Kirkbya permiana, Jones. (Pl. III. fig. 1 .), 1859

Gunther, Albert C. L. G., Dallas, William S., Carruthers, William & Francis, William, 1885, The Annals and Magazine of Natural History, Including Zoology, Botany, and Geology, Reptiles and Batrachians from Brazil, LONGMANS, GREEN, AND CO.; SIMPKIN, MARSHALL, AND CO.; KENT AND CO.,; WHITT AKER AND CO.: BAILLIERE, PARIS: MACLACHLAN AND STEWART, EDINBURGH: HODGES, FOSTER, AND CO., DUBLIN: AND ASHER, BERLIN: TAYLOR AND FRANCIS, pp. 1-96 : 177-179

1. Kirkbya permiana, Jones. (Pl. III. fig. 1.)

Dithyrocaris permiana, Jones, 1850 , in King ’s ‘ Monograph of Permian Fossils ’ (Pakeont. Soc.), p. 66, pl. 18. figs. 1 a-d.

Ceratiocaris? permiana, Jones , in Morris's Catal. Brit. Foss. 1854, p. 103.

Leperditia? permiana, Kirkby, 1858 , Ann. & Mag. Nat. Hist. ser. 3, vol. ii. p. 434, pl. xi. figs. 5-13.

Kirkbya permiana, Jones & Kirkby, 1859 , Trans. Tyneside Field-Club, vol. iv. p. 129, pl. viii. a. figs. 1, 2, 3, and 5 (figs. 4 and 7, K. glypta), pl. x. figs. 5, 7, 9-12 (figs. 6 and 8 K. glypta ).

Kirkbya permiana, Kirkby, 1861 , Quart. Journ. Geol. Soc. vol. xvii. p. 308.

Kirkbya permiana, Jones & Kirkby, 1867 , Trans. Geol. Soc. Glasgow, vol. ii. p. 220; 1871, vol. iii Suppl. p. 28.

Kirkbya permiana, Armstrong and others, 1876, Catal. Western-Scottish Foss. p. 44.

Kirkbyapermiana, J. & K. 1880, Quart. Journ. Geol. Soc. vol. xxxvi. p. 588.

This species, as a Permian “ recurrent,” was fully described in the ' Annals and Magazine of Natural History ’ for Nov. 1858; and again, in more detail, in the ‘Transactions of the Tyneside Field-Club ’ for 1859. The descriptions and figures there given of Permian specimens from the Mag ­ nesian Limestone of Tunstall Hill would do equally well for most of the many Carboniferous examples of the species that have come under our notice; but, for convenience, we describe it from the latter as follows:—

Carapace ark-shaped or suboblong, flatly convex or com ­ pressed, height half the length or rather more. Dorsal border straight, sometimes the full length of the valve, some ­ times rather less, according to the relative boldness of the curve of the extremities; ventral border faintly incurved, straight, or gently convex in its middle third, and boldly curved at the extremities, the anterior extremity being the most acute. The extremities and ventral portion of each valve are bordered by two parallel, concentric rims or expan ­ sions, v hicli project a considerable distance beyond the surface of the valve. A small oval pit occupies a subcentral position on each valve, and the surface is beautifully reticu ­ lated. Length inch.

The Carboniferous specimens of this species vary consider ­ ably in character. The drawing here given (Pl. III. fig. 1) is that of an average good specimen; other illustrative figures would have been given had circumstances allowed.

The outline of the valves is usually as described above; but sometimes the extremities and ventral margin almost approximate the curve of a semicircle in the regularity of their contour; from this extreme the ends by degrees become more abruptly sloped, and the ventral border straightened, until an oblong figure is approached.

Many examples have the valves much depressed, others have them moderately convex (and so form a carapace of fair capacity); and there are some few where the regularity of their surface is interfered with by one or more lobe-like swel ­ lings. In this feature it resembles K. Schrenkii, Keyserling*; but the latter has a rounded, and not ridged, ventral margin.

The ventral rims vary in development, and are apparently largest in old individuals. In some cases the mesh-walls on the reticulated surface show a tendency to run in faint riblets within and parallel to the marginal ridges.

The reticulation of the surface is relatively large, in most cases with a more or less angular form of mesh, and is very beautiful in well-preserved specimens.

The subcentral spot is often obsolete or not to be seen.

Kirkbya ptermiana is of common occurrence in the marine shales of the Carboniferous-Limestone series of Scotland and the north of England. It is found in a similar shale in the upper portion of the Calciferous Sandstone of Fife.

As a Permian species it is met with in the Magnesian Limestone of Durham and Yorkshire, also in Germany.

Some of its British localities are as follows:—

Scotland. Calciferous Sandstone: coast west of Pittenweem, Fife. Carboniferous Limestone (Lower): Brockley, Calderside Quarry, Brankumhall Quarry, in Lanarkshire; Galabraes, Whitebaulks, in Linlithgowshire; Corrieburn, Scullengour, Craigenglen, in Stirlingshire; Fullerton, Currielee Lime-works, Darcy Limestone Quarry, Magazine Lime ­ works, Hillhead Quarry, near Cockmuir Bridge, in Edin ­ burghshire; Catcraig, near Dunbar, Burlage Quarry, East Saitou, in East Lothian; coast near Abden, Glenniston Quarry, Inverted Quarry, Ladedda Quarry, Wilkieson, Cults, Teasses, in Fife; Carlops, Whitefield, in Peeblesshire. Car ­ boniferous Limestone (Upper): Robroystone, Orchard, Kennox Water, Auchenbeg, in Lanarkshire; River Avon below Kinneil, in Linlithgowshire; &c.

England. Carboniferous-Limestone series: Scremerston, Ridsdalcf, Ancroft, in Northumberland; Barnard Castle, Dur ­ ham; Wyebourne, Calces, in Cumberland; in the Scar Limestone at Stainton Quarry, Lancashire.

As a “ recurrent ” in Permian strata it is found in the following localities:—

In Lower Magnesian Limestone: Westoe, Eldon, East Thickley, Walworth, Morton Tinmouth, Summerhouse, and Langton, in Durham; railway-cutting at Chapel Houses (west of Pierce Bridge), Crakehall, Thornton Watlass, Nosterfield, and Hampole, in Yorkshire. In Middle Magnesian Lime ­ stone: Tunstall Hill, in Durham. In Upper Magnesian Limestone: Byer ’s Quarry, and cliffs to the south of Marsden, on the Durham coast.