24 SEASONAL DEPOSITION IN AQUEO-GLACIAL SEDIMENTS. 
In the valley of the Ammonoosuc River, which joins the Connecticut at 
Woodsville, there are many places where laminated glacial clays may be found. 
At Bath, on the west side of the river, and about 200 feet above it, there are some 
well-banded clays. These clays are at least 150 feet above the highest part of 
the Woodsville clay-pit. 
At the top of the hill on the main highway just south of North Bath, there 
is a deposit of banded clays and silts, about 150 feet above the river. The 
clay here has not the fine texture found at Woodsville and the silt is almost a 
fine sand. The regularity of interval between the layers is not as marked as 
at Woodsville. In places near the bottom of the exposures, the irregularity 
of interval is so marked that seasonal deposition might well be questioned. 
(See Plate 3, fig. 2). The causes of these irregularities lies probably in shifts 
of the current or differences in the seasons from year to year. Higher up the 
regularity is much more marked, the two components of the banding having 
thicknesses varying between three fourths of an inch and one and one half 
inches, until near the top of the section, where coarser sands appear, with little 
approach to regular banding. As stated above, the seasonal origin of some 
of these layers might be questioned, and this is also true of the coarser parts 
of the Squantum slate (p. 45). The texture of these clays and silts appears 
to be about the same as the coarser slates at Squantum. The clay has not 
that plastic quality of the very fine material at Woodsville. 
At a place about a mile north of North Bath, banding in clays may be seen 
on the right of the road, and about twenty feet above the river. In this section 
there is a contorted zone one foot thick lying between horizontal, undisturbed 
layers. (See Plate 8, fig. 1.) Neither pebbles nor till were found in this zone 
of folding in the very limited exposure seen. 
At Lisbon, back of the lumber yards, a terrace of clay and silt layers rises 
about fifty feet above the river. The banding is peculiar in showing abrupt 
changes in the thicknesses of the seasonal units. At the bottom of the deposit 
the bands are regular in interval and the thicknesses vary between one inch and 
ten inches. From bottom to top the thicknesses of the units vary suddenly. 
(See Plate 3, fig. 1). Such sudden changes in the amounts of sediment deposited 
annually are probably too abrupt to be explained by either advances or retreats 
of a glacier or by differences in the seasons. The shifting of the stream which 
supplied the material for each year was probably the cause of the sudden alter- 
nations in deposition. The texture of the materials is coarser than at Woods- 
ville, and this is equally true of all other banded clay and silt deposits of 
