124" ARTESIAN WELLS ON THE ATLANTIC COAST. [bull. 138. 
WELL PROSPECTS IN DELAWARE. 
From the evidence of wells now yielding water supplies, it appears 
probable that the entire Coastal Plain area of Delaware is underlain by 
waters, and in the map, PI. Y, it is so represented. About Middletown 
and northward the Potomac waters are to be expected at depths which 
decrease at the rate of 30 feet per mile nearly to Wilmington, where the 
Potomac beds come to the surface. These waters may extend down the 
dip south from Middletown for many miles, but as no wells have been 
bored to them in that direction no positive prediction can now be made. 
At Dover they should be expected at about 1,000 feet below the surface, 
of the dip continues south at a uniform rate. 
The Chesapeake waters begin a couple of miles north of Clayton and 
extend to the southern border of the State. The basal Chesapeake 
waters, which are important sources of supply in Maryland and south- 
ward, have not been tested by any wells in Delaware, but I should 
expect them to extend over a wide area. The Clayton boring to 150 
feet nearly reached this horizon, and it lies about 450 feet below the 
surface at Dover. The Dover waters no doubt are widespread, for they 
are probably the same as those found at 234 feet at Federalsburg. The 
water horizon which appears to extend from Milford to Lewes probably 
also underlies all of eastern Sussex County, but it is not reported in 
any of the Maryland wells. In both Kent and Sussex counties there 
are almost certain prosi:>eets for Chesapeake waters at one horizon or 
another within 500 feet of the surface. The sections 1 and 2, PI. VI, 
show the conditions so far as there are any data to present concerning 
them. 
MARYLAND. 
GEOLOGIC RELATIONS. 
The Coastal Plain region in Eastern Maryland presents the usual 
general structural relations, but certain local features are conspicuous. 
The Paritan formation merges down into the Potomac formation; the 
upper marl of the marine Cretaceous thins and changes to more clayey 
beds, and only the middle and lower members continue southward, 
where they have been designated the Severn formation; thePamunkey 
greensand marls come in, and the plateau areas capped by the Lafay- 
ette formation become characteristic features. The general structural 
relations are shown in sections 2 and 3, PI. VII. The formations are 
as follows: 
Formation. Characteristics. Age. 
* • f 
.2 a ■> Columbia. Loams, sands, and gravels on terraces. 
S°l 
£ © | Lafayette. Gravels, sands, and loams. Pliocene! 
h£ © j Cbesapeake. Sands, clays, infusorial earth, and marl. Miocene. 
