The South Staffordshire Coalfield/Chapter 7

by Joseph Beete Jukes

CHAPTER VII.

Description of the Rocks—continued.

5. The Silurian Rocks.

Of the Silurian formation we have, in or near the South Staffordshire coal-field, parts of three different subdivisions:—

1st. A portion of the Ludlow rocks containing a band of limestone, believed to be the same as the Aymestry limestone.

2nd. The Wenlock and Dudley rocks entire.

3rd. A portion of the Llandovery (formerly considered part of the Caradoc) sandstone.

These rocks have been so fully described by Sir R. I. Murchison in his "Silurian System" that there remains but little to say respecting them.

Ludlow and Sedgley rocks.—The mass of the Ludlow and Wenlock rocks, or, as they might here be called, the Sedgley and Dudley rocks, consists of a brown or blueish grey argillaceous shale, always very smooth and compact, thick-bedded and regularly jointed. In the upper portion is a band of dark brown nodular and concretionary limestone, some 20 or 25 feet in thickness. It is locally called the "Brown lime." From its containing the Pentamerus Knightii, and other fossils, and from its position, it is with great probability identified with the Aymesy limestone. This limestone shows itself at Sedgley, at Turner's Hill, and at the Hayes near the Lye Waste, 2 miles east of Stourbridge.

At a certain depth below this, is the Wenlock and Dudley limestone, which is locally called "White lime."

What is the exact thickness intermediate between these two limestones, or how far they were vertically apart at their period of deposition, we have no means of determining. In the only place where they both crop to the surface in one area, namely, at Sedgley Beacon and Hurst Hill, a fault runs between the two which has been traced on one side in the workings, but without arriving at any means of determining the amount of its "throw." I have, however, assumed 800 or 1,000 feet as the vertical distance between the limestones. This thickness enabled me to draw the sections, with the least amount of dislocation and disturbance, of which there was no decided evidence; but I feel by no means confident that that thickness ought not to be either diminished or increased.

There is no lithological distinction between the shale or bavin above the Dudley limestone and that below it, but the one above is assumed to belong to the Ludlow group, and that below it to the Wenlock.

Wenlock and Dudley rocks.— The Wenlock and Dudley limestone forms two bands of solid concretionary and flaggy limestone, with many calcareous nodules, concretions, and small flaggy beds, both between, above, and below them.

At Dudley, we have the two following sections of the limestone given in the Silurian System:—

The Castle Hill.
	FT.	IN.
Upper limestone or thin measures	23	1
Intermediate shale
Lower limestone or thick measures	35	7
The Wren's Nest.
	FT.	IN.
Upper limestone	28	4
Intermediate shale	90	0
Lower limestone	42	3

At Hurst Hill, the beds are collectively thinner and the limestones closer together. At Mr. Bagnall's limestone pits at Dudley Port they found two bands of limestone,—upper, 27, and lower, 24 feet thick,—resting directly one on the other. At Mr. Giles's pit, however, according to Sir R. I. Murchison, the limestone worked was 21 feet thick, and they reached, by boring, another mass of limestone 150 feet below it. At Deepfield's, a little east of Hurst Hill, according to "Smith's Miner's Guide," they sank below the Coal-measures through 150 feet of blue rocky clunch, probably Silurian shale, and then came on limestone in about ten beds of nearly 3 feet each. In the neighbourhood of Walsall the Dudley and Wenlock limestone consists of—

	FT.
Thin or upper limestone	12
Intermediate shale, &c.	120
Thick or lower limestone	34

The following more detailed section of these beds has been furnished by Mr. Beckett, of Wolverhampton, who procured it from Mr. B. R. Smith, of Walsall:—

