weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1895. 59 
336 Merriam (John C). Sigmogomphius lecontei, a new castoroid 
rodent from the Pliocene, near Berkeley, Cal. 
Univ. of Cal., Dept. of GeoL, Bull., vol. i, pp. 363-370. 
Gives a history of Castorkke, a description of the fossil remains col- 
lected, and a comparison with other castoroid genera, and describes 
their geologic and geographic distribution. 
330 Merrill (Frederick J. H.). The geology of natural scenery. 
Pop. Sci. Monthly, vol. xlvi, pp. 240-244. 
Describes geologic phenomena in New York and in portions of Europe. 
337 The geology of Moriah and Westport townships, Essex County, 
N. T. 
See Kemp (J.F.), No. 245. 
338 Clay industries of New York. 
SeeRies (?L), No. 398. 
339 Merrill (George P.). -The onyx marbles: their origin, composition, 
and uses, both ancient and modern. 
U. S. Nat. Mus., Rept. for 1893, pp. 539-585, pis. 1-18. 
Discusses its origin, mode of occurrence, and chemical and physical 
properties, and describes its occurrence in Arizona, California, eastern 
Appalachian region, Colorado, Utah, New Mexico, Mexico, and in foreign 
countries. 
340 On the formation of stalactites and gypsum incrustations in 
caves. 
IT. S. Nat. Mus., Proc, vol. xvii, pp. 77-81, pis. ii-v. 
Describes the formation of stalactites and incrustations in Wyandotte 
Cave, Indiana, Luray Caves, Virginia, and the Mammoth Cave, Kentucky. 
341 The formation of sandstone concretions. 
U. S. Nat. Mus., Proc, vol. xvii, pp. 87-88, pi. vi. 
Describes the formation of nodular masses of siliceous sand and iron 
disulphide in the Potomac division of the Cretaceous in the District of 
Columbia. 
342 Notes on some eruptive rocks from Gallatin, Jefferson, and 
Madison counties, Montana. 
U. S. Nat. Mus., Proc, vol. xvii, pp. 637-673. 
Describes the petrographic characters of the following rock types in 
this region : Enstatitc andesite, basalt ? (with chemical analysis), augite 
andesite, hornblende andesite, lamprophyr, porphyrite ? (with chemical 
aualysis), hypersthene andesite (with chemical analysis), diorite rhyolite, 
andesite, hornblende picrite (with chemical analysis), saxonite (harz- 
burgite) (with chemical aualysis), pyroxenite (with chemical analysis), 
diabase, liparite, pyroxenite (websterite) (with chemical analysis), dio- 
rite porphyrite, quartzose hornblende porphyrite (with chemical analy- 
sis), and lamprophyres (with chemical analyse?). 
343 Disintegration of the granitic rocks of the District of Columbia. 
Geol. Soc. Am., Bull., vol. vi, pp. 321-332, pi. 16. 
Describes the character of the rock and the extent of the disintegra- 
tion of a particular locality and gives chemical analyses of the- fresh 
rock, of that partially decomposed, and of the soil. Gives analyses of 
material separated by solvents and also mechanically separated. Dis- 
cusses the conditions affecting the results and compares them with 
analyses of material from other localities. Discusses the evidence of 
the time limit and causes of the disintegration. 
