188 Reports & Proceedings — Geological Society of London. 



the time problem is to be found in a reversion to other lines of 

 reasoning. The sea-salt methods, and those based on the thickness 

 of the sedimentary rocks in particular, need careful reconsideration. 

 Reference is made to a number of papers which show that the first of 

 these is worthless, and the second based on a misapprehension of the 

 nature of deposition. The argument from tidal retardation is still of 

 value, as also is that from the evolution of carbonate of lime. To the 

 author radio-active experiments come as a confirmation of views held 

 on other grounds, but are not sufficiently important in themselves to 

 be authoritative against the balance of the evidence derived from 

 other lines of investigation. 



3. March 10, 1915.— Dr. A. Smith Woodward, F.B.S., President, in 



the Chair. 



The following communications were read : — 



1. "The Plants of the Late Glacial Deposits of the Lea Valley. " 

 By Clement Beid, E.R.S., F.L.S., V.P.G.S. 



Large collections of plants from the Lea Yalley deposits, already 

 described, have been made by Mr. S. H. Warren, Mr. E. T. Newton, 

 and Mr. Wrigley. The localities from which the plants were 

 obtained are Angel Poad, Hedge Lane, Ponders End, and Temple 

 Mills. A list from Ponders End has already been given by Dr. Lewis; 

 but the new collections include many unrecorded species, several of 

 which have not previously been noted as British fossils. Although 

 there are slight differences, the collections from all four localities are 

 so similar as to leave no doubt that the deposits are contemporaneous. 

 The whole assemblage points to a very cold climate, though perhaps 

 not quite so cold as that indicated by the Arctic plants found at 

 Hoxne, in Suffolk. 



Among the more interesting novelties may be mentioned Armeria 

 arctica, a species of thrift now confined to Arctic America, although 

 it has also been recorded as a Pleistocene fossil from the continent 

 of Europe by Dr. C. A. Weber. Leaves of Salix lapponum are also 

 abundant, though this species does not seem to have been found fossil 

 elsewhere. Some delicately-veined membranes, probably identical 

 with the "petal-like objects" mentioned by Dr. Lewis, prove to be 

 pods of the Alpine Draba incana. Other shorter forms are pods of 

 a scurvy-grass, not yet satisfactorily determined. 



The extinct forms are a new species of Silene, near to S. noctiflora 

 but quite distinct, and a new Linum with large seeds. This latter 

 apparently is closely allied to our cultivated flax ( L. usitatissimum), 

 of which the origin is unknown. It may be an ancestor of our 

 common flax, but this latter is unknown far north, and will not grow 

 with Arctic plants; the seeds of the two are perceptibly different. 

 No large-seeded flax is now living in the Arctic regions. 



2. " The Genus Lonsdaleia and Dibunophyllum rugosum (McCoy)." 

 By Stanley Smith, B.A., M.Sc, E.G.S. 



The present paper discusses the literature, structural characters 

 and development, descent, classification, and distribution of the corals 



