Fragmented whale bones are commonly found on beaches along the rivers of the Coastal Plain after they erode out of marine sediments in exposed bluffs. Larger bones, especially vertebrae, ribs, skulls, and jaw bones can sometimes be found in outcrops, though they are less common after the lower Yorktown Formation (4.5 to 4.3 million years ago), when seas were too shallow for whales to be common, or the Coastal Plain was above sea level. An impressive whalebone bed at Carmel Church Quarry in Caroline County has yielded a number of partial and entire skeletons, one of which is from a species known only from that locality. Skeletons are sometimes exposed in bluffs and excavations in the Tidewater area of Virginia.