MICHIGAN ACADEMY OF SCIENCE. 
121 
Davidson,* and the discussion by LeConte, f Lawson, § Fairbanks,:!; 
Uphamfl and others. 
Davidson found 20 or more submerged valleys along the coast of 
California and Lower California, of which the most classical example 
is the one heading up in the Bay of Monterey. Several small streams 
empty into this bay but there are no large rivers; Fairbanks however 
shows how this may not always have been the case. Davidson's plate 
ix show’s a beautifully marked valley which he has sounded out to about 
20 miles from shore. About 10 miles out it received a tributary from the 
northeast. Capt. Tanner of the U. S. S. “Albatross” is cited as having 
sounded 80S fathoms (5,208 feet) in the main channel 1 6 1 /-? miles off 
shore. Davidson's soundings cease sooner than we might wish, for the 
edges of this valley, as of several of the others, are still running out to 
sea when his figures stop. The 80S fathom depth is a good five miles 
inside the valley as shown on plate ix and we have nothing to indicate 
the real outer limit. 
Considering all the features along this coast and northward to 
Alaska, Uphani thinks that there must have been an elevation during 
the Glacial Epoch amounting' to 3,000 to 5,000 feet. LeConte’s esti- 
mate is somewhat less, 2,000 to 3,000 but even the largest of these 
figures appear to be well on the side of caution for with 5,208 feet only 
16. 5 miles out in the submerged Monterey valle t y and the contours run- 
ning out in typical form upwards of five miles more it is evident that 
if this valley was formed by river erosion the old base-level is now’ more 
than 5,208 feet submerged. 
It may be remarked parenthetically in this connection that there 
are excellent reasons for suspecting that the whole Gulf of California 
may be a drowned valley down which formerly coursed the low er reaches 
of the Colorado River. 
LeConte, Fairbanks and Upham agree in making the elevation con- 
temporaneous with glaciation, and the depression which followed is 
made an equivalent of the Champlain Epoch in the East. This matter 
of the time is of great importance. We shall see as we proceed how 
many of the signs of former elevation followed by subsidence seem to 
fall into this same correlation. 
The mouth of the St. Lawrence has a w’ell marked submarine gorge 
which lies drowned to the depth of 3,666 feet.** Spencer places the 
glacial elevation of North America at “3,000 feet or more,” but there 
are reasons for believing that the observed depth at the mouth of the 
St. Lawrence gorge (3,666 ft.) may fail to express the whole of the 
elevation, especially elsewhere on the continent, at the time that the 
gorge was in process of formation. 
At the mouth of the Hudson, Lindenkohlff sounded out a typical gorge, 
*Davidson, George, “The Submerged Valleys of the Coast of California U. S. A., and of Lower Cali- 
fornia, Mexico.” Proc. California Acad. Sei., Ser. 3, Geology, Vol. 1, No. 2. 1897, pp. 73-103 and 
plates IV-XII. 
tLeConte, Joseph, “The Mutual Relations of Land-elevation and Ice-accumulation during the 
Quaternary Period.” Bull. Geol. Soc. Am., vol. 2, 1891, pp. 323-330. 
§Lawson, A. C., Bull. Dep’t. Geol. Univ. California, vol. 1, pp. 57-58, 157-159. 
JFairban’ks, Harold W., “Oscillations of the Coast of California During the Pliocene and Pleistocene.” 
Am. Geol. vol. xx, 1897, pp. 213-245. 
IfUpham, Warren, 1892, loc. cit. 
**Spencer, J. W., “The High Continental Elevation Preceding the Pleistocene.” Bull. Geol. Soc. 
Am., vol. 1, 1890, pp. 65-70. 
tfLindenkohl, A., “Geology of the Sea-bottom in the approaches to New York Bay.” Report of 
the Sup’t. U. S. Coast and Geodetic Survey. 1884, Appendix No. 13, pp. 435-438, with plate. 
