Figure F6. Dark gray to black nannofossil claystone intervals in Unit IV from intervals (A) 183-1138A-69R-3, 2-22 cm, and (B) 183-1138A-69R-3, 80-100 cm. Top of black organically rich claystone at base of Unit IV from (C) interval 183-1138A-69R-5, 14-35 cm.