Figure F15. Digital close-up photograph of an ash layer at ~41.3 mcd (interval 202-1237B-5H-3, 80-104 cm). The base of this ash layer defines the boundary between Subunits IA and IB.

Figure F15. Digital close-up photograph of an ash layer at ~41.3 mcd (interval 202-1237B-5H-3, 80-104 cm). The base of this ash layer defines the boundary between Subunits IA and IB.