Slave Rock - Montgomery County, MO
Posted by: 
Wampa-One
N 38° 54.075 W 091° 34.577
15S E 623456 N 4306781
A notable outcropping of St. Peter sandstone which is conspicuously visible in the median of Interstate 70 near Mineola, MO.
Waymark Code: WM5CJA
Location: Missouri, United States
Date Posted: 12/18/2008
Views: 28
This mass of St. Peter sandstone has been preserved between the lanes of I-70 a little over two miles west of the Danville interchange. The protrusion is between 11-20 feet high and 50 feet in diameter. St. Peter sandstone is believed by geologists to have formed from fine sand deposited along the coastline of a prehistoric sea stretching from Minnesota through Iowa, Illinois, and Missouri approximately 455 million year ago during the Ordovician period. In the book "Geologic Wonders and Curiosities of Missouri" by Thomas R. Beveridge, it is hypothesized that this formation could have been created either as a result of a fossil sinkhole fill or just an especially resistant remnant of the main sandstone mass.
This particular outcropping has an interesting local history and has been known by the names "Graham Rock" or "Picnic Rock". It is also referred to as "Slave Rock" due to the belief that it was formerly used as an block for auctioning slaves.
~ abridged from Wikipedia (
visit link) and Montgomery County Journal (
visit link)
*Please note that parking is not permitted on the interstate shoulder, so most observers must view as they drive by at not less than 40 mph. Coordinates were recorded by marking a waypoint while passing by in each direction on two separate cross-state trips, then taking the average of the four values.