The floodplain ends at a rise in the road not far east of Hadley. The rise is a scalloped embankment, reminiscent of the high bank on the river bend downstream from Hadley; even the long narrow swamp at the base looks like a filled ox-bow, and the scallops look like bites which the hungry river took from its banks. This embankment continues northward past Mount Warner, following the present channel closely through North Hadley, and it passes just east of Sunderland village. Corresponding banks are present on the west side of the stream in South Deerfield and Hatfield. Within the confines of those terraces the Connecticut has had free play, but its course has never strayed east or west of these well defined boundaries.
Wave-like hills of sand cap the embankments in several localities north of Hatfield and North Hadley. Some, perched on the terrace edge, were partly cut away when the river was establishing the limits of its floodplain. Wherever the pine trees are cut down, or the grass plowed under, the sand within these hills begins to drift. They look and act like those hills of the desert, the sand dunes, and they record the drift of wind-whipped sand across a naked land, before the river had established a floodplain within its present confines.
The Landscape Changes
Fine sand, silt, or clay is found beneath the windblown sand wherever the river banks undercut the dunes. The clays are especially widespread, for each of the numerous local brickyards has its clay pit, and there are many more clay banks which have no brickyard. The clays are rhythmically banded. One band, composed of very fine material which settles from suspension only after weeks of absolute quiet, retains moisture tenaciously; adjacent bands dry more rapidly, are somewhat sandy, and settle from suspension in less than a week. A large body of quiet water in which so much fine clay could settle must have occupied the valley before the river was there, and the only type of water body which could have provided the proper environment is a fresh-water lake, free from agitation during the long winter months when its surface was frozen over. These thin clay bands are deposits of a winter season, when streams are low and their load light. Then, even the finest particles can settle, during the many weeks of quiet water, as a paper-thin layer upon the lake bottom. The coarser sandy layer just above the finest clay records the spring break-up, the melting of the ice, and resuscitated streams flowing from the hills with a vigor that can be acquired only when the melt-water from the winter snow combines with the normal run-off. The sand which these freshets bring to the lake diminishes as the spring floods subside, and the sediment becomes progressively finer until next spring comes around.
Pl. 2. Features of the landscape which originated during comparatively recent time.
a. Air view of the ox-bow lake between Northampton and Mt. Tom.
b. Roches moutonnées of the Pelham Hills seen from Hadley.
