MARYLAND GEOLOGICAL SURVEY 329

———— The Potomac River Section of the Middle Atlantic Coast
Eocene.

Amer. Jour. Sci., 4th ser., vol. i, 1S96, pp. 365-374.

The middle Atlantic coast phase of the Eocene constitutes a single geologic unit of
very homogeneous character, representing the major part of the " Lignitic," " Buhr-
stone," and " Claiborne " of Smith. Two well-defined faunas are described: the " Aquia
Creek " and the " Woodstock."

DARTON, N. H. Artesian Well Prospects in the Atlantic Coastal
Plain Region.

Bull. U. S. Geol. Surv. No. 138, 1896, 22S pp., 19 plates.
House Misc. Doc., 54th Cong., 2nd sess., vol. —, No. 28.
Considerable detailed local Information. Md. ref. 22, 124-155.

———— domini Folio, Explanatory sheets.

U. S. Geol. Surv., Geol. Atlas, folio 23, Washington, 1896.

Brief epitomized account of the geology of the " quadrangle " studied.

DARTON, N. H., and TAFF, JOSEPH. Piedmont Folio, Explanatory
sheets.

U. S. Geol. Surv., Geol. Atlas, folio 28, Washington, 1896.

Epitomized account of the geology, structure and economic resources of the " quad-
rangle " studied.

DAY, D. T. Minor Minerals of the United States.

Eng. Mag., vol. xi, 1896, pp. 299 and 504.

DORSEY, CLARENCE W. The Soils of the Hagerstown Valley.
Md. Agr. Exp. Sta. Bull. No. 44, College Park, 1896.

A study of the soils resulting from the disintegration of the Cambrian sandstone,
Hudson River shales and Trenton limestones. Distinguishes five types.

FONTAINE, WM. M. The Potomac Formation in Virginia.

Bull. U. S. Geol. Surv. No. 145, 1896, 149 pp., plates.
House Misc. Doc., 54th Cong., 2nd sess., vol. —, No. 35.

GILBERT, G. K. Age of the Potomac Formation.
Science, n. s. vol. iv, 1896, pp. 875-877.

Reviews Professor Marsh's article on the Jurassic formations of the Atlantic Coast
and points out certain discrepancies.

HILL, R. T. A Question of Classification.
Science, n. s., vol. iv, 1896, pp. 918-922.
Regards the Potomac group as Cretaceous.

KEYES, C. R. Central Maryland Granites.

Stone, vol. xiii, 1896, pp. 421-428 seq.

This is the paper published in the 15th Ann. Rept. U. S. Geol. Surv. in somewhat
condensed form.