red and gray sandstones and easily-eroded shales of the Newark formation, Triassic in age. It is the former which weathers to the heavy reddish lands that make the excellent farming lands for which the Frederick and Hagerstown valleys are famous.

Catoctin Mountain consists of Weverton quartzite which forms the cap rock that has prevented it weathering down to the general level. There are lesser exposures of Harpers shale and Loudon slates, limestones, shales, and sandstones. These are all ancient sedimentary rocks of Cambrian age. From Catoctin Mountain to the Blue Ridge the underlying rocks are igneous rocks, highly crystalline, and comprising granites, gneisses, and acid volcanics.

SURFACE WATERS

Small streams are well distributed throughout the county, but because of the dangers of contamination are not available for potable supplies unless the water is taken near their sources in thinly settled uplands like Catoctin Mountain, although they furnish small water powers that are utilized for local milling operations. The Potomac, which forms the southern boundary of the county, carries large amounts of water. While not available for domestic purposes without scientific filtration it furnishes a large amount of power which is practically not utilized. As measured at Point of Rocks, the mean annual flow from 1897 to 1906 was 10,575 second-feet per day. Measuring the horsepower at 80 per cent efficiency per foot of fall this would mean about 1000 horsepower per foot of fall.

The only large stream within the county is the Monocacy River which rises in Adams County, Pennsylvania, and flows southward to the Potomac in the Frederick Valley which is sometimes called the Monocacy Valley. The water is not suitable for public supplies because of more or less pollution. The flow as measured over a period of 10 years at Mount Pleasant, 4 miles northeast of Frederick, gives a mean annual discharge of 1130 second-feet a day.

UNDERGROUND WATERS

Artesian Waters

Because of the essentially agricultural occupation of the residents of Frederick County and the consequently thinly settled condition throughout most of the county, together with the abundance of springs and the ease with which water is obtained from shallow dug wells, the demand for artesian water has been slight. Consequently but few artesian wells have been put down, even large towns like Frederick relying largely on springs and streams on Catoctin Mountain for their municipal supplies. The Frederick authorities have drilled two deep wells, 996 and 1140 feet deep, in the Shenandoah limestone, about 4 miles west of the town, without striking very productive underground horizons, the yield being reported as 70 gallons per minute from the two. Other towns in the county that derive their supplies from wells are Blue Ridge Summit, which is just over the border in Pennsylvania, Braddock Heights, and Brunswick. At Blue Ridge Summit two wells, 100 and 312 feet deep, yield respectively 50 and 40 gallons per minute. At Braddock Heights an 8-inch well was drilled to a depth of 510 feet. At about 200 feet water was struck and rose to within 15 feet of the surface. The amount was small, however, the yield being but 10 gallons per minute.

Water seems to be more readily obtainable in the Triassic area in the western part of the county. The town of Brunswick utilizes a 315-foot well which pumps 100 gallons per minute, the water heading within 5 feet of the surface. There are a number of wells at Frederick, but with the exception of those mentioned none are of great depth and the yields are generally small and the water, as might be expected in a limestone country, is hard. The Frederick Abattoir Company has put down two wells, one 96 feet and the other 123 feet, and both furnish considerable water. The 96-foot well, which is 8 inches in diameter, heads 20 feet below the surface and pumps 100 gallons per minute. The 123-foot well, which is 4 inches in diameter, heads 70 feet below the surface and pumps 60 gallons per minute. The other wells throughout the county are all less than 200 feet in depth and the recorded yields are small.

Regarding the artesian prospects throughout the county no predictions can be made with confidence. The intricate folding of the strata and the frequent faulting and joining preclude continuous water beds so that a well may strike water at one level and another well a short distance away may be dry or find water at a totally different depth. In that part of the county underlain by the Triassic, as at Brunswick, water is apt to be more uniformly distributed, and supplies can be expected within 150 to 300 feet of the surface.

Non-Artesian Waters

SPRINGS.-Springs are abundant throughout the county, particularly in the broken uplands along Parr's Ridge, Catoctin Mountain, and Blue Ridge. They are extensively utilized for domestic and farm purposes, and a number of towns obtain their public supplies from this source which is frequently augmented by drawing from spring-fed mountain streams near their sources. The town of Frederick utilizes both of these sources on Catoctin Mountain, the water being carried by gravity to two reservoirs with a capacity of 12,000,000 gallons. Middletown, with a daily consumption of 8000 gallons, obtains its water from a spring on Catoctin Mountain. Braddock Heights draws from two springs and a well, the daily consumption in summer running up to 40,000 gallons, but declining to about one-fifth this amount during the winter season.

The Burkittsville Water Company and the Emmittsburg Water Company both utilize springs, and the Mechanicstown Water Company which supplies Thurmont draws its water from High Run Creek and six springs. Walkersville also uses both spring and stream water.

SHALLOW WELLS.-Shallow wells are common throughout the rural districts and in small towns. Water can usually be reached at no great distance below the surface in the mantle of unconsolidated materials overlying the rocky floor. The conditions vary from place to place, and such wells are liable to show great seasonal variation. If properly located with respect to drainage they may be used with safety in rural districts, but they are always dangerous in centers of population since it is almost impossible to prevent contamination.

COUNTIES OF WESTERN MARYLAND

GARRETT COUNTY

Garrett, the westernmost of the three Appalachian counties of Maryland, extends from the western boundary of the state to the North Branch of the Potomac and the arbitrary line running from the crest of Big Savage Mountain at the Pennsylvania line to the mouth of the Savage River.

Its surface features fall naturally into three groups-mountain ridges, the wide elongated valleys of an intermediate elevation, and narrower, steeper-sided valleys which the present streams have cut below the average valley levels. The highest ridge is the Great Backbone-Big Savage Mountain extending in a northeast-southwest direction the length of the county and with an average elevation of about 3000 feet. Parallel and at somewhat lower levels are the crests of Meadow Mountain, Roman Nose Range, Negro Mountain, Winding Ridge Range, and Snaggy Mountain. The main valleys are those of the Potomac and Georges Creek east of Great Backbone-Big Savage Mountain; the Savage Valley and Glades district lying between Great Backbone-Big Savage Mountain on the east and Meadow Mountain-Roman Nose Range on the west; Castleman Valley lying between Meadow Mountain-Roman Nose Range on the east and Negro Mountain on the west; and Youghiogheny Valley comprising the rest of the county lying northwest of Negro Mountain.