Geological Society of London. 231 



the Eurypteridee. The thoracic plate in the fossil species no doubt varied in form in 

 the male and female, as it is found to do in the recent King Crabs, and this variation 

 might be connected with sex. In some Slimonim from Lesmahago the only difference 

 to be found was in the thoracic plate, and it had been suggested by the speaker that 

 this was due to difference of sex. He had also suggested that the small Pterygotus 

 and the great Slimonia might be only the male and female forms of the same species, 

 a great diversity in size between the male and female existing in many living 

 crustaceans — the males, too, having clasping organs for holding the female — of 

 which the chelate antennae of Pterygotus might be the homologues. On fragmentary 

 remains it was, " however, unsafe to attempt to generalize ; but he thought 

 Eurypterus BrocUei was a well-marked species. 



Eev. H. H. Winwood inquired whether there was any evidence as to Eurypterus 

 being fresh-water or marine. 



The Chairman observed that the seeds from the passage-beds did not appear to 

 him other than those of land-plants, and had been previously described by Dr. 

 Hooker as spore-cases of Lycopodiacese. 



2. " On the Cliff-sections of the Tertiary Beds west of Dieppe in 

 Normandy and at Newhaven in Sussex." By William Whitaker, 

 Esq., B.A., F.G.S. 



The author gave details of the sections of the Tertiary beds at 

 the above places, and noticed the occurrence of London clay. Below 

 this formation, at Dieppe, is a mass of sand, the same as that of the 

 "Old Haven beds " in East Kent, but here less markedly divided from 

 the clay above; and beneath this sand come the estuarine shelly 

 clays, &c. of the Woolwich beds. 



In the older accounts of the Newhaven section a much less thick- 

 ness of the Tertiary beds is chronicled than may now be seen ; indeed 

 the successive descriptions end upwards with higher and higher 

 beds, owing to the destruction of the coast and the wearing-back of 

 the cliff into higher ground, the highest point seeming to have been 

 at last reached. 



Here the Oldhaven sand is absent, but the Woolwich clays are in 

 greater force : and the ditch of the new fort shows some very irre- 

 gular masses of gravel, more or less wedged into those clays. 



Both sections show the comparatively wide extent of like condi- 

 tions to those of the Woolwich beds of West Kent. 



Discussion. — The Chairman, in inviting discussion, called attention to the existence 

 of Tertiary beds of similar character near Epemay and Eheims, and in other parts of 

 France. 



Mr. Evans remarked on the bearing which this extension of soft, yielding strata 

 had on the excavation of the Channel. The disturbances in the sands and clays 

 might be due to the springs having formerly, owing to the distance of the sea and the 

 river-vaUey not having been excavated, stood at a higher level, and having thus 

 softened or even washed away, the bed beneath the gravels. 



Mr. Pattison mentioned that in all the combes along the French coast towards 

 Treport there were traces of soft Tertiary beds, possibly Thanet sands. 



Mr. Whitaker, in reply to a question from the Chairman, stated that, to the best of 

 his belief, the sandstones at Dieppe were not calciferous. The sands were above the 

 "Woolwich beds, and therefore not Thanet sands. 



3. " On New Tree Ferns and other Fossils from the Devonian." 

 By Prof. J. W. Dawson, LL.D., F.E.S., F.G.S. 



The author referred to the numerous species of ferns known in the 

 Upper and Middle Devonian of America, and to the fact that he had 

 described several large petioles as probably belonging to arborescent 

 species, and also two trunks covered with aerial roots, viz., Fsaronius 



