386 THE JOURNAL OF GEOLOGY. 



hypothesis is a rational one. There is, however, no direct evi- 

 dence that the Farmington once occupied Cook's Gap. 



The Tariffville ait. Before attempting to answer the second 

 question, "why the river flows north at Farmington?" let us con- 

 sider for a moment the history of the Tariffville cut. The river 

 occupies a gorge whose sides are steep and talus covered, but 

 which is not at all clogged with drift. There is naturally no 

 room at or near the water level, even for the wagon road, place 

 for which has been blasted near the top of the gorge. The pro- 

 file of the gap shows a gentle ascent from the top of the gorge, up 

 to the nearly level crest line of the ridge. That is to say, the 

 recent gorge has been cut in the botton of a sag in the ridge. 

 We have already given our reasons for believing that the gorge 

 here is much younger than the Westfield river gap; that it is a 

 part of the work of the next cycle; that it is post-Tertiary. The 

 sag, however, in the bottom of which the gorge is cut, is clearly 

 of the earlier cvcle. The bottom of the sag is much above the 

 level to which the rivers had cut their valleys in the late Tertiary, 

 and, therefore, it is certain that a river could not have occupied it 

 at the close of that cycle. It was probably an abandoned water- 

 gap whose stream had been captured in the same way and in 

 the same cycle as the river, which formerly occupied Cook's 

 Gap. 



The fact that the sag and gorge, although located very near 

 a fault line, do not correspond to it, but are transverse and inde- 

 pendent of it, is instructive and needs a moment's attention. It 

 seems probable that the stream consequent upon the faulted 

 blocks would have flowed down the slope of the tilted block and 

 then along the fault line at the foot of the fault cliff and would 

 have held this course during the baseleveling of the country. 

 When the area was baseleveled the stream must have swung 

 from side to side in its broad flood plain, and thus departed from 

 the fault line. When it was revived by the post-Cretaceous uplift, 

 it was confined to the course it had unwittingly taken on the 

 sandstones just above the hard ridge, and it was forced to cut 

 down through the trap. Subsequenlty a rival, which did not have 



