Geologists' Association. 133 



Downing, LL.D. Secretaries : Rev. S. Haughton, M.D., F.R.S. ; Prof. Ramsay H. 

 Traquair, M.D. Council: Sir Robert Kane, F.R.S. ; Alphonse Gages, M.R.I.A. ; 

 B. B. Stoney, C.E. ; W. Frazer, F.R.C.S. ; Alexander Carte, M.D. ; W. H. S. 

 Westropp, M.R.I.A.; C. R. C. Tichborne, M.R.I.A.; Rev. Maxwell Close, M.A. ; 

 Francis M. Jennings, F.C.S. ; John Ball Greene, Esq. ; William H. Baily, F.G.S. ; 

 William Ogilby, F.Z.S. ; R. A. Gray, C.E. ; J.Emerson Reynolds, M.D. ; Edward 

 Hardman. From the statement of the Treasurers, it appeared that the financial con- 

 dition of the Society was highly satisfactory. The thanks of the Society to the 

 President for his very able address were moved by Col. Meadows Taylor, and 

 seconded by the Rev. Maxwell Close, and cordially agreed to by the Meeting. 



Geologists' Association. — I. — The annual general meeting was held on Friday, 

 February 7th, at University College, the Rev. T. Wiltshire, M.A., F.G.S., the 

 retiring President, in the Chair.— The report for 1872 shows that by educational 

 field-meetings, as well as by the papers published in the Proceedings, the Associa- 

 tion has been the means of imparting a considerable amount of geological know- 

 ledge to the members, many of whom are earnest students of Geological Science. 

 Henry Woodward, Esq., F.G.S. , F.Z.S., etc., etc., was elected Fresident for 

 1873 ; and R. Etheridge, Esq., F.R.S., etc., etc., Prof. Morris, F.G.S., J. Thorne, Esq., 

 F.S.A., and the Rev. T. Wiltshire, M.A., Vice- Presidents. Messrs. U. Hislop, J. L. 

 Lobley, and A. Bott were re-elected Treasurer, Hon. Secretary, and Ron. Librarian 

 respectively. The Rev. T. Wiltshire, M.A., was elected an Hon. Member in recog- 

 nition of his early services to the Association, of which he was one of the founders, 

 and a cordial vote of thanks was given to Mr. Wiltshire for his services as President 

 during the past two years. Votes of thanks to the other ofiicers of the past year and 

 to the auditors terminated the proceedings. 



II.— February 7th, 1873.— Henry Woodward, Esq., F.G.S., F.Z.S., President, in 

 the Chair.—" On the Diprionida; of the Moffat Shale," by Charles Lapworth, Esq., 

 F.G.S. 



After reviewing the history of investigation among the biserial graptolites, and the 

 antagonistic opinions regarding their internal structure held by different palaeon- 

 tologists, the author stated that a careful decomposition and examination of specimens, 

 of Cliinacograptus from the Moffat shale, preserved in a state of relief, had forced 

 him to the conclusion that the view of the duplicate nature of the polypary in this 

 genus advocated by Prof. Nicholson is substantially correct. The internal characters 

 are identical with those of Biplograptus. The diprionidian polypary is composed of 

 two distinct monoprionidiau polyparies (each having its own cseuosarc, virgula, and 

 separate hydrotheca) placed back to back and coalescing along their flattened dorsal 

 walls. There is certain evidence that this type of structure obtains among all, or 

 nearly al), the Moffat Climacograpti. Nevertheless he was not prepared to deny the 

 accuracy of Prof. Hall's interpretation of the internal characters of his Climacograptus 

 ? typicalis. As long as a doubt remained upon this point it was argued that it would 

 be unsafe to exclude Eetiolites and its allies from the Biprionidce, which might mean- 

 while be considered as embracing three such families, viz. Biplograptidce, Petiolitidce, 

 and a third and intermediate sub-family of which Glim. ? typicalis (H.) is the only 

 known example. The sub-family Diplograptidce will include all those species it- 

 present referred to Biplograptus and Climacograptus. Now that the type of structure 

 in these two genera has proved to be identical, a new classification is necessary. The 

 only remaining characters that can in all cases be employed for the purpose of 

 separation at our command are, the form of the polypary and the shape and arrange- 

 ment of the hydrotheci.fi. It was shown that the different species of the Diplograptidse 

 naturally arranged themselves into five groups, clearly individualized by striking 

 distinctions in these characters. Each of these groups it was contended was of 

 sufficient importance to be considered as forming a separate genus. In this way the 

 genera Climacograptus (Hall), and Ceplialograptus (Hopk.), would remain untouched, 

 and the author suggested that the generic term Biplograptus _ (M|Coy) should he 

 restricted in future to those species of which Bip. folium (His.) is the type, and 

 proposed two new genera, viz. Orthograplus to include those species resembling 

 Biplogr.qttadrhmicrotiatus (Hall), and Ghjptograptus for those found after the pattern 

 of Biplogr. tamariscus (Nich.) 



