Shaler.] 282 [May 7, 
It should be noticed, also, that a curious confusion may exist in 
these bedded deposits, a thickness of a few feet near the shore may 
represent hundreds of feet in deep water. 
This is best shown in the annexed 
diagram. 
This doubt must always rest upon all 
coast-shelf deposits. When they are de- 
posited rapidly, the difference in time 
taken in laying down of their shoreward 
and seaward borders may not be great; 
when they deposited slowly the differ- 
ence may be great enough to lead to 
some confusion in the record. 
It may also be noted, that on the sea- 
ward edge of such deposits the transi- 
tion from a deep sea to shallow water 
species may be shown, while near the 
shore line there may be no such transi- 
tion. 
The conclusions suggested by this 
preliminary inquiry may be briefly 
summed up as follows, viz. : — 
1st. The coast shelf is the place of 
storage of the coarser detrital matter 
worn from the land; it generally accum- 
ulates with great rapidity, principally 
through the carrying power of the tides. 
2d. In case of subsidence, this shelf 
may be buried in the shape in which it 
is formed; in case of elevation it will be 
distributed on the deep sea deposits for 
a distance proportionate to the extent 
of the upheaval. . 
3d. Being essentially a cross-bedded 
deposit, though the false bedding is on 
too large a scale to be visible to the eye, 
the successions in time are not from be- 
low to above in the section, but from the 
shore line to the sea front. 
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