Correspondence. 363 
One more misstatement should be mentioned. Prof. Penrose says 
that the book relates "mostly to the ore deposits of this country."' Ex- 
clusive of the index and appendix, there are 456 pages in the book, only 
190 of which are devoted to ore deposits, including the portions on for- 
eign ore deposits. About half of the book is devoted to ores, if we in- 
clude those preliminary chapters relating to ores and mining methods. 
There are errors in the book — few text hooks are free from them: but 
only two of those pointed out by Prof. Penrose are errors of mine, and 
these two are blunders which, though inexcusable, are not at all vital. 
I welcome fair criticism and am glad to know of any errors in order 
that they may he corrected in possible future editions: but, entirely 
aside from my delicate position as author of the book in question, I em- 
phatically object to a review like the one in question. The reason for 
it is not thoroughly apparent. I should hesitate to ascribe it to malice, 
and certainly will not retaliate by referring it to "an extremely super- 
ficial knowledge of economic geology.'" The only other cause that I 
can find for its inaccuracies is a hasty and superficial examination of 
the book, begun, perhaps, with the preconceived opinion that the book 
was worthless. The evident Eagerness and the occasional violence of 
denunciation may. perhaps, have grown with the fancied discovery of 
errors. Ralph S. Tahr. 
Ithaca, New Fork, April 11. 1894. 
Early Man in Minnesota. The Archasologisl for March. 1894, pre- 
sents a paper on this subject by Prof. W. H. Holmes, which he hail 
previously published in the American Geologist for April, 1893; bul 
no mention is made of this magazine, nor of the previous publication of 
the paper. In this republication, Prof. Holmes inserts a new sentence. 
saying that I "have been misled by the unverified statements of an in- 
experienced observer into constructing a section, repeated by Prof. 
Wright, in which an Implement-bearing bed is carried entirely across 
the immediate valley of the Mississippi at the base of the glacial depos- 
its."' The section referred to.* however, shows the "stratum contain- 
ing quartz chippings" (not implements in a finished state) as restricted 
to the locality of Miss Babbitt's examination on the east side of the 
Mississippi river close above Little Falls, though tin' section itself is ex- 
tended across the valley to show the relation of this place and its drift 
with the river and the land surface on both its sides. This stratum, 
furthermore, is nol "at the base of the glacial deposits." An undeter- 
mined thickness of till is shown below the modified drift, and the quartz- 
bearing layer is wholly above the till and in the basal pari of this modi- 
fied drift, as was observed by Miss Babbitt. 
Having again attentively read her statements! of the condition of this 
most plentifully quartz-bearing bed of the modified drift at Little Falls. 
with its occasional grouping of numerous quartz fragments of similar 
*First published in a paper in the Proceedings of the Hoston Society of Natural 
History, vol. xxiii, pp. 436 447. Dec. 21, 1887; mostly reprinted in Wrights "Ice Age in 
North America," 1889, pp. 538-550. 
fProc. A. A. A. S., vol. xxxn.for 1883, pp. 385-860. Am. Naturalist, vol. xvm, pp. 
i94-605, 697-708, June and July, 1884. 
