II. GLACIAL PERIOD.
It would be quite out of place here to give anything like a dissertation on this subject. It cannot, however, be wrong to state one or two facts which in a measure bear on the discoveries of the Kesslerloch. Although the Glacial period after the Tertiary is acknowledged by all thinking persona, yet every additional fact brought to light strengthens the theory—if in fact it can be now called by this name. The evidence of an Arctic or reindeer period in France is given so clearly in the valuable work called 'Reliquiæ Aquitanicæ,' that no one can gainsay it, and it is needless to refer to a volume of such standing; two other cases, one in Switzerland and the other in South Germany, may not be so well known.
In a hamlet called Schwerzenbach, which is reached by railway in about half an hour from Zürich, on the line to Wetzikon, there is a section of great interest, to which I was directed by Dr. Keller and guided by Mr. Jacob Messikomer. Here, on the banks of a small lake, and under a covering of about three feet of regular peat, there was a bed of about the same thickness of loam, and in this loam there were numerous leaves said to be of glacial age. The water unfortunately came in upon us when we dug towards the bottom of the loam, so that we could not reach the base nor ascertain what was below it, but Mr. Messikomer told me that it was what he called 'diluvium.' The loam bed is said to extend completely under the little lake. The leaves in the loam were in tolerable abundance, and apparently in fair preservation, and we brought away some masses of the clay, intending, if the specimens, after being soaked and dried, turned out well, to give a separate plate of them in the present volume. Unfortunately, however, when brought to England and soaked in water, no specimen worthy of being drawn could be secured. But the reader will have much better authority than a plate in the following extract from Professor Heer's Life of Arnold Escher Von der Linth, p. 261.
'A year ago a young Swedish geologist, Mr. Nathorst, discovered in the glacial clay of different parts of Sweden and Denmark a number of plants belonging to the extreme north, but which at that period must have lived in those districts, though at present they are only found in North Lapland and Spitzbergen. Mr. Nathorst last autumn came to Switzerland, to seek for this northern flora here, and he succeeded in finding it at Schwerzenbach, in the Canton of Zürich, in a bed of loam under a deposit of peat. With the assistance of Dr. Ferdinand Keller, who aided him by his rich fund of experience, masses of this loam under the peat were dug out and brought to Zürich; and in it were found seven species of Arctic plants. They were, Betula nana, Salix polaris, Salix retusa, Salix reticulata, Arctostaphylos uva ursi, Polygonum viviparum, and Dryas octopetala. All these are species which belong to the far north, and, with the exception of the polar willow, live also in our Alps. The Polygonum and the Dryas are very plentiful at the foot of the glaciers, and the Arctostaphylos
