712 REPORT OF COMMISSIONER OF ‘FISH AND FISHERIES. [30] 
mals and plants which had lived there vanished, and in their place 
came North Sea animals, and among them, in 1851, the oyster was first 
noticed. From year to year they spread over more surface. In 1860 
only 150,000 weredredged; presently 98 places were known where oysters 
had become established, and in 187172 the oystermen were able to take 
for foreign consumption seven millions of mature oysters from the beds 
of Lim Fiord. Their distribution was very rapid. In 1851 the first 
were found; had there been many there before this time, they would 
certainly have been noticed by the fishermen. The water must first 
contain a percentage of salt of 3 per cent before they can enter a new 
territory. If we admit the first appearance of oysters here in 1840, 
then in an interval of thirty years they had spread over an extent of 
surface 15 miles (German) in length, which shows a yearly advance, in 
territory covered of about one-half mile in length, or rather more, 
about 3,700 meters. The beds ofthe Lim Fiord are from 1 to 8 kilo- 
meters from one another. Their length is from 1 to 7 kilometers and 
their breadth somewhat less. These facts show that the young swarm- 
ing oysters are capable of moving over a stretch of bottom 8 kilometers 
in length. In the same manner as it has thus immigrated into the Lim 
Fiord the oyster would have established itself in the Baltic had the 
water been similar in its characteristics to that of the North Sea, and 
this would be the condition of affairs if the connection between the North 
Sea and the Baltic were broader and deeper than it is at present. At 
one time it was broader and deeper, and, for this reason, oysters once 
lived four miles east of the point where the city of Kiel now stands. 
This is proven by the fossil oyster-beds found near Waterneversdorf, in 
the eastern part of Holstein, which, together with the entire bottom of 
the western portion of the Baltic, have been raised more than 30 meters. 
By this elevation the Cattegat, the Belt, and the Sound were made shal- 
lower and smaller pathways for the water coming in from the North Sea 
than they were in olden times, when the oyster-beds of Waterneversdorf 
still produced oysters. Yet, by this elevation of the sea-bottom, which 
took place thousands of years ago, the percentage of salt in the water 
has been lessened but very little. Thousands of years later, when the 
oyster-beds of Waterneversdorf had been dry land for a long time, oys- 
ters were found in such abundance along the coast of the Danish Islands 
that they served as food for the people of the Stone Period who lived 
in this vicinity, since great masses of oyster-shells are found in the heaps 
of kitchen refuse of that time. 
And since the oyster-shells of Waterneversdorf and of the kitchen- 
heaps of the Stone Age fully agree with those of to-day, since they are 
also bored like ours by the boring sponge (Clione celata), and since the 
whelk (Buccinum undatum) and other animals at present found upon 
the sea-flats lived with them, conditions favorable to their growth 
must have existed at that time in the meridian of the present Cimbrian 
Peninsula, the same as now to the west of Schleswig-Holstein. The 
