24 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY, [bull. 135. 
22ft Beecher (C. E.) and Schuchert (Charles). Development of the 
brachial supports in Dielasma and Zygospira. 
Abstract: Am. Nat., vol. xxviii, p. 267 (§- p.). 
Noticed in Bibliography and Index for 1892 and 1893. 
23 Bell (Robert). Pre-Paleozoic decay of crystalline rocks north of 
Lake Huron. 
Geol. Soc. Am., Bull., vol. 5. pp. 357-366, pis. 15-16. 
Abstract: Am. Geol., vol. xiii, p. 214 (^ p.). 
Discusses the evidence of pre- Paleozoic erosion, the conditions affect- 
ing this ancient erosion and the contacts of Archean and Paleozoic 
rocks. Discusses the significance of the absence of Paleozoic deposi- 
tion and the effect of glacial denudation. 
24 Bergeat (Alfred). Zur Kenntniss der juugen Eruptivgesteine der 
Eepublik Guatemala. 
Zeit. der deut. geol. Gesell., Band xlvi, Heft 1, pp. 131-157. 
Describes the physiography of the region and the geologic distribu- 
tion, occurrence, and petrographic characters of the recent eruptive 
rocks of Guatemala. 
25 Berkey (Charles P.). Preliminary report of leveling party. 
Minn. Geol. and Nat. Hist. Surv., 22d Ann. Kept., pp. 134-140. 
Describes the topographic charcter of portions of Cook County, 
Minn., and includes two profile sections showing the principal elevated 
regions, and tables showing the elevations of a number of localities 
above sea level. 
20 Blake (William P.). The mineral deposits of southwest Wisconsin. 
Am. Inst. Mg. Engrs., Trans., vol. xxii, pp. 558-568. 
Describes the geology of the region and the character and structure 
of the ore deposits. 
27 [The lead and zine deposits of the Mississippi Valley.] 
Am. Inst. Mg. Engrs., Trans., vol. xxii, pp. 621-634. 
In discussion of paper by W. P. Jenney on the same subject. 
28 [The genesis of ore deposits.] 
Am. Inst. Mg. Engrs., Trans., vol. xxiii, p. 587 (l p.). 
In discussion of paper on the same subject by F. Posepny. 
29 [Terrestrial submergence southeast of the American Continent.] 
Geol. Soc. Am., Bull., vol. v, p. 21 (^ p.). 
In discussion of paper by J. W. Spencer on the same subject. 
30 Wisconsin lead and zinc deposits. 
Geol. Soc. Am., Bull., vol. v, pp. 25-32. 
Reviews the literature on these deposits, discusses the relation of 
deformation to ore deposition, the evidences of deformation and the 
general distribution of zinc in the Silurian seas, and gives the author's 
conclusions. 
31 Trilobites in the "Oil Pock" horizon of the Trenton limestone. 
Am. Geol., vol. xiv, pp. 133-134 (correspondence). 
Mentions the occurrence of species of Ceraurus, Dalmania, Encri- 
nurus, Orthis, Murchisonia, Ortboceras, Cypricardites, Raphistoma, 
Hyolithes, Streplelasma, and encrinal stems in the Trenton limestone 
of Wisconsin. 
