SURVEY OF SPARROWS' POINT, 1891.-In May, 1891, a closely detailed topographical survey of the locality of the works of the Maryland Steel Company at Sparrows' Point, Patapsco river, and the hydrographic survey of its water-front to the Baltimore ship channel, and Bear creek to the railroad bridge, were made by Assistant J. W. Donn.

SURVEYS OF OTHER PORTIONS OF MARYLAND AND ADJACENT TERRITORY.

The following report shows in a partly tabulated form the work of the Coast Survey in other portions of the state of Maryland and the District of Columbia between the years 1832 and 1896.

TRIANGULATION.-In 1844-45-46 the primary triangulation was carried across from the Delaware Bay to the head of the Chesapeake and down to the Kent island base-line, established during this period by Assistant Edward Blunt and James Ferguson. In the latter year the work was extended to the District of Columbia, and in 1847 had reached Point No Point and Hooper's island. In 1848 the entrance of the Potomac river was included in the lines.

The secondary triangulation progressed with the primary, but incidental to topographic work was continued over the Chesapeake and its Maryland tributaries during the entire period closing with 1870. Primary triangulation was begun in 1864-65 by Assistant J. A. Sullivan, in western Maryland, as a part of the trans-continental scheme. Afterward this was continued by Assistant C. O. Boutelle. At the present time the stations Maryland Heights and Sugar Loaf Mountains are connected with the work of Chesapeake Bay and the work passing over western Virginia. The position of Rockville, Md., has also been determined as described by Assistant Edwin Smith, in Bulletin No. 25.

The map shows the primary and secondary triangulation; the tertiary work cannot well be put on, owing to the great detail, the number of lines would be confusing.

The geographic positions in Maryland, determined by the United States Coast and Geodetic Survey up to the end of 1896 number 1173. Base-lines were measured at Kent island (primary), 1844; at Sinepuxent Beach (secondary), 1853; at Port Tobacco (tertiary), 1862; at Baltimore (secondary), 1886 and (tertiary) 1894.

ASTRONOMY.-Stations were established and observations made in 1844-45-46-47 at the following primary points: Osborne's river (head of Bush river), Taylor (near Severn river), Marriott (near West river), S. Base (Kent island), Poole's island.

Astronomic latitudes were determined at the trigonometric stations: Marriott, 1846 and 1849; Taylor and Poole's island, 1847; Soper, Hill and Webb, 1850; Cumberland, 1864; Principio, 1866; Maryland Heights, 1870; Calvert, 1871; Sugar Loaf Mountain, 1879; Rockville, 1892.

Astronomic longitude was determined telegraphically at Cumberland, 1864. To this might be added Washington, D. C.

Astronomical azimuths were measured at Marriott, 1849; Soper, Hill and Webb, 1850; Davis, 1853; Principio, 1866; Maryland Heights, 1870; Calvert, 1871; Sugar Loaf Mountain, 1879.

HYPSOMETRY.-Elevations above half-tide or mean level of the ocean were determined by zenith distances at various times at stations Taylor, Linsted, Webb, Marriott, Agricultural College, Hill, Blair's House, Soper, Stabler, Sugar Loaf Mountain and Maryland Heights.

A line of spirit levels was carried from Washington, D. C., to Annapolis in 1875, published as Appendix No. 15, Report for 1889. The line of spirit levels from Sandy Hook, N. J., to St. Louis enters Maryland near Hagerstown and leaves it near Oakland, 1878, published as Appendix No. 11, Report for 1882. A third line of spirit levels was run from Hagerstown to the District of Columbia, 1883, published as Appendix No. 4, Report for 1896.

GRAVITY.—The stations where pendulum observations were made for relative gravity and, consequently, also roughly (at present) for absolute measure, are Baltimore, Johns Hopkins University, 1893, and Deer Park, 1894.

MAGNETICS.-Between the years 1845 and 1897 there were occupied 22 different stations for the determination of the magnetic declination, dip and total intensity of the magnetic force. Several of these stations were occupied more than once, see Appendix No. 11, Report for 1889, and Appendix No. 6, Report for 1885, the latter for dip and intensity. The secular variation of the magnetic force, in direction and inten

sity, has been studied for Baltimore and a number of surrounding stations available for Maryland. Appendix No. 1, Report for 1895, covers the whole period from the discovery of the country to the present time. The latest isogonic chart for the United States is given in Appendix No. 1, Report for 1896, and is for the epoch January, 1900. Isoclinic and isodynamic charts, the latter for the horizontal component of the magnetic force and for the total intensity, have likewise been constructed for the same advanced epoch.

INVESTIGATION OF OYSTER-BEDS.-The investigations were conducted by Francis Wilson, U. S. N., in Manokin river, Nanticoke river, Wicomico river, Big Annemessex river, Fishing Bay, Kedge Strait, Hooper Strait and Holland Strait. The object of this work was to determine the extent of the oyster-beds and to study the habits of the oyster, as will be seen in Appendix No. 11, Report for 1881. The examination was conducted between August 7, 1878, and October 15, 1878, in the Coast Survey schooner "Palinurus."

HYDROGRAPHY.-The work was executed by both civilians and naval officers, and includes the ocean shore as well as Chesapeake Bay and the rivers tributary to it. The area covered by this hydrography is about 2600 square miles. The number of miles of shore line is approximately 2800.

In connection with the hydrography, tidal observations were made at 113 stations, varying from two days to several months in duration, depending upon the needs of the hydrographic party.

TOPOGRAPHICAL SHEETS WITHIN BOUNDARIES OF THE STATE OF

MARYLAND.

ON FILE IN THE ARCHIVES OF THE U. S. COAST AND GEODETIC SURVEY, GEOGRAPHICALLY ARRANGED, GIVING NUMBER OF SHEET, LOCALITY OF SURVEY, SCALE, TOPOGRAPHER AND DATE.