MODE OF REPRESENTING TERRACES AND BEACHES. 13 



curacy must be the result, and often total discouragement. For I should thus be 

 charged with errors of observation by future geologists, when the fault lay solely 

 in the maps. Massachusetts is the only State in New England that has con- 

 structed an accurate map of its surface. And in that State the topography was 

 omitted till near the close of the survey, and then hastily observed ; so that it only 

 presents us with insulated hills and ranges, as if they rose out of a level surface ; 

 whereas, no idea is presented of the longer and broader features of the country ; 

 the comparatively low region, for instance, of twenty miles from the coast ; the 

 valley of Worcester, of the Merrimack, of the Connecticut, and the deep valleys of 

 Berkshire. Imperfect maps are one of the great disadvantages under which 

 American geologists labor, of which the European geologist knows but little. And 

 it must be a long time before the matter is much mended. 



Basins on the Tributaries. 



The tributaries of the Connecticut exhibit successive basins of the same general 

 character as those above described. But there are two of unusual importance, 

 which I have examined. One is on the Agawam river, in Westfield, and the other 

 on Deerfield river, in Deerfield. In the latter basin especially, we have an epit- 

 ome of most of the facts concerning river terraces and changes in the beds of 

 rivers. That spot I have, therefore, studied with care, and shall present a separate 

 map of its features, and also of the "Westfield basin. 



♦ Of some other peculiarly interesting places in respect to their terraces, I shall, 

 also, present maps, on a larger scale than the general one. One will be given of 

 the terraces at Bellows Falls, another of those in Brattleborough, and a third of 

 those on Fort river, in Amherst and Pelham. 



Mode of Representing the Terraces and Beaches. 



On the general map of Connecticut river, from its mouth to Wells river in 

 Vermont, a distance of two hundred and ten miles, I have attempted to exhibit the 

 principal terraces by colors. There are many smaller ones, however, omitted; nor 

 have I attempted to give the true width of the terraces with any degree of accu- 

 racy. Only where the basins are the widest,. there I have represented a greater 

 breadth of terraces. To give the terraces with entire accuracy, over so wide a 

 region, would require a great amount of labor in observation, and then it would all 

 be useless, because of the great imperfection of our present maps. All I have 

 attempted, therefore, is an approximation to the truth. In the vicinity of my 

 residence (Amherst) I have delineated the terraces with more accuracy, I hope. 

 But in some parts of the river, especially its southern aud northern limits, I have 

 not been able to examine with the care which would have been desirable. I trust, 

 however, that my maps will answer for all the purposes I have in view. This I 

 believe is a first attempt of this kind, and I have been led to feel how desirable a work 

 it would be to present a map, on a similar plan, of all the terraces, beaches, drift 

 and other forms of surface geologj^ in the northern parts of our country. In the 

 vicinity of Amherst I have attempted to show what I conceive would be a desirable 



