Correspondence I Q 5 
Whitaker, M. C 
An olivinite dike of the Magnolia district and the associated pic- 
rotitanite. (Colo. Sci. Soc, Proc; 14 pp.; to be presented at the 
meeting of Feb. 5, 1898.) 
Willis, Bailey. 
Stratigraphy and structure of the Puget group, Washington [Ab- 
stract. (Geo). Soc. Amer., Bull., vol. 9, pp. 2-6, Dec. 30, 1897.) 
CORRESPONDENCE. 
Correlation of Moraines with Beaches on the Border of 
Lake Erie. In two papers published in the American Journal of 
Science (April, 1892, and July, 1895,) I have advanced the view that 
certain moraines on the south and east borders of lake Erie are correla- 
tives of beaches which encircle the western end of the Lake Erie basin, 
an interpretation which signifies that while a lake was occupying the 
district inclosed by these beaches, the ice-sheet was occupying districts 
to the east. This interpretation was based upon studies carried on in 
part by Mr. Gilbert and in part by myself, Mr. Gilbert's studies being 
confined mainly to the beaches and mine to the moraines. Later studies 
by Mr. Warren Upham, at Cleveland, and by Prof. H. L. Fairchild, in 
western New York, the results of which are published in the Bulletin 
of the Geological Society of America (Upham, Vol. VII, March, 1896. 
pp. 340-345, and Fairchild, Vol. VIII, March, 1897, pp. 269-281), have 
brought to light the continuation of these beaches to points farther east 
than had previously been observed. It seems necessary, in view of these 
observations, that a brief supplementary statement should be made. I 
am especially prompted to do this because Dr. Spencer has intimated 
in the February American Geologist that these later studies have re- 
moved the supposed evidence of ice occupancy of the eastern part of the 
region during the formation of beaches in the western part, and that 
they sustain his cherished view that the shore lines are marine. In this 
"diagnosis" Dr. Spencer departs from the views of Mr. Upham and 
Prof. Fairchild, as well as from those of Mr. Gilbert and myself. 
The view that the beaches in the western end of the Lake Erie 
basin pertain to a glacial lake has been adopted after due consideration 
of other hypotheses. The nature of the outlet has been carefully looked 
into. The pioneer work by Mr. Gilbert, in the Maumee valley of north- 
western Ohio and adjacent parts of Indiana brought to light the south- 
western outlet to the Wabash, an outlet which wa; clearly recognized 
by him to be the product of a stream. Mr. Gilbert likened the upper 
twenty-five miles of the outlet to the Detroit river, while the portion 
immediately below is compared to the Niagara at Buffalo, where it 
