Geologic Map of Maryland
Image courtesy Maryland Geological Survey (fair use policy)
Maryland is a small state that includes a surprising variety of geology, from the Atlantic coastal plain on the east, just recently emerged from the sea, to the Allegheny Plateau on the west, the far side of the Appalachian Mountains. In between, going west, are the Piedmont, Blue Ridge, Great Valley, and Valley and Ridge provinces, distinct geologic regions that extend from Alabama to Newfoundland. Parts of the British Isles have these same rocks, because before the Atlantic Ocean opened in the Triassic Period, it and North America were part of one continent.
Chesapeake Bay, the large arm of the sea in eastern Maryland, is a classic drowned river valley and one of the nation's preeminent wetlands. You can learn more detail about Maryland geology at the state geological survey site, where this map is presented in county-sized chunks at full fidelity.
This map was published by the Maryland Geological Survey in 1968. The 800x550 pixel version (260 KB), is legible, although you'll find the 1200x850 version more reader-friendly (500 KB).
The big map (2050x1420 pixels, 680 KB) is an enhanced version of the file on the state site. On your screen it's 2.5 times as big as the paper original.
More Maryland resources on About.com:
About Baltimore
About Washington DC
Maryland Maps
Maryland Geography, State Symbols & Facts
Maryland Campgrounds
Maryland Attractions
Maryland National Parks
Maryland Forests
Maryland Fishing
Maryland Archaeology
Back to Geologic Maps of the States
