326 The American Geologist. November, i895 
their importance. Should it be decided that these defects really annul 
their priority of discovery, there is no doubt that Glazier's claim wouldi 
at once be admitted. 
Mr. Glazier's second volume is a very creditable production. It is 
probable that, had his first volume been issued with as close an adher- 
ence to fact and with as careful regard to the rights of earlier author- 
ship, and to the usages of good literature, it would have received better 
acceptance. There are serious defects in this, of which it is here bnly 
necessary to mention one on page 270, in which the author speaks of 
Prof. A. Randall as being connected with "the Geological Survey of 
Minnesota" before Minnesota was yet a state. 
All in all, the author, on the basis of the facts which he himself pub- 
lishes, can hardly be admitted to have established his principal thesis, 
viz., that he discovered the true source of the Mississippi in 1881. If the 
true source be not Itasca lake, it must be either the head of Excelsior 
or of Nicollet creek, and of these Nicollet creek has the stronger claims. 
If, however, we admit that it be E.xcelsior creek, that has but recently 
been fully defined. If Elk lake be supposed to have the honor of stand- 
ing at the source of the Mississippi, that lake was surveyed and mapped 
six years prior to Glazier's visit. N. H. Win(;hell. 
Warm Temperate Vegetation near Glaciers. In the July number 
of this magazine (pages 65, 06) Dr. George M. Dawson supposts that, if 
the ice-sheet still remained over the country north and northeast of To- 
ronto and lake Ontario when the interglacial beds of the Don River valley 
in Toronto and of Scarboro' Heights were deposited, the district must 
have had "killing frosts nearly every clear night during the summer." 
Similarly Prof. A. P. Coleman asks, in the last number of the Journal 
of Geology (page 640), "Can any one believe that meantime, while elms 
and oaks and maples, not tf) mention the papaw, were growing along the 
Don, the ice-field, with no lofty slopes to supply gathering ground for 
neve, was lurking a few miles off, ready to advance and overwhelm the 
deciduous forests'?" 
To this inquiry the present writer replies, Yes, that he holds this as 
the most probable explanation of the repeated accumulations of till 
above the stratified and fossiliferous beds: but No, concerning the ab- 
sence of lofty slopes, by which he thinks that the predominantly w^ast- 
ing ice border rose probably to the altitude of 5,000 feet within 100 
miles from its edge while being dissolved by the warm Charajjlain cli- 
mate with somewhat lower altitude of the land than now. If the retreat 
of the ice-sheet from the northern United States and Canada occupied, 
as I think, some three to five thousand years, disappearing earliest from 
the upper Missouri and Mississippi basins, and latest from New Eng- 
land, the province of Quebec, and Labrador, the extension of a warm 
temperate flora and faunacould well keep pace with the glacial recession, 
so that, as on the waning Malaspina ice-sheet, a flora like that of the 
same latitude to-day, and concomitant temperate molluscan and insect 
life, may well have thrived up to the very boundary of the ice, or per 
haps in the case of the plants and insects even extending as in Alaska, 
upon the drift-covered ice border. 
