96 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY- [bull. 162. 
843 Walcott (Charles Doolittle). Report of the Director of the U. S. 
Geological Survey for the fiscal year ending June 30, 1898. 
U. S. Geol. Surv., 19tli Ann. Rept., Pt. I, 422 pp., pis. i-ii, 1898. 
Gives a general review of the work undertaken by the Survey during 
the year 1897-98. 
844 Fossil Medusae. 
U. S. Geol., Surv., Mon. XXX, 198 pp., pis. i-xlvii, figs. 1-26; Review by 
H. S. Williams, Am. Jour. Sci., 4th ser., vol. vi, p. 509, 1898. 
Describes the occurrence and preservation of Medusse, and the char- 
acters of the forms from the Middle and Lower Cambrian, Jurassic, and 
Permian strata. 
845 Note on the brachiopod fauna of the quartzitic pebbles of the 
Carboniferous conglomerates of the Narragansett Basin, 
Rhode Island. 
Am. Jour. Sci., 4th ser., vol. vi, pp. 327-328, 1898. 
Names the Cambrian fossils found in the pebbles and discusses the 
evidence as to the locality from which the pebbles were derived. 
846 Walker (T. L.). Causes of variation in the composition of igneous 
rocks. 
Am. Jour. Sci., 4th ser., vol. vi, pp. 410-415, 1898. 
Discusses various theories on the subject. 
847 Ward (L. F.). A new fossil Eucalyptus from Kansas. 
The Plant World, vol. i, pp. 75-76, 2 figs., 1898. 
Describes Eucalyptus gouldii n. sp. 
848 Warren (C. H.). Mineralogical notes. 
Am. Jour. Sci., 4th ser., vol. vi, pp. 116-124, figs. 1-11; Review, Am. 
Geol., vol. xxii, p. 379 (£ p.), 1898. 
Describes the occurrence of melanotekite and kentrolite, pseudo- 
morphs after phenacite, crystallized tapiolite and tantalite, aod cobal- 
tiferous smithsonite. 
849 Washington (Henry S.). Solvsbergite and tinguaite from Essex 
County, Massachusetts. 
Am. Jour. Sci., 4th ser., vol. vi, pp. 176-187; Review, Am. Geol., vol. 
xxii, p. 380 (i p.), 1898. 
Describes and compares their chemical composition with that of 
material from other localities. 
850 The Jerome (Kansas) meteorite. 
Am. Jour. Sci., 4th ser., vol. v, pp. 447-454; Review, Am. Geol., vol. 
xxii, p. 377 (i p.), 1898. 
Describes the microscopic and chemical characters of the material. 
851 The petrographical province of Essex County, Massachu- 
setts. I. 
Jour, of Geol., vol. vi., pp. 787-808, 1898. 
Describes the characters of granite, akerite, nordmarkite, nepheline- 
syenite and pulaskitic syenite. Includes a number of chemical analyses. 
