Field Notebook: Texas 1957a
Page 268
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Transcription
47) Sandstone, very fine quartz, very silty; light gray-brown weathering, no apparent bedding irregular blotches of varying shades of color. 0-1'. 48) Collection 8/1/57/2. Siltstone, light gray-brown weathering, rests on irregular top of #48, in one location rests directly on #47. Fills the trough so formed evenly and within 1.5' is evenly bedded. 14'. 49) Collection 8/1/57/1. Calcarenite, very fine grained; weathers light bluish- grey. Rich in brownish silt. Has a small coiled cephalopod fauna, see bed 38, sect 17. 2'. (a unit like #51 between the 2 limestone beds of this unit). 50) Covered, 9', probably similar to #49. Light brown, sandstone very silty, poorly cemented. 51) Calcarudite and chert quartzite conglomerate with one or two siltstone beds. 8' light gray weathering except for cherts and quartzite pebbles, some limestone cobbles medium gray. PG. 150 52) Limestone, organic frag.; light gray weathering Productids, crinoid columns; upper 2" rich in siliceous cement and fossils. 2.5'. 53) Alternation of limestones like #52 and siltstones like #45, at least 4 alternative interval is poorly exposed; siltstones have siliceous bands. 12'. 54) Calcarudite, cobbles 3" to 6" diameter; about 5% or less siliceous rocks in this unit. 8'. This seems to form the base of King's 1st Basal Leonard limestone. 8/1/57/3, float found near bed 43. I believe it has come down from either bed 50 or in the Leonard above. 8/1/57/10 - NE of Section 20, 200 yards, from bed #24 - one light colored black, grayer ones are in matrix of rock. PG. 151 Afternoon (8/1/57) walked along Wolfcamp interval to the NE about 1 mile. The upper shale of the Wolfcamp is poorly exposed along here and even the basal conglomerate of the Wolfcamp is incompletely exposed. The Dimple is exposed in a window (?) in the Dugout Ck Thrust sheet. Dimple is the apparent source for much of the lower Wolfcamp conglomerate at this point. Collection 8/1/57/8. Haymond? is exposed just to the SW of the Dimple; (8/1/57/9)is from sand and siltstone in Haymond. {note: illustration followed} PG. 152 Collection 8/1/57/11 - This bed is dipping slightly toward the town of Marathon, not a good exposure, but believe this is Gaptank thrust over Haymond onto Dimple. The diagram on page 151 shows 2 limestones thickening and thinning. This is really caused by a fault - raising the NE side about 60-70' with respect to the SW side. The thickening and thinning of the Hess limestone I'm sure does take places but perhaps not on the order of magnitude pictured on page 151. The Sullivan Canyon fault cuts the NE end of the Decie (Lenox) Hills. The lower Leonard limestone is dropped on the NE side to a point below the Hess sacchinella reef. The picture is confused by several twisted or rotated fault