OCTOBER 22, 1897. ] 
the silty and probably lacustrine deposits 
on the plains farther east of the mountains 
than the region here described, may not all 
the facts of composition, structure and 
fossil contents, above set forth, be ex- 
plained as well by fluviatile as by lacustrine 
conditions? Instead of assuming a series 
of warping and tilting movements by which 
lake basins were made and drained, is it 
not equally legitimate to assume changes of 
altitude, attitude, climate, drainage areas, 
etc., by which the rivers of the region al- 
tered their behavior from aggrading to de- 
grading? The decision between these al- 
ternatives must, of course, not be attempted 
by an observer away from the ground ; but 
in the meantime the lacustrine origin of 
the Arapahoe and Denver beds does not 
seem to be fully substantiated. 
If they should finally be shown to be 
fluviatile, several corollaries that follow 
from the acceptance of a lacustrine origin 
would require modification. For example: 
“Movements of elevation and subsidence, 
rather of an epeirogenic or continental na- 
ture, are indicated by both Tertiary and 
Pleistocene deposits that have a lacustrine 
origin, since the present inclination of the 
plains region, which shows an average de- 
scent, in round numbers, of 10 feet to the 
mile from the foothill region to the valleys 
of the Missouri and Mississippi, would not 
admit of the holding of lake waters on its 
surface.” (P.40.) Fluviatile deposits are, 
on the other hand, characteristically in- 
clined ; and the present slope of the Plains 
may be not far different from their slope 
when the Arapahoe, Denver and later beds 
were formed, if they were spread out by ag- 
grading rivers. I cannot help wondering 
whether even the peculiar cases of lapsing 
and overlapping strata, so well worked out 
by Eldridge about Golden and Boulder, 
may not find at least some part of their ex- 
planation by alterations of fluviatile ac- 
cumulation and denudation, prompted by 
SCIENCE. 
621 
changes in grade, climate, drainage, area, 
ete., rather than depend altogether on move- 
ments of elevation and depression. The 
latter interpretation seems to postulate es- 
sential horizontality and rather regular 
continuity of strata at time of deposition ; 
the latter permits or even requires signifi- 
eant declivity, inequality of thickness and 
irregularity of overlaps at time of deposition. 
Indeed, since the question of the fluviatile 
origin of some of the younger deposits on 
the Plains has been accepted by geologists 
familiar with that great field, the possibil- 
ity of a fluviatile origin for some of the 
older formations springs to mind. The 
coarser and non-fossiliferous strata of the 
foothill belt in particular may, perhaps, be 
the fluviatile equivalents of finer and fos-~ 
siliferous strata of lascustrine or marine 
origin farther eastward on the Plains. 
W. M. Davis. 
CAMBRIDGE, MAss., September, 1897. 
THE GRANT SARCOPHAGUS. 
On one of the most beautiful sites on the 
Island of Manhattan stands the mausoleum 
which the gratitude of a nation has erected 
to the memory of its illustrious hero. _ 
The altar in this temple of the dead is 
the sarcophagus, beautiful and imposing in 
its severe simplicity. The stone out of 
which it is hewn is a dark red granite, 
quarried at Montello, Marquette county, 
Wisconsin. 
Concerning the granite of this region 
Professor Allan D. Conover wrote :* ‘‘ The 
rock shows almost no tendency to decom- 
pose. It hasa medium grain, close texture, 
is of a bright pinkish color, and without 
sign of arrangement of the ingredients 
in lines. These are: Rather large flaked, 
pinkish, cleavable feldspar, predominating ; 
*Gannett’s Report on the Building Stones of the 
United States and Statistics of the Quarry Industry 
for 1880. 
