300 BIBLIOGRAPHY AND CARTOGRAPHY

BODFISH, D. H. On the new Topographical Map of Baltimore and
vicinity.

Johns Hopkins Univ. Cir. No. 65, vol. vii, 1888, p. 72.
Letter describing map.

CLARK, WM. B. On three Geological Excursions made during the
months of October and November, 1887, into the southern counties of
Maryland.

Johns Hopkins Univ. Cir. No. 63, vol. vii, 1888, pp. 65-67.

Stratigraphic description and lists of fossils.

———— Geology of Eastern Maryland.
Johns Hopkins Univ. Cir. No. 65, vol. vii, 1888, p. 73.

Abstract of lecture showing that there is no proof of the deposition of sediment
prior to Middle Mesozoic time, to the east of the Archean belt.

DAY, D. T. (Editor). Infusorial Earth.
Mineral Resources U. S., 1887, Washington, 1888, p. 554.

Analysis of Infusorial earth from Pope's Creek made by P. de P. Ricketts of New
Fork.

———— Useful Minerals of the United States.

Idem, pp. 739-742.

Gives list of economic minerals and their occurrence and workings.

DAY, WM. C. Structural Materials.
Idem.

Statistics of the granite Industry for 1887, p. 515; marble, p. 518; slate, p. 524; lime,
p. 533; brick, pp. 536-538. Quarry opened at Guilford by Messrs. Smith & Johnson, p. 515.

GILBERT, G. K. Administrative Reports. Geologic and Paleon-
tologic Investigations.

7th Ann. Rept. U. S. Geol. Surv., 1885-86, Washington, 1886, p. 67.

HALL, JAMES, and CLARKE, J. M. Paleontology, vol. vii. Text
and Plates containing descriptions of the Trilobites and other Crust-
acea of the Oriskany, Upper Helderberg, Hamilton, Portage, Che-
mung and Catskill Groups. Geological Survey New York. Albany,

1888.

Description and figures of numerous forms from Cumberland and vicinity.

HOBBS, WILLIAM H. On the rocks occurring in the neighborhood
of Ilchester, Howard county, Maryland; Being a detailed study of the
area comprised in sheet No. 16 of the Johns Hopkins University map.

Johns Hopkins Univ. Cir. No. 65, vol. vii, 1888, pp. 69-70.

(Abst.) Amer. Nat,, vol. xxii, 1888, p. 527.

Describes hypesthene gabbros, gabbro-diorite, and hornblende gneiss as a series due
to progressive metamorphism; pyroxenltes changing to talc and serpentine; granite
porphyry carrying allanite-epidote.