340 Dr. J. FE. Marr & Miss LE. W. Gardner— 
conditions under which Pleistocene floras are preserved, in order to 
draw attention to their probable occurrence under similar conditions 
elsewhere, it is thought advisable to give a preliminary account of 
the discovery of an Arctic flora of this date in a pit at Barnwell, 
a suburb of Cambridge, long noted for its Pleistocene deposits. 
The pit in which the plant-seams are exposed is situated to the 
west of the railway, close to Barnwell Station. The section in this 
pit was described and figured by the late Mrs. McKenny Hughes in the | 
GuotocicaL Macazine for 1888 (Dec. III, Vol. V, pp. 194-6), and 
the figure is reproduced with slight alterations in Professor Hughes’ 
recently published paper, ‘‘ The Gravels of East Anglia”? (Cambridge 
University Press, 1916). The section has been much enlarged in the 
last few years, and at present there is a continuous exposure with 
a length of about 500 feet along the north pit-face in a direction 
nearly east and west, that is, at an angle of about 45° to the section 
given in Mrs. Hughes’ paper. 
Along this line of section the beds are very even and approximately 
horizontal, thus showing a contrast to the unevenly bedded deposits 
figured in the papers cited. These uneven beds are still seen in a face 
nearly at right angles to the present long face. In this shorter face 
the base of the deposits is seen to rise towards the south, that is, in 
the direction of the Newmarket road. 
The even- and uneven-bedded deposits belong to the same series, 
and indeed the one set passes into the other. The uneven-bedded set 
was deposited against a slope, and where the bedding becomes more 
even, indications point to deposition on a flatter floor. 
The following section is a representation of the beds towards the 
| western end of the north face. It is in this part of the face that the 
peaty seams are most abundant and the bedding most even. The 
section shows clearly that the peaty seams are part of the Pleistocene 
strata and not deposits of later date banked up against them. The 
section as figured is about one-tenth of the length of the whole 
northern face along which the beds are now clearly seen. 
The gravels are not very coarse, and some sand beds are seen 
among them. The loams vary in coarseness, some being sandy, 
others more clayey. The peaty bands, varying in thickness from 
one-eighth to half an inch, consist of loamy peat, from which good 
specimens of leaves, seeds, etc., are readily extracted. Where best 
developed there are at least five layers of these seams seen in vertical 
section. The plants hitherto obtained were extracted from the most 
persistent seam, which is the lowest but one. The section shows 
the manner in which the various seams die out laterally. 
We obtained abundant leaves of a plant which we regarded as 
Betula nana, and Mr. Clement Reid, F.R.S., who kindly examined 
our plants, has confirmed this, and in a preliminary list has noted the 
presence of several additional Arctic forms. There is therefore no 
doubt that we have here another addition to the Pleistocene Arctic 
beds of this country. 
We do not propose to discuss at present the relationship of this 
low-level series of deposits to the other Pleistocene accumulations of 
the district, but content ourselves with stating that their mode of 
