Page:Quarterly Journal of the Geological Society of London, vol. 34.djvu/48

24 24 E. ETHERIDGE, JTJN., ON LOWER- CARBONIFEROUS INVERTEBRATE. the Arthur's -Seat beds) ; hut at present these appear to he all we know of. Proceeding upwards, however, we meet with some de- batable beds of sandstone and shale resting on the felstones of Warklaw Hill along the north flank of the Pentland Hills *, which Prof. Geikie informs me he is inclined to place at the base of the Cement- stone group. These beds, where cut by the Clubbidean Burn, contain Sphenopteris affinis, L. & H., Leperditia scoto-burdi- galensis, Hibbert, and a crushed bivalve which Mr. Salter considered an oval species of Myalina f . In the south bank of the Clubbidean Eeservoir a limestone of the same set of beds is seen to be almost entirely made up of Spirorbis helicteres, Salter, with Sp>. carbo- narius, Murchison. This appears to be the first appearance of which we have any record of Pelecypoda and Annelida in the Lower Carboniferous of this district, and was regarded by Mr. Salter as indicative of marine conditions!:. In some shales overlying the Greenstone of Craiglockhart Hill, seen in an old quarry on the north side of the Colinton road, near Edinburgh, a more copious fauna has been found by Mr. Henderson. We there meet with Discina nitida, Phill., Lingula squamiformis, Phill. ?, L. mytiloides, Sow., Avicula Hendersoni, mihi, Myalina sublamellosa, mihi, and Anihracosia ? nu- cleus, Brown. On passing to the strata more properly known as the Wardie Shales, we meet with a still further increase in the life of the Lower Carboniferous. The Annelida are augmented by the appearance of Serpulites carbonarius, M'Coy, at Woodhall. The Actinozoa also first put in an appearance in this horizon ; for we find many of the Orthoceratites occurring in the Woodhall shale covered with a para- sitic Chaitetes. Brachiopoda had previously been recorded from the Wardie Shales, as before stated, by Mr. Davidson and Mr. Salter, in the form of Lingula squamiformis at Wardie. A well-marked ex- ample of this species has been obtained by Mr. Henderson in the Water of Leith at the Dean Bridge, Edinburgh; whilst Lingula mytiloides has passed from the Craiglockhart Shale to the Woodhall horizon, accompanied by Avicula Hendersoni. The occurrence at Juniper Green of the frequently-mentioned bed of shale below the ford at Woodhall Mill brings us, perhaps, to one of the most impor- tant points in connexion with the Carboniferous geology of the south-east of Scotland ; for we here meet with the first appearance of several species of marine shells which pass upwards from these beds and ultimately become some of the most characteristic fossils of the Carboniferous Limestone. The species contained in this bed which have previously made their appearance are Sjpirorbis car- bonarius, Discina nitida, Lingula mytiloides, and Avicula Hendersoni. Those which first make their appearance here are Chmtetes, sp. ind., Serpidites carbonarius, Aviculopecten, sp. ind., Myalina crassa, Elem., var., Schizodus Salteri, Pandora typica, Pleurotomaria moni- liferal, Murchisonia striatulal, Bellerophon decussatus, Elem., var., Conularia, sp. ind., Nautilus cariniferus 1 ? , and Orihoceras. One spe- cies, Nuculana Sharmani, is peculiar to this bed.
 * Memoir 32, p. 18. t Ibid. j Ibid. p. 144.