328 Reports and Proceedings — 



refers the sandy beds above mentioned. 



Discussion. — Prof. Duncan, though accepting zones as useful in stratigraphical 

 arrangement, agreed with the author that they could not be used for fixing hard and 

 fast lines of demarcation. 



Mr. Evans pointed out that the main question at issue was whether the sandy 

 beds below the Cephalopoda-bed of Bradford Abbas were really the equivalents of 

 those which were found above the analogous bed in Gloucestershire. 



The Chairman regretted the absence of Fellows more especially interested in this 

 question. For himself, he regarded it as impossible to correlate particular zones over 

 any large area, and thought that the whole series might be considered as passage- 

 beds, the order of which might vary even within a limited distance. 



4. " Cetarthrosaurus Walkeri (Seeley), an Ichthyosaurian from the Cambridge 

 Upper Greensand." By H. G. Seeley, Esq., F.L.S., P.G.S. 



In this paper the author described a small Ichthyosaurian femur, discovered by 

 Mr. J. F. Walker in the Upper Greensand of Cambridge. He noticed the general 

 characteristics of the femur in Ichthyosaurians, and pointed out, as the chief 

 peculiarities of the bone that he was describing, the subovate form of its head, and 

 the presence of large flattened lateral trochanters, which, if of equal dimensions on 

 both sides of the bone, would have made its greatest transverse measurement greater 

 than its length. _ Upon this bone he proposed to found a new genus, Cetarthrosaurus. 



Discussion. — Sir P. Egerton was inclined to regard the trochanters as vertical 

 rather than as lateral. 



Mr. Seeley remarked that in calling the two trochanters lateral, he was guided by 

 the position in which it appeared to him that the Hmbs were carried during the life 

 of the animal. 



III. — Geologists' Association. 



Excursion to Charlton, April 26th.— The well-known section showing the 

 junction of the English Secondaries and Tertiaries was visited by a very numerous 

 party, under the direction of Prof. Morris, who, in an excellent lecture, described the 

 Chalk and the Lower Eocenes, with their foreign equivalents. Leaving this section, 

 the Professor conducted the members to that nearer the town of Woolwich, which 

 well displays the Shell-beds of the Woolwich and Reading series, with Thanet Sands 

 below, overlying the Chalk._ Ostrea and Cyrena form the great mass of the Shell- 

 beds, but the genera Melania and Cerithium, especially the former, are well repre- 

 sented. 



Excursion to Aylesbury, May 5th.— Prof. Morris, in the unavoidable absence 

 of Mr. W. Whitaker,_ B.A., conducted the party. The Hartwell exposure of the 

 Kimmeridge Clay, yielding Ammonites biplex and Astarte Hartwellensis, was first 

 visited, and afterwards the fine sections of Portland, Purbeck, and Neocomian beds 

 in the neighbourhood of Hartwell and Stone. Many fossils were obtained. 



Excursion to Eastbourne and St. Leonards, May 23rd and 24th.— Directors, 

 the Rev. B. S. Dewick, M.A., F.G.S., and Mr. John Hopkinson, F.G.S. On arrival 

 at Eastbourne, the party visited the Museum of Eastbourne College, and afterwards 

 the Caldecott Collection, and that of Dr. Ogier Ward. During the afternoon, an 

 exposure of Alluvium overlying the Gault at " the Wish " was seen, and the fine coast 

 section extending to Beachy Head, showing the Upper Cretaceous series, examined. 

 On the following day, Bexhill and St. Leonards were visited, and under the guidance 

 of Mr. J. E. H. Peyton, F.G.S., the members had opportunities of studying sections 

 of the Weald Clay, Tunbridge Wells Sands, Wadhurst Clay, Ashdown Sands, and 

 the Ashburnham Beds. The members of the Association were most hospitably 

 entertained by Mr. Roper at Eastbourne, and Mr. Peyton at St. Leonards. 



Excursion to Pinchley, May 31st.— Director, Mr. H. Walker, F.G.S. At East 

 End,_ the efi'ect on the physical features of the neighbourhood produced by the 

 Glacial deposits was pointed out, and by the aid of an enlarged SurveyMapof the district, 

 a copy of which was given to each member of the party by Mr. Walker, the area of 

 these deposits was seen to be triangular, with Muswell Hill, Hendon, and East Barnet 

 indicating i\j^ extent. At the Marylebone Cemetery a large number of fossils from 

 the Drift were seen, and at the Manor brickfield a good exposure of the great Chalky 

 Boulder-clay was examined. Mr. Walker explained its relations and the conditions 

 of its deposition, and then conducted the party to the high ground near Finchley 

 Station, where Mr. Caleb Evans, F.G.S., described the physical geology of the 

 northern parts of Middlesex, and exhibited diagrams showing the extension and out- 

 crop of the formations seen in the district. 



Excursion to Brighton, June 11th. — Directors : the President, and Professor 

 T. Rupert Jones, F.R.S. On arrival at Brighton, the party crossed the South Downs 



