Review of Recent Geological Literature. 51 
saiidsiono and shale. Thi^ strata from the top of the Mi'diiia up to and 
including' the Niagara limestone, can be studied in' the (ienesee ravine. 
From the Niagara to the present no deposits, except those of glacial or- 
igin, are known. V. s. o. 
Thv' leiKjth of (jcidcKjic time. \\\ H. L. Faifichilu. (Proc. Rochester 
Acad. Sci., vol. ii, pp. 20.3-2f)G, July, 1894.) This article will be of value 
for reference, as it gives a concise stat('ment of the various estimates, 
from that of Charles Lyell to the recent ones of King, Upham, Walcott 
and others, of the time required for the deposition of the sedimentary 
rocksof the globe. Nineteen ditferent estimates, with complete biblio- 
graphic references, are i)r(-sented. U. s. G. 
Preliminary report (if field work duriiuj IS'flJ in northeastern Minnesota, 
cJdefly relating to the glacial dinft. By Wahken Upiiam. (Geol. and Nat. 
Hist. Survey of Minnesota, 22d [189^5] Ann. Rept., pt. iir. i)p. 18-G(). pis. 
1 and 2, 1894.) The first {)artof this paper is devoted to a brief outline 
of tlie topograpliy of the northeastern i)art of the state, and the altitudes 
of a large number of points are given; these are taken from r.iilroad pro- 
files and from recent determinations made by members of the Minnesota 
Survey. Following this are descriptions of the only rock outcrops 
known in Aitkin and Cass counties. 
The most important and interesting i)art of this report is that treating 
of the glacial drift; an outline of the glacial geology is given and special 
attention is called to certain points, the chief of which are mentioned 
below. A map is ])resented, which, among other features, shows the 
results of the most recent wt)rk as to the location of the moraines in the 
northern part of the state, and the area occupied by I^eltrami island of 
the glacial lake Agassiz; this island lies just to the northwest of Red 
lake. A very comi>lete list of glacial striie is given, and attention is 
called to the divergent directions of the.se stri;p at certain points, the 
most marked being in the vicinity of Duluth. Drift from three princi- 
pal .sources is recognized; (1) on the west, from the north and north- 
west; (2) east of the Hig fork, from the north and northeast; and (3) in 
the same region, from the east. Drift from the last direction is easily 
recognized by its boulders, which are characteristic of the rock of the 
Keweenawan areas on the north shore of lake Superior. Several sec- 
tions from cuts on the Mcsabi range show alternations of htyers of till 
from th(^ last two directions. The locations of four moraines north of 
lake Superior are indicated much more accuratelj- than has heretofore 
been possii)le, and the most northerly, named tiii> Vermilion or Twelfth 
moraine, is here described for the first time. 
Several pa^'cs are desoted to a discussion of the raised beaches on the 
north shore of lake Superior, and a brief account is given of the history 
of the ice-dammed lakes that made these beaches. Three beaches are 
referred to the Western Superior glacial lak(\ eight to the glacial lake 
\Varren. and one to the glacial lake Algon(piin. The last beach is 
united witli the present beach at Duluth, but it gradually ascends east- 
ward, reaching a bight of 49 feet above lak(,' Superior at Saull Ste. 