						FT.	IN.	FT.	IN.
1.	Surface matter, Diamonds ironstone grit rock, and Flying reed limestone binds					61	4
2.	The Four-yard stone, first thick band of limestone							12	0
3.	Mush, clunch, &c.					108	6
4.	Covering Burr, not gettable	1	6	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right\}\,}$	Thick Limestone			34	2
5.	Burr	1	8
6.	Thick Burr	3	3
7.	Chattering Burr	1	6
8.	Chippers	3	3
9.	Captain	1	0
10.	Seven floors	1	8
11.	Fourth shot	1	6
12.	Third shot	1	0
13.	Strong stone	3	0
14.	Yellow clay floor	0	10
15.	Flints	2	9
16.	Half yard measure	1	6
17.	Bell flag	2	3
18.	Knotty floor	2	0
19.	Thick floor	3	8
20.	Rottens	2	4
21.	Clunch					8	0
						177	10	46	2
						46	2
	Total					224	0

At Hobbs Hole, a little east of Darlaston, the Silurian rocks lying below the Coal-measures have the following composition, according to the information of Mr. Smallman:—

	FT.	IN.	FT.	IN.
From surface to bottom of Heathen coal	15	0
From that to bottom of Coal-measures	292	6
	307	6
Limestone shale			60	0
Thin limestone			16	6
Limestone shale			90	0
Thick limestone			30	0
	307	6	196	6

In this neighbourhood (Walsall) the Dudley limestone crops out at a gentle angle, and the lower shale rises from underneath it, spreading out to the east over a tract nearly 2 miles in width, till another band, known as the Barr limestone, rises to the surface at Hay Head, near Great Barr. There is but little to be seen in the space between those two limestones, but where seen, as in the cutting of the new canal that runs from Hay Head to the Tame Valley, the shale was always found in a nearly horizontal position.

At the Hay Head quarries the Barr limestone rises from beneath the shale at an angle of about 8° or 10° on an average. Drawing the section from these data, the Barr limestone will probably lie at a depth of about 500 or 600 feet below the Dudley limestone, though it may easily be more.

In mineral character, the Barr limestone much resembles that of Woolhope^[1] in Herefordshire, which lies at the junction of the Wenlock and Llandovery rocks, and it may very easily be at or near the actual base of the Wenlock rocks as they exist in Staffordshire. In this case we ought to have the Llandovery sandstone rising out immediately to the east of the Barr limestone.

In the former edition of this Memoir I stated that there was no appearance of this sandstone from underneath the Barr limestone, or below the base of the Wenlock rocks, in the neighbourhood of Great Barr or Hay Head, as I thought I had examined every place where it could appear and had not found it.

The late Mr. Daniel Sharpe, however, called my attention to a quarry of it, which had escaped my notice, in consequence of its small size, and its being situated under a steep bank, overgrown with brambles and nettles, at the side of a field in which, when I visited it, the wheat was high and in full ear.

Llandovery sandstone.—I revisited the locality in the year 1853 and was guided to the old quarry by Mr. George Eglinton, of Shustoke Lodge, who had himself pointed out the quarry to Mr. Sharpe.

In the ploughed field, which slopes gently up to the quarry, fragments of grey shale were observable on the ground with small cakes and concretionary flakes of limestone, like those described below as being found at the Colmers, near the Lickey.

It is probable that these are the representatives of the Barr limestone, which is very likely of partial occurrence, as an actual limestone, though thin calcareous courses may be found generally on its horizon. At the upper end of the field, under the hedge, was the small quarry. There was but a very small exposure of rock, not enough to show the dip of the beds, which, however, may be presumed to be the same as that of the other Silurian rocks of the neighbourhood, or about 5° to the west. The rock was a pale yellow or brown sandstone, in some placcs nearly white and purely quartzose, in others stained with ferruginous bands forming concentric rings. Other portions were calcareous, almost deserving the name of an arenaceous limestone. It was greatly jointed, splitting into sharp angular fragments.

Some parts of it were highly fossiliferous, and Mr. Salter determined the following species in the few blocks of the rock I was able to carry away;^[2] one or two more were brought by other observers.

Fossils in the Llandovery Sandstone, south-east of Shustoke Lodge.

