346 Rcvieir of liecent Geolof/ical Literature. 
within the interstices of which air and atmospheric moisture are condensed 
over the entire area and loclved up in the most constant and intimate con- 
tact; or tliese invisible cavities may be partially occupied by other sul- 
phides, clay, quartz, etc., whose presence is shown by chemical analysis. 
(I.) Discoverpof the ancient courne of tfie St. Lawrence river. (5.) Ori- 
gin of the basins of the great lakes. (3.) Establishment and dismemberment 
■ of lake Warren. (4.) Discovery of the outlet oftheUuron-Michigan-Supe- 
rior lake, into lake Ontario by the Trent mlley. (5.) Erie the youngest of 
all the great lakes. By Prof. J. W. Spencer, Pu. D., F. G. S. (Read at the 
late meeting of the Am, Assc. Adv. Sci.) (I.) Previous investiga- 
tions by the author showed that there was a former river draining the 
Erie basin and flowing into the extreme western end of lake Ontario, and 
thence to the east of Oswego, but no further traceable, as the lake 
bottom rose to the north-east. Upon the southern side there 
was a series of escarpments (some now submerged) with vertical 
cliffs facing the old channel. By recent studies of the elevated beaches 
it is demonstrated that the disappearance of this valley is due to subse- 
quent warpings of the earth's crust, and that the valley of the St. Law- 
rence was one with that of lake Ontario. Recent discoveries of a deep 
channel upon the northern side of lake Ontario (a few miles east of To- 
ronto) and of the absence of rocks to a great depth under the drift so far 
beneath the surface of lake Iluron between lake Ontario and the Georgian 
bay, and in front of the Niagara escarpment between these lakes, of the 
channel in Georgian bay, at the foot of the escarpment, and of the channel 
across lake Huron, also at the foot of a high submerged escarpment 
across that lake, show that the ancient St. Lawrence during a period of 
high continental elevation rose in Lake Michigan, flowed across lake 
Huron and down Georgian bay and a drift-filled channel to lake On- 
tario, thence by the present water to the sea-receiving on its way the 
ancient drainage of the Erie basin and other valleys. 
(3.) The two questions involved are "origin of the valleys" and 
"cause of their being closed into water basins." The basins of 
lakes Ontario and Huron are taken for consideration. The previ- 
ous paper upon the course of the ancient St. Lawrence shows that the 
Huron and Ontario basins are sections of the former great St. Lawrence 
valley, which was bounded,especially upon the southern side, by high and 
precipitous escarpments, some of which are submerged. But upon their 
northern sides there are also lesser vertical escarpments, now submerged, 
with walls facing the old valley. The valley was excavated when the con- 
tinent was at high altitude, for the eastern portion stood at least 1,200 feet 
higher than at present, as shown by the channels in the Lower St. Law- 
rence, in Hudson's straits and in the New York and Chesapeake baj's. 
The valley was obstructed in part by drift, and in part by a north and 
north-eastward differential elevation of the earth's surface, due to internal 
movements. The measurable amount of warping defied investigation un- 
til recently, but now it is measured by the amount of uplift of beaches 
and sea-cliffs. Only one other explanation of the origin of the basins has 
been "-iven—tlie "Erosion by Glaciers." ^a) Because the latter occur in 
