Index map
Crowleys Ridge, evident on the map in eastern Arkansas
as a long yellow-orange ribbon against a gray background, is an
erosional remnant of 40- to 50-million-year-old sedimentary rock
in the upper Mississippi
River Embayment. The ridge formed late in the Pleistocene
as the river, gorged with glacial meltwater, continually shifted
course and broadened its floodplain at the expense of Tertiary
rock forming its banks. Crowleys Ridge is located near the site
of the great 8+ magnitude New Madrid earthquakes of 1811-1812.
|
