Note 103 — Chapter VII · GEOLOGICAL WORK IN NORTH AMERICA.

The lake-ridges and raised beaches around the Great Lakes, indicating margins of the water when it stood at a higher level than now, have received much attention of late years from Canadian and American geologists. They are found to vary somewhat in level, thus indicating unequal movements of the earth's crust. References to literature prior to 1890 will be found in a paper by Professor J. W. Spencer, Quart. Jour. Geol. Soc., vol. xlvi. (1890), p. 523.