weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1896. 39 
224 Foerste (Aug. F.). An account of the Middle Silurian rocks of 
Ohio and Indiana, including the Niagara and Ohio Clinton, 
and the bed at the top of the Lower Silurian strata, formerly- 
considered the Medina. 
Cm. Soc. Nat. Hist., Jour., vol. xviii, pp. 161-199, 1896. 
Describes local details of the succession of Lower and Upper Silurian 
rocks at various places in southeastern Indiana and southwestern Ohio, 
and discusses the evidences as to correct separation of these two groups 
and the correlation of the several members. 
225 Fontaine (William M.). The Potomac formation in Virginia. 
U. S. Geol. Surv., Bull., No. 145, 149 pp. 2 pis., 1896. 
Describes the character and occurrence of Potomac strata at various 
localities in Virginia and discusses the evidence as to the age of the 
formation. 
226 Notes on some Mesozoic plants from near Oroville, California. 
Am. Jour. Sci., 4th ser., vol. ii, pp. 273-275, 1896. 
Gives a list of the plants collected and discusses their bearing on the 
evidence as to the age of the deposits, which is considered to be Jurassic. 
227 Foote (H. W.). On the occurrence of pollucite, mangano-columbite, 
and microlite at Bum ford, Maine. 
Am. Jour. Sci., 4th ser., vol. i, pp. 457-461, 1896. 
Gives a brief description of the occurrence of the minerals and the 
chemical composition of pollucite. Describes the erystallographic char- 
acters of mangano-columbite and microlite. 
228 Forbes (E. H.). On the epidote from Huntington, Mass., and the 
optical properties of epidote. 
Am. Jour. Sci., 4th ser., vol. i, pp. 26-30, 1896. 
Gives the chemical analysis of the epidote and describes its erystallo- 
graphic characters. 
229 Fenfield (S. L.) and. Fayalite from Kockport, Mass., and 
on the optical properties of the chrysolite- fayalite group and 
of monticellite. 
See Penfield (S. L.) and Forbes (E. H.), No. 539. 
230 Fowke (Gerard). Pre Glacial and recent drainage channels in 
Ross County, Ohio. 
Denison Univ., Sci. Lab., Bull., vol. ix, pp. 15-24, pi. i, 1895. 
Discusses the origin of certain drainage features and gives a map of 
the region. 
231 Frazer (Persifor). Two supposed new trap dikes in Chester 
County, Pennsylvania. 
Phil. Acad. Nat. Sci., Proc, 1896, pp. 206-207, 1896. 
Remarks on the occurrence of trap dikes in Chester County. 
232 Fuller (Myron L.). A new occurrence of Carboniferous fossils in 
the Narragansett Basin. 
Boston Soc. Nat. Hist., Proc, vol. xxvii, pp. 195-199, 1896. 
Describes the lithologic character of the strata, with notes on the 
occurrence of Calamites and Sigillaria. 
