80 HISTORICAL SKETCH

adjacent states. As Maryland is often mentioned in these publica-
tions, they have been referred to in the bibliography of the state.

The work of Dr. T. A. Conrad¹ of the Philadelphia Academy of
Natural Sciences deserves especial mention. His publications deal
entirely with the Tertiary fossils of eastern and southern Maryland,
many articles appearing between the years 1862-67. Professors
Joseph Leidy and Edward D. Cope, ² colleagues of Dr. Conrad in Phila-
delphia, made several contributions to Maryland geology during this
time, the latter describing in several papers the vertebrate fauna of the
Miocene period in Maryland and Virginia.

During these years Professor James Hall of Albany, New York,
continued his elaborate study of the Paleozoic fossils of the eastern
border region, investigating among other forms large collections of
Maryland fossils which had come into his possession. Numerous
descriptions and figures of these forms are given in the reports of the
State Geological Survey of New York.

Just after the close of the war there began to be renewed activity
in the development of Maryland resources, and a few articles of an
economic character appeared already prior to 1870. In 1871 Credner, ³
Harden ⁴ and Tyson ⁵ discussed the coal and iron deposits of the west-
ern portion of the state, and the same year Professor N. S. Shaler
describes in two articles the physical features of the Middle Atlantic
slope, in which the origin of the Delaware and Chesapeake bays is
considered.

The appointment of commissioners on the part of the states of
Maryland and Virginia to ascertain the boundary line between those
states led to the publication in 1873-74 of official reports regard-

¹ Proc. Acad. Nat. Sci., Phila., vol. xiv, 1862, pp. 559-582, 583-586; vol. xvi,
1864, pp. 211-214; vol. xvii, 1865, pp. 70-73; Amer. Jour. Conch., vol. i, 1865,
pp. 1-35, pp. 210-212; vol. ii, 1866, pp. 65-74; vol. iii, 1867, pp. 257-270; Smith.
Misc. Coll., vol. vii, Art. 6, 1866, pp. 41.

² Proc. Acad. Nat. Sci., Phila., vol. xix, 1867, pp. 138-156; vol. xx, pp.
184-194.

³ Petermann's Mittheil., vol. xvii, pp. 41-50.
⁴ Trans. Amer. Inst. Min. Eng., vol. i, pp. 136-144.
⁵ Proc. Amer. Phil. Soc., Phila., vol. ix, pp. 9-13.