The Karnes of the Oriskany Valley. — Harris. 387 
clerberg limestones, the Clinton and Salina shales, and the 
sandstones of the Clinton and Hudson River groups, which 
crop out along the course of the valley to the north. The 
sizes of these pebbles are various, ranging from that of a man's 
head, down. 
As regards structure, the kames are coarsely stratified in 
cross-bedded layers, which always slope southward, as is 
shown in numerous cuttings along the railroad which follows 
the valley. The gravel composing the kames, is often loosely 
cemented together by carbonate of lime, derived doubtless 
from the limestone pebbles which abound in the mass. 
The history of the formation of these kames is simple. As 
the ice margin retreated down the Oriskany valley, the basin, 
which it left open, was filled with water from the melting 
glacier, which it discharged southward over the col into the 
Chenango valley, after the manner of the classical example 
of this type of valley history, lake Agassiz, as described by 
Mr. Warren Upham (Geological Survey of Minnesota, 8th An- 
nual Report, p. 84). In the Chenango valley, a tolerably 
rapid and continuous current distributed the detrital materials, 
which had been furnished from the ice, in the form of a long 
flood-plain; but in the Oriskany valley, where the outlet was 
temporarily blocked, the stream assumed the form of a lake, 
through which the water flowed more slowly and without suf- 
ficient force to accomplish an even distribution of the coarse 
gravel which the subglacial streams cast forth. These streams 
must have been under a considerable head of pressure, and 
must hence have emerged from the ice with a considerable 
velocity. This is shown by the fact of their having trans- 
ported very coarse material; but, on coming to the light, their 
rapid movement was quickly checked in the quiet water of 
the lake, and their load of Stones and earth was dumped just 
outside the ice margin. The irregularity of the deposits shows 
the fluctuating nature of the stream which brought them, 
sometimes making its exit from the ice at one spot, sometimes 
at another, according to the courses of the channels beneath 
the ice, or to the changes in the How of water through them, 
as they became in turn choked with accumulated debris or 
were opened by the melting of the surrounding ice. This 
process must have continued so long as the glacier occupied 
