The Antrim shale, which underlies most of the Lower Peninsula of michigan, is a black Devonian shale which generally contains organic matter which was deposited as dead vegetation along with muds and silts in a large shallow epicontinental sea. Over the millions of years, the mud with compacted and transfromed into shale as the vegetation was coalified into a high molecular weight material called kerogen. When the oil shale is heated to about 500 degrees C (932 Degrees F), the kerogen breaks down into oils and gases. In in situ processing, this pyrolysis reaction is carried out undergound, using wells to access the zone of interest. The Antrim has potential yields of 5-15 gallons of oil per ton as well as significant quantities of low Btu gases.