MARYLAND GEOLOGICAL SURVEY 309

———— Notice of a relief map of Baltimore.

Science, vol. xvii, 1891, p. 339.

Brief description of the model now in the Geol. Laboratory of the Johns Hopkins
University.

CLARK, WM. B. Correlation papers—Eocene.

Bull. U. S. Geol. Surv. No. 83, 1891.

House Misc. Doc., 52nd Cong., 1st sess., vol. xx, No. 25.
(Abst.) Johns Hopkins Univ. Cir. No. 103, vol. xii, 1893, p. 50.
The author gives the literature and an historical discussion of the same, pp. 20-33;
characteristics of the formation, pp. 43-45, and correlation, p. 80.

———— Report on the Scientific Expedition into Southern Mary-
land. [Geology; W. B. Clark. Agriculture; Milton Whitney. Arch-
aeology; W. H. Holmes.]

Johns Hopkins Univ. Cir. No. 89, vol. x, 1891, pp. 105-109.
Describes areas previously considered, giving structural and columnar sections with
a few of the type fossils.

CLARKE, F. W. Report of work done in Division of Chemistry
and Physics, 1889-90.

Bull. U. S. Geol. Surv. No. 78, 1891.

House Misc. Doc., 52nd Cong., 1st sess., vol. xx, No. 25.

Analyses by T. M. Chatard of Websterite, and diopside from Hebbsville, p. 122.

DARTON, N. H. Mesozoic and Cenozoic Formations of Eastern
Virginia and Maryland.

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 431-450, map, sections.

(Abst.) Amer. Geol., vol. vii, 1891, p. 185.
Amer. Nat., vol. xxv, 1891, p. C58.

A general discussio'u of the different formations and the'ir type iQcalities, accom-
panied by a geological map and sections.

DAVIS, W. M. The Geological Dates of Origin of Certain Topo-
graphic Forms on the Atlantic Slope of the United States.

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 541-542, 545-586.

(Abst.) Amer. Geol., vol. viii, 1891, p. 260.

(See figs. 3 and 4 on pp. 650-561 for Cretaceous peneplain in Maryland, also neigh-
boring text). A general study of the peneplains and the Piedmont Plateau of the
Atlantic slope, in which it is maintained that the Permian and Jurassic constructional
topography of the Atlantic slope was practically obliterated over the greater part of the
area, resulting in a Cretaceous peneplain.

DOUGLAS, JAMES. The Copper Resources of the United States.
Trans. Amer. Inst. Min. Eng., vol. xix, New York, 1891, pp. 678-703.
Merely a mention of the abandoned Liberty mines.

DUNNINGTON, F. P. Distribution of Titanic Oxide upon the Sur-
face of the Earth.

Amer. Jour. Sci., 3rd ser., vol. xlii, 1891, pp. 491-495.

Percentage of titanic oxide found in a " limestone soil " from Worthington's Valley,
Baltimore county, Md. Air dried 1.17 per cent., ignited 1.26 per cent., p. 492.