Trilobites.
Encrinurus punctatus	4
Phacops caudatus	1
Phacops„ Stokesii	1
Phacops„ truncato-caudatus?	1
Mollusca.
Chonetes lata ? (probably only a Leptæna)	1
Strophomena compressa	2
Atrypa reticularis	6
Rhynchonella, 2 plaited sp.	8
Rhynchonella„ Wilsoni	20
Rhynchonella„ small smooth species	50
Pentamerus liratus and P. lens	2
Pterinea	1
Acroculia Haliotis	1
Crinoidea.
Periechocrinus moniliformis? stem joints	30
Bryozoa and Corals.
Fenestella (with close meshes)	1
Favosites alveolaris.
Petraia bina.

Mr. Eglinton also showed me just at the back of the house called Daffodilly at Hay Head, in a little deep ditch or gully overgrown with brambles, some beds of exactly similar sandstone, in which, however, we could find no fossils.

This was overlaid to the west, or in the direction of the old quarries of the Barr limestone, by Coal-measure shale containing a small two-foot coal, and cut off to the east by the Permian red marls, &c. North and north-east of it also Coal-measures containing small beds of coal had been found. These Coal-measures, no doubt, rest unconformably on the upturned and denuded edges of the Silurian rocks, and it is quite possible that the Llandovery sandstone would be found under the greater part of those Coal-measures which spread over the space north-east of the Three Crowns Inn, between the outcrop of the Barr limestone and the Permian rocks which come in on the east side of the Boundary fault. In the Lower Lickey Hills, between Birmingham and Bromsgrove, there is a ridge of quartz rock determined by Sir R. I. Murchison to be altered sandstone of this age. I can add little to the full and accurate description of this rock and neighbourhood which is given in the "Silurian System," and shall, therefore content myself with the following quotations from it:—

"On first examining the tract in 1834. I observed, that at two points on its eastern and south-eastern flank (Colmers and Kendal End) the quartz rock was overlaid by a limestone and shale which contained some corals and shells of the Wenlock formation. At Kendal End, the solid limestone extracted, 23 years before, did not exceed a yard in thickness, but it was accompanied by small concretions called 'batch cakes.' The existence of another thin band of limestone was ascertained by sinking for coal at the Colmers." * * * "The sheds of coal and shale" * * * "were easily penetrated; and the sinkings were continued through a thin layer of impure limestone, only 13 inches thick, which, from its appearance and organic remains. I consider to be one of those calcareous courses which underlie the Wenlock shale, and form the top of the Caradoc ('Llandovery') sandstone (Woolhope limestone)." * * * "After penetrating this limestone, the coal speculators sunk till they were stopped by a hard quartzose sandstone and reddish slaty clay, similar to that which rises on the eastern flank of the quartz hills. Near the southern extremity of Snead's Heath, the cutting of a new road exposed a reddish siliceous sandstone, made up of rounded grains of quartz, containing casts of characteristic Caradoc ('Llandovery') fossils. These fossiliferous sandstones, having in themselves a half-fused appearance, form the upper portion of the true quartz rock of these hills, into which they graduate insensibly at Snead's Heath, so that it is impracticable to draw any defined line between the reddish fossiliferous sandstone and the quartz rock."

The little fragments of limestone or calcareous flags lying on the old spoil banks in the Long Wood near the Colmers, when I examined the ground, were precisely similar to those which I, afterwards saw in the ploughed field at Shustoke Lodge. I have, therefore, now no doubt that those calcareous courses at the Colmers, as well as the band of limestone formerly worked at Kendal End at the south end of the Lower Lickey range are also the representatives of the Barr limestone, and that the shales in which they lie repose directly on the Llandovery sandstone. Sir R. I. Murchison, indeed, expressly says above, that after penetrating the limestone bands at the Colmers, the speculators were stopped by hard quartzose sandstone and slatey clay similar to that which rises near the eastern flank of the Quartz Hills (see Fig. 21).

The beds of quartz rock in the Lower Lickey range are tilted at high angles, and in some places much contorted, and the whole must have a thickness of 300 or 400 feet at least.

