310 BIBLIOGRAPHY AND CARTOGRAPHY

GANNETT, HENRY. A Dictionary of Altitudes in the United States.
(Second edit.)

Bull. U. S. Geol. Surv. No. 76, Washington, 1891.

House Misc. Doc., 52nd Cong., 1st sess., vol. xix, No. 24.

Gives the altitude of about two hundred points in Maryland.

GEIGER, H. R., and KEITH, ARTHUR. The Structure of the Blue
Ridge near Harper's Ferry. (Read Dec. 1890.)

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 155-164, plates iv and v.
(Abst.) Amer. Geol., vol. vii, 1891, p. 262.
Amer. Nat., vol. xxv, 1891, p. 658.

The authors conclude that the sandstones are not Potsdam, as previously considered,
but Upper Silurian. The paper is accompanied by geological map and sections.

JONES, JOHN H. (Spec. Agt.). Census Bulletins of the Coal In-
dustry in 1889.

Eng. and Min. Jour., vol. li, 1891, p. 238.

Contains remarks on Maryland and a table of the output from the Cumberland
region from 1870 to 1889 inclusive.

KEYES, CHARLES ROLLIN. Paleozoic fossils of Maryland.

Johns Hopkins Univ. Cir. No. 94, vol. xi, 1891, pp. 28-29.
Enumerates the fossils and type localities.

———— A Geologic Section across the Piedmont Plateau in Mary-
land.

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 319-322. (Published separately,
1890.)

(Abst.) Amer. Geol., vol. viii, 1891, p. 331.

Besides the general treatment of the structure from Washington to Catoctin Mt.
there is a very brief discussion of structure of Sugar Loaf Mt, p. 322.

KINNECUTT, L. P., and ROGERS, J. F. Fire Clay from Mount
Savage, Allegany Co., Md.

Jour. Anal, and Appl. Chem., vol. v, 1891, p. 542.

Gives analyses and mode of occurrence of the Mt. Savage fire clay (quoted in Jour.
Iron and Steel Inst., vol. i, 1892, p. 306).

LINDENKOHL, A. Notes on the submarine channel of the Hudson
river and other evidences of postglacial subsidence of the middle
Atlantic coast region.

Amer. Jour. Sci., 3rd ser., vol. xli, 1891, pp. 489-499, 18 plates.

The arguments are based on submarine topography and bathymetric contours, and
embrace many hitherto unpublished facts which point to a subsidence since glacial time
of several hundred feet (Hudson), fifty feet (Havre de Grace), eleven feet (Georgetown).

McGEE, W J The Lafayette Formation.

12th Ann. Rept. U. S. Geol. Surv., 1890-91, Washington, 1891, pp. 347-521.

A monographic study introducing a description of the coastal plain and the typical
areas of the Lafayette; a discussion of its synonymy and a development of the history
recorded in the formation.