most of the water comes from the base of the Wicomico. The Wicomico has a much larger surface exposure and hence contains more water. The common depth for shallow wells is from 15 to 30 feet and usually the water is of good quality, but local pollution by inhabitants or by drainage from some of the numerous swamps may render the water unfit for use or impart a disagreeable marshy taste or odor. At Federalsburg and at several other points the shallow water contains iron which is in the form of a colloidal hydrate, especially noticeable if a vessel of water is left standing for some time.

The shallow wells commonly supply enough water for household or farm uses and occasionally two or three such wells will furnish enough water for a canning factory. At Preston the usual depth for wells is 45 feet, the water being reported from a coarse yellow sand. This is the maximum depth for Pleistocene water in this county. The most widespread type is the dug well, so common during the early history of the region, but in many localities this type is being replaced by wells constructed by driving a pipe of small diameter into the ground. In some places the driven wells draw from the same water horizons as the shallow wells, but locally they reach deeper water-bearing beds. The driven well is generally superior to the dug well because the casing is better adapted for excluding impure surface waters.

TALBOT COUNTY

Talbot, lying between Queen Anne's on the north, Caroline on the east and south, and Chesapeake Bay on the west, is centrally located on the Eastern Shore. It is a region of low relief, no part rising above 65 feet above sea level. The streams are tidal estuaries and the surface is but little dissected by erosion and is consequently a gently undulating, broad, flat, fertile plain.

GEOLOGY

The surface of the county consists almost entirely of the two latest Pleistocene terrace plains, the Wicomico occupying the eastern half of the county and lying at an altitude of from 40 to 60 feet. This is separated from the lower-lying Talbot plain, which occupies the western half of the

county, by an escarpment or steep slope extending in a north and south. direction from Wye Mills to near Chancellor Point on the Choptank River. Beneath these surficial formations of loam, sand, and gravel are the Choptank and Calvert formations of the Miocene. These outcrop in limited areas in the stream valleys and comprise clays, sands, and marls. These are in turn underlain by the Eocene which is an important water horizon but does not reach the surface on the Eastern Shore south of Kent County. The Eocene is in turn underlain by the deeply buried formations of the Cretaceous.

The surface streams of Talbot County are not important sources of supply because the large streams are all tidal and either salt or brackish, and the small streams contain very little water in dry weather. The streams all receive drainage from inhabited areas and are of doubtful sanitary character. The conditions enumerated have prevented the use of surface water and there is no prospect of its future development.

UNDERGROUND WATERS

Artesian Waters

Attempts to procure artesian water in Talbot County have been uniformly successful, but flowing wells have been obtained only where the surface is less than 20 feet above sea level. The deepest artesian well in the

county is the 1015-foot well at the Easton Water Works, and the shallowest is a 29-foot well at Copperville. This well is discussed by Miller,' who believes that " although the well was not driven below the Pleistocene deposits the water probably comes from a greater depth and finds its way to the base of the pipe through some deep-seated fissure in the Calvert strata." The flow of the well is very small and the water is highly charged with iron, a feature not usual with the Calvert waters, but which has probably been acquired in this case through the passage of the water through the Pleistocene gravels.

The Miocene deposits are represented in this county by the Choptank formation which outcrops in some of the stream beds in the southern part of the county, and by the Calvert formation which is seen at the surface at a few places in the northern part along Wye River and its tributaries. The Choptank formation is not important as a water-bearing horizon, but the Calvert water has long been known and utilized. This water is soft and very good. An analysis of the water from the 135-foot wells at Easton is given on a subsequent page. The Calvert water levels are incapable of as close correlation as in the neighboring counties due to the horizontal gradation of the materials. The Calvert wells vary in depth from 166 to 195 feet. A well at Cordova, about 40 feet above sea level, is 116 feet deep with the water within 8 feet of the surface. At Easton the Calvert long supplied the city with its water, the water bed being reached at 104 to 135 feet. These wells all flowed originally, but when the deep well was sunk the water in the shallower wells fell to 10 feet and would furnish no water while the 10-inch well was being pumped.

