WICOMICO COUNTY

Wicomico County, lying between Dorchester County, Maryland, and Sussex County, Delaware, on the north and Somerset and Worcester counties, Maryland, on the south, is a region of low relief. Its surface is essentially a plain but little dissected by streams and with broad, flat stream valleys. The streams are slow and considerable areas are covered with swamps. In the western part of the county there are extensive salt marshes along the Nanticoke and Wicomico rivers. The elevations range from only a few feet above sea level in the western part of the county to a maximum of 84 feet in the vicinity of Parsonsburg in the eastern central part of the county.

The geology of Wicomico County is monotonously simple, since at no point has an outcrop of any materials older than the Pleistocene been observed. The Pleistocene, however, is well developed and covers the entire county with a mantle of sands and sandy loams. Gravels are not so extensively developed as in the counties farther northward. The oldest terrace in the county is the Wicomico (named from its development on the Wicomico River in Charles and St. Mary's counties). It is delimited. below by an escarpment at an elevation of 40 feet. Lying at a lower level

than the Wicomico is the Talbot terrace which extends from the 40-foot contour line down to sea level and is broken at several levels, notably at 30 feet, by minor intra-formational scarps.

The Pleistocene deposits are underlain by the Miocene deposits, a deep well at Parsonsburg showing that the several Miocene formations extend to a depth of about 1100 feet.

SURFACE WATERS

The only large streams in the county are the Nanticoke, which forms its northwestern boundary and expands in its lower course into a broad tidal estuary; the Wicomico, which rises within the county and is navigable for steamboats as far as Salisbury in the central part of the county; and the Pocomoke, which rises in Delaware and forms the eastern boundary separating Wicomico from Worcester County. There are many creeks, such as Barren, Rewastico, and Quantico, which flow into the Nanticoke; Rockawalking, Beaverdam, Tonytank, and Passerdyke, which flow into the Wicomico; and Nassawongo, which eventually reaches the Pocomoke; but none of these are of any size or commercial importance.

The Nanticoke and Wicomico rivers are tidal and the water is consequently salt or brackish. The smaller streams are sometimes dammed for grist mills, but the waters receiving the surface drainage of inhabited areas is unsanitary and should not be used for domestic purposes.

UNDERGROUND WATERS

Artesian Waters

Under this heading will be included all of the wells in Wicomico County, since even wells in the Talbot terrace are known to flow, and many wells on the Wicomico plain have large heads, frequently sufficient to cause overflows. Several wells have been sunk beyond the lowest Pleistocene horizon but none of these wells, among which the deepest was one 402 feet at Delmar, has been able to secure good water.

The Pleistocene waters come from several different levels, but there is little variation in quality although the amount of water in the deeper wells is usually greater and more dependable.

TALBOT FORMATION.-At Clara some wells 15 feet deep were unsatisfactory because of the large amount of salt in the water. This condition may be encountered on the lower end of the peninsula between the Wicomico and Nanticoke rivers, so that it will not be prudent to use this shallowest level. At Tyaskin and Bivalve, however, the wells 10 to 15 feet deep are reported satisfactory. At Quantico the usual depth for wells is 10 to 25 feet where a suitable supply is found, and at Sharptown the Talbot wells are from 25 to 35 feet deep, the depth below tide being about 20 feet. Some of the wells at Sharptown rise to within 15 feet of the surface. The other wells from the Talbot have varying heads, all very small and some of them hardly noticeable. The quality of this water is very good so long as pollution from buildings is avoided. Iron is present only in small quantities, and with the exception of the tip of the peninsula salt will probably not be met with.

WICOMICO FORMATION.-The main water levels in the Wicomico are relatively constant, and have yielded many good flows. Typical wells are at Rockawalking, 50 feet deep with a head of 3 to 5 feet below the surface; near Melson, 60 feet deep with a head of 12 feet below the surface; at Pittsville, where wells range in depth from 15 to 60 feet, but here the water is scarce; at Willards, where the depth is 50 to 60 feet; and at Sharptown, 50 to 70 feet deep, where the head varies from below tide. several feet to 8 feet above. At this last locality there is a flowing well down within 10 feet of the bank of the Nanticoke and only 4 feet above mean tide. The flow of this well, called a "spring" by the residents, is perhaps 4 gallons per minute of water containing both iron and sulphur. At Hebron the wells are 40 to 45 feet in depth, do not flow, but have a head 20 feet below the surface; at Delmar this upper level of the Wicomico is struck at 40 to 65 feet, and although the head raises the water to within 5 feet of the surface the taste is so objectionable that usually the

wells are sunk deeper. At Salisbury this level is found from 45 to 65 feet, but since there are many wells drawing from the bed none of them flow.

The quality of the water, while not unsanitary or unpotable, is frequently unpalatable because of the occurrence of iron. This mineral is very widespread and very abundant at this horizon and is frequently accompanied by marsh gas and at Sharptown by sulphur. In some wells the amount of iron is so great that it will, on oxidation, clog up the pipes. A maxim among the well drillers in this region is, "The deeper you go, the more iron you get." This is true as between the first or Talbot level and this upper Wicomico horizon, which among the Pleistocene waters has the maximum content of iron, but the next horizon which lies at a rather uniform depth over the whole county does not show the increase in iron content that the driller's aphorism would imply.

The water at the base of the Wicomico terrace is the most widely used in Wicomico County. The wells to this horizon supply the most water in the county and the best. The depth, which varies somewhat, 80 to 100 to 120 feet, gives nearly the maximum thickness for the Pleistocene deposits in Maryland, although they are a few feet thicker along the Atlantic coast in Worcester County. In Darton's report these wells were classed as "high in Cheasapeake," but the uniformity of depth over the entire county and apparent absence of dip requires that they be referred to the Pleistocene.

The water from the base of the Pleistocene is used from wells at Whitehaven, 70 to 100 feet deep which flow several gallons a minute at an elevation of 5 feet above tide; at Mardela Springs, wells 70 to 97 feet have a head 20 feet above sea level at an elevation of 27 feet above tide; and at Delmar, where the depth ranges from 80 to 120 feet and the head is sufficient to raise the water to within 8 feet of the surface. At Salisbury there are many wells that originally flowed, some of them 25 gallons or more a minute, but there have been so many wells sunk to this horizon that the consumption has overreached the supply. The following analysis of the Salisbury Public Supply water shows a hard water which will probably incrust boilers: