Professor Nehring, who has made a special study of the characteristic fauna of the Arctic and sub-Arctic regions under the names of Tundra and Steppe fauna, finds that a corresponding series of animals formerly existed in the regions around Schweizersbild, both of which were superseded by a forest fauna, thus indicating that a gradual change from an Arctic climate and fauna to those of the present day has taken place since man appeared in the district—a transformation which is fully borne out by the stratigraphical arrangement and contents of the deposits. Accordingly, we find the deposits which yielded these different remains characterised as Tundra, Steppe, Forest, and Domestic fauna, as illustrated by the following tabular statement :—
| Deposits. | Depth in centimetres. | Age in years. | Characteristic fauna. |
| (1) Humus bed | 40-50 | 4,000 | Domestic fauna, Iron and Bronze Ages. |
| (2) Grey relic bed | 40 | 4,000 | Forest and lake-dwelling fauna of the Neolithic period. |
| (3) Breccia bed. This deposit had a thin layer of dark earth, some 10 centimetres thick, about its middle, called upper Rodent bed. | 80-120 | 12,000 | Forest fauna: transition from the previous (Steppen fauna). |
| (4) Yellow relic bed | 30 | 3,000 | Sub-Arctic fauna (Steppen fauna). |
| (5) Lower Rodent bed | 50 | 5,000 | Arctic fauna (Tundra fauna). |
| (6) Gravel bed (glacial deposits) | 150 | ... | No relics. |
The following notes may serve to give some general idea of the industrial remains of man found in these deposits, as well as of a few of the fauna associated with them; but they are utterly inadequate to convey to your minds the great ability and fullness with which all the details have been worked out.
The lowest stratum, according to Professor Penck, is a fluviatile deposit of the last glacial epoch in Switzerland, formed just as the ice was finally retreating from the valley. It was dug into to the depth of 1.5 metre without reaching the bottom, but, as it contained no human relics, it is of no special importance beyond determining its geological character. Subsequently, when the locality became dry, man frequented the rock-shelter, and the lower Rodent bed, No. 5, began to accumulate.
