14 * SURFACE GEOLOGY. 



map for the whole country. But the work would be Herculean, even for New 

 England. Yet if I were a younger man, I should have the ambition to attempt it. 



The colors on all the maps are the same for the same terraces, reckoning upward 

 from the river. The lowest meadow I call the first terrace, and then count them 

 upward; thence it follows, that the same color does not always represent terraces 

 of the same height, since they vary in this respect on different streams ; and, in 

 general, the size and height of the terrace correspond to the size and height of the 

 river. 



As to the beaches, I represent them all by one color, as I have not explored 

 them with sufficient accuracy to enable me to make any correct distinction between 

 the higher and the lower, nor do I know of any important object to be accom- 

 plished by such a distinction. 



1. Sections of Terraces and Beaches. 



The larger part of the terraces which I have measured, I have also shown by 

 sections across them, down to the level of the rivers on which they are situated. 

 This will give a clearer idea of their relative size than description can do. 



Tables of their Heights. 



To save prolix details, I have thrown together into a table at the end of this 

 paper the heights of all the terraces and beaches which I have measured ; their 

 heights above the river on which they are situated; and usually, also, above the 

 ocean. The manner in which the heights were obtained is also indicated. "When 

 measured by levelling, no mark is attached ; when by the Aneroid Barometer, the 

 letters A B; and when by the Syphon Barometer, the letters S B are added. The 

 number of heights given is 219. 



Details of Sections. 



By means of maps, and sections, and tabulated heights, I hope to make facts on 

 this subject understood without much detail. Yet the sections will require some 

 explanations. I shall describe them by reference to the basins in which they 

 occur. 



1. In Basin No. l,from Middletown to HolyoTce, commencing at the North End. 



1. In South Hadley. (See Section No. 1, Plate I.) The section commences at 

 Mt. Tom, in Northampton, and runs east across Connecticut river. On the east 

 side it strikes a high gorge terrace, which has been partially worn away by the river. 

 The line of the section is only a few rods south of the gorge between Holyoke and 

 Tom. East of the high terrace is a small stream, that seems to have been instru- 

 mental in forming the lower terrace, which runs along the south side of the Hol- 

 yoke range to Belchertown, sloping towards the Connecticut. This section might 

 have been more instructive if extended to that place ; but I have not obtained the 

 requisite data, and those which I have used are merely barometrical. 



2. No. 2 extends from Connecticut river at Willimansett, in the north part of 



