9. Shaly chalk, light-olive-gray to yellowish-gray mottled with light gray, like 23, with much powdery gypsum and a conspicuous gypsum parting 4.9 feet above base; FOSSILS - Ostrea congesta, Inoceramus platinus, baculi- tid? mold, fish remains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 8. Bentonite, nearly white to very pale orange, 0.02-foot-thick, sandwiched between seams of jarosite, limonite and powdery gypsum; scattered nodules of marcasite, largely weathered to limonite and jarosite, up to 0.23 foot thick and 2.3 foot across . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05 7. Shaly chalk, light-olive-gray weathering yellowish gray to grayish orange, like 23, with much powdery gypsum; FOSSILS - smooth baculitid, Ostrea congesta, Inoceramus platinus . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.35 6. Bentonite, light-brown, slightly silty, with sparse limonite-jarosite nodules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 5. Shaly chalk, light-olive-gray to moderate-yellowish-brown, mottled, tough, laminated, speckled, with much powdery gypsum; FOSSILS - Inoceramus platinus, Ostrea congesta, fish remains . . . . . . . . . . . . . . . . . . . . 4.2 4. Shaly chalk, olive-gray to light-olive-gray, soft, laminated, speckled, unit conspicuously darker than adjacent units; FOSSILS - Ostrea congesta, fish remains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 3. Shaly chalk, light-olive-gray, tough, laminated, speckled, with much powdery gypsum; FOSSILS - Inoceramus platinus, Ostrea congesta, fish remains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.15 2. Bentonite, grayish-orange to grayish-yellow, with jarositic marcasite nodule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 1. Shaly chalk, light-olive-gray mottled light gray, very tough, obscurely laminated, speckled, with much powdery gypsum; FOSSILS - Inoceramus platinus, Ostrea congesta . . . . . . . . . . . . . . . . . . . . . . . . . . 2.65 Thickness of exposed part of Smoky Hill Chalk Member 85.3 Total thickness of measured section 85.3 Description of Section Measured at STOP 9 NIOBRARA CHALK Smoky Hill Chalk Member Feet 59. Chalk and shaly chalk, chalk weathered very pale orange to nearly white, evenly bedded, very thinly laminated in part, burrowed in part; shaly chalk, weathered grayish orange to dark yellowish orange; 0.02-foot- thick, light-brown bentonite lies near middle; FOSSILS - Inoceramus platinus, Ostrea congesta . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9 58. Shaly chalk, weathered grayish orange, soft, laminated; bentonite, 0.08-foot-thick, lies 0.6 foot above base . . . . . . . . . . . . . . . . . . 1.6 57. Chalk and shaly chalk, weathered very pale orange to dark yellowish orange, all soft, thick bed of chalk is laminated; FOSSILS - Inoceramus platinus, Ostrea congesta, fish remains . . . . . . . . . . . . . . . . . . 3.5 56. Shaly chalk, lower 4 feet are olive gray to light olive gray, remainder dark yellowish brown, grayish orange and dark yellowish orange in upward succession, all soft, laminated, speckled, softer where weathered; two bentonite seams, each less than 0.01 foot thick; lower bentonite under- lies 0.15-foot-thick seam of selenite; sparse limonite nodules in zone lying approximately 8 feet below top . . . . . . . . . . . . . . . . . . . 19.1 55. Shaly chalk, weathered grayish orange, with beds of very pale yellowish grey to pale-yellowish-orange chalk at top and base of unit, soft, banded by limonite near top . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 64