135 
occurs is much wider than this, and might easily lead to an erron- 
eous inference concerning its width. 
The depression corresponding to the dike can be readily 
traced across the bed of the stream where it is filled with detritus 
to a similar depression in the north bank of the gorge, which is 
filled with earth and overgrown with weeds. Its strike was not 
taken but it was very nearly parallel to the adjoining dikes which 
occur but a few rods to the westward. 
Dike II. This occurs a short distance west of the new bridge 
and between the two falls. It is from 2% to 3 inches wide. It 
differs in color quite materially from the other dikes, which have 
a general family resemblance. This rock is of a light gray color 
with numerous small white particles disseminated through it. 
Besides these there are many lenticular inclusions of dark black 
color giving the mass when freshly broken an earthy appearance 
quite different from the dark green crystalline peridotites of the 
adjoining dikes. 
It strikes N. 10 degrees W. (?) 
Dike II]. Twelve inches west of No. 2 a third dike occurs. 
It is six inches wide and strikes parallel to No. 2. It is different 
in appearance from No. 2, having the general aspect of the other 
peridotites, and resembling especially the glistening crystalline 
appearance, so characteristic of the Dewitt dike. 
Dikes two and three were traced a few feet across the stream 
through water high at the time, and while they may occur on the 
north bank a rather cursory examination failed to disclose them. 
There is little question but that a careful examination of the 
gorges of Six Mile* and Fall Creeks which extend parallel to 
Cascadilla Creek at this locality, would reveal other traces of 
these dikes whose discovery would amply repay a search for the 
same. It is also probable that other glens farther north and south 
than these points might furnish additional exposures. 
*Kemp in the Amer. Jour. Sci., Nov., 1891, p. 410, mentions a peridotite 
dike occuring in the gorge of Six Mile Creek, about two miles from the 
Cornell campus. Like the others he says that this dike occurs in the north 
and south joints which are so abundant in the shaly sandstones; that it crosses 
the stream like a narrow ribbon; and that it pinches out a few feet above the 
surface of the water. It has a light brown, or drab color. 
