weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1894. 59 
30G Iddings (Joseph P.). Petrographical character of the lavas. 
U. S. Gcol. Surw, 14th Ami. Rept., pt. 2, pp. 520-521. 
Describes the petrographic character of the basaltic rocks collected 
by C. D. Walcott in the Grand Canyon of the Colorado. 
307 and Weed (Walter H.). Livingston Folio. Montana. 
U. S. Geol. Surv., Geologic Atlas of the United States, folio 1. 
Abstract: Am. Jour. Sci., 3d ser., vol. xlviii, pp, 170-172. 
Describes the geography and topography, the geologic relations of 
the mountain ranges, the character and occurrence of the Algonkian, 
Cambrian, Devonian, Carboniferous, Juratrias, Cretaceous, Tertiary, 
aud Pleistocene strata and of the igneous rocks, and the occurrence 
of gold and coal. Includes topographic, colored areal geologic, eco- 
nomic geologic, and structure section maps, and a sheet of columnar 
sections. 
307a Yellowstone Valley from Livingston to Cinnabar. 
Int. Cong. Geol., Compte Rendu, 5th Session, pp. 32G-335. 
See Weed (W. H.) and Iddings (J. P.), No. 615. 
3076 Indiana, Department of Geology and Natural Resources. 
Eighteenth Annual Report, 1893. 
■ Abstract: Am. Geol., vol. xiv, pp. 125-12G. 
30S Ingall (Elfric Drew). Preliminary note on the limestones of the 
Laurentian system. 
Can. Rec. Sci., vol. vi, pp. 88-91. 
Describes the inclusions of gneisses and similar rocks in these lime- 
stones, and considers that they represent areas of gneiss altered into 
limestone in place and that their location has been determined by the 
bends and contortions of these rocks. 
309 Ingersoll (Charles A.). On hemimorphic wulfenite crystals from 
New Mexico. 
Am. .lour. Sci., 3d ser., vol. xlviii, pp. 193-195. 
Describes the cry stallo graphic characters of the crystals. 
310 Ingram (Henry B.). The great bluestone industry. 
Pop. Sci. Monthly, vol. xlv, pp. 352-359. 
Abstract: Jour, of Geol., vol. ii, p. 647 (£ p.). 
Describes the occurrence and character of flagstones in New York of 
Devonian age. 
311 James (Joseph F.). On the value of supposed algrc as geological 
guides. 
Am. Geol., vol. xiii, pp. 95-101. 
Abstract: Am. Assoc. Adv. Sci., Proc, vol. xlii, pp. 172-173 (£ p.). 
Quotes from different authors as to the geologic occurrence and 
range of algae and their value as evidence in determining geologic 
horizons. 
