, 239 
The dikes crossed the trench about N. 60 degrees EH. and 8S. 60 degrees 
W. They were from 4 to 12 inches in width and were nearly vertical from 
the clay down to a depth of 2 or 3 feet, and then curved to the north- 
ward more and more as the depth increased. At their junction with the 
main body the clay was compact and solid, but further down it became 
lumpy, the lumps haying the appearance of having been rolled and rubbed 
over sand, and intermingled with the lumps was an amount of sand 
increasing with the depth. The lower portion of the dikes had the appear- 
ance of having been filled by dry sand, and the clay lumps dropped in 
loosely from above. 
At the junction of the dikes with the main body of clay the angle on 
the south side was rounded off while on the north side the angle was 
sharp, and was less than a right angle and in some cases became quite 
acute. The line of contact at base of the clay indicated that a rubbing 
movement had taken place from the north or northwesterly to the south 
or southeasterly. The lower half of the dikes were so nearly horizontal 
that they could not have been filled by clay and sand dropping from the 
top. From the nature of the fine sand it would be impossible to open 
crevices, or cracks, therein, to be filled with the clay from above, unless 
the sand were frozen solid. From these facts I conclude that the strati- 
fied sand must have been deposited with the horizontal markings continu- 
ous across the dikes, where they are now faulted. That in this condition 
the sand was frozen during an interglacial period, or a temporary retreat 
of the ice. While so frozen some convulsion opened cracks or fissures in 
the frozen sand to the depth of the dikes, and probably produced the 
faults in the horizontal stratification at the same time; that when so 
opened the fissures were so nearly vertical that clay lumps and sand from 
the top could drop to the bottom; that while in this condition the sand 
with its open fissures was overridden by ice, the base of which transported 
or shoved the clay over the sand, rubbing off particles of clay and sand to 
fall to the bottom of the crevices until the dikes were formed (and in this 
connection it may be of interest to state that in the bottom, or toe, of one 
of these dikes I found well preserved bits of wood). 
That after the crevices were filled the sand, protected by ice and clay 
from the low temperature to which it had been exposed, gradually 
thawed out from below by the heat of the earth. That the movement of 
the clay was communicated, to some extent, to the sand beneath it, the 
. 
