BEACHES AND TERRACES. 51 



Rhine, near Rhinefelder, 306 feet. Some of the accumulations of gravel and sand 

 above these might perhaps be called terraces ; but I think they are more appropri- 

 ately called beaches. So far up the sides of the valleys as these banks appear to 

 have been formed mainly by the rivers that now run through them, when at a 

 higher level, and forming a chain of narrow lakes, thus high should I denominate 

 them terraces. But when we reach such a height that the waters producing the 

 banks must have overtopped most of the hills and communicated with the ocean, 

 or constituted a part of it, then they ought to be called, as they undoubtedly were, 

 beaches — it may be the shores of a bay, or estuary, or frith; but still produced 

 more by breakers than by currents, and, therefore, have not a level top. 



6. The most perfect beaches in New England vary in height from 800 to 1200 

 feet above the ocean. (In Pelham, Shutesbury, Whately, Conway, Ashfield, &c.) 

 Others occur less distinct, as we might expect they would be, from 1200 to 2600 

 feet above the ocean (at Dalton, Hinsdale, Washington, Peru, White Mountain 

 Notch, and Franconia Notch). I can hardly 'doubt that further examination will 

 discover others at a still greater altitude. 



On Snowden, in Wales, I found a few traces of sea-beaches at several altitudes, 

 the highest 2547 feet above the' ocean. Still more distinct marks of a beach occur 

 a little east of Cader Idris, 762 feet above the same level. 



In the north part of Switzerland, near Mumpy, I measured what I called a 

 beach, 1670 feet above the ocean; on the west side of Lake Zurich, another, a 

 little doubtful, perhaps, 2105 feet; between Lucerne and Bern, near Scupsheim, 

 another, 2274 feet; and between Bern and Vevay another, 2640 feet, above the 

 present ocean level. 



7. The number, height, and breadth, of the. river terraces, vary with the size of 

 the river, the width of the valley, and the velocity of the current above the 

 place where the deposits are made. Generally the number is greater upon small 

 than large streams, while the height is less. This may be seen upon the subjoined 

 sections. Thus the terraces on the Connecticut rarely exceed three or four ; but 

 on its tributaries, where they enter the Connecticut especially, the number rises 

 sometimes as high as ten, as on the Ashuelot, in Hinsdale, Whetstone brook, and 

 West river in Brattleborough, and Saxon's river, at Bellows Falls. In these cases 

 the terraces on the tributaries are formed in the terraces of the principal stream ; 

 yet though the former are more numerous they rise no higher than the latter. 



8. The river terraces, excepting the delta terraces, rarely correspond in number 

 or in height on opposite sides of the stream. The delta terrace, whenever worn 

 through by a stream, will, of course be of equal height on both sides of the river. 

 When the valley is wide, and several terraces exist on opposite sides, by the eye 

 alone we are apt to imagine an exact correspondence in height. But the applica- 

 tion of the level usually dissipates such an impression, as nearly all the subjoined 

 sections, which extend across the stream, will show. Had I carried these sections 

 across the river more frequently, it would have appeared that sometimes no terraces 

 exist on one side, while there are many on the other ; or that the number differs 

 much on opposite sides. 



9. River terraces usually slope toward the mouth of the stream, to the same 



