“OCTOBER 29, 1897. ] 
wherever it was struck. Its level was 
twenty inches below our zone of doubt, or 
thirty-five inches below the surface. Upon 
our last visit, however, two well-formed 
argillite implements were found at still 
greater depth, and if possible in still more 
unequivocal position. One of these, found 
by Professor Hollick, was in the main trench 
more than twenty feet farther east. This 
was, also, below the second clayey band, 
which is here nearly ten inches thick. The 
implement was three feet five inches be- 
low the surface, or twenty-six inches be- 
low the arbitrary line we had fixed as our 
zone of doubt. The order of strata was as 
follows: one foot, disturbed soil; eighteen 
inches, compact yellow sand; first wavy 
reddish clayey band, one-half inch; yellow 
sand, two inches; second reddish clayey 
stratum, with inclosed lenticular sand 
patches, ten inches; sandy layer, five 
inches, containing the implement ; reddish 
clayey band, five inches. Below this, with- 
out any signs of unconformity, were several 
successive alternating strata of sand and 
reddish clayey material to the total depth 
dug, six feet nine inches. 
indication that the entire deposit up at 
least to the upper wavy reddish clayey 
stratum was built up by a continuous pro- 
cess of water deposition, the upper portion 
representing the waning cycles of deposi- 
tion characteristic of floods which were 
reaching their limit both by reason of in- 
ereased elevation of the flood-plain and of 
a diminution of the water supply. 
Hight feet north of this implement, across 
the end of the trench, with the strata con- 
tinuous between, Mr. Volk had previously 
photographed another argillite implement 
in place one inch lower than this and be- 
neath almost exactly the same succession 
of strata. Again, on the face of one of our 
earlier pits farthest from the bank, about 
forty feet disant from this one, we found on 
the second visit and photographed, and Mr. 
SCIENCE. 
There was every | 
641 
Mercer took out with his own hands, a well- 
formed argillite implement three feet three 
inches below the surface, or two feet below 
our arbitrarily chosen line of doubt. There 
were two of the clayey bands above this, 
the order being closely similar to that de- 
scribed in the trench. The second of the 
clayey bands, which is here about two inches 
thick, contained a pebble more than two 
inches in diameter, which was pressed down 
into the stratum as if by its own and the 
superincumberent weight. On removing 
the pebble the clay adhered to it, but was 
not cemented to it. It could all easily be 
removed with the fingers. Two or three 
feet east of this implement were the marks 
of the tap-root of a tree which had pene- 
trated all the strata to a depth of something 
over two feet. It was perfectly easy to 
distinguish the course of this root, but there 
were no other signs of such disturbance 
around the face of the exposure in the vi- 
cinity of any of the implements described. 
Extent of the Reddish Clayey Bands.—To 
determine the extent of these deposits and 
the manner of their formation, pits were 
dug at three points, from two hundred to 
five hundred feet farther in from the edge 
of the bluff. Two of these were upon a 
slightly elevated ridge, from two to three 
feet higher than our main trench, being the 
highest portion of the plain. The other 
was in the center of a shallow basin, towards 
which there was a gradual slope in every 
direction, it being from two to three feet 
lower than the trench and about two hun- 
dred feet away. In all these pits the suc- 
cession of strata was similar to those in the 
main trench, with this difference, however, 
that the reddish clayey bands were encoun- 
tered several inches lower down in the cen- 
ter of the basinlike depression than upon 
the higher elevations. This effectually dis- 
poses of the theory that the slight irregu- 
larities in the surface were produced by wind 
action. If the elevations were wind accu- 
