004 sir. s. it. waerex ox the [vol. lxxlx, 



than we have nowadays during the earlier stage. I think that it 

 would he unwise to put the Ponders End conditions hack into any 

 part of the Taplow Terrace group, without much more satisfactoiy 

 evidence than we have here. My suggestion is that this patch 

 of Arctic Bed represents the silting of a stream-course of Low 

 Terrace age, which cut across the Taplow Terrace. But I could 

 not prove this contention against criticism — I merely think it the 

 more probable assumption. 



There is evidently a spring here, as a streamlet still rises just 

 below the level of the site. This stream has to-day a distinct, 

 though very diminutive, valley of its own, which comes out very 

 clearly on the Geological Survey 1-inch map of the London District 

 (Sheet 2) immediately north and east of 'Huxley Farm', where 

 the streamlet concerned cuts through the brick-earth down to the 

 gravel below. There might very easily have been a small swamp 

 here, associated with this spring and streamlet and its diminutive 

 valley. 



As a possible explanation of the occurrence of non-Arctic plants 

 in these Arctic deposits, I would quote a fact mentioned by 

 Prof. A. C. Seward in his lecture on Greenland to this Society : 

 namely, that in the immediate vicinity of springs, certain plants 

 are enabled to live far to the north of their normal habitat, owing 

 to the warmth supplied by the spring-water. Such geological 

 deposits as we are considering are largely fed from the neighbour- 

 hood of springs. 



Appendix. — The Barrowell Greex (Lea Valley) Arctic 

 Floea. By Mrs. Eleanor Mart Beld, B.Sc, F.L.S., F.G.S., 

 and Miss Marjorie Elizabeth Jane Chandler. 



The Barrowell Green material was examined by Mr. Beid in the 

 spring of 1916. By the request of Mr. Hazzledine Warren we 

 have re-examined it, with the result that we have added a few new 

 species and made a few alterations in Mr. Beid's list. In this list 

 a species of Cochlea via is recorded. In other Lea- Valley deposits 

 and in the Cam-Valley deposit fruits were found, and the deter- 

 mination was correct ; but at Barrowell Green we have only seen 

 seeds referred to this species, and in this case the determination 

 was incorrect, the seeds being those of a Cerastium allied to 

 C. vulgatum Fries, an Arctic species. It is possible, of course, 

 that there were pods which we have not seen. 



With regard to the description of this deposit, we cannot do 

 better than quote Mr. Beid's original description from his letter of 

 February 4th, 1916, to Mr. Warren :"— 



' The Barrowell Green flora certainly points to the same period as the floras 

 of the other Lea Valley localities. It shows the same Arctic or Sub-Arctic 

 conditions, and contains several of the same peculiar plants, such as Sileve 

 rtelata, Linum Prsecwsor, Salix Lapponum and the undetermined Cochlearia. 

 No doubt the list includes about a dozen species which have not yet been 

 found at Angel Koad, Hedge Lane, Ponders End, or Temple Mills; but none 

 of these are significant species : that is to say, they are species that one 



