MARYLAND WEATHER SERVICE til 



formations.* Clays are widely distributed over the region of acid 

 and basic volcanics in central Carroll, eastern Frederick and western 

 Montgomery counties, and also on the red shales of the Newark for- 

 mation in western Carroll, central Frederick and western Mont- 

 gomery counties. The former of these areas is made up, however, of 

 clay-loams and loams (Cecil loam), which are frequently full of 

 small rock fragments ; the latter of the areas also embraces consider- 

 able clay loam and sandy loam. The most extensive clay areas are 

 in the Frederick and Hagerstowu valleys, overlying the Shenandoah 

 limestone, where a loam (Hagerstowu loam) also occurs. Through 

 the Catoctin and Blue Ridges many soil types are found — clays (the 

 Porters clay), loams (Porters stony loam, Penn loam) and sandy 

 loams. West of North Mountain shales and sandstones are the pre- 

 dominant rocks, and loams or clay loams together with sands are the 

 commonest soil types. There are restricted outcrops of limestone in 

 the Niagara and the Jennings-Romney formations, yielding local 

 areas of heavy clay. The shale soils are invariably thin and filled 

 with small rock fragments, which renders them unfavorable for the 

 development of the highest type of forest. 



Mountain Zone.- — The soils of the Mountain Zone are similar in 

 their general character to those of the Upper Midland District west 

 of North Mountain. The shales and sandstones of the Jennings 

 Hampshire and Conemaugh formations occupy a large part of the 

 area of the Zone and have given rise to loams, sandy loams and sands. 

 The Mauch Chunk and Allegheny formations are more restricted in 

 area, but similar in the character of the soils to which they have given 

 origin. Small areas of limestone in the Greenbrier and Conemaugh 

 have weathered to clay soils. The Pocono and Pottsville formations 

 are of sandstone and have given rise to sandy-loams and sands. 



*Among these are the surveys of Adams, Lancaster and Lebanon counties, 

 Pennsylvania. 



