318 GENERAL VIEWS ON ARCHAEOLOGY. 



by a wall of peat from six to ten feet high. But what is the most 

 curious is that there were found on these ancient islands burial- 

 tumuli belonging to the age of bronze. 



It is not only at this point that the formation of a shore-line by the 

 action of the waves has been of some importance. It must have played 

 a great part in the history of the changes of the soil in Denmark, 

 particularly in Jutland, where it has combined to form the "downs." 



Decrease of the Saltness of the Sea. — This we have seen proved 

 as regards the interior waters of the Kattegat by the mollusks of the 

 Kjoekkenmoedding . It may be owing to two different causes. First, 

 to the fact that the communication between the Kattegat and the 

 North sea has sensibly diminished by the accessions of land in Jut- 

 land, which were alluded to ; but it may also be consequent upon the 

 great mass of fresh water continually poured into the Baltic by the 

 rivers, for there is no sea that has, in proportion to its size, so great 

 an affluence of fresh water. This circumstance establishes a sensible 

 difference between the sea-bathing outside and inside of the Sound. 

 The further we go towards the interior of the Baltic, the more the 

 saltness of the sea diminishes. Thus, at Rostock, it is no more 

 than half of that of the North Sea at Aurich, 1 and at the bottom of 

 the Gulf of Bothnia, it is scarcely brackish. In the Sound and in 

 the Belt may be observed decided currents. In the Sound, which is 

 the best known of these straits, there are on the average twelve days 

 of current going out of the Baltic, for five days of current coming in. 

 This excess is no doubt compensated for, partially at least, by the cur- 

 rents of the Great Belt. But it may be, that the efflux from the 

 Baltic is so much greater than the influx, that in the long run the 

 saltness of its waters becomes less and less. 



It might be objected, that if this effect had made itself so sensible 

 since the appearance of man in the north, the waters ought to have 

 become much fresher during the later ante-human ages, so that the 

 primitive population would already have found no oysters in the in- 

 terior of the Kattegat. To this it may be answered, that formerly 

 there was a communication between the White Sea and the Baltic, 

 which was not closed long before the arrival of man. 



Level of the Land. — The situation of the Kjoekkenmoedding proves 

 that there has been no permanent change of any importance in the 

 general elevation of the dry land in Denmark, since the coming of 

 man. For if the non-stratified Kjoekkenmoeding , of which a great 

 many descend only to ten feet above the present level of the sea, had 

 formerly been a few feet lower, they would have been reached by the 

 waves, during rough weather, and their interior would be partially 

 stratified at these points. On the other hand, if the shore had been 

 more elevated than nowadays the Kjoekkenmoedding on the shores, 

 that have a stratified construction, could never have been reached by 

 the waves. 



1 The hydrological data are taken from the excellent work Der Danische Staat von A., v. 

 Baggeson. Copenhagen, 1845. 



