is the closest rock that I can find to Trenton Limestone and it is South of Lexington, Kentucky. I need it for our geological rock column that will show all the important Ohio oil & gas formations. Students are helping to build this geologic pillar. This rock has a tinge of blue and is used as building stone. It comes from the Ordovician era of geologic history when there was an ancient sea covering Ohio. The Trenton field was the first major oil field discovered in Ohio and it is where John Rockefeller of Standard Oil Company made his fortune. This rock is almost as pretty as my daughters Laura Cross Jenna Stonerock-Lavy Diedra Stonerock and baby K.