.893-] 167 f^^^'s- 
of science for January 1894, together with a full list of writings 
upon this subject. The following observations were prompted 
by Mr. Woodworth's suggestions. 
Stratified sands and gravels cover the greater part of Cape Cod. 
For the most part, they were dejsosited as a frontal wash from 
the ice sheet along whose border the morainic hills were built, 
pi-oducing what is often called the back-bone of the Cape. A 
similar distribution of features is seen in Long Island and in the 
outlying islands of Martha's Vineyard and Nantucket. 
The stratified gravels of the Cape frequently contain facetted 
pebbles, some of which are now in process of carving by wind- 
blown sand ; some of which have been lately carved, but are now 
protected from further carving by a scanty cover of vegetation ; 
some of which were carved at the time when the stratum of 
which they are members was the uppermost of the then accumu- 
lated gravel beds, later covered by similar deposits. 
Pebbles now in process of carving may be found in great abun- 
dance in a gravel bed at the face of the cliff at Highland Light, 
near the northeastern end of the Cape. They are seen at the 
head of one of the ravines or gulfs in the cliff face, just north of 
the Signal Station, and full in the sweep of the strong winds of 
that exposed situation. They may be gathered in all stages of 
carving. Some are slightly carved ; some strongly facetted on 
the upper surface as they still lie on the wasting gravel bed ; 
some are distinctly facetted on two sides ; that is, they indicate 
wind carving for a time with one side up, followed by similar 
action after the pebble had rolled over so as to turn the other 
side up. When only one side is facetted, the pebble is either 
still in place, more or less exposed by the removal of the sur- 
rounding sand, or else it lies loose on the surface. The varying 
stages of advance in the carving seems to be a natural result of 
the retreat of the cliff face under the attack of the waves, the 
wind, and the weather. The retreat is a steady one, and must 
cause the removal of the lighthouse before many decades elapse. 
The pebbles found here show all the variety of facetting, as 
dependent on rock texture, that will be referred to later on. 
Pebbles recently facetted but now untouched by wind action 
may be found near the surface of the ground in many railroad 
cuts ; probably in nearly all the cuts on the Cape, judging from 
the ease with which they were found in the several that I 
