628 EDWAHD HULL ON THS CLASSIFICATION Stage F. Coal-measures. — Sandstones, clays, and shales, with numerous feet, beds of ironstone and coal. Fish-remains abundant, also Anthra- cosia, Anthracomya, and Anthracoptera. One or two marine bands occur over the " Ten-foot Coal of Hanley"* 3500 Stage E. Gannister Beds. — Black shales and flags, with a few thin coals and red ironstone. Orthoceras, Goniatites Listeri, Lingula, Aviculo- pecten papyraceus, Anthracomya 1000 Stage D. Millstone Grit. — Coarse grit, shales, and flags , 1000 Stage C. Yoredale Beds.— Dark shales and yellow grits, with marine shellst, — Goniatites excavatus (Phil.), G. obtusus (Phil.), G. reticu- lata (Phil.), G. truncatus (Phil.), Macrocheilus, Aviculopecten pa- pyraceus, A. alternatus, Inoceramus, Ctenodonta gibbosa, Myalina, Discina nitida, Productics longispinus, &c 3100 Stage B. Carboniferous Limestone. (Base not visible). The very complete lists drawn up by the late Mr. Salter J, prove that the great mass of the central measures were either estuarine or freshwater — the Mollusca being represented by Anthracosia and its congeners, — while those of the Lower Coal-measures are distinctively marine. Mr. Ward, F.G.S., of Longton, however, has discovered two bands of marine shells amongst the Middle Coal-measures. One of these, in the black shale, overlying the " Bay Coal " contains shells of the genera Nautilus, Goniatites, Aviculopecten, Melania, Prochictus, Discina, and Lingula ; and Mr. Ward informs me that he has lately discovered another band with similar fossils above the " Ginmine" coal, near the bottom of the Middle Measures §. (4) Flintshire and Denbighshire. feet. Stage G. Upper Coal-measures. — Red and grey sandstones, red clays, shales, and a few thin coals. A band of limestone with Spirorbis carbonarius. 1000 Stage F. [Middle'] Coal-measures. — Sandstones, shales, &c, with coal- seams and ironstones, fish-remains || and Anthracosia, &c 800 Stage F. Gannister Beds. — Grits, flags, and shales, with thin coals. Go- niatites, Aviculopecten, &c.^[ 1000 Stage D. Millstone Grit — Massive grit, coarse and fine, with shales 800 Stage C. — Shales (series thin here) 100 Stage B. — Carboniferous Limestone 1000 to 1500 Stage A. — Shales, thin or absent to 30
- Salter, ' Iron-ores of Great Britain,' part ii. Appendix. Mr. Salter has
given very complete lists of the beds in descending order. With two exceptions, the truly marine genera are confined to the Lower Measures. t Determined by Mr. Salter and Mr. Etheridge, " Geology of Stockport, &c," Mem. Geol. Survey, 1866.
Loc. supra cit. § Letter, dated Aug. 4, 1876.
|| Bhizodus, Cozlacanthus, Platysomits, and Palceoniscus, according to Sir P. Egerton. ^[ Determined by Mr. Binney, F.R.S., and communicated to the writer, ' Coal- fields of Great Britain,' 3rd ed. p. 149.
