MARYLAND GEOLOGICAL SURVEY 255

1840.

ALEXANDER, J. H. Report on the Manufacture of Iron addressed
to the Governor of Maryland by J. H. Alexander. Printed by order

of the Senate. Annapolis, 1840, 8vo, 369 pp., 3 plates.

Deals particularly with the Iron Industry in Maryland, and gives many analyses.

ANON. Charters of the Union Potomac Company and the Union
Company, with a description of their Coal and Iron Mines, &c. 1840.

CONRAD, T. A. Fossils of the Medial Tertiary of the United
States. No. 2. 1840. [Description on cover 1840-1842.] pp. 33-
56. Plates XVIII-XXIX.

(Repub.) by W. H. Ball, Washington, 1893.

The descriptions of many typical Maryland forms. See also 1S3S.

DUCATEL, J. T. Annual Report of the Geologist of Maryland,
1839. 8vo, 45 pp. [Annapolis, 1840.]

Md. House of Delegates, Dec. Sess., 1839.

This gives a history of the survey, and deals with the geology and physical geog-
raphy and mineral resources of Frederick and Carroll counties. Maps of northern part
of State in hachure.

LOOMIS, ELIAS. On the Variation and Dip of the Magnetic Needle
in the United States.

Amer. Jour. Sci., vol. xxxix, 1840, pp. 41-50.
Gives determinations made at Baltimore.

1841.

ALEXANDER, J. H. Trigonometrical Survey for the New Map of
Maryland. 1841. n. d. 8vo. 8pp. [Dated Feb. 2nd, 1841.]
Md. House of Delegates, Dec. Sess., 1840.

———— Trigonometrical Survey for the New Map of Maryland.
1841. n. d. 8vo. 4pp. [Dated Feb. 19, 1841.]
Md. House of Delegates, Dec. Sess., 1840.

BOOTH, J. C. Memoir of the Geological Survey of the State of
Delaware; including the application of the Geological Observations
to Agriculture. I-XI, 9-188 pp. Dover, 1841.

Part I.—General view of the Geology of the State.
Part IL—Special Geology.

Part III.—Economical Geology. This includes numerous analyses and is followed
by chapters on agriculture, arts of construction and chemical arts.

CONRAD, T. A. Description of Twenty-six new Species of Fossil
Shells discovered in the Medial Tertiary Deposits of Calvert Cliffs, Md.
Proc. Acad. Nat. Sci., Phila., vol. i, 1841, pp. 28-33.