nches at
the southern end like the distributaries of an aggrading river. The
material of the eskers ranges from coarse sand to pebbles four inches
in diameter, the average size being from one to two inches. No
exposures were observed which showed a regular diminution in the
coarseness of the material toward their southern end. The clean-washed
esker gravels afford little encouragement to plant growth, and the
rain water drains away rapidly through the porous gravel.
Consequently, accumulations of stratified drift are commonly barren
places. A desert vegetation of coarse grasses, a kind of wiry moss,
and "everlastings" (_Gnaphalius decurrens_) are the principal growth.
Rattlebox (_Crotolaria sagittalis_), steeplebush (_Spiraea tomentosa_),
sweet fern (_Comptonia asplenifolia_), and on the more fertile
eskers--especially on the lower, wetter part of the slope--golden rod,
ox-eyed daisy, birch, and poplar are also present. All the eskers
observed were found to be similar: they ranged in breadth across the
top from 100 to 150 feet and the side slopes were about 20 degrees.
Only a single heavily wooded esker was found, and this ran through a
forest region.

The accumulations of stratified drift are distinguished from other
features in the landscape by their smoother and rounder outlines, by
their habit of lying unconformably on the bedrock without reference to
old erosion lines, and by a slightly different tone in the color of
the vegetation covering the water-laid material. The difference in
color, which is due to the unique elements in the flora of these
areas, may cause a hill of stratified drift in summer to present a
lighter green color than that of surrounding hills of boulder clay or
of the original rock slopes; in winter the piles of stratified drift
stand out because of the uniform light tawny red of the dried grass.

[Illustration: ~State Geol. Nat. Hist. Survey Bull. 30. Plate I.~
View south on the highland northeast of Neversink Pond. The base
of a ridge in which rock is exposed is seen at the left; a
crescent-shaped lateral moraine bordering the valley lies at the
right.]

ROCKY RIVER

DESCRIPTION OF THE RIVER AND ITS VALLEY

Rocky River begins its course as a rapid mountain brook in a rough
highland, where the mantle of till in many places is insufficient to
conceal the rock ledges (fig. 1). Near Sherman, about four miles from
its source, it enters a broad flood plain and meanders o