-245- Top of measured sequence. Gaptank Formation 17. Limestone, light to medium gray weathering, fine grained organic fragmental, 1 to 4 foot beds, coll. 43-17, Triticites ohioensis . . . . . . . . . . . . . . . . . . 75 16. Sandstone, brown weathering; and shale, blue-gray, covered for most part . . . . . . 124 15. Limestone, medium gray to light brown weathering, fine grained organic frag- mental and calcarenite in part, 2 to 3 foot beds, coll. 43-15, Triticites joensis . . . . . . . . . . . . . . . . . . 40 14. Sandstone, light brown weathering, beds composed of well sorted quartz sand, 3 inch to 2 foot beds, coll. 43-14 (near top of unit), Triticites jo eshis . . . . . . 230 13. Limestone, medium to dark gray weathering, organic fragmental and calcarenitic, green silt common in large percentage locally, 6 inch to 1 foot beds, coll. 43-13, Triticites ohioensis . . . . . . . . . . 55 12. Sandstone, brown-yellow weathering, and shale, light brown weathering, much of unit covered . . . . . . . . . . . . . . . . 120 Thickness (feet)