312 BIBLIOGRAPHY AND CARTOGRAPHY

WHITNEY, MILTON. Soil Investigations.
4th Ann. Rept. Md. Agri. Exper. Sta. College Park, pp. 249-296.
General discussion of methods and a classification of the soils based on study of
samples from various parts of Maryland.

———— On the structure and Some Physical Properties of Soils.

Johns Hopkins Univ. Cir. No. 90, vol. x, 1891, pp. 123-125.
Shows that the exhaustion of soils is physical rather than chemical and that the
action of ammonia and lime affects the state of aggregation of the soils.

WILLIAMS, G. H. Administrative Report. Report of Work done
on the Piedmont Crystallines.

In McGee's Administrative Report.

11th Ann. Rept. U. S. Geol. Surv., 1889-90, part i, Washington, 1891, pp.
66-68.

———— Administrative Reports. Report of work done on the
crystalline and semi-crystalline rocks of Maryland during 1890-91.

12th Ann. Eept. U. S. Geol. Surv., 1890-91, part i, Washington, 1891, pp.
73-74.

———— Petrography and Structure of the Piedmont Plateau in
Maryland.

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 301-318, plate xii.

Covers in a general way the physiography, petrography and structure. The paper
is accompanied by geological map and sections. In the discussion following the author
mentions Triassic fossils from near Frederick and Utica Mills.

———— [On Transition of Crystalline and semi-crystalline rocks in
Maryland.]

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 223-224.

During discussion of Prof. Pumpelly's paper on " The relation of secular Rock
disintegration to certain Transitional Crystalline schists," Williams alludes to the
contact between the two series as an illustration of a contact obscured by similarity in
material and subsequent metamorphism.

———— The geological excursions by University students across the
Appalachians in May, 1891.

Johns Hopkins Univ. Cir. No. 94, vol. xi, 1891, pp. 25-27.
Gives structural and columnar sections with an Itinerary of trip.

———— Anglesite, Cerussite, and Sulphur from the Mountain View
Lead Mine, near Union Bridge, Carroll Co., Maryland.
Johns Hopkins Univ. Cir. No. 87, vol. x, 1891, pp. 73-75.
Includes brief account of surrounding geology and figures numerous crystals.

WILLIAMS, H. S. Correlation Papers—Devonian and Carbonifer-
ous.

Bull. U. S. Geol. Surv. No. 80, 1891.

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