MODIFIED DRIFT ALONG CONNECTICUT RIVER. I9 
say of its history through this vast extent of time is, that it probably had 
for the most part a temperate climate, and witnessed the same slow suc- 
cession in its forms of vegetable and animal life of which the coal meas- 
ures and later rocks in other parts of the United States bear witness. 
This comparative stability through long ages makes it more probable that 
these recent changes in the relative heights of land and sea are due to 
the cause which we have explained rather than to movements of the land. 
The exploration of the modified drift in New Hampshire, under direc- 
tion of the state geologist, was principally made in 1875. In this work 
on the Connecticut and Merrimack rivers the author had the valuable 
assistance of William F. Flint, being thus enabled to map all the terraces 
of these rivers, and measure their heights by an engineers’ level. On the 
Connecticut, this was more conveniently done, and the expense lessened, 
by employing a boat, which was built by Mr. Flint, for the journey be- 
tween McIndoe’s Falls and Massachusetts line. The particular descrip- 
tion of the modified drift of the state will be taken up in the following 
order: Connecticut river, followed by such of its tributaries as have been 
examined; Merrimack river, followed by Contoocook river and Winnipi- 
seogee and Squam lakes; Androscoggin river; Saco river and basin of 
Ossipee lake; basin of Piscataqua river; and the sea-coast. 
Mopirizep Drirr ALONG CoNNECTICUT RIVER. 
The sources of Connecticut river, its hydrographic basin, its course 
and descent on the west side of New Hampshire, and its tributaries from 
this state, have been described in the first volume of this report.* The 
territory of Vermont extends to the west shore of this river, but in explor- 
ing its modified drift equal attention has been given to both sides. Only 
by this study of the whole valley could the history of these deposits be 
discovered, and the portion in this state be understood. A series of 
maps occupying three plates accompanies the following descriptions. 
The various terraces which border the river are there delineated, and 
their heights stated in feet above the sea. The extent and contour of 
the modified drift is thus shown along the whole valley. Throughout 
this distance the alluvial area is bounded on each side by high hills, 
which are only interrupted by the entrance of tributaries. 
* Vol. i, pp. 222-224, 299, 302-305, and 318, 
