Page:The Journal of geology (IA journalofgeology11893univ).pdf/400

sents another interesting problem, which is not free from difficulties. From its source in Massachusetts it flows southeast across the crystallines to the village from which it takes its name, where it turns abruptly north along the Triassic sandstones for ten or twelve miles, when with another wide sweep it crosses the trap ridges at Tariffville by a deep gorge. and resumes its southeasterly course to the Connecticut. Of this latter part I will speak later, but now arise the questions, "what has been the history of this river," and "why does it turn north at Farmington?"

The Farmington in the Tertiary cycle. A course more accordant with the structure would seem to be south along the Quinnipiac and Mill river valleys to the sound at New Haven. As has been said before (page 376), Prof. Dana has expressed the opinion that the gorge at Tariffville was occupied by the Farmington in Tertiary times, and that the Westfield river gap further north and the gorge of the Quinnipiac southwest of Meriden are also of earlier date than the glacial epoch. One reason has also been given why I differ from him in regard to the Quinnipiac and Tariffville gorges—they are narrower and steeper than those made in similar rocks during the Tertiary cycle. But more than this, the constructional topography, resulting from the tilting and faulting of the region, could not, it would seem, have caused the Farmington to take its present course. Even if it had taken this roundabout course during the baseleveling of the country, it must, since it would have had to cross three trap sheets, have been captured and led to the sea by the shorter and easier way along the sandstone area. The fact that the Connecticut probably persisted in its consequent course is no argument for similar conditions for the Farmington, because the latter is much the smaller stream, and so more easily captured. Nor could the river have been forced into this course during or after the post-Cretaceous uplift, for the land was then raised more at the north than at the south, and any changes from this cause would have been to confirm the river in its southward course. It is very probable, therefore, that in at least the latter