392 S. V. Wood—Origin of the Loess. 
the modification which is the essential part of the theory which I 
have formed of the beds described under the letter y in my memoir 
on the Newer Pliocene period, viz. the permanently frozen condition 
of all but the upper part of the ground; for though in Canada and 
Vermont, however deeply the winter frost penetrates, it may all be 
dissolved by the warmth of summer, this is not so in Arctic regions, 
as we see by the case of the perennial ice of Alaska just described ; 
though, from the much lower latitude -of the regions where the 
phenomena in question took place during the Glacial period, the 
more vertical position of the sun may possibly, notwithstanding its 
generally diminished heat, have thawed the ground to a somewhat 
greater depth in summer in these latitudes, than now takes place in 
the case of land in the Arctic regions. That it did not thaw the whole 
depth in Europe, appears to me proved by the arrest in the formation 
of stalagmite during the accumulation of the cave earth; for this 
clearly shows that a stoppage of percolation then took place, which, 
so far as I can see, admits of no other explanation. Nor do I see 
(for the case has no analogy with the explanation which has been 
offered of glacier motion by the freezing of water penetrating the 
glacier fissures,) how motion would have been imparted to the mass 
by the mere freezing and thawing of the whole; as it is to the 
semifluid condition acquired by the upper portion, when saturated 
with water, without any downward escape for this water by reason 
of the permanently frozen condition of the deeper portion of the 
ground, that I attribute the sliding motion. 
Although Professor Kerr makes no mention of land shells, or 
mammalian remains in this material, yet he speaks of peaty black 
gravelly soil with blackened stems and bark of trees, and fragments 
of wood, and grass blades, roots, and stems occurring in it, as Dall 
coes of vegetable matter “in some places in strata in, and in others 
indiscriminately mixed with” the Alaska clay; and it seems to be 
identical in its character with the beds grouped under the letter y in 
my memoir; but instead of representing, as those do, the action of 
the atmosphere on terrestrial surfaces beyond the limit of the land- 
ice during the minor glaciation only, it represents this during both 
glaciations.* 
1 Although the evidence of the minor glaciation in the Western States seems 
ample, yet Prof. Dana says that no sufficient evidence of it has yet been detected in 
the Atlantic States of the Union. It seems to me, however, that the ‘ till-like 
deposit,’’ ¢ g of the section at p. 182 of his paper in the American Journal of Science 
for March, 1882, shown as wrapping unconformably the stratified sand which was 
deposited in the Connecticut Valley by the flood which resulted from the melting of 
the ice of the major glaciation. during the wane of that glaciation, affords such 
evidence. The Hessle clay of Yorkshire wraps thus unconformably the sand and 
gravel of the Cyrena formation; and its boulders are, like those of this bed ¢ g, of 
the ‘‘ Cobble-stone”’ character, and small in comparison with those of the clay of the 
major glaciation. As the less volume of the ice of the minor glaciation from which 
the Hessle clay originated, instead of so greatly overwhelming the valley partings 
as that of the major did, passed through the middle part of the Vale of York to 
the sea, so may the ice of the minor glaciation originating on the mountains of New 
England have been insufficient so to overwhelm the partings of the New England 
valleys, as that of the great glaciation did, but have escaped to the sea down 
those yalleys, and there left its moraine. on the sands which had previously been 
deposited there. 
