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of Newfoundland and there spread broadcast over the sea 
bottom. 
In the Drift deposits above the blue clay, remains of 
Elephant and Mastodon have been repeatedly found still 
more frequently in the Peat-bogs of the present surface, and 
the much-discussed question has been, whether these mamma- 
lian remains were deposited with the upper layers of the 
Drift or were buried in them by subsequent shifting, as in 
the valleys of streams. The facts to which attention is now 
specially directed would seem to decide that question. 
It has long been known that in many parts of the valley of 
the Mississippi, wells penetrating twenty, thirty or more feet, 
the superficial accumulations of drifted materials—clays and 
sands with gravel and bowlders brought from the far north— 
encounter sticks, logs, stumps and sometimes a distinct car- 
bonaceous soil. Combining facts of this character, of which 
records haye been accumulating from year to year, with 
those brought to light by recent investigations directed 
specifically to this object, itis proven that over a great area 
at the West a sheet of buried timber, a vegetable soil, beds 
of peat covered with sphagnous moss, erect stumps, and in 
«some cases standing trees,—form a distinct line of demarca- 
tion between the older and newer drift deposits. 
In or above the horizon of this ancient soil have been 
found numerous animal remains: Hlephas, Mastodon, Castor- 
oides (the great extinct beaver) and some others. 
All these facts show that in the sequence of events includ- 
ed in our Drift period there is a marked break, a middle 
period, during which, over most of the north-western states, 
no Drift deposits were made and when most of this area was 
covered with a forest growth and sustained many and large 
animals. At a subsequent period, all parts of this area, less 
than 500 feet above the highest of our present great lakes, 
was submerged, and most portions of it covered to a greater 
or less depth, with new Drift deposits, clays, sands, gravel and 
bowlders, a large part of northern and remote origin. Nearly 
all the large bowlders of the Drift belong to this later epoch, 
are sometimes of great size, (100 tons) and have been floated 
