Editorial Com incut. S77 
one-eighth of the present amount of water, and the cataract 
was then a less powerful agent of erosion. The deeper parts 
of the gorge, which now contain pools, were excavated by the 
cataract when the volume of the river was large. The shallow 
parts, which now contain rapids, were excavated when the vol- 
ume was small. 
"The determination of the age of the river, or the time 
which has been consumed in the making of the gorge, is a 
problem of great interest, to which much attention has been 
given. As the length of the gorge is known and as the rate 
at which the cataract now lengthens the gorge is known, it 
would seem a simple matter to compute the time. Taking the 
gorge length as a dividend and the annual change in length as 
a divisor, we obtain 7,000 as a quotient, and this has been as- 
sumed by some to represent the number of years occupied by 
the river in the work. But this computation fails to take ac- 
count of a number of important considerations. The thickness 
of the limestone is not the same in all parts of the gorge ; the 
hight of the cataract was not the same through the whole 
period ; and, as just pointed out, the volume of the river was 
sometimes much less. The last-mentioned qualification is the 
most important of all, for the diminished river would erode 
much less rapidly than the full river. If we knew precisely 
what difference the change of volume would make, a fairly sat- 
isfactory result might be obtained, but this we do not know. 
The smaller of the two divisions of the cataract, known as the- 
American fall, now contains nearly as much water as did the 
whole river during times of diminished drainage basin. But 
the crest line of the American fall has not changed its forny 
appreciably since the year 1827, when the first accurate draw- 
ings of it were made. Its recession must be many times slower 
than that of the Horseshoe fall. This fact indicates that the 
rate of erosion of the narrowest parts of the gorge was exceed- 
ingly slow and the time consumed exceedingly long. Its esti- 
mation is little better than a guess. One may say with some 
confidence that 7,000 years is altogether too small an estimate 
of I, the age of the river, but whether the real age is expressible 
in tens of thousands or in hundreds of thousands of years is 
at present a matter of doubt.'' 
The Term Hudson River. — Dr. Rudolf Ruedcmann has 
reviewed the rather quixotic record of this term in geological 
