Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/761

Rh OF THE CARBONIFEROUS SERIES. 651 classification as a whole, but thought that such hard separate groups as appeared to be indicated could not be sustained. In Shropshire we have at the top of the Coal-measures the Sjrirorbis Limestone, then beds with various marine fossils, and below these deposits with Anthracosia?. In Belgium the Coal-measures are also associated with beds containing BelUrophon and other marine forms. He considered the character of the Carboniferous series to be depen- dent on conditions of depth in the different areas. Mr. Etheridge thought that previous speakers had been rather hard on Prof. Hull, seeing that the sharp lines objected to are pre- cisely those which we have been long working on, and the author had merely attempted to correlate certain beds. The author's lists of fossils seemed to him to be of great use as evidence of very sig- nificant changes. Mr. Etheridge maintained that in the correlation of these, as of other deposits, palaeontological as well as physical evidence must be taken into consideration. It was difficult to understand how such a flora as that of the Coal-measures came to be associated with a marine fauna. Mr. Hull's groups were not new ; but the grouping was important, and Mr. Etheridge was dis- posed to agree with him in his correlations. Mr. Warentgton W. Smyth referred to the work done in connexion with these questions more than thirty years ago by Mr. Binney, and expressed a hope that due credit was given to that gentleman in the paper. It seemed to him that the author had set out by esta- blishing the homotaxis in this country, but that he had then jumped to a cod elusion about the deposits in Scotland. He inquired if there was evidence of the Gannister beds between those generally so called in England and those in Scotland, as, for example, in Durham. Prof. Morris agreed with Prof. Dawkins as to the difficulty of recognizing a break at the Gannister beds, the distribution of which was very interesting ; but they differ in their characters somewhat in their E. and W. range to Wales, as compared with their trend from S. to N. towards Scotland. Some of the marine forms in these rocks are species continued from the old Carboniferous sea. He said that Anthracosia was certainly not a Unio. In Shropshire there are intercalated marine beds, and with these the same Anthracosia. In Scotland the horizons are not so distinct. The Author, in reply, said that some of the points raised b}* the speakers were already met in his paper. He stated that he had on principle rejected both fish and plants as furnishing data for classi- fication : the fish were Ganoids, and therefore probably migratory. Hence we are compelled to fall back on the Mollusca. Throughout the investigation Anthracosia had been his bane, since it occurs sometimes with marine and sometimes with freshwater companions. As regards the term " Yoredale series," he used it in this paper in the sense adopted by the Geological Survey in the districts of Derby- shire, Lancashire, and Yorkshire. It seemed to him that sufficient importance had not been given by the speakers to the palaeontological break above the Gannister beds ; out of 75 species of marine genera below this line not more than 6 pass upwards.