SOME RIVERS OF CONNECTICUT, 389 



and a long stretch of comparatively still water extended north 

 from Farmington, in which nearly horizontal deposits were made. 

 South of Farmington the terrace deposits are much coarser than 

 to the north, and the face of the terraces is much greater. It is 

 not impossible that, as the deposits between Farmington and the 

 Massachusetts state line approached nearer and nearer to hori- 

 zontalit}^, the waters of the upper Farmington began to divide, 

 part flowing north and part south, the northward flowing portion 

 finding an outlet at the sag at Tariffville. If this was the case, 

 the terraces between Farmington and Tariffville must have had 

 a slight slope to the north. Their present southward slope could 

 readily be accounted for by the re-elevation of the land after 

 the disappearance of the ice. This explanation rests upon the 

 ability of the upper Farmington and the Pequabuck to have 

 completely dammed the southward flowing current and turned 

 it northward by the great mass of their deposits. If this was not 

 the case, and there may be some doubt on the matter, the subsid- 

 ence which accompanied the later stages of the ice -retreat is 

 the other factor in the problem. It is estimated that an average 

 depression of 1.25 feet^ through the Connecticui valley would 

 restore it to an altitude approximating that at the close of glaci- 

 ation. It seems highly probable that these terrace-deposits 

 were built before the maximum depression was reached. If this 

 was the case, the depression would be efficient in reversing the 

 Farmington, and this factor would supplement the first. It is 

 impossible at present to say to what extent these two factors 

 enter into the problem. That they are not mutually exclusive 

 is evident, and that they are together quantitatively competent 

 seems certain. Among the several hypotheses which have been 

 considered, this seems the most probable, and in the light of the 

 present evidence the most rational. 



At first thought it might seem that if the Farmington was 

 rev^ersed by the differential subsidence of the land, the Con- 

 necticut ought to have suffered a similar fate, and since it did 

 not, the explanation cannot apply to the Farmington. But 



'J. D. Dana, Amer. Jour, of Sci., 3d sen, vol. xxiii, p 198. 