What influence it was that converted the rather soft sandstone that is to be seen at Barr into hard quartz rock at the Lickey we cannot exactly say, but as the quartz rock has apparently no other cement than a siliceous one, it seems impossible that dry heat could have effected it. If, moreover, there had been heat of a sufficient intensity to cause this alteration, it seems scarcely possible to conceive that the Wenlock shales and limestones should not have been equally effected.

We may, perhaps, be permitted to speculate on the possibility of hot springs having at some period burst out along the line of the Lower Lickey, the water having either itself contained silica in solution, or having dissolved some of the silica of the sandstone and thus eventually cemented the grains together.

Note on the fossils; by J. W. Salter, Esq.

No traces of true Lower Silurian fossils occur in the district.

1. The fossils of the Bromsgrove Lickey have already been adverted to. It is sufficient to note that they are the common Llandovery or May Hill shells, such as Pentamerus oblongus, with P. lens, Spirifer elevatus, and a variety of Orthis calligramma, &c. They occur always as casts in the incoherent red grit, and are generally of full size. The fossils of the small patch of sandstone visible at Shustoke Lodge, near Barr, are also clearly referrible to the Upper Llandovery (or May Hill) zone. Among a number of Upper Silurian forms, such as the common species—

• Phacops caudatus,
• P. Stokesii,
• Atrypa reticularis,
• Rhynchonella Wilsoni,
• Acroculia Haliotis,
• Periechocrinus montliformis,
• Favosites alveolaris, and
• Petraia bina,

we have the characteristic shell Pentamerus lens, a species never known to range out of the Llandovery rocks (P. liratus does rise into the Woolhope shales). This shell, with other fossils, was found here in plenty by Mr. J. E. Davis, after Mr. Sharpe had discovered the locality.

2. Woolhope Limestone.

The limestone of Hay Head, near Barr, has been generally regarded, from its position, as the equivalent of the Woolhope band, but there is not much palæontological evidence to prove this, except the occurrence of very large specimens of the Illenus (Bumastus) Barriensis, for which well-known fossil it is the original locality.^[3]

The following are found either there, at Ginity Graves, or at Daffodilly, on the same band:—

• Calymene Blumenbachii; Phacops caudatus;
• Strophomena depressa, S. pecten, S' imbrex, S. funiculata, S. euglypha, and S. antiguata;
• Leptena transversalis;
• Obolus transversus; Orthis elegantula, O. biforata;
• Atrypa reticularis, A. marginalis;
• Spirifer elevatus, S, plicatellus;
• Athyris tumida;
• Rhynchonella nucula, R. deflexa., R. Grayii;
• Pterinea(?) planulata;
• Euomphatus discors, E. funatus;
• Orthoceras annulatum.

With a few corals, such as—

• Heliolites interstinctus;
• Thecia Swindernana;
• Favosites alveolaris (or F. Gothlandica);
• Halysites catenularius—the chain coral;
• Cyathophyllum truncatum, C. angustum;
• Omphyma turbinatum (the largest of the Silurian cup corals);
• Aulopora serpens, which is now found to be the creeping base of a Syringopora or tube-coral.

It will be seen that this is a Wenlock Limestone list, and there are, indeed, few localities where the Woolhope band possesses any great distinctive character to separate it from the Wenlock. At Presteign. Radnorshire, it has, perhaps, the most peculiar facies. (See "Siluria," 2nd ed., p. 118.)

3. A few localities in the Weenlock Shale, such as the "Five Lanes" near Walsall, and the Bell in the same neighbourhood, are full of the characteristic fossils; a few are not known in the beds below. There are the ordinary brachiopod shells above mentioned, with Strophomena imbrex of Davidson, and Obolus transversus; the last is most abundant. This curious shell occurs also in the May Hill sandstone (but not of this district). Pentamerus galeatus and Athyris tumida, two or three species of Pterinea, especially the Pt. (?) planulata, which grows to a large size. Cardiola striata, a Lower Ludlow shell. Acroculia Haliotis, Bellerophon, Phragmoceras pyriforme, and a smooth Orthoceras, Encrinurus punctatus, and Phacops caudatus, are the common trilobites. Ptychophyllum patellatum and Heliolites inordinatus are conspicuous corals in the shale.

