i a ern Nine te 
_ ARCTIC PLANTS DURING THE POST-GLACIAL EPOCH, 227 
in Sweden and Denmark. A peat-moss with stems and leaves of Oak, 
Scotch Fir, and Birch covered a fresh-water clay, which rested on the 
boulder clay. In the clay I found leaves of Betula nana, Linn., 
Dryas octopetala, Linn., Salix reticulata n., S. retusa, Fr., 8. 
myrtilloides, Linn., S. ” polaris, Wahlb., Arctostaphylos Uva- Ursi, 
Linn., Polygonum ‘viviparum, Linn., Azalea procumbens, Linn., and 
some others. On a second visit I was accompanied by Dr. Keller, of 
Zurich, and Prof. Heer was so good as to determine the leaves. I hope 
that he maT give a lengthened co Pa of them. I ought to say 
that I am not quite satisfied that the leaves referred to Salix 
polaris are inked that species. The specimens of those leaves which 
I have found in Sweden and Denmark, and also at Cromer in Norfolk, 
are generally (though not always) closed together, while the leaves at 
Schwerzenbach were flattened out. It is a singular contrast to the 
condition of things which fastallodl when these plants were growing 
in te district, to find as I did the hills now covered with the Vine 
t! 
ae continued my investigations to England, and there first visited 
Bovey Tracey, where Mr. Pengelly had in 1861 found leaves which 
Prof. Heer had determined to eae | : ba sat nana, Linn.* 
the Betula again, with leaves of different species of Salix which have 
not yet been determined. I have gat from Prof. Heer that he now 
thinks the Salix repens, Linn., of his Bovey Tracey memoir mos 
probably belongs to S. neyrtilloiee, ‘Linn In this second locality we 
found also a leaf of Betula alba, Linn., a Potamogeton, and some seeds 
and leaves of Arctostaphylos Uva-Ursi, Linn., which at the present 
seis patois et skatithetions,. "The v. J. Gunn, of Norwich, was 
80 good as to give me some valuable specimens from the Cromer beds, 
and he pointed out to me some leaves of Salix cinerea, Linn., which 
* Heer and ae on the Lignites and Clays of Bovey Tracey. Philo- 
sophical Transactions, 1 . 
Q 
