Sir H. H. Hotcorth—The Baltic— The Ancylus Sea. 347 



Husum in a submarine peat bog, or immediately under the same, 

 there was found a grave mound dating from the Stone age, and also 

 in other places flint knives and pieces of burnt clay dating from the 

 Stone age. Among the plants from this submarine turf he mentions 

 birch, oak, spruce, and hazel, but he mentions no beech. 



I may further add that similar flint tools to those above mentioned 

 have been found in the ancient submerged forest outside Landskrona, 

 while A. F. Cadson has similarly found flint tools in the submerged 

 oak forest lying 300 to 400 metres outside the present beach at 

 Limhamv. 



At Islaby in Bleking, De Geer found a bone weapon a metre 

 deep in a turf moss which was partly under the post-GIacial marine 

 boundary and partly under a marine mud. 



Lastly, Lindstrom found charcoal, together with bits of a fish 

 skeleton, which had obviously come from a human feast, under 

 a post- Glacial beach at Wisby, situated 15 metres above the sea 

 (Nathorst, op. cit., pp. 308 and 309). 



I will now turn to another kind of evidence. In J. Petersen's 

 memoir, " Om de Skalbaer molluskers utbr. i de danske have 

 indenfor Skagen," Copenhagen, 1888, p. 86, quoted by De Geer, 

 we are told that he found on the bank called Bochers bank, east of 

 Laeso, at a depth of 25 metres, Litorina litorea and other shore shells 

 in a sub-fossil condition. He also found similar shells in a similar 

 condition from 18 to 25 metres deep, between Anholt and Kullen, 

 probably near Stora Middelgrund, and De Geer argues thence that tlie 

 sea-bottom there was once at least 20 metres higher than at present, 

 and that Anholt and Laeso were probably then connected with the 

 mainland of Denmark (Geol. For, i Stockholm Forh., xii, 107). 



The case seems, in fact, complete for those who urge not only that 

 the proved succession of the fresh-water Ancylus sea by the salt- 

 water Litorina sea necessitates our postulating the breakdown of 

 a former land barrier between the North Sea and the Baltic, but 

 that such a breach is amply attested by evidence of every kind, and 

 further that it occurred comparatively lately, and probably during 

 the so-called Neolithic age. 



The next question that arises is one in which I cannot see quite 

 eye to eye with the Northern geologists. Like their contemporaries 

 in England, they are devoted to what I deem the quite fantastic 

 development of Lyell's theory of Uniformity which now widely 

 prevails, and they have consequently argued that the breach in 

 question was a gradual and continuous one, due to the wearing 

 away of the banks of the Sound and the Belts by the sea. To this 

 view I cannot in any way subscribe. It seems plain to me that 

 instead of this movement having been gradual and continuous, it 

 was impetuous and rapid and even sudden. 



In the first place there is everywhere a distinct gap between the 

 Ancylus beds and the Litorina beds. Wherever they occur together 

 there is an absolute failure of continuity between them. Nowhere, 

 so far as I know, have we any mixture of the typical fresh-water 

 shells of the Ancylus time with the typical brackish-water shells of 



