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370:. Fossils have been recovered from every rock type in the Llewellyn but are predominantly found in the siltstone, shale, and coal layers. The compression fossils from the Llewellyn formation are well known for the striking white color on the dark stone. An important location for these fossils is near
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The economic gains of this formation have been exploited to their greatest potential in years past. The peak year of anthracite production was in 1917 when nearly 100 million tons were mined. Anthracite production has declined every year since then. Recently, the old spoils of the mining operations
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The
Llewellyn was deposited upon a broad flat plain with sediment-choked rivers delivering detritus from the eroding uplands that were located to the southeast. Fluctuations in sea level, coupled with the shifting nature of the rivers and highlands, allowed dense
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in repetitive sequences. Although gray (light to dark) is the dominant color, other colors described include: buff, dark to light brown, and black. It contains the worlds thickest anthracite coal bed, the
Mammoth vein.
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to grow on the broad plain. As a result, a large amount of organic matter was buried and eventually turned to coal. The repetitive nature of these sediments have been well documented and are often called
476:
Wood, G.H., Trexler, J.P., Kehn, T.M., (1964). Geology of the West-Central Part of the
Southern Anthracite Field and Adjoining Areas, Pennsylvania. United States Geological Survey, C-46.
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457:(culm) have been refined to extract more coal for power production. There are 40 coal seams in the Llewellyn the largest is the Mammoth vein which is nearly 20 feet thick.
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in age, but no fossils have been found from that era. The bottom of the formation is placed either at the bottom of Buck
Mountain (no. 5) coal bed or at the bottom of the
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Berg, T.M., Edmunds, W.E., Geyer, A.R. and others, compilers, (1980). Geologic Map of
Pennsylvania: Pennsylvania Geologic Survey, Map 1, scale 1:250,000.
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sp., Carboniferous (Pennsylvanian), Llewellyn
Formation, St. Clair, Schuylkill County, Pennsylvania, US - Houston Museum of Natural Science - DSC01757
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Berg, T.M., et al., (1983). Stratigraphic
Correlation Chart of Pennsylvania: G75, Pennsylvania Geologic Survey, Harrisburg, Pennsylvania.
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Oleksyshyn, J. (1982). Fossil Plants from the
Anthracite Coal Fields of Eastern Pennsylvania. Pennsylvania Geologic Survey, G72.
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428:, being deposited between 308 and 300 (Β±1) million years ago. It was thought that the uppermost beds of the Llewellyn were of
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Edmunds, W.E., (2002), Coal in
Pennsylvania (2nd ed.): Pennsylvania Geological Survey, Educational Series 7.
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Nearly 100 fossil species have been identified in the
Llewellyn; almost all of them plants. The major
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Hornberger, Rodger J.; Loop, Caroline M.; Brady, Keith B. C.; Houtz, Nathan A. (19 March 2024).
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Relative and fossil age dating of the Llewellyn places it in the late-Middle to Late
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or shale bed below this coal measure. Since this is the last bed deposited in the
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The Llewellyn is defined as a gray, fine- to coarse-grained
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in eastern Pennsylvania that still exists, only recent
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of the Llewellyn Formation in the south wall of the
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Pennsylvania Department of Environmental Protection
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113:A hand sample of the bottom of the Llewellyn from
599:Carboniferous southern paleotropical deposits
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346:of flora that have been recognized include:
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500:"GEOLOGY OF THE PENNSYLVANIA COAL REGIONS"
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569:Sandstone formations of the United States
143:none (most economic coal beds are named)
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594:Carboniferous geology of Pennsylvania
579:Shale formations of the United States
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256:is a mapped bedrock unit in eastern
584:Geologic formations of Pennsylvania
414:Northumberland County, Pennsylvania
392:Northumberland County, Pennsylvania
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223:Anthracite fields of Pennsylvania
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161:up to 1,500 feet (460 m)
589:Paleontology in Pennsylvania
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305:Depositional environment
554:Geology of Pennsylvania
372:St. Clair, Pennsylvania
237:Llewellyn, Pennsylvania
115:St. Clair, Pennsylvania
448:deposits rest on top.
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406:Bear Valley Strip Mine
384:Bear Valley Strip Mine
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574:Siltstone formations
367:Pteridospermatophyta
152:Pottsville Formation
254:Llewellyn Formation
25:Stratigraphic range
19:Llewellyn Formation
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408:, located west of
386:, located west of
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332:Alethopteris serli
29:Late Pennsylvanian
438:Appalachian Basin
378:Notable exposures
270:Schuylkill County
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208:Appalachian Basin
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452:Economic use
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361:Pteridophyta
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294:conglomerate
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258:Pennsylvania
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228:Type section
189:Conglomerate
402:Concretions
355:Arthrophyta
336:Neuropteris
276:Description
126:Sedimentary
563:Categories
461:References
317:cyclothems
262:Pottsville
446:colluvial
434:underclay
344:divisions
286:siltstone
282:sandstone
266:Llewellyn
233:Named for
175:Sandstone
166:Lithology
158:Thickness
140:Sub-units
548:See also
442:alluvial
410:Shamokin
388:Shamokin
243:Named by
212:eastern
199:Location
148:Overlies
430:Permian
323:Fossils
312:forests
171:Primary
132:Unit of
364:, and
296:, and
220:Extent
204:Region
503:(PDF)
290:shale
185:Shale
181:Other
444:and
334:and
252:The
193:Coal
135:none
122:Type
43:Preκ
420:Age
412:in
390:in
268:in
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210:of
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93:Pg
37:Ma
27::
509:.
98:N
88:K
83:J
78:T
73:P
68:C
63:D
58:S
53:O
48:κ
32:~
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