DEPARTMENT OF THE INTERIOR PROFESSIONAL PAPER 1398
U.S. GEOLOGICAL SURVEY PLATE 1

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LITHOLOGY OF MEASURED SECTION

fea

Ts

: SANDSTONE—Gray or tan, fine-grained, showing types of
bedding, (flat-bedded, ripple-bedded, crossbedded, tabular
or massive

SANDSTONE—Gray or tan; rooted (top); scattered clay
pebbles (bottom)

Oyster marker
bed (OMB)

ali

SILTSTONE—Gray, showing types of bedding, flat-bedded
(top), ripple-bedded (bottom)

=|
a

SHALE—Gray

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SHALE—Gray or brown, carbonaceous

GE

COAL

Oyster ridge
marker (ORM)

BAKED STRATA—Includes burned coal

COVERED INTERVAL

POORLY EXPOSED INTERVAL

Beir]

OYSTER SHELLS—Occasionally mixed with other mollusks

TER

CRUSTACEAN BURROWS—includes other trace fossils

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Ge

ion

Barrier Bar G

1 2 MILES

A. MEASURED SECTIONS OF BARRIER BAR G, THE PINTAIL COAL BED AND ASSOCIATED ROCKS, ALMOND FORMATION,
ROCK SPRINGS UPLIFT, WYOMING. THE LOCATIONS OF MEASURED SECTIONS ARE SHOWN ON FIGURE 2

Barrier Bar F

pase of

DEPOSITIONAL ENVIRONMENTS AND LITHOLOGY
OF RESTORED SECTION

SHALLOW MARINE—Gray shale

LOWER SHOREFACE—Tan, silty to shaly parallel-
bedded sandstone

MIDDLE SHOREFACE—Tan, massive sandstone

SURF—Light-gray, trough crossbedded sandstone

=] FOREBEACH—Light-gray, subparallel to tabular bedded
sandstone

Marine erosion (MU) at the base

of the Barrier Bar F sequence has
removed the barrier bar associated

with the bay-fill (BF) deposits

overlying the oyster ridge marker (ORM)

DUNE—Light-gray, crossbedded sandstone

WASHOVER—Light-gray, massive, tabular or crossbedded
sandstone

=| TIDAL CHANNEL—Tan or gray, crossbedded sandstone, partly
s interbeddded with gray shale

TIDAL INLET—Tan crossbedded sandstone

Marine RECURVED SPIT—Light-gray, tabular sandstone

Transgression

Abandonment EBB-TIDAL DELTA—Tan, trough crossbedded sandstone

‘Old Age

FLOOD-TIDAL DELTA—Tan or gray, planar crossbedded or
trough crossbedded sandstone

Pa

~ Maturity

TIDAL FLAT—Gray, ripple-bedded sandstone, siltstone and
mudstone

BF BAYFILL—Gray shale and mudstone

FIT

ous) OYSTER REEFS—Oyster marker bed (OMB); oyster ridge
marker (ORM); undesignated oyster beds (OB). Composed

mostly of reworked oyster shell fragments in a sandstone

matrix

SALT MARSH—Gray or brown carbonaceous shale

PEAT SWAMP—Coal deposited as vegetation in freshwater

LITHOFACIES LOCALITY—Described in the text

Stages of barrier bar-lagoon dewelopment described in text
A
(

UNCONFORMITY (Marine Unconformity)— Caused by marine
transgression and erosion

Finch coal bed ~LU~ UNCONFORMITY (LAGOONAL UNCONFORMITY)—Caused

by progradation of lagoonal rocks onto back barrier flats

B. GENERALIZED RESTORED CROSS SECTION OF BARRIER BAR G, THE PINTAIL COAL BED AND ASSOCIATED ROCKS SHOWING
DEPOSITIONAL ENVIRONMENTS AND LITHOFACIES, ALMOND FORMATION, ROCK SPRINGS UPLIFT, WYOMING

THE PINTAIL COAL BED AND BARRIER BAR G-A MODEL FOR COAL OF BARRIER BAR-LAGOON ORIGIN, |
UPPER CRETACEOUS ALMOND FORMATION, ROCK SPRINGS COAL FIELD, WYOMING