CaCO3 Clay Designation Petrographic Desig.
65-75 25-35 Calcareous Marl Calcareous Marl
35-65 35-65 Marl Marl
25-35 65-75 Clayey Marl Clayey Marl
15-25 75-85 Marly Clay Clay
Loess
5-15 85-95 Clay Claystone
Mudstone
0-5 95-100 High Grade Clay Siltstone
Shale