Field notes and maps from Glass Mountains, West Texas, 1964
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The Smithsonian Institution Archives welcomes personal and educational use of its collections unless otherwise noted. For commercial uses, please contact photos@si.edu. Glass Mtns.
April 18 - 19
1964
[[circled]] 54 [[/circled]]
985
April 18
BW4 25 - 28 Leonard & Hess unconf. King 1oc 104
In the ravines there is one contour interval about 53' of shale from igneous contact to base of conglomerate.
Shale N83[[degree symbol]]W 3[[degree symbol]]N.
Ls opposite King 104 to igneous dike or fault is [elnstitella?]
731c - fusilinids near top of figure - 8 - shaped hill at N end of Hess Horst Ranch Horst.
731A -fusiinids between fault and top of elliptical knob.
731d - About 20' below cgl in Neal Ranch shale, west of fault at head of valley
BW4 - to end Hess Horst, E end at fault
BW5 - 0 - 6 same views of narrow hill at east end Horst of Seacchinelles at 720e
C7 - to 12 - same as BW5
[[circled]] 55 [[/circled]] 986
Examined east end of Horst Basal cgl. of Lenox Hills is in contact with Neal Ranch shale at N end of valley in which igneous body exists. The shale occupies an elevation of 1 contour = 50' on west side valley but igneous body is in contact with cgl. at fault. The fault runs down west side of elliptical hill with a zone about 20' wide. A large baked zone is evident and the igneous body is in contact with the shale on the west side but tapers up to the cgl on the east. The elliptical hill is composed mostly of Hess limestone tipped up 50 - 60°. On the NE slope 80' above the road is a patch of biohermal limestone with Institella, probably overlying the Hess uncomformably as it does at King loc 104. No Institella was seen in the middle part of the elliptical hill but it appears on the south side (loc 724t) and extends some distance to the south
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[[circled] 56 [/circled]]
987
April 19
as at 724r (check)
In afternoon examined locality 720e and went to see Road Canyon at 726c and others.
April 19
730e W side Dugout Mtn.
A - Thick bedded sandy limestone with hard silicious brown skins on top. Sponges abundant Rock dark gray finely granular Small productids (Elliottella?) and mostly fragmentary specimens & bryozoa scattered on surfaces Sponges very abundant on surfaces
G - Thinner bedded some rock in layers 6" - 1' mostly the former
This sequence is in the upper part of the Leonard #3
[[diagram in left margin]]
--------------| { 5' | ------------|
g { 6' | ------------| { 15' | 730f
--------------|
f 5' | covered
--------------|
E 10" | ls
--------------|
D 5' | covered
--------------|
C 3' |
--------------|
B 2' | covered or thin
--------------|
A 730e 9' |
[[/diagram in left margin]]
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988
730g
Leonard #4 - Thick bedded dark gray sandy limestone with siliceous surfaces often covered with sponges and fragments of fossils. Layer is about 5' thick of 2 or three layers Overlain by cherty beds and sandstone and fine bedded ss. Ammonites common but hard to get. Sponges very abundant
730h- is a limy bed 50+ above Leonard #4.
730j
Leonard ls #4- Poorly exposed on surface of hill - consists of thin bedded sandy ls & calcirudite with beds of shell breccia but with few recognizable fossils. Dark gray sandy limestone with ammonites like those below. Tom says about 15'. Many sponges in places. Small pebbles. Rock is sandy, fossils mostly badly broken.
[[circled]] 58 [[/circled]]
989
Bioherms in hill 4801
20' of limestone on top of big bioherm under 4801.
A' - 1' yellow siliceous shale
A - lower 10' of dark gray chunky ls. with occasional goniatites
B - 3 or 4 feet biohermal ls.
C - 6 or 7 " of calconite with 2" siliceous skin on top.
730K - Ammonites from 5' above large bioherm in hill 4801.
730 - [l?] Fusulinids from between bioherms, hill 3801, Decie Ranch.
BW5 - to 13 Dugout Mtn and hill 4801
C7 - to 29 same
Leonard #4 is lithologically and formally like the Leonard #2 & 3 limestones. Also have the same goniatites out of dark gray blockey limestones in limestone #1 in hill 4801 of the Lenox Hills. This suggests that from the Seacchinelle beds up we have essentially the same fauna. I do not have good brachiopod.
[[circled]] 59 [[/circled]]
990
collections from these beds but in all the collecting done did not turn up Institella or the characteristic higher Leonard species.
The bed #5 has calcirudites or shell breccias like those below but we saw no goniatite beds like those below and it is quite easy to locate Institella or other early Cathedral Mtn. types.
In afternoon visited bioherms in hill 4801 where I collected goniatites, same assemblage as in limestones #2, 3, 4. If it were not for the bioherms near the top of the 20' above the big bioherm I would think it possible that these beds represent the three ls. Thinned down and with intervening shale pinched out. This is a possible explanation but the whole sequence seems to belong to limestone #1-
49 2 1/2
_____ 22 88
_____
110 55/38 7 6
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3030 355
35 35