SUPPOSED PAUSES IN THE UPLIFTS. 59 



paper, and to the tabular heights of the terraces, will show that the facts are 

 widely diverse from this supposition. Along the Connecticut, indeed, the most 

 usual number is three or four: but on some of its tributaries they rise as high as 

 eight or ten. Which number, in such a case, shall we assume as indicating the 

 pauses in the vertical movement? If the smallest, then how are we to explain 

 the excess? If the larger number, then why did not the waters leave traces of 

 their influence alike numerous wherever they acted an equal length of time. 



2. On this supposition, the terraces ought to agree essentially, at least in height, 

 on opposite sides of a valley. Circumstances might, indeed, erase all traces of 

 their action in particular spots, but such great irregularity as exists in this 

 respect, cannot be thus explained. Terraces thus formed would leave evidence of 

 their existence, as the Parallel Roads of Lochaber have done, on the steep flanks 

 of the Scottish Highlands; which I am willing to admit were produced by succes- 

 sive uplifts of the land, or subsidence of the waters. 



3. The difference in the number and height of the terraces upon the principal 

 stream and its tributaries at their debouchure, affords decisive proof that said ter- 

 races were not the result of the paroxysmal elevation of the land. Here we find 

 two sets of terraces formed in the same bank of detritus; one set, usually the 

 smallest in number, on the main river, and the other set, formed by the erosion of 

 the tributary through the first. Of these, the maps and sections appended, afford 

 numerous examples. Thus, at the mouth of the Ashuelot river, in Hinsdale (No. 

 25), we have five terraces on that river, and three, or perhaps four, on the Con- 

 necticut. Just below Bellows falls, we find at the mouth of Saxon's river (No. 

 30), as many as six terraces, while on the Connecticut, a little to the south, in 

 Westminster (No. 29), are only four. In the north part of Vernon (No. 26), are 

 only four on the Connecticut: but on West river, in Brattleborough, perhaps 

 two miles north, we find nine, and on Whetstone brook, ten (No. 28 and Plate 

 III). Moreover, the latter rise no higher than, if as high, as the former. And 

 since both sets are found in the same bank of sand and gravel, it is certain, that if 

 one set were produced by pauses in the retiring waters, the other set could not be : 

 since no possible reason can be assigned, why in the same bank of materials the 

 terraces on one stream should be twice as numerous as those on the other, if pro- 

 duced by pauses in the retiring waters. 



26. These facts, especially the last named, afford almost equally strong evidence 

 that river terraces could not have been produced by the sudden bursting of bar- 

 riers. In the valley of the Connecticut, if such barriers existed, they must have 

 consisted of sand and gravel, choking up the gorges, and not of solid rock, since the 

 traces of drift agency occur so low down at those gorges. That detrital barriers 

 may have existed to some extent, perhaps with the addition of ice, I will admit. 

 But that they had little to do with the-formation of terraces, is clear from the above 

 facts ; since if suddenly lowered they could not have produced a different number 

 of terraces on the principal stream from those on the tributaries, nor such irregu- 

 larity as we find in their height and number upon opposite sides of the river, 

 although they might have formed more in one basin than in another. 



27. In a former paragraph (11) I have given an intimation of the views which 



