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the
Silurian Coldwell beds, forming the upper part of the Coniston Flags, are the equivalents of the Lower Ludlow. They are succeeded by the Coniston Grits (4,000 ft./1,230 m), the Bannisdale Slates (5200 ft./1,600 m) and the Kirkby Moor Flags (2,000 ft./615 m).
213:, the Lower Ludlow portion consists of mudstones, flaggy shales, and greywackes; and the upper Downton Castle Sandstone part is made up principally of thick red and yellow sandstones and conglomerates with green mudstones.
402:
The Upper Ludlow sub-group rocks are mainly soft mudstones and shales with some harder sandy beds capable of being worked as building-stones. These sandy beds are often found covered with ripple-marks and
163:, which is irregular in thickness, is sometimes absent, and where the underlying Wenlock limestones are absent the shales of the Ludlow group graduate, downwards into the Wenlock shales.
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At the top of this sub-group a brown layer occurs, from a quarter of an inch to 4 in. (63 mm to 100 mm) in thickness, full of the fragmentary remains of fish associated with those of
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the upper portion of the
Denbighshire Grits belongs to this horizon. Those from lower to upper are: the Nantglyn Flags; the Upper Grit beds; the
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tracks. One of the uppermost sandy layers is known as the " Fucoid bed " from the abundance of the seaweed-like impressions it bears.
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shales are occasionally grouped together under the term
Downtonian. They are in reality passage beds between the Silurian and
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districts by the
Raeberry Castle Beds and Balmae Grits (500–750 ft.). In the northern belt within Lanarkshire and the
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374:(many species of Orthoceras and also Gomphoceras, Trochoceras) are well represented. Other fossils are
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459:; trilobites (less common than in the older Ludlow sub-groups); numerous brachiopods (
420:. This layer, known as the "Ludlow Bone bed," has been traced over a very large area.
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by E. M. R. Wood. The zonal forms in order from older/lower to younger/upper are:
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The common Upper Ludlow fossils include: plants (Actinophyllum, Chondrites),
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559:. Vol. 17 (11th ed.). Cambridge University Press. p. 113.
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439:. They are mostly grey, yellow or red micaceous, shaly sandstones.
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The Ludlow Group formations of
Ireland include the Salrock beds of
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Lower Ludlow sub-group formation (350 to 780 ft./108 m-240 m).
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This article incorporates text from a publication now in the
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This group contains the following formations in descending order:
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in character, except towards the top, where the beds become more
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178:, and it occurs also in the detached Silurian areas between
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The Lower Ludlow rocks are mainly grey, greenish and brown
435:, and were originally placed in the latter system by Sir
248:. The Lower Ludlow series has been zoned by means of
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Upper Ludlow sub-group formation (140 ft./43 m),
501:); and fish (Cephalaspis, Cyathaspis, Auchenaspis).
156:and pass gradually into the Old Red Sandstone. The
170:the group is typically developed between namesake
38:1911 Encyclopædia Britannica article outdated.
8:
201:, the Ludlow rocks are represented in the
574:Geologic formations of the United Kingdom
34:needs attention from an expert in Geology
579:Geological groups of the United Kingdom
16:Geological formations in UK and Ireland
49:may be able to help recruit an expert.
244:shales. They contain an abundance of
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310:fossil, was found in these rocks at
197:In the Silurian areas of southern
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148:The Ludlow group is essentially
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293:beds; and the Dinas Bran beds.
118:formation (90 ft./27.7 m),
599:Geologic formations of Ireland
594:Geologic formations of England
220:, and the Croagmarhin beds of
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521:Silurian geologic formations
332:Homolonotus delphinocephalus
291:Monograptus leintwardinensis
276:Monograptus leintwardinensis
134:Aymestry Limestone Formation
318:, a noted fossil locality.
136:(up to 40 ft./12.3 m),
36:. The specific problem is:
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639:Silurian System of Europe
584:Geologic groups of Europe
425:Downton Castle Sandstone
116:Downton Castle Sandstone
614:Silurian United Kingdom
556:Encyclopædia Britannica
516:Silurian United Kingdom
306:, the earliest British
491:Platyschisma helicites
398:Upper Ludlow sub-group
232:Lower Ludlow sub-group
114:Tilestones Formation,
344:Leptaena rhomboidalis
336:Calymene Blumenbachii
272:Monograptus tumescens
182:and the mouth of the
74:deposited during the
443:Upper Ludlow fossils
348:Rhynchonella Wilsoni
297:Lower Ludlow fossils
268:Monograptus scanicus
264:Monograptus nilssoni
260:Monograptus vulgaris
604:Geology of Scotland
499:Orthoceras bullatum
497:; and cephalopods (
360:Cardiola interrupts
303:Cyathaspis ludensis
127:270 ft./83 m),
72:geologic formations
47:WikiProject Geology
437:Roderick Murchison
364:Ctenodonta sulcata
352:Atrypa reticularis
629:Silurian Scotland
433:Old Red Sandstone
429:Ledbury Formation
122:Ledbury Formation
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63:
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624:Silurian Ireland
619:Silurian England
609:Geology of Wales
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511:Silurian Ireland
477:); crustaceans (
423:The Tilestones,
324:Phacops caudatus
222:Dingle Peninsula
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468:Lingula minima
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322:are numerous (
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240:and sandy and
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211:Pentland Hills
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32:This article
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589:Ludlow epoch
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551:Ludlow Group
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487:Phyllocarida
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453:phyllocarids
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392:Palaeodiscus
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376:Ceratiocaris
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312:Leintwardine
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76:Ludlow epoch
68:Ludlow Group
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55:October 2017
52:
44:for details.
37:
33:
457:eurypterids
372:cephalopods
340:brachiopods
256:Graptolites
254:species of
251:Monograptus
568:Categories
527:References
483:gastropods
475:striatella
413:Pterygotus
388:Palaeocoma
380:Pterygotus
368:gastropods
356:pelecypods
320:Trilobites
308:vertebrate
242:calcareous
205:Shore and
106:Formations
479:ostracods
449:ostracods
384:Protaster
238:mudstones
207:Riccarton
176:Aymestrey
161:limestone
42:talk page
505:See also
495:bivalvia
473:Chonetes
418:mollusca
199:Scotland
158:Aymestry
96:Scotland
40:See the
544::
462:Lingula
405:annelid
246:fossils
189:In the
144:Geology
92:Ireland
88:England
82:in the
78:of the
538:
464:cornea
427:, and
366:) and
274:; and
184:Severn
180:Dudley
172:Ludlow
125:shales
98:, and
168:Wales
154:sandy
150:shaly
100:Wales
416:and
390:and
370:and
285:and
174:and
102:.
70:are
66:The
553:".
493:);
481:);
354:),
338:);
314:in
281:In
224:of
166:In
90:,
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