BY A. GIBB ilAlTLAND, .C.E., F.G.S. 21, 



Delaware Eiver, and also on the east and west line, extending 

 from Trenton to Woodbridge, New Jersey. These wells cannot 

 possibly draw water from the Tertiary strata, because the latter 

 are entirely absent from this belt. The wells in the Tertiary 

 region may be continued till they tap the water in the Cretaceous 

 beds, in which four distinct water-bearing horizons have been 

 proved. 



The New Jersey Cretaceous series is continuous across the 

 narrow portion of the State of Delaware, whilst the sandy series, 

 resting on Archean Rocks, passes through the City of Wilmington 

 to the north-west corner of the State, and thence into Maryland. 

 To the Cretaceous succeed the Tertiary beds, which have a low 

 •dip to the south. 



In the State of Maryland, as is the case in the two last 

 mentioned, the Cretaceous beds are divided into an upper and 

 lower series. They occur in what is known as the Coastal 

 Plain, comprising an area between the Atlantic Ocean and a line 

 passing north-east and south-west from Wilmington to Wash- 

 ington, through Baltimore. The surface of the Coastal Plain is 

 characterised by broad level-topped stretches of country, which 

 extend, with gradually increasing elevations, to its western edge, 

 where heights of 300ft. are found. 



The Lower or Potomac series rests directly upon ancient and 

 impervious crystalline rocks. It consists chiefly of sands and 

 clays, with gravels at certain localities. x\n attempt to sub- 

 divide this series into a lower sandy and an upper clayey 

 member has not been altogether successful. In the centre of 

 the State, the width of the outcrop of the Lower Cretaceous is 

 about 15 miles. The formation is continuous into the Gulf 

 Region, where it is known as the Tuscaloosa Group. 



The Upper or Severn series consists of fine sands and 

 laminated clays, and is on the whole much more argillaceous 

 than the Potomac beds. To the south of Maryland, the Upper 

 Cretaceous does not again appear at the surface until North 

 Carolina is reached, in which State, and in South Carolina as 

 well, as throughout the Gulf region, it is weU developed. 



The Potomac River crosses the catchment area of the 

 artesian water-carrying beds from Washington to Glymont for 

 about 20 miles. According to the various sections exposed, 



