30 TflE PHYSICAL FEATURES OF ST. MARY's COUNTY' 



his geological report of St. Mary's County. This report was accompanied 

 by a map of the region prepared by John H. Alexander. This map of 

 St. Mary's County was the best that had been produced and was not ex- 

 celled until the present Geological Survey published the St. Mary's 

 County map. In the Alexander map, the topogTaphy was expressed 

 by contours and the map executed on the scale of 1 : 200,000. The promi- 

 nent points along the Bay shore and the Patuxent River were mapped 

 and named, and the little streams which drain the interior of St. Mary's 

 County were indicated. A new feature in the map was here introduced 

 in the mapping of roads, of whicli the principal ones were shown. 

 Prominent points in the topography were indicated. 



During the summer of 1845, the United States Coast and Geodetic 

 Survey began a detailed survey of Chesapeake Bay. Work was com- 

 menced first about Havre de Grace and the head of the Bay and by 1851 

 had reached as far south as Point Lookout. The Potomac and Patuxent 

 rivers were last to receive attention and the latter was not mapped until 

 1860. 



The maps, which were subsequently published, attained a very high 

 grade of workmanship. Besides the position of the shore line, they in- 

 dicated by means of numerals, the depths of water in feet and fathoms, 

 the character of the bottom and the topography of the coast for about 

 two miles back from the shore line. 



With the exception of the State map published by Martenet in 1865, 

 which has been revised from time to time, no other map work of im- 

 portance was undertaken until 1890, when the United States Geological 

 Survey began systematic topographic work in southern Maryland. In 

 that year, the coast line and the interior of St. Mary's County were sur- 

 veyed and subsequently published in eight sheets. Each one of these 

 sheets, however, included portions of territory lying outside of St. Mary's 

 County. These sheets are, beginning with the northern. Prince Fred- 

 erick, Brandywine, Drum Point, Leonardtown, Wicomico, Point Lookout, 

 Piney Point, and Montross. The cartographic work of the United 

 States Geological Survey was in advance of any which had been pre- 

 viously attempted in St. Mary's County. The quality of the work was 



