152 ARTESIAN WELLS ON THE ATLANTIC COAST. [bull. 138. 
started at an elevation of abont 150 feet, was sunk 384 feet before it 
was abandoned, and would in all probability have found water within 
the next 200 feet. 
The basal Potomac waters may also be expected along the Potomac 
Valley in this county at a fairly uniform depth of 500 feet. Other waters 
will probably be found in higher beds of this formation at less depths, 
for these waters are obtained in some of the wells in the District of 
Columbia, and at Barrow, in Virginia. The new Marlboro well found a 
fine supply of water at a depth of 215 feet, with considerable head in 
sands which are either in the Magothy beds at the base of the Severn 
formation, or near the top of the Potomac formation. This same hori- 
zon may be expected to furnish water over the entire southeastern sec- 
tion of the county at depths which increase at the rate of about 12 feet 
per mile to the south of Marlboro and decrease at the same rate to the 
north and west. There is a fair degree of probability that the basal 
Potomac waters will also be found in the same section at about 500 feet 
below the horizon of the Marlboro water. 
In the extreme southeastern corner of the county water may be 
expected at depths of from 75 to 100 feet in basal Chesapeake beds, 
and possibly also 250 feet deeper in basal Pamunkey beds. 
HARFORD COUNTY. 
The southern portion of this county, adjoining the bay, is underlain 
by the Potomac formation, at or near the base of which a large supply 
of water may probably be expected. The area is included in the wide, 
low neck lying between Bush Eiver and the head of the bay. The 
depth to the basal waters at Michaelsville is about 250 feet. Possibly 
waters may also occur at higher horizons in the formation, as they do 
in Baltimore and vicinity, but of this we have no definite knowledge 
at present. 
CECIL COUNTY. 
The basal Potomac waters underlie the portion of this county south 
of the Philadelphia, Wilmington and Baltimore Eailroad. These basal 
beds are at tide level at Elkton and at Northeast, and dip to the south- 
east at the rate of about 45 feet per mile. This dip carries them to a 
depth of about 250 feet at Chesapeake City, 500 feet on the middle por- 
tion of Bohemia Eiver, and over 600 feet in the southeastern corner of 
the county. They were found at Middletown, Del., at 535 to 552 feet. 
Water may also be looked for in higher Potomac beds at a less depth, 
but these horizons are less trustworthy. The Magothy formation, 
which passes beneath the surface along a line extending from Grove 
Point to Chesapeake City, is a water bearer which may be expected to 
furnish water east of that line. Its dip is to the southeast at a rate 
of about 20 feet per mile, which carries it to a depth of 150 feet in the 
southeastern corner of the county. It furnishes water in many of the 
dug wells of Sassafras and Bohemia Neck regions. (See PI. X.) 