4. The Wenlock Limestone (divided into two bands by a thick layer of shale, as above described) contains all the fossils above noted, with the addition of a host of others. Indeed, the quarries of Dudley are the most famous in the world for Upper Silurian organisms. Shells, corals, encrinites of very numerous genera and species, and trilobites, are all in a state of perfection such as no other locality in Britain exhibits. The well known collections of Messrs. Gray and Fletcher at Dudley, and the cabinets of nearly every public museum in Britain or elsewhere, are evidences of the great labour expended in collecting and developing these beautiful remains. A mere list of them would include nearly all the Upper Silurian forms in Britain. It will be necessary, therefore, to give only the more striking forms. The asterisks denote the comparative abundance of the species.

Among the trilobites the following are conspicuous:—

Calymene Blumenbachi *****, the Dudley trilobite or Dudley locust, an universal Silurian fossil.

Homalonotus delphinocephalus, a fine species, more common in the Woolhope limestone.

Lichas Anglicus ****, and L. Barrandii, with three other species.

Acidaspis Brightii ***, A. quinquespinosa ***. A. crenata, the large A. Barrandii, ***, &c.

Staurocephalus Murchisoni, found also in Lower Silurian rocks and in Bohemia.

Cheirurus bimucronatus *, and Spherexochus mirus ** (this last ranges to America).

Encrinurus punctatus ******, and E. variolaris ******, the strawberry-headed trilobites of Dudley, among the commonest of all the Dudley species.

Phacops Downingia ****, P. Stokesii, and P. caudatus **, all of them very common species.

Proetus latifrons, M'Coy, with another species, and the beautiful little Cyphaspis megalops ****, in which last, as well as in several other species above mentioned, the Dudley specimens show more or less clearly both sexes—the males narrower and with longer spines than the females.

Then of other classes, the Annelida for instance, we have Cornulites serpularius and Tentaculites ornatus in myriads. Dudley is especially rich in corals and Crinoidea. Of the last, multitudinous species are in the hands of Messrs. Fletcher and Gray, and are yet unpublished. The Cystidæ belong to another order of Echinoderms, and of these there are no less than ten species of the genera Apiocystites, Echino-encrinites, Ischadites (a doubtful Cystidean), Prunocystites, and Pseudoerinites; all which are described by Prot. Forbes in the Memoirs of the Geological Survey.^[4] Of true Crinoids we have no less than 23 forms already catalogued, but double that number are yet undescribed. Among the more conspicuous are the Crotalocrinus rugosus, a crinoid with net-like arms and a singular tuberculate stem, covered at its lower part with root-like processes.

Cyathocrinus, four species.

Dimerocrinus decadactylus and D. icosidactylus. The names imply the difference of character in the arms.

Of the genus Eucalyptocrinus, with its massive stomachal plates, two species occur at Dudley. E. decorus and E. polydactylus, and one at Walsall, E. granulatus. Platycrinus? retiarus is not rare.

Cheirocrinus serialis is a remarkable pendulous form. Marsupiocrinus celatus, two species of Pisocrinus (a minute fossil), Tarocrinus tuberculatus, and Icthyocrinus pyriformis, with Glyptocrinus expansus, are quite common fossils; and the long necklace-like stems of Pertechocrinus moniliformis occur on almost every slab of Dudley limestone.

