Geologists can be categorized on the basis of the composition of the oil shale is divided by a carbonate-rich shale, mudstone with silica or coal much meat and oil.
Geologists can classify rock oil, on the basis of the elements divided into abundant carbonate schist schist, with silica and or and texture of coal oil.
A geology can be divided into categories on the basis of elements of the rock oil and is divided into the rich soil of Dan with carbonate, silica rock hard soil that has a lot or coal, meat and oil is firmly.