792 C. K. LEITH 
points at issue are of general interest or of fundamental importance, it 
is advisable to make comments and enter into discussions, even if the 
space taken by such comments be greater than that given to the sum- 
mary of the original articles. In such comments neither commenda- 
tion nor censure will be made, but the aim will be to point out the 
conclusions announced which fail of complete establishment and the 
generalizations which appear to go beyond what is warranted by the 
facts published. ‘The purpose of indicating what appear to the editor 
as deficiencies of these kinds is neither to put himself dogmatically in 
opposition to the statements of the author reviewed, but to direct 
attention to the questions involved, and in cases of doubt to keep them 
open for further study in the field and laboratory. 
ADAMS, F. D. 
Norian oder Ober-Laurentian von Canada. (Neues Jahrb., B. B. VIII, 
1893, pp- 419-498.) Summarized Journ. of Geol., vol. 2, p. Ilo. 
On the typical Laurentian area of Canada. (Journ. of Geol., vol. 1, 
1893, pp- 325-340.) Summarized Journ. of Geol., vol. 2, p. 111. 
Preliminary report on the geology of a portion of central Ontario situ- 
ated in the counties of Victoria, Peterborough, and Hastings, together 
with the results of an examination of certain ore deposits occurring in 
the region. (Ann. Rept. Geol. Surv. of Canada, for 1892-3, vol. 6, 
part J, pp. 15. 1895.) Summarized Journ. of Geol., vol. 3, p. 229. 
A further contribution to our knowledge of the Laurentian (Art. VII). 
(Am. Journ. of Sci., 3d ser., vol. 50, 1895, pp. 58-69. With plates I 
and II.) Summarized Journ. of Geol., vol. 4, p. 364. 
Laurentian area in the northwest corner of the Montreal sheet. Sup- 
plementary chapter to Ells’ report on a portion of the Province of 
Quebec. Ann. Rept. Geol. Surv. of Canada, for 1894, vol. 7, part J, 
pp- 93-112. 1896.) Summarized Journ. of Geol., vol. 6, p. 850. 
Report on the geology of a portion of the Laurentian area lying to the 
north of the island of Montreal. (Ann. Rept. Geol. Surv. of Canada, 
for 1895, vol. 8, part J, pp. 184. 1897. With geol. map.) Summar- 
ized Journ. of Geol., vol. 7, p. 411. 
and BAaRLow, A. E. 
On the origin and relations of the Grenville and Hastings series in the 
Canadian Laurentian. (Am. Journ. Sci., 4th ser., vol. 3, 1897, pp. 
173-180.) Summarized Journ. of Geol., vol. 7, p. 413. 
AGUILERA, JOSE G. 
Sinopsis de Geologia Mexicana. (Bol. del Inst. Geol. de Mexico, Nums, 
4, 5, and 6, part 2, 1897, pp. 189-250. With geol. map.) Summar- 
ized Journ. of Geol., vol. 7, p. 707. 
