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•"Member D is a resistant cliff- and ledge-forming sequence of thick and very thick bedded limestones interstratified with sandstone and minor amounts of clay shale, conglomerate, and siltstone. The limestone is typically gray or blue gray, weathers brownish gray in some place, and is locally very hard and dense. A few of the limestone beds have sets of planar cross-strata, and others are noticeably pyritic. Almost all are fossiliferous, containing crinoid columnals, colonial and solitary corals, bryozoans, brachiopods, and, locally, formainifers. Many of the limestone strata have 'stringers' and thin beds of dark chert granules and pebbles; others contain abundant silt-size quartz and chert grains and grade into limy siltstone. The nonlimy siltstone present is olive gray, thin bedded and occurs also as the matrix of the limestone-phenoplast conglomerate of theis member. The clay shale interclated with the limestone is gray and fissile, weathers olive gray, and is locally either pyritic or limy. Small brachiopod casts occur in some of the beds. Light-gray, brown, and light-brown, fairly well sorted, fine-grained sandstone in beds 7.5-75 cm thick occurs between the limestone beds. Most of the sandstone is hard, dense and moderately well sorted. Some is pyritic and some is conglomeratic. The conglomerates in the sequence are gray or brownish white and weather to brownish gray and darker brown. Chert and quartzite form the rounded pebbles and cobbles, which are a maximum of 10 cm in diameter. The chert fragments tend to be more angular and are red, white, gray, and black. Some of the conglomerates grade to sandstone; others contain relatively little sandstone matrix and are cemented with calcite."