Description of Section Measured at STOP 7 NIOBRARA CHALK Smoky Hill Chalk Member Feet 34. Chalky limestone, weathered pale yellowish orange to dark yellowish orange, punky to brittle, speckled, bed edges rounded, unit forms cap rock on cliff; FOSSILS - fish scales . . . . . . . . . . . 3.8 33. Chalk, much weathered, grayish-orange to dark-yellowish orange, abundant gypsum along joints and bedding produces ragged face, four prominent partings are probably weathered seams of bentonite, lowest with large, hollow limonite nodules; unit forms part of cliff . . . . . 5.2 32. Bentonite and gypsum; weathered very dark yellowish orange, gypsum adjacent to bentonite comprises most of unit . . . . . . . . . . . 0.4 31. Chalk, much weathered, grayish-orange to dark-yellowish-orange, lower part much stained by limonite; unit forms part of cliff, steep and spally in water courses; less steep, softer and flaky on spurs; prominent parting is probably weathered bentonite seam . . . . . . . . 2.5 30. Shaly chalk or soft chalky limestone, medium- to dark-yellowish-brown, weathering pale to dark yellowish orange, tough, appears to be non-laminated or poorly laminated but laminae are weathered into relief locally, speckled; this is highest little-weathered unit in section; two prominent partings in lower half are probably weathered bentonite seams, upper one has large limonite nodules, some of which have marcasite cores; sparse limonite nodules also lie 1.2 feet below top; unit crisscrossed by veins of gypsum; FOSSILS - Inoceramus platinus?, Ostrea congesta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 29. Bentonite, nearly white, weathering dark yellowish orange, 0.1-foot-thick, with sparse marcasite nodules, and with seams of limonite and gypsum above and below . . . . . . . . . . . . . . . . . . . . . . . . . 0.17 28. Shaly chalk or soft chalky limestone, medium-dark-gray to medium-light-gray, stained light brownish gray to grayish orange, tough, laminated, speckled; unit forms steep, spalling slope; bentonite near middle is 0.1 foot thick, grayish orange; prominent parting below bentonite is probably weathered bentonite; gypsum-filled joints common . . . . . . . . . . . . . . 4.1 27. Bentonite, yellowish-gray, 0.2-foot-thick, with seam of coarsely crystalline gypsum above and below . . . . . . . . . . . . . . . . . . . . . . . . 0.23 26. Shaly chalk, very light olive gray, weathering moderate yellowish brown to grayish orange, tough, laminated, speckled, softer and somewhat flaky where slightly weathered, in part with hackly surface and intensively burrowed appearance; seams of gypsum crisscross unit; unit caps one of tallest pinnacles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 25. Bentonite, grayish-yellow weathering dark yellowish orange, bedding surfaces limonitic, very thin seam of granular gypsum at top of unit and locally beneath bentonite . . . . . . . . . . . . . . . . . . . . 0.11 24. Chalky limestone, light-olive-gray weathering grayish orange to dark yellowish orange, tough, mostly nonlaminated but distinctly bedded, speckled, lower 2.25 feet with rough surface owing to intensive burrowing that produced a mottled appearance; three partings marked by re-entrants may be weathered bentonite seams, lowest marked by continuous ferruginous-gypsiferous streak; FOSSILS - Ostrea congesta, Inoceramus sp. . 3.9 23. Bentonite, 0.08-foot-thick, nearly white weathering dark yellowish orange with ferruginous seam at top of unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 22. Chalky limestone, very light olive gray weathering grayish orange to moderate yellowish brown, tough, nonlaminated, speckled; FOSSILS - Ostrea congesta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 60