22 BIBLIOGRAPHY AND INDEX OF N A. GEOLOGY, [bull.-135. 
8 Ami (IT. M.). Notes ou fossils from Quebec City, Canada. 
Ottawa Nat., vol. viii, pp. 82-90. 
Gives a list of 90 species occurring in the Silurian strata, near the 
city of Quebec. 
B. 
Backstrbm (H.). Causes of magmatic differentiation. 
Abstracts: Am. Geol., vol. xiii, pp. 194-195 (A p.); Am. Nat., vol. 
xxviii, p. 515 (£ p.). 
Noticed in Bibliography and Index for 1892 and 1893. 
10 Bain (H. Foster). Structure of the Mystic coal basin |Iowa]. 
Iowa Acad Sci., Proc, vol. 1, pt. iv, pp. 33-36. 
Describes the lithologic character of the beds and gives several sec- 
tions displayed at various localities. 
11 Sigourney deep well [Iowa]. 
Iowa Acad. Sci., Proc, vol. i, pt. iv, pp. 36-38. 
Gives the section of the well to the depth of 1,888 feet, and discusses 
the evidences as to age of the formations represented. 
12 Peculiarities of the Mystic coal seam [Iowa]. 
Am. Geol., vol. xiii, pp. 407-411. 
Describes the occurrence of this coal seam and the associated strata, 
which, in contrast with the complexity of structure and nonpersist- 
ence of the beds of the Coal Measures in other parts of Iowa, has an 
extent of about 50 miles north and south and 40 miles east and west. 
13 Baldwin (S. Prentiss). Pleistocene history of the Champlain 
Valley. 
Am. Geol., vol. xiii, pp. 170-184, with map and one figure. 
Describes the deltas, moraines, and other glacial deposits of this 
region and the pre-Glacial and post -Glacial drainage systems. 
13a Ballard (Hetty O.), Crosby (W. O.) and. Distribution and proba- 
ble age of the fossil shells m the drumlins of the Boston 
basin. 
Am. Jour. Sci., 3d ser., vol. xlviii, pp. 486-496. 
See Crosby (W. O.) and Ballard (H. O.), No. 106. 
13b Barlow (A. E.). Relations of the Lauren tian and Huroniau rocks 
north of Lake Huron. 
Review : Am. Geol., vol. xiii. pp. 63-64 (4- p.). 
Noticed in Bibliography and Index for 1892 and 1893. 
14 Barrois (Charles). [Correlation of clastic rocks.] 
Int. Cong. Geol., Compte ReDdu, 5th session, pp. 172 and 175. 
Remarks on the impossibility of comparing in detail the Paleozoic 
formations of Europe and North America. 
15 Barton (G. H.). [Remarks on drumlins.] 
Bost. Soc. Nat. Hist., Proc, vol. xxvi, pp. 23-25. 
Reviews the theory advanced by Warren Upham in a paper on the 
origin of drumlins. 
