MARYLAND GEOLOGICAL SURVEY 251

JOHNSON, WM. COST. Report of the Hon. Wm. Cost Johnson to
Congress.

House Misc. Doc., 26 Cong., No. 168, Washington, 1836.

PURVIS, M. On the use of Lime as a Manure.

Translated for Farmer's Kegister, Shellbanks, Va., 1835.

(Rev.) Amer. Jour. Sci., vol. xxx, 1836, pp. 138-163.

Reference to the occurrence of the greeusand formations in Maryland, p. 160.

1837.
ALEXANDER, J. H.

(See Ducatel and Alexander.)

BACHE, A. D., and COURTENAY, E. H. Observations to determine
the magnetic dip at Baltimore, Philadelphia, New York, West Point,
Providence, Springfield, and Albany. (Read before Amer. Phil. Soc.,
Nov. 7, 1834.)

Trans. Amer. Phil. Soc., n. s. vol. v, 1837, pp. 209-211.

Observations taken opposite Holliday Street Theater in July, 1834, give mean dip
70° 08.6'.

DUCATEL, J. T. Outline of the Physical Geography of Maryland,
embracing its prominent Geological Features.

Trans. Md. Acad. Sci. and Lit., vol. ii, 1837, pp. 24-54, with map.
General discussion with many local features and details.

DUCATEL, J. T., and ALEXANDER, J. H. Report on the New Map
of Maryland, 1836. 8vo, 104 pp. and 5 maps. [Annapolis, 1837.]

Md. House of Delegates, Sess. Dec., 1836.

Another edition, 117 pp.

Report of the geologist deals with the geology of Frostburg and of Calvert, Anne
Arundel, St. Mary's, Charles and Prince George's counties. Several maps and sections
in black and white (pp. 1-60).

Engineer's report includes several small maps and their explanation, together with
estimates on the location of certain canals and railroads (pp. 61-104).

ELDREDGE, N. T. Report of the Special Agent sent to examine
the Mines of the Company, sm. 8vo, 13 pp. New York, 1837.

This is a report to the Boston and New York Coal Company, which is usually
appended to the " Charters and By-Laws." It contains considerable information
regarding the coal and iron deposits. There are opinions quoted. One analysis of the
coal and 15 of the iron are given.

HUMPHREYS, H. The Latitude of Annapolis.

Trans. Md. Acad. Sci. and Lit., vol. i, part 1, 1837, pp. 135-137.

Notices some variations in compass needle and barometer during auroral displays
of January 25, April 3 and 21 and 24, 1837. Also gives the magnetic variation at
Annapolis; needle set up on the college green, St. John's College, as beiug 2° 4l' west.
Latitude is determined as 38° 58' 35.617" north.