sulphurous, or both. By observation, however, these minerals are shown to be rather limited in distribution. An analysis of the water from the well at the Court House in Marlboro shows a hard water, but the amount of iron is very small and the only sulphur present is in the form of sulphates. The analysis follows: A comparison of this analysis with that of the water from the Easton well, which is also down to the Magothy level, shows that there is only a slight increase in mineralization with depth, and in the Easton water, also, the quantities of iron and sulphur are small enough to be unnoticed. The Magothy water then, at least in Prince George's County, will be a palatable, unobjectionable drinking water, and when used in boilers the soft scale which it will deposit can readily be removed by boiler compounds. Another well in Marlboro 160 feet deep has struck water that is reported to come from a "hard rock" bed, probably the same as that at 185 to 190 feet in Darton's section. The water is soft and stands down in the pipe at a distance of 20 feet or more, although the level is very little higher than that of the other wells in the vicinity. The low head together with the fact that none of the other five or six wells. which have been drilled in the neighborhood have reported any water bed higher than the Magothy makes it appear improbable that this well has struck any other definite horizon. More likely the water is an upward seepage from a lower level. The rapidly intergrading clays and sands of the Lower Cretaceous formation form excellent traps for underground water, but because of this very rapidity of change in lithology these small horizons cannot be traced even short distances. Locally, however, they have been proven for large yields, the most important in this county being in the valley of the Eastern Branch, northeast of the District line. Beside these restricted water veins there are in the Lower Cretaceous two other levels that have been explored in a belt along the northwestern and western edge of the county where the deposits do not lie too far below the surface. The deepest of these, the basal Patuxent, is tapped from Laurel southwest to the District of Columbia. The other level which is in the Patapsco formation supplies only four wells, three of which can be correlated with one another, while the fourth, at Fort Washington, is at the site of a deeper well which, because of its interesting revelations, makes inadvisable a close correlation of the 260-foot well with the other Patapsco wells of the county. Around Baltimore and south of Anne Arundel County the Patapsco yielded water in large quantities, and although this particular horizon has not been very extensively used in Prince George's County, the few wells that have been sunk to it have reported a plentiful supply of good water. The water at the base of the Patuxent, or the water which flows along the crystallines, as it is sometimes denominated, has been reached only in wells northeast of the District line. A well west of the Baltimore and Ohio Railroad station at Hyattsville was drilled 206 feet and struck water in a coarse sand. A comparison of the log of this Hyattsville well with that of a well at the Maryland Agricultural College shows interesting parallels. WELL AT HYATTSVILLE. MR. WM. M. LEWIN'S PROPERTY The water from this sand bed rose to within 15 feet of the surface. Blue clay with streaks of sand bearing considerable water (quite irony) .... .126-145 Hard gneiss rock at which depth well was abandoned. No water found in the rock formations... ...209-284 The well mouth at the Agricultural College is 145 feet above sea level and is about 2 miles up the dip from the Hyattsville well, which is at an elevation of 30 feet above sea level. Since the Agricultural College well struck the blue clay with sand at 128 to 145 feet and the Hyattsville well struck the same bed at 188 to 300 feet, the corrections for elevation give a dip of just about 100 feet to the mile for the basal Cretaceous beds at this point. Other wells at Hyattsville, notably those that supply the town with water, have entered the basal Patuxent water at depths of near 250 feet. These wells have a slight flow, 4 to 6 gallons per minute, if the well top is within 30 feet of tide. The municipal supply at Hyattsville is obtained from six wells located in the Anacostia Valley at approximately 20 feet above sea level. Four are 242 feet deep, two being 8 inches and two 2 inches in diameter, one is 218 feet deep and 6 inches in diameter, and one is 212 feet deep and 6 inches in diameter. The wells are about 50 feet apart, and in 1908 when first pumped they yielded 136 gallons per minute. Since that date the yield has decreased to 80 gallons per minute. Since the experience at Hyattsville illustrates conditions in the Lower Cretaceous all along the inner margin of the Coastal Plain from Wilmington to Washington it merits some discussion. While pumping tends to clog the strainers with sand which can be temporarily cleared by the various methods of back flushing, tests show that there is free connection and interference among the wells, heavy pumping of one lowering the capacity and head of the others. There are two ways to obviate this. Wells tapping the same water horizon should be at least 300 feet apart. They should be located in a direction at right angles to the flow of the underground water. Here and along the Coastal Plain border throughout Maryland the catchment area is only a few miles away and the water is flowing toward the southeast. Batteries of wells should therefore be in a northeast-southwest line. The following section is of a well near Muirkirk. This section is unaccompanied by any data regarding diameter, owner, water, etc., but the depth to the basement rocks is definitely shown, as well as some of the weathered crystallines. In this well the Patuxent formation extends from near the surface to a depth of about 123 feet, and the basal bed consists of a pink pebbly sand 5 feet in thickness. Beneath this is a light-yellow micaceous sand which evidently represents a weathering product of the underlying crystalline rock. A well at the Experiment Station of the U. S. Department of Agriculture, 1 mile east of Beltsville, struck water at a depth of 323 feet. The altitude of the well mouth is around 200 feet and the water is reported to stand 180 feet down in the pipe. This well yields a large quantity of good water, slightly alkaline, and the engineer states that he can pump the well 50 gallons a minute for 24 hours and not lower the water appreciably. These wells which draw from the water vein at the base of the Patuxent add a little more evidence to that already collected at the outcrops regarding the dip of this old sea floor. The Maryland Agricultural College well compared with that at Hyattsville shows that at that point the crystallines dip at the rate of a little more than 100 feet to the mile. A little farther north the Muirkirk well definitely establishes the thickness of the Patuxent at that point, and this depth, when corrected and applied to the Experiment Station well, gives an inclination each mile of a little less than 100 feet. Throughout the greater part of Prince George's County the Patuxent will be too far below the surface to be of use. A deep well prospecting for oil about 1 mile south of Meadows had not passed through the Patuxent at a depth of 1522 feet. The following log was compiled by N. H. Darton from samples received by the U. S. Geological Survey. From the depth of this well it would seem that the steep declination of the crystalline floor does not diminish greatly in Prince George's County. Fine to coarse grayish sand with yellow red and dark-greenish clay. Glauconite and shell fragments... 48-108 .... ..... Dark sandy micaceous clay, not limy.. 108-120 ... 120-126 ..... 126-136 ..... Medium fine dark-green clayey sand and limy clay, containing a glauconite, a greensand marl...... 136-148 ...... Red pebbly clay and a medium to coarse greenish sand containing glauconite 148-159 Shell fragments, with a little coarse sand and glauconite.. ...159-189 Rock and sand, no sample.... 189-192 Fine to medium greenish-gray limy sand, contains much glauconite and a few shell fragments... 192-200 Soft rock, no sample..... 200-202 Medium to fine dark-green limy and clayey sand, much glauconite and a few shell fragments.. 202-220 Hard rock, no sample..... 220-223 Coarse gray and yellowish sand with a little pink and a little dark greenish clay, some glauconite and shell fragments.... 223-263 Coarse grayish sand and fine gravel, with shell fragments and a little glauconite 263-350 .... |