The corals are still more numerous, and though there is no evidence that the Dudley limestone possessed the character of a coral reef, yet the floor of the sea must have been nearly covered with them. They are chiefly solitary forms, however, never exceeding a foot or two in diameter, and even this is rare. The more massive compound ones are Acerrularia ananas, Arachnophyllum typus, Cyathophyllum truncatum, Favosites alveolaris, and F. Gothlandica; the chain coral, and Heliolites interstinctus; occasionally one or other of the five species of Syringopora, Sarcinula organum. Linn., is more commonly Lower Silurian. Of the large cup corals, Cystiphyllum Siluriense and C. cylindricum, Cyathophyllum angustum, Ptychophyllum patellatum, and Zaphrentis lata, are conspicuous, with Omphyma turbinatum, the largest and commonest of all. Three species of Paleocyclus, a little mushroom coral, are beautiful forms. The smaller Millepores and branched corals are the most numerous. Alveolites Labechei, A. repens and A. seriatoporoides, Chatetes Fletcheri, Conites intertextus, C. juniperinus, and C. labrosus are minute-celled species. Favosites cristata has larger tubes. Two or three species of Heliolites, such as H. Grayi, H. petalliformis, and H. tubulatus, Labechia conferta, Thecia Swindernana. The last four species are everywhere found in Wenlock limestone.

There are a good many minute coral-like forms now more correctly referred to the Bryozoa, some of which are encrusting and parasitic (Diastopora and Discopora), others have free cup-like or net-like fronds, Fenestella, Polypora, Glauconome. Some are foliaceous, like the Eschara of our coasts; Ptilodictya lanceolata and P. scalpellum represent these, and are very common species.

Many of the brachiopod shells have been quoted above from the lower limestone band. To these the following must be added, and the more abundant ones are indicated by asterisks:—

		D. Dudley;	W. Walsall.
Orthis Bouchardi			W. **
O. Lewisii		D.	W.
O. hybrida****		D.	W. *****
O. biloba ****		D.	W. *****, very large.
O. rustica		D.	W. *****
O. var. rigida		D.
O. calligramma,	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	D.	W.
var. Davidsoni
var. Walsalliensis			W.
Strophomena filosa		D.
S. antiquata, large	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	D. ****, these are but one species.
(S. scabrosa, Davidson)
Spirifer sulcatus		D. ****, a minute species.
Sp. plicatellus		D. *******
Sp. var. interlineatus		D. **
Sp. var. globosus		D. ****
Sp. trapezoidalis		D. ****	W.
Sp. crispus		D. ****	W. ***
Pentamerus galeatus		D. ****
Rhynchonella Stricklandi		D. ******
Rh. deflexa			W. *****
Rh. didyma			W. *
Rh. Wilsoni		D., several varieties.
Rh. borealis		D. ****
Rh. Lewisii		D. ****
Retzia cuneata		D. ****
R. Salteri		D. ****
R.? Capewellii		D. **	W.
Discina rugata		D.
D. Forbesii		D. *
Crania (a radiated species)		D.

There are but few lamelli-branchiate shells; Orthonota cingulata, however, is not uncommon, and

Pterinea retroflexa **		D.
P. Danbyi, or allied species		D.
Avicula mira, Barrande		D. ***	W. ***
Mytilus mytilimeris		D. *****	W. *****
Ctenodonta Anglica		D.

are a few of the more ordinary forms.

Of Pteropods and ordinary spiral shells, Conularia Sowerbyi is abundant enough, and of several varieties, and probably there is another species.

Murchisonia Lloydii, M. undata, M. balteata, M. articulata, and at least seven other species, chiefly from the limestone.

Euomphalus alatus, E. funatus, E. sculptus, E. discors, E. rugosus, E. carinatus, and two or three undescribed ones.

Cyclonema carinata, and E. corallii; Turbo cirrhosus?; Macrocheilus; Natica; Acroculia prototypa, and A. Haliotis, with many species as yet unnoticed of all these genera.

Lastly, there are several Cephalopodous shells, though most of these are among the rarer forms.

Orthoceras annulatum and its variety, O. fimbriatum, is most common.

Phragmoceras pyriforme occurs at Dudley, Lituites comu-arietis, and L. tortuosus are only occasionally met with.

