MARYLAND GEOLOGICAL SURVEY 315

ROTHWELL, RICHARD P. Gold and Silver.

House Misc. Doc., 52nd Cong., 1st sess., vol. 1, pt. i, No. 340.

Eleventh Census, Beport on Mineral Industries, 1892, pp. 33-152.

RUSSELL, I. C. Correlation Papers—The Newark System.
Bull. U. S. Geol. Surv. No. 85, 1892.

House Misc. Doc., 52nd Cong., 1st sess., vol. xliii, No. 337.
Bibliography and areal distribution for Maryland, pp. 20-85.

SCHARF, J. THOMAS. The Natural Resources and advantages of
Maryland, being a complete description of all of the counties of the
State and the City of Baltimore. Annapolis, 1892.

This paper contains general information presented in a popular style.

SWANK, JAMES M., and BIRKINBINE, J. Iron Ores.
Mineral Kesources U. S., 1889-90, Washington, 1892.
Statistics, pp. 24, (34), 35, 36, (38), 39, 40, 41.

UHLER, P. R. Albirupean Studies.

Trans. Md. Acad. Sci., vol. i, 1890-92, pp. 185-202.

A general discussion of different areas of the " Albirupean " (between the top of the
"Variegated clays" of the Iron ores series and the bottom of the marine Cretaceous).
This formation is considered distinct in origin, deposition, extent and fossil contents.

VAN HISE, CHAS. R. Correlation Papers—Archean and Algonkian.

Bull. U. S. Geol. Surv. No. 86, 1892.

House Misc. Doc., 52nd Cong., 1st sess., vol. xliii, No. 339.

Gives a summary of the literature on Maryland pre-Cambrian, pp. 410-411. " Of the
eastern crystalline area of Maryland nothing can be said as to age, except that it is
pre-Cambrian," p. 415.

WALCOTT, C. D. The Geologist at Blue Mountain, Maryland.

Nat. Geog. Mag., vol. v, 1892, pp. 84-88.

Sci. Amer. Supp., vol. xxxvii, 1892, pp. 14,753-14,754.

———— Notes on the Cambrian Rocks of Pennsylvania and Mary-
land from the Susquehanna to the Potomac.

Amer. Jour. Sci., 3rd ser., vol. xliv, 1892, pp. 469-482.

The portion of Maryland studied lies in the Blue Ridge and Catoctin mountains
from Mechanicstown (Thurmont) to Monterey, Pa., along the W. M. R. R. and southward
to Harper's Ferry, W. Va.

WHITNEY, MILTON. Soil Investigation at Clifton.
Monthly Rept. Md. State Weather Service, vol. ii, 1892, pp. 13-15.
Many facts concerning the Maryland soils.

———— Report of the Physicist. Soil Investigations.

4th Ann. Rept. Md. Agr. Exp. Sta., 1891. Annapolis, 1892, pp. 249-296.

WILLIAMS, G. H. (Editor). Guide to Baltimore, with an account of
the Geology of its environs and three maps.