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| | Geologic Maps of Maryland: |
 | | Red and green shale, siltstone, and sandstone, with thin lenticular beds of argillaceous limestone and thin beds of impure coal; thick-bedded, white conglomeratic sandstone at base; thickness greater than 200 feet; occurs only on hilltops in center of Georges Creek Basin. |
 | | Red and green shale, reddish-purple mudstone, and red, green, brown, and gray thin-bedded and cross-bedded sandstone; thickness 500 feet in west, increases to about 800 feet in east. |
 | | Red to greenish-gray, thin- to thick-bedded siltstone, shale, subgraywacke, and protoquartzite; interbedded conglomerate; thickness 180 feet in east, increases to 500 feet in west. |
| www.mgs.md.gov /esic/geo/lgdalleg.html (1229 words) |
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