Vol. 68.] LATE GLACIAL STAGE IN THE VALLEY OF THE LEA. 215 



feet thick, intercalated in the loTver part of the section. Some 

 of the mammalian remains are found within this dark bed, others 

 beneath or above it. 



Upon examination, the dark bed was found to contain much 

 vegetable matter. It was seen to vary considerably in lithological 

 character in different places, being sometimes clayey, sometimes 

 sandy ; occasionally the vegetable matter was in very small propor- 

 tion, sometimes it formed the bulk of the deposit. The bed was 

 also observed to contain numerous shells of land and freshwater 

 mollusca, the elytra of beetles, and other remains. 



In certain spots it assumed a deep blue-black colour, was greas}' 

 to the touch, and emitted a fetid odour when freshly dug. 1 

 think this must be due to the impregnation of adipocere, from the 

 carcases of the animals whose bones are also found associated 

 with the deposit. I imagine that the larger patches showing this 

 condition may be places where the carcases of big animals have 

 lain. The same peculiar condition is found in the material that 

 is in immediate contact with the bones. 



Upon washing out a sample of this deposit, I found that seeds 

 and leaves of plants were abundant and in good condition. I 

 submitted these to Dr. P. J. Lewis, with whom I was corre- 

 sponding upon another matter, and he kindly undertook their 

 examination. He reported at once that the flora was Arctic, and 

 that it was well worth fuller examination. I accordingly set to 

 work on a more extensive scale, washing out the material, and 

 sorting the determinable remains into their various classes. 



II. The Steatigeapht of the Arctic Bed. 



This Arctic Bed has been found over the whole of the extensive 

 excavations of the Bonder's End pit. At the same time, it is very 

 discontinuous, being much broken up and disturbed. Owing to its 

 disturbed condition, the actual depth beneath the surface at which 

 it is found varies considerably, but is commonly about 15 to 17 

 feet. 



The Arctic Bed is occasionally seen in continuous section for 20 

 or 30 yards, but usually the individual masses are much smaller 

 than this. Not infrequently these detached masses are in- 

 clined at a considerable angle, masses of gravel (probably frozen) 

 having apparently been thrust beneath one end. Occasionally 

 masses or tablets of this bed, several yards across, have been thrust 

 over each oth.er, with strata of gravel or sand intervening between 

 them : thus duplicating the bed. At one place, which is named the 

 ' Special Site ' in the lists of species tabulated in the reports appended 

 to this paper, a still more complicated section was exposed early in 

 1911. Here three large masses of Arctic Bed were seen in vertical 

 succession, separated one from the other by strata of gravel and sand. 



I collected separate samples from these beds, which have been 

 separately examined throughout, in order to see whether there was 

 any evidence to suggest that they represented a succession in time, 



