-318 Sir E. H. Howorth—The Baltic— The Litorina Sea. 



Norcleuskiold and Nylander, in their monograph on Finnish shells, 

 mention the occurrence of shell -beds of this time in the Aland 

 Archipelago, e.g., at Soderjurino, near Nadeudal (near Abo), on 

 Ingo Island, at Kiiilko, near Helsingfors, and at Kampen ; and 

 Schmidt has described the presence of the beds with this fauna on 

 the shores of the Eastern Baltic. He tells us that they are found 

 entirely covering the iisar at Karris in the island of Oesel, and also 

 those on the Isle of Worms, while the iisar in the interior of 

 Esthland are free from them. Similar beds, however, are found 

 in that province, along which were once apparently inlets and gulfs 

 of the sea up to a height of 60 feet. They cover a strip of country 

 about 10 versts in width, and at Fickel form a tongue extending 

 further inland. At Awaste we apparently have the old boundary of 

 the sea forming a low terrace, and here blocks of granite are found 

 mixed with shells of Cardium edule. Similar beds with the same 

 fauna exist in the islands of Nucko, Worms, and Dago. In North 

 Esthland similar deposits wash old gulfs projecting into the land 

 such as Eahna and what Schmidt calls "die ganze Baltischporter 

 Halbinsel." They occur in long mounds of rolled gravel, sand, 

 etc., and contain Litorina litorea (which is no longer found there) 

 and other species of shells found in the neighbouring Baltic. 

 These mounds, with the same marine fauna, are found as far east 

 as Narva, to the east of which there are no such deposits, and this is also 

 the eastern limit of living marine shells in the Gulf of Finland. 

 Such marine shells, either living or fossil, also entirely fail us in 

 the neighbourhood of Lakes Onega and Ladoga, whose Crustaceans 

 and fish have been sometimes quoted as affording evidence of a 

 former communication between the Gulf of Finland and the W"hite 

 Sea (Schmidt, Z.D.G.G., xxxvi, 266, etc.). 



The island of Gotland has been fruitful in discoveries of the 

 Litorina period. Lindstrom found in beds there, besides the 

 ordinary Baltic shells, Rissoa lahiosa {'?), Litorina rudis (var. tenehrosa), 

 and others, Spirorhis horealis, and the shells of Cardium edide, 

 larger in size than those now living; and Munthe reports from the 

 same horizon remains of the seal Baliclioerus gryphus. Munthe 

 mentions Litorina deposits in the north of Gotland at a height of 

 27 metres, and Lindstrom names them north of Wisby at 24 metres. 



De Geers, Munthe, and Nathorst have given admirable maps 

 showing the extent to which the Litorina sea, when at its full 

 extent, encroached upon what is now land in the Eastern Baltic. 

 This encroachment involved a considerable strip round the whole 

 east coast of Sweden, beginning at Karlskrona and including the 

 whole of the Gulfs of Bothnia and Finland and the coasts of 

 Esthland with the islands off it, and the similar coasts of the island 

 of Gotland. This invasion of the present land surface was especially 

 i-emarkable in the district round the Malar Sea and round the coast 

 of Finland. It means that the general depth of the water over the 

 area of the Central and Northern Baltic was considerably greater 

 in the Litoi-ina sea than it is now. 



This, again, accounts most reasonably for the greater salinity of 



