GEOLOGICAL DISTRIBUTION. 101 
as those of the Yorkshire beds, but the same forms of Hyalostelia and Reniera can 
be recognised in them. 
At the head of the Gwydfyd Valley, on the Great Orme’s Head, there are 
portions of broken-up beds of white and bluish cherty rocks, which have been 
described by Mr. George Maw, F.L.S8.,' and estimated by him to be about 50 feet 
in thickness. They apparently belong to the series above the Carboniferous 
Limestone ; the fragments are filled with spicules, principally minute acerates, 
similar to those in the beds at Gronant. 
Scortanp.—The beds which have yielded the remarkable series of Sponge 
remains in Ayrshire, belong to what is known as the Upper-Limestone and Lower- 
Limestone series of the Scotch geologists, which are situated beneath the Millstone- 
grit, and thus on the horizon corresponding to the Yoredale series of Yorkshire 
and North Wales, in which Sponge-beds are so largely developed. 
In Ayrshire, however, the Sponge-remains” have principally been obtained from 
decayed material in the joints and fissures in the limestone, and in soft, siliceous 
clays infilling irregular cavities in the same rock. Mr. John Smith, of Kilwinning, 
has supplied me with the following list of localities in Ayrshire which have yielded 
Sponge-spicules; Stacklawhill, thirty feet above the Linn-Spout Limestone; Glencart, 
Lambridden, Linn Spout, and Monkeastle, in the Upper-Limestone series; Birkhead, 
Thirdpart, Blackstones, Cunningham Baidland, Low Baidland, Law, and Auchens- 
keith, in the upper part of the Lower-Limestone series ; and Crawfield in the lower 
part of the same series. Other localities are Dockra, Hillhead, near Beith, and 
Dunlop, Ayrshire. They have also been met with in the limestones at Corrie- 
burn, Campsie Hills, near Kirkealdy, Fifeshire, near Linlithgow, Charlestown 
Quarry near Inverkeithing, Roscobie Quarry, near Dunfermline, Macbiehil, Peebles, 
near Cupar, and near Dalkeith. The forms most widely distributed are the 
anchoring spicules of Hyalostelia and the cylindrical spicules of Reniera; m the 
Ayrshire district these are accompanied by the remarkably large spicules of Geodites, 
Asteractinella, Tholiasterella, and Acanthactinella. Though the beds of Sponge 
remains in Scotland are of much less thickness than those of Yorkshire and North 
Wales, yet, owing to the preservation of the spicules in loose materials, they have 
yielded a greater number of species. 
Trevanp.—A well-marked series of Sponge-beds, hardly inferior in importance 
to those of Yorkshire and North Wales, is developed in the so-called Upper Lime- 
stone of the Carboniferous series of the Irish Geological Survey. The Sponge- 
beds principally occur in the higher portions of the Upper Limestone, and they have 
been included with this as the equivalents of the Carboniferous or Mountain Lime- 
1 “Geol. Mag.,’ vol. i, 1865, p. 200. 
2 © Catalogue of the Western-Scottish Fossils,’ 1876, p. 36; also ‘ Proc. Nat. Hist. Soc. Glasgow,’ 
1882, p. 234. 
oO 
