However, the geology of the Peach Bottom Slate that runs from Harford County, Maryland, through York County and into Lancaster County is another story. You see, slate is a metamorphic rock.

SUN-STAR PHOTO BY MARCI STENBERG The rocks known as 'Tombstone Rocks' line the side of the road between Planada and Mariposa ... a comprehensive look at the geology of Yosemite National Park ...