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90 Erratic Phenomena about Lake Sup oie 
everywhere these surfaces are more or less scratched and furrow- 
ed, and both scratches and furrows are rectilinear, crossing each - 
other under various angles: however, never mre many points” 
of the compass on the same spot, but in general showing that 
where there are deviations from the most iominall direction, . 
they are influenced by the undulations of the soil. It has been 
said, that the main direction of these striae was from northwest 
#to southeast, but I have found it as often strictly from north to 
south, or even from northeast to southwest; and if we are to 
express a general result, we should say that the direction, assigned 
that they have been formed under the influence of a movement - 
from north to south, varying more or less to the east and west, 
according to logal, influences in the undulations of the soil. It 
is, indeed, a vety important fact, that scratches which seem to 
have been produced at no great intervals from each other, are not 
absolutely parallel, but may diverge for ten, fifteen, or more 
egrees, 
ees is one feature in these phenomena, however, in which 
we never observe any variation. The continuity of these lines 
is abesinisly the same everywhere. They are rectilinear and 
2 pomp and capnot be better compared than with the effects 
stones or other hard materials dragged in the same direction 
‘san flat or rolling surfaces; they form simple scratches extend- 
ing for yards in straight lines, or breaking off for a short space to 
continue again ina straight line in the same me _ as if 
interrupted by a jerk. There are also deeper sc of the 
same kind, presenting the same phenomena, only, Peers trace- 
able for a greater distance than the finer ones. These scratches, 
instead of appearing like the tracing of diamonds upon glass, as 
the paige do, would rather assume the appearance of a deeper 
roove, made by the point of a graver, or perhaps still more 
par resemble the scratches which a cart-wheel would produce 
upon polished marble, if the wheel were chained, and coarse sand 
spread over the floor, the wheel continuing to move onward but 
without revolving. ‘The appearance of the surface, crushed by the 
moving mass, is especially distinct in limestone rocks, where 
grooves are seldom nicely cut, but present the appearance: of a 
Violent pressure combined with the grooving power, thus giving . 
to the groove a character which is quite peculiar, and which at 
once strikes an observer who has been familiar with its charac- 
teristic aspect. Now, I do not know upon what the assertions of 
some geologists rest, that gravel moved by water under strong 
heavy currents will produce et effects. Wherever I have 
gone since studying these phenomena, I have looked for such 
cases, and have never yet found ‘mame gravel currents produce 
any thing more than a smooth surface with undulating furrows 
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