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The fossils are generally met with in the Magnesian Limestone or Marl slate; plant remains, however, are found in the Lower Red Sandstone: they include Fenestella retiformis, Productus horridus, Spirifera alata, Avicula speluncularia, Schizodus obscurus, Bakevellia, Palæoniscus, &c.; also remains of Protorosaurus and Labyrinthodont reptiles. The flora, which includes Sigillaria, Alethopteris, and Neuropteris, is nearly allied to that of the Coalmeasures; but Mr. Carruthers has observed that the Permian vegetation possesses Mesozoic affinities, and in fact that the commencement of the Mesozoic flora is to be sought in the Permian.

Professor Phillips first suggested that the Magnesian Limestone should on palæontological grounds be classed as Palæozoic.

The following localities where the beds are represented are given by Murchison :

Red Sandstone and Marl.-West of Doncaster; St. Bee's
Head and Corby Castle, Cumberland.

Magnesian Limestone.—Coast Cliffs from Tynemouth to
Hartlepool, Clacksheugh, Eldon, Thickley, Ferry Hill,
Humbleton Hill (Durham); Masham, Roach Abbey,
Bramham Moor, Ferrybridge, Tadcaster, Knares-
borough, Bolsover Moor, Creswell Crags (100 ft.), and
Steetly (Yorkshire, Derby, and Notts.)

Marl Slate.-Thickley, Ferry Hill, Durham; Escarp-
ment of Magnesian Limestone from Bramham Moor to

Lower Red Sandstone, &c.-Clacksheugh, Durham; Plumpton Rocks, near Knaresborough, and Pontefract, Yorkshire; Astley, Lancashire; Penrith; Wolverhampton to Coalbrook Dale, South of Shrewsbury, West of Birmingham, and around the Dudley Coal-field.

This statement will explain the use of some local names, such as the Pontefract rock (W. Smith), which forms a natural base to the Magnesian Limestone; the Bolsover Limestone, which is a yellowish-brown dolomite; the Knottingley Limestone, the Weldon Wood Stone near Ferrybridge, the Fulwell Limestone near Sunderland, &c.

The lower portion of the Plumpton rocks has been considered by some geologists to be Millstone Grit (see p. 90.) In Durham the thickness of the Permian rocks is about 600 feet.

Lower Permian Beds.-Professor Hull has pointed out that the Lower Permian series of the western and central parts of England may be arranged under two distinct types of strata, of which those at Enville in Shropshire, and the sandstone of Collyhurst, near Manchester, may be considered as representative beds. To the Salopian type may be referred the whole of the Permian rocks as they occur in Shropshire, Staffordshire, and Warwickshire; and to the Lancashire type, the rocks of this formation as they occur at Stockport in Cheshire, in South Lancashire, and the north-west of England.

The beds of the Salopian type attain a thickness of about 1,500 feet, and include:

Red and purple sandstones and marls; breccia, calcareous conglomerate, sandstone and marl; purple, red, brown and white sandstones, often calcareous.

The beds of the Lancashire type include:

Red marls with numerous bands of fossiliferous limestone, worked for lime, 130 feet. (These beds are considered to be the representatives of the Magnesian Limestone of Yorkshire and Durham.)

Bright red and variegated sandstone, about 1,500 feet.

The evidence furnished by these types led Professor Hull to conclude that a ridge of Lower Carboniferous rocks crosses the plain of Cheshire beneath the Trias, and forms a boundary between them.

Magnesian Limestone.-The Magnesian Limestone is sometimes globular or botryoidal in structure; it is usually of a yellowish colour, and sometimes contains cavities lined with crystals of calc spar. In composition it contains nearly equal proportions of the carbonates of lime and magnesia: and it is sometimes termed Dolomite or Dolomitic limestone.2 The dolomitic limestone of Marsden, near Sunderland, is flexible. Some beds in Yorkshire are said to be fetid.

The thickness of the Magnesian Limestone is 300 feet in Durham, and this thickness is maintained at Pontefract, the series gradually diminishing in thickness to about 120 feet near Annesley.

