weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1895. 77 
496 Upham (Warren). Departure of the ice sheet from the Lauren tian 
lakes. 
Abstract : Geol. Soc. Am., Bull., vol. vi, pp. 21-27. 
Describes the phenomena attending the retreat of the ice sheet, the 
character of the shore lines, the height of the beaches of the western 
Superior glacial lake and of lakes Warren and Algonquin, and the 
formation of these glacial lakes. Discusses the character and progress 
of the uplift following the recession of the ice sheet. 
497 Discrimination of glacial accumulation and invasion. 
Geol. Soc. Am., Bull., vol. vi, pp. 343-352. 
Discusses the mode of formation of ice sheets, the character of the 
drift and morainal phenomena, and the causes of ice accumulation and 
departure. Describes the phenomena attending an invasion by the 
advancing border of an ice sheet, and discusses the meteorologic expla- 
nation of the irregularity of glacial invasion and the criteria of ice 
accumulation and invasion. 
498 Quaternary time divisible into three periods — the Lafayette, 
Glacial, aud Recent. 
Abstract : Am. Assoc. Adv. Sci., Proc, vol. xfiii, pp. 219-223. 
Describes the character of the Glacial and post-Glacial phenomena, 
and gives an estimate of the duration of Quaternary time. 
499 Minor time divisions of the Ice age. 
Am. Nat., vol. xxix, pp. 235-241. 
Discusses the evidences of fluctuations of the ice sheet and gives the 
author's classification. 
500 Late Glacial or Ghamplain subsidence and reelevation of the 
St. Lawrence Eiver Basin. 
Minn. Geol. and Nat. Hist. Surv., 23d Ann. Rept., pp. 156-193. 
Discusses the evidences of uplift and subsidence prior to and during 
the Glacial period as shown by beaches of the glacial lakes of the St. 
Lawrence Basin. 
V. 
501 Van Hise (Charles E.). The origin of the dells of the Wisconsin. 
Wis. Acad. Sci. Arts, Letters, Trans., vol. x, pp. 556-560. 
Discusses the evidence of the position of the dells of the Wisconsin 
River and tributaries as being controlled by a rectangular system of 
joints in the strata. 
502 Summary of current pre-Cambrian North American literature. 
Jour, of Geol., vol. iii, pp. 227-236 and 709-721. 
Reviews a number of recent papers describing pre-Cambrian rocks of 
North America. 
503 and Bay ley (William Shirley). Preliminary report on the 
Marquette iron-bearing district of Michigan. 
U. S. Geol. Surv., 15th Ann. Rept., pp. 477-650, pis. xiii-xxvi. 
Describes the distribution, geologic relations, andlithologic characters 
of the rocks forming the Basement Complex, Lower Marquette series, 
and the Upper Marquette series, and discusses the dynamic movements 
Avhieh have affected these formations and their correlation with other 
formations. Includes a chapter on the Republic Trough, by H. L. Smyth. 
