Editorial Comment. 289 
lakes. Newberry, N. H. Winchell, Gilbert, Leverett, and the 
present writer, have referred these old beaches to glacial 
lakes, obstructed in the present direction of outlet by the bar- 
rier of the waning continental ice-sheet. Spencer and Taylor 
have regarded the higher and more important shore lines as 
probably of marine formation, believing that after the Glacial 
period the sea extended in great inland gulfs to lakes Michi- 
gan and Superior. Lawson, examining these beaches on the 
north side of lake Superior, concluded that there they are lacus- 
trine, but due to dams of land rather than of ice. Those glacial- 
ists who have studied the records of lake Agassiz, the grandest 
example of these Late Glacial lakes, of lake Newberry and 
many others in the region of the Finger lakes in western and 
central New York, of lake Passaic in New Jersey, of lake Con- 
toocook in New Hampshire, and of lakes Bouve, Charles-Ne- 
ponset, and Shawmut in eastern Massachusetts, all of which 
seem to be clearly referable to the barrier of the continental 
glacier during its final retreat, will gladly approve the letter 
of Mr. F. B. Taylor, given in our present number, in which, 
after a thorough study of these old shore lines about the up- 
per Laui*entian lakes and search for their continuation east of 
lake Nipissing, he declares his conversion, with little doubt 
remaining, to the doctrine that all these shores were formed 
by ice-dammed lakes. 
Mr. Taylor further states in this letter that he cannot ac- 
cept the opinion of Spencer, Lawson, and the present writer 
that lake Warren (or, as Spencer might call it, the Warren 
gulf) extended over the present four lakes, Superior, Michi- 
gan, Huron, and Erie. Instead, according to Mr. Taylor's 
view, based on his exploration and correlation of the old 
beaches and deltas, lake Warren, so named by Spencer from 
his careful survey of the beaches adjacent to lake Erie and 
the southern part of lake Huron, had indeed no farther ex- 
tent, never including the area of lakes Michigan and Supe- 
rior, but overflowing to the glacial lake Michigan by the Pe- 
wanio channel, southwest of Saginaw bay. which has been 
recently described by Mr. E. H. Mudge.* 
*Am. Jour. Sci., III. vol. l, pp. 442-445, Dec, 1895. Compare also Mr. 
Mudge's papers in the Am. GEOLOGIST for Nov., 1893, and \m .. ls'.i). 