The Magnesian Limestone has been largely quarried at Bolsover in Derbyshire, from which locality the stone used in the construction of the new Houses of Parliament was procured. There is about 12 feet of workable stone, of a pale brownish-yellow colour.3 Southwell Minster was also to some extent constructed from this stone, and partly from that at Mansfield. Quarries have been largely worked at Roach (or Roche) Abbey, near Bawtry, in Yorkshire; also in the neighbourhood of Doncaster, at Brodsworth, and Park-nook, Worksop, &c.

The stone employed in the Museum of Practical Geology was obtained at Anston. At Huddlestone, the rock used in the construction of Westminster Hall was obtained. Jackdaw Craig, near Tadcaster, and Smawse on Bramham Moor,

1 Termed Redland limestone by Wm. Smith.

2 So called after the geologist Dolomieu.
3 Sometimes termed Dunstone in Derbyshire.


are well known localities for this building-stone. York Minster was partly constructed of stone from Jackdaw Craig, and Beverley Minster of stone from Smawse.

The yellow crystalline limestone of Mansfield Woodhouse is well known as furnishing a good building-stone; in the neighbourhood of Mansfield, red and white sandstones, which are probably on the same horizon, and, according to Mr. Aveline, only siliceous varieties of the Magnesian Limestone, have been much quarried for building purposes: they are

known as the Mansfield White and Mansfield Red Sandstones. The Mansfield sands have been used for casting. Quicksand occurs at the base of the Magnesian Limestone south of Harthill.

The Magnesian Limestone forms light, arable, and dry soil; it has been used for agricultural purposes, being burnt for manure, the limes of Kinnersley, Knottingley, Roach Abbey, Brotherton, Ferrybridge, Mansfield, &c., being celebrated.

Slabs of Magnesian Limestone are said to have been polished at Knaresborough, Sunderland, &c.

The Lower Magnesian Limestone near Tadcaster contains beds of hard flinty rock, called Calliard or Galliard, which is used for road metal.

In some of the chemical works on the Tyne the dolomites of the northern counties are used for the production of carbonate of magnesia; while the magnesian limestones of Marsden are taken in considerable quantities to Sunderland, where, being treated with sulphuric acid, the magnesia is dissolved out, and from the liquor obtained, Epsom salt (sulphate of magnesia) readily crystallizes. A considerable proportion of the Epsom salts now sold is thus obtained.'

1 Hunt and Rudler, Descriptive Guide to the Museum of Practical Geology.'

The Permian beds of the Lake district occupy the Vale of Eden or Cumberland Plain, resting unconformably upon the Carboniferous rocks. They also border the sea-shore from St. Bee's Head to the estuary of the Duddon, and occur further south at Walney Island and the adjoining land.

The unconformability is shown near Appleby, and near Whitehaven. Here the beds are well developed. The lower division consists of red sandstones and breccias, including the Penrith sandstones, and also in places magnesian limestone; the middle division consists of red gypseous shales and clays (Hilton shales), with thin limestones; and the upper of red and white sandstones (Corby Sandstones) and shale.

Dr. Nicholson states the maximum thickness of the group to be 8,000 feet in the neighbourhood of Penrith, and from 3,000 to 4,000 feet in the vicinity of Appleby. Professor Harkness considers that there is little prospect of workable coal beneath the Permian beds of the Vale of Eden.

Mr. Goodchild informs me that pseudomorphous crystals of rock salt occur in the marls, and that the Lias and Rhætic Beds come on close above the series at Carlisle : facts suggesting the possibility of some of the so-called Permian turning out to be Trias. The term 'brockram' is locally applied to the breccias, which are formed to a large extent of fragments of Carboniferous Limestone imbedded in a red sandy matrix. They are well developed near Appleby and Kirkby Stephen, and are largely quarried in places for lime.

Some plant-remains, Alethopteris, Cardiocarpum, Odontopteris, Sphenopteris, and Ullmania, found in the Hilton Shales, are the only organic remains recorded from the Permian rocks of the Vale of Eden.

At St. Bee's Head, the Permian and Trias are considered by some authorities as unconformable. Sedgwick considered

the red sandstone to be Bunter.

The following is the section at St. Bee's Head :

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