darton.] MARYLAND. 149 
are several strata of water in higher beds in the Potomac, and in other 
formations at more moderate depths. The easternmost successful 
wells which have reached the base of the Potomac formation are those 
in the southeastern portion of the Baltimore region, in the District of 
Columbia, and at Middletown, in Delaware, all of which are only a few 
miles from the outcrop of the formation, so that the eastern extension 
of the basal Potomac waters is not known over a very great breadth 
of territory. The failure of the well at Sparrow Point to find water in 
the basal beds indicates also that the sheet of water is not general at 
this horizon. 
The water horizons at various distances above the basal beds, but 
lying within the Potomac formation, have been extensively explored in 
the vicinity of Washington and Baltimore, where they appear to be 
widespread and satisfactorily productive. They have also been reached 
in the Marlboro well at a depth of 216 feet, and in the Indian Head well 
at 459 feet. The well at Bowie found no satisfactory supply of water 
to within about 200 feet of the base of the formation, nor was the well 
on Spesutie Island a success, though it appears to have penetrated the 
Potomac beds to a considerable distance. The sands of the Magothy 
formation, which underlie the Potomac formation, appear to be water 
bearers over a wide area on the Eastern Shore of Maryland, as prob- 
ably indicated by the wells at Claiborne, Tilghman Island, and Cris- 
field, and possibly also at Tunis Mills. They underlie the central area of 
the Western Shore southeast of a line from Bowie to the mouth of the 
Patapsco Biver, but do not appear to yield water in Marlboro, Annap- 
olis, and Bay Bidge wells. The boring to 600 feet at Easton, unfortu- 
nately, probably did not thoroughly test this horizon, otherwise we might 
have had some important evidence for thatx^ortion of the Eastern Shore 
region. The 265-foot well on Miles Biver Neck appears to draw its 
water from a horizon in the Pamunkey formation, but this well is the 
only indication of a water horizon in these formations in the Eastern 
Shore region. In the wells at Colonial Beach, Va., and in the wells at 
Nanjemoy, Chapel Point, and Bock Point, in Charles County, the basal 
Pamunkey beds yield water which probably underlies much of southern 
Maryland southeast of a line from Herring Bay to Liverpool Point. 
The basal Chesapeake water horizon, which is well explored in Vir- 
ginia, yields water over a wide area in the southern counties of the 
western shore at depths from 200 to 300 feet, as in the wells at Sol- 
omons Island, Leonardtown, Piney Point, St. Inigoes, and St. Georges 
Island. At Cornfield Harbor it is 365 feet. This horizon also furnishes 
large water supplies at Denton, Cambridge, and LeConrpts Store, and 
possibly in the well to 195 feet on Miles Biver Neck, on the Eastern Shore. 
It was not found at Crisfield, nor in the deeper boring at Easton, 
although the asscoiated sandstone bed was reported at Easton. Its 
probable area is shown on the map (PI. V) by a separate color, which 
comprises also the higher Chesapeake horizons to the south and east. 
These higher Chesapeake horizons are important in New Jersey and 
