10 MR. LYELL ON THE PROOFS OF A GRADUAL RISING OF 



place was found that they could form no other opinion than that it had been a human 

 habitation. In order to explain the position of beds of shells at various heights in the 

 strata intersected by the canal, an hypothesis was suggested by Colonel Nordewall, 

 in his published report, that Lake Maeler may once have been shut out from the sea 

 by a high barrier. Sand, gravel, and shells may then have been deposited at its bot- 

 tom, which on the subsequent removal of the barrier were left at their present height 

 above the lake. But if the shells had been submitted to a conchologist, they would 

 have been at once recognized as consisting for the most part of marine species, such 

 as do not exist in the present waters of Lake Maeler, but are characteristic of the 

 Baltic. Whatever doubts, therefore, may hang over the causes which brought the hut 

 into the extraordinary position in which it was discovered, it is impossible to reflect 

 on this and the other facts brought to light during the excavation of the Sodertelje 

 canal, without being convinced that very important movements have taken place in the 

 land and the bed of the sea since the Baltic was inhabited by the existing Testacea, 

 and even since the sea was navigated by vessels, and this country inhabited by man. 



In regard to the shells, I may observe that the My a arenaria is the only one found 

 by me in great abundance in any part of the Baltic which I did not see among the 

 fossils of any of the localities already mentioned, or those afterwards to be alluded 

 to, further to the north. But this shell does not, I believe, extend so far north in the 

 Gulf of Bothnia as Sodertelje ; I could not find it even at Calmar, and further south, 

 at Solvitzborg, it was rare, and of very small size. The analogy, in fact, of the fossil 

 shells to those now living in the Bothnian Gulf is most complete : the shells are the 

 same species, partly freshwater and partly marine, the species taken collectively be- 

 ing few in number, and the marine attaining a smaller average size than in the 

 ocean, where the water is more salt. The Tellina Baliica is everywhere in great 

 abundance. Hence we may conclude, that since the time when an inland sea of 

 brackish water, like the Baltic, existed in the North of Europe, considerable fluctua- 

 tions in the position of land and sea have taken place ; a conclusion to which I 

 shall revert in the sequel. 



The elevated position of the marine shells around Sodertelje prepares us to expect 

 similar deposits scattered far and wide over the valleys bordering the various branches 

 of Lake Maeler. Accordingly, in examining the country about forty-five miles north- 

 west from Sodertelje, between the towns Torshalla and Arboga, I was fortunate 

 enough to meet with abundance of Tellina Baltica (see the variety represented in 

 Plate II. figs. 3,4.) in an unctuous clay, of a deep blue colour when wet, which filled 

 the bottom of a valley near Lake Maeler, in a district of gneiss covered with huge 

 erratic blocks. This locality, which is by far the most distant from the Baltic of all 

 the places where similar beds with marine shells had previously been observed, lies 

 between the village of Smedby and Kongsor, about seventy miles from Stockholm, 

 and more than eighty from the general coast line. The clay is exposed to the depth 

 of fifteen feet, being cut through by a streamlet, which is crossed by a small bridge 



