122 GEOLOGY. 



Geological Survey of the Territories, Miscellaneoiis Publications, 

 84 pp. 8vo. 

 Many of the descriptions treat of the rocks shown. 



Jei^ney, Walter P. Notes on the Geology of "Western Texas, near 

 the thirty-second parallel. Amer. Journ. ser. 3, vol. vii. pp. 

 25-28. 



Refers to " the occurrence of a remarkable Lower- Silurian section 

 in the Organ Mountains," in which the author recognizes the equiva- 

 lents of the Potsdam, Calciferous sandrock, Chazy, Trenton, Hudson, 

 Oneida conglomerate (?), and Niagara groups, although the beds iden- 

 tified with the last .group may turn out to be of Carboniferous age. 

 The whole scries is fairly fossiliferous. The second part of the paper 

 is on the geology of the Llano Estacado, a desert of Cretaceous beds 

 resting on probably Triassic rocks. The " Caprina Limestone" of 

 Shumard is recognized with little doubt ; and it is the highest bed of 

 this region. G. A. L. 



Knox, M. V. B. Drift in Kansas. Amer. Journ. ser. 3, vol. viii. 



pp. 466, 467. 

 Extract from a letter describing the drift and boulders of the region. 



Le Coi^te, Prof. Joseph. On the great Lava-flood of the West; and on 

 the construction and Age of the Cascade Mountains. Amer. Journ. 

 ser. 3, vol. vii. pp. 167-180, 259-367 [by a printer's error the 

 pagination runs on from p. 261 to p. 362], 7 figs, in text. 

 Divided under the following heads: — 1. The great Lava-flood: 

 Extent (not less than 200,000 square miles) ; Source (from fissures in 

 Coast, Cascade, and Blue-Mountain ranges) ; Thickness (average 2000 

 feet, extreme not less than 3700 feet). 2. Structure of the Cascade 

 Mountains. 3. Age of the Cascade Eange : a suh-lava conglomerate 

 with a leaf-bed are the means of ascertaining this. The range began 

 probably at the end of the Jurassic period; but its great bulk was 

 .formed at the end of the Miocene* 4. Theory of the ejection of the 

 lava-flood and of the formation of the Cascade Mountains. 5. Some 

 important points suggested by the previous discussion: successive 

 outflows of Cascade lava; relative age of different kinds of lava; 

 Drift-covering in Oregon and Washington; oscillations during Post- 

 Tertiary times on the Pacific Coast ; formation of the Canon of the 

 Columbia Eiver ; Prairie mounds. G. A. L. 



Leslet, Prof. J. P. The Brown-Hematite- Ore Banks of Spruce 

 Creek, Warrior's-Mark Run, in Huntingdon and Centre Counties, 

 Pennsylvania, along the line of the Lewisburg, Centre-County 

 and Tyrone Railroad. Proc. Amer. Phil. Soc. vol. xiv. no. 92, 

 pp. 19-83 (and 99-107 ?), see also pp. 2-4 ; 44 illustrations in 

 text (plans, sections, and views), 1 plate (map). 



Preliminary Chapter. The area of the district is about 100 square 

 miles. General Geological Considerations, pp. 22-30. The rocks are 