There are several rarer fossils, which we can scarcely do more than notice here; among others, two species of Chiton; an Ischadites, distinct from I. Kenigii; Pleurorhynchus aquicostatus; new species of Bellerophon; Pleurotomaria; Chemnitzia; Cyclonema; and other spiral shells. We may hope to have several of the new species published under the auspices of the Palæontographical Society.

The limestone was evidently a deep-water formation, and very tranquilly deposited.

5. Lower Ludlow.

Of the next succeeding or Lower Ludlow formation no list has been yet published. From the neighbourhood of Parkes Hall a good many species have occurred to the persevering search of Mr. John Gray. The following are a few of these. Bivalves seem to have been the most abundant, such as—

Orthonota semisulcata, O. impressa, O. rigida, O. amygdalina; Pterinea lineatula, P. Sowerbyi; Avicula ampliata and A. mira; Mytilus mytilimeris; Goniophora cymbaformis; Schizodus; Cardiola striata; and many others.

Several of the Brachiopods which occur in the limestone are also found in the shale, and need not be repeated here.

The Lingula Lewisti and Discina rugata, D. striata, and a new species, are frequent. Strophomena euglypha, S. depressa, &c. Orthis is rare. Spirifer interlineatus, Pentamerus galeatus and P. linguifer, Althyris tumida, and Rhynchonella Wilsoni, are some of them.

Spiral shells are numerous, though not of many species.

Pleurotomaria undata, and a new discoid species; Murchisonia Lloydii; Euomphalus alatus; Conularia; Cyrtolites, large and fine specimens; Bellerophon dilatatus, B. trilobatus, of very large size, and at least two other species; of Cephalopods, Orthoceras angulatum, O, bilineatum, O. annulatum, O. perelegans, Phragmoceras compressum; the large Lituites giganteus, and the small and rarer species, L. articulatus, all occur in these prolific shales.

Encrinites and corals are but scarce; and of Bryozoa only Ptilodictya lanceolata has yet been found; Trachyderma squamosa, an annelide common in the Lower Ludlow rocks of other localities, is found also here. There are six or seven species of trilobites, the Calymene and Encrinurus variolaris being the chief. Phacops caudatus is not uncommon; and the valves of a large Ceratiocaris are in Mr. John Gray's collection.

6. Aymestry Limestone (Sedgley, &c.)

But few fossils have been collected from this band, which nevertheless has an historical interest in connexion with the Silurian System. The limestone of Sedgley was clearly distinguished from the underlying Wenlock bands by the late Rev. T. T. Lewis, who correctly compared it with his native Aymestry rocks. The Pentamerus Knightii is found in it abundantly, but it is worth notice that this most characteristic shell occurs (though rarely) in the Wenlock of this very locality, and also of Presteign. It is also found in the Lower Ludlow rocks of several districts. Its true place is, however, clearly in the Aymestry limestone. At Sedgley, at the Beacon Hill, and at the Park School, some of the other Aymestry fossils have been found, viz., Phacops caudatus, the common Atrypa reticularis, Spirifer plicatellus, variety interlineatus, and Rhynchonella Stricklandi, together with Strophomena depressa, a Turbo, and a cup coral. There must be many more if the rock were carefully searched.

From the Upper Ludlow rocks, if they exist above these, no organic remains have yet been collected.

The chief peculiarity in the Silurian strata in this district is the separation of the Wenlock limestone into two bands. The same fossils occur in both bands and in the intermediate thick band of shale.

The list above given is the first corrected catalogue. I believe, yet published of the rich fauna of the Dudley limestone. It might be greatly extended.

J. W. S.

---

---

1. I state this on the authority of Professor Ramsay, who, on one occasion, accompanied me to Hay Head, and who was perfectly acquainted with the limestone of Woolhope, a district I never had the good fortune to visit.
2. See Journal Geol. Soc. Lond., vol. ix, p. 181. April 1853.
3. See Magazine of Nat. History, vol. 2, p. 41, figs. 8, 9, 10, 1829.
4. Vol. II, Part II.