Field Notebook: Texas 1957b
Page 7
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Transcription
2) Covered, 105'. There seems to be a few quartz rich calcarenite, and rubbly limestone (?), but mostly shale in this interval. Collection 8/3/57/1 at top. 3) Organic frag. Limestone, orange-brown near base light brown higher, in bed 6" to 1', 1' to 2'; eight gray shale interbeds. 44'. Collection 8/3/57/2 near base. 4) Covered 25'. 5) Conglomerate; light gray, many limestone cobbles here. Almost a pure calcarudite. Small boulders up to 10" diameter. Collection 8/3/57/3. 8' exposed; One pebble or cobble in this collect has fusulines and seems to be related to the organic frag. Limestone #3 (which is definitely present in this conglomerate). PG.3 8/4/57 Dugout Mt. 1-21 Collection 8/4/57/1 - Above rubble and conglomerate in well bedded Hess Limestone; this bed helps form NW dip slope of the Knolls on SW extent of Dugout MT. - This is from the SW side of 2nd knob NE of the SW end of Mt. Collection 8/4/57/2 - Fossil wood found loose on Wolfcamp Conglomerate slope. This is near concrete tank on top of Wolfcamp ridge extending NE of Dugout Mt.; no other source for these fragment obvious, I assume it to be from Wolfcamp, conglomerate. Collection 8/4/57/3 - near base of Wolfcamp slope and near Gaptank (?) contact with Wolfcamp. The lower most Wolfcamp conglomerate here is a breccia of chert fragments with siliceous hematite cement. I would like to suggest this represents the untouched (more or less) thrust sheet breccia and it served as a gravel veneer pavement over the smooth surface of the truncated and folded Gaptank. Silica and hematite (lateritic times?) combined to cement the lower part together (of the Wolfcamp formation as defined or interpreted.). This might fully explain some of the breccias on the Decie Ranch. PG. 4 The NE ridge of the Dugout Mt. ridges contains Wolfcamp which swings about in strike to about N80°E. - This I would judge is a change from about N60°E (to SW). Oh for some photographs. The Gaptank goes through some beautiful folds and contortions. The small folds and faults near the top of the Gaptank I feel are geol. evidence for the extent of thrusting. PG. 5 8/5/57 Section 1 SW knob of Dugout Mt.; Sect. 24.