 

 We have only seen the most southern of these ponds, so that we cannot certainly say that 

 they are all surrounded with terraces : but feel confident in saying that when the water in 

 them shall have disappeared, terraces will be found in the beds that are left behind. 

 Counting all the ponds that feed this branch, they amount to more than thirty. The ter- 

 races which surround lakes and ponds, indicate the former different levels at which the 

 water stood in them. 



III. MAEITIME TERRACES. 



Perhaps we ought not to regard the accumulations of gravel and sand upon the sea 

 shore as terraces, but beaches. A few of them, however, are so nearly level-topped as not 

 to differ from genuine terraces, and this is the main distinction between terraces and 

 beaches. It is not, however, a distinction of much practical importance. At the mouths 

 of rivers the two varieties are often seen running into each other. 



IV. MORAINE TERRACES. 



This term is applied to a peculiar form, already spoken of, not unfrequently assumed by 

 the more elevated terraces, exhibiting great irregularity of surface, elevations of gravel 

 and sand, with correspondent depressions of most singular and scarcely describable forms. 

 The term moraine is prefixed to terrace, under the impression that stranded ice, as well as 

 water, was concerned in their production. It also embraces those alluvions that frequently 

 occur on the height of land between the sources of streams flowing in opposite directions. 



V. SEA BEACHES. 



The most perfect of these are seen along the sea coast in the course of formation. They 

 consist of sand and gravel, which are acted upon, rounded, and comminuted by the waves, 

 and thrown up into the form of low ridges, with more or less appearance of stratification 

 or lamination. As we rise above the terraces along our rivers, and often on the sides of 

 our mountains, we find accumulations of a similar kind, evidently once deposited by 

 water and having the form of modern beaches, except that they have frequently been 

 much mutilated, by the action of water and atmospheric agencies, since their deposition. 

 These have hitherto been confounded with drift, but they always lie above it, and show 

 more evidently the effects of some comminuting, rounding, and sorting agency of water, 

 indeed, since this is the only agent that could produce such effects. They evidently belong 

 to a period subsequent to the drift, and we cannot doubt that they once constituted the 

 beaches of a retiring, ocean. The proof of this will be given further on. 



We have spoken of these beaches as lying above the terraces. We mean that they are 

 at a higher level often, but geologically they are lower. When terraces occur as well as 

 beaches, the latter always are seen at a higher level than the former ; usually forming- 

 fringes along the sides of mountains. Yet in other places rivers may exist at a much 