Two wells at Grubin Neck, 160 and 186 feet deep, draw from the Calvert horizon but do not flow, and at Windy Hill a well 180 feet deep has a small flow of water from the same stratum.

Two horizons have been recognized in the Eocene, one at the base of the Aquia and one at or below the base of the Nanjemoy. The basal Aquia water is in use at only three localities, while the Nanjemoy wells are more scattered.

1 Miller, B. L. Geologic Atlas of the U. S., U. S. Geol. Survey, Choptank Folio No. 182, 1912, p. 8.

AQUIA. The well at "The Anchorage," 265 feet deep, which has a small flow of hard water, and two other wells on Miles River Neck, 255 and 272 feet deep, which yield hard water but do not flow, are the shallowest wells in the county that draw from the Aquia water. At Oxford the basal Eocene water is 350 feet deep, hard, with no flows, and at Barkers Landing on the Choptank River the water is at a depth of 370 feet, is hard and rises to within 8 feet of the surface.

NANJEMOY.-The 195-foot well on Long Point reported by Darton (Bull. U. S. Geol. Survey No. 138, p. 133) and assigned by him to the Calvert level is probably Nanjemoy. More information concerning this well than that given by Darton could not be obtained.

About 2 miles directly south of the Long Point well a boring at Royal Oak 224 feet deep found water which was in a dark sand underneath a sand rock. The water is hard and slightly turbid, both qualities which are fairly constant in the Eocene water.

About 3 miles west of Easton a well was drilled on Dr. Nickerson's property to a depth of 297 feet in which the water in use was encountered in a bed of sand and gravel that was 48 feet thick, according to the following log supplied by the driller:

There are two wells at Trappe, 375 and 400 feet deep, and another one about 1 mile west, 311 feet deep, reaching hard water that stands at -14, -46, and 15 feet respectively. By the character of the water and the low head it would seem to be from the Eocene beds, but the shoal depths at which the water is reached operates somewhat against such a con

clusion. It may be suggested here that the upper member of the Eocene is at this point making its first appearance on the Eastern Shore, nowhere cropping at the surface. This suggestion finds support in a slight thickness of clay and sand shown in the log of the Easton well, which has been referred to the Nanjemoy. It does not seem likely that the Calvert has as great a thickness as is demanded by the reference of these wells of that horizon. In the Choptank folio (loc. cit.) Miller gives contours for the Eocene water level and states that the main stream is probably at the base of the Nanjemoy formation. This does not seem to be the position occupied by the main stream in this county since the main stream is thought to be that which supplies St. Michaels at 260 feet, Miles River Neck at 255 to 270 feet, and Oxford at 380 feet, with a distant well at Barkers Landing 370 feet deep. The wells at Royal Oak 224 feet, west of Easton 249 feet deep, and near Trappe 311, 375, and 400 feet (the latter two are at an elevation of 50 to 65 feet, the 311-foot well at 20 feet, and all the others at less than 10 feet) are thought to be at the base of the Nanjemoy. This is the level which becomes important across the river in Dorchester County and is about 75 feet above the lower water level of the Eocene. These are exactly the same relations as were observed in Caroline County, where at Denton the first Eocene stream is encountered at 270 feet and the second at 350 feet below sea level.

The wells drawing from Upper Cretaceous streams fall into two classes: First, the numerous wells on Tilghman Island near Sherwood and near McDaniel around 340 to 400 feet in depth; second, the wells at Claiborne and Tunis, 440 and 486 feet deep respectively, and also the 1015-foot well at the Easton Water Works.

The wells of the first group draw from one of the best streams in the Upper Cretaceous, barring the Magothy, and the horizon is thought to be the upper part of the Matawan. A log of a well on Tilghman Island, 380 feet deep, is given below.'

1 Fuller, M. L., and Sanford, Samuel. Record of Deep-Well Drilling for 1905, U. S. Geol. Survey, Bull. No. 298, pp. 233, 234.