14 MISS M. E. J. CHATs^DLER O^ THE [vol. Ixxvii,. 



in both cases was almost equally large, there was an amazing 

 number of plants represented in either list that were not recorded 

 in the other one — in fact, only about thirty species, or roughly a 

 third of the plants known to occur at Barnwell, were common to 

 the two deposits (see the floral list). Further, different families 

 were represented in the two cases : thus, out of a total of twenty - 

 seven families in each locality, the following from Barnwell were 

 not found in the Lea Valley : Papaveracea?, Fumariaceee (?), Cis- 

 tacese, Greraniaceie, Saxifragacea?, Dipsace?e, Campanulacese, Eri- 

 caceie, Scrophulariacese, and Primulaceae ; while these from the Lea 

 Valley were unrecorded at Barnwell : Portulacese, Leguminos£e, 

 Umbelliferse, Ca])rifoliace2e, Valerianacese, Compositse, Solanacea?, 

 Chenopodiaceai, Urticacese, and Alismacea^. The apparent absence 

 in the Barnwell peat of Composites which were represented in the 

 Lea Valley by several different species is rather curious, in view of 

 the present abundance and wide distribution of the members of 

 that family, and in view also of the preservation at Barnwell 

 of numerous delicate seeds. 



Another difference brought out by a study of the floral lists is 

 that the Arctic chai-acter of the flora was far more pronounced at 

 Barnwell than in the Lea Valley, for in the former locality 42 per 

 cent, of the plants were Arctic and Alpine species, as against 

 22 per cent, in the latter area. Similarly, the number of plants 

 not now indigenous in Britain (chiefly Arctic and Alpine species) 

 was greater at Barnwell, and included the following : — 



RanunciUus aconitifolius L. 



Pajpavev alpinuin L. 



Silene caelata Eeid. (Extinct.) 



Lych7iis sp. 



Arenaria biflora L. 



Geranitim sp. y. 



Linum Prsecursor Reid. (Extinct.) 



Scahiosa sp. 



Cam2yanula sp. 

 Gentiana cruciata L. 

 Primula sp. 

 Ar^neria arcfica Wallr. 

 Salix Polaris Wahl. 

 Carex capitata L. 

 Carex ustulata Wahl. 



In the Lea Valley this class of plants was considerably smaller,, 

 consisting of 



Silene caelata Eeid. (Extinct.) I Potentilla cf. nivalis. 



Lychnis sp. Armeria arctica Wallr. 



Limtm Prsecursor Eeid. (Extinct.) | 



The occurrence of the extinct plants Silene ccelata and Linum 

 PrcBCiirsor in both localities is not necessarily a proof that the 

 peat-beds were contemporary ; for, given suitable conditions, these 

 species would have been preserved in deposits formed at any point 

 along their time-range.^ 



Again, the calcareous-soil element was more clearly defined in 

 the Barnwell Flora than in that of the Lea Valley, and this con- 

 stitutes another difference between them. 



^ That is, during the existence of the genera, from their evolution to their- 

 extinction. 



