Geologic units in Blackford county, Indiana

Pleasant Mills Formation (Silurian) at surface, covers 39 % of this area

Dolomite, limestone, and argillaceous dolomite

Louisville Limestone through Brassfield Limestone (Silurian) at surface, covers 36 % of this area

Sexton Creek Limestone at base in Kentland area and on cross-section

Wabash Formation (Silurian) at surface, covers 15 % of this area

Limestone, dolomite, and argillaceous dolomite

Ordovician rocks, undifferentiated (Silurian) at surface, covers 10 % of this area

Shale and limestone; upper part of Maquoketa Group in deep buried valleys; Maquoketa to upper part of Knox Supergroup in Kentland area