30 THE PHYSICAL FEATUEES OF CALVERT COUNTY 



shore was an improvement on that of Herrman, but the shore line of the 

 Patuxent Eiver was considerably generalized. There was additional in- 

 formation regarding the small streams which drain the surface of the 

 region and many of the localities which occur on the most recent maps 

 were indicated. 



A marked advance in the cartography of this region occurred in 1836, 

 when Prof. J. T. Ducatel, then State Geologist of ]\Iaryland, published 

 his geological report of Calvert County. This report was accompanied 

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

 Calvert County was the best that had been produced and was not ex- 

 celled until the present Geological Survey published the Calvert County 

 map. In the Alexander map, the topography was expressed by hachure 

 and the map executed on the scale of 1 : 150,000. The prominent points 

 along the Bay shore and the Patuxent Eiver were mapped and named, and 

 the little streams which drain the interior of Calvert County were indi- 

 cated. A new feature in the map was here introduced in the 

 mapping of roads, of which the principal ones were shown. Prominent 

 points in the topography, such as Hollin Cliff, Flag Pond, Drum Point, 

 etc., 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 



