—-:1868.] Amber ; tts Origin and History. 179 
upheaval of the country lying east and north-west of the Bay. And 
the Bay itself, which had been so extended by an earlier depression, 
was now confined to the small flat trough whose most northerly 
portion we have now learnt to know. As it arose, however, it was 
filled up with the mud which the river carried into it, for the 
barriers which had formerly stopped its deposits were now destroyed 
by the upheaval of the coast. With the sand, which it derived 
from a variety of the Cretaceous Sandstone, poor in Glauconite, 
it took up also, out of the lakes and marshes through which it 
flowed, the Amber which was deposited there, and carried it into 
the trough, as well as numerous fragments of such plants as a river 
would bear away from an old forest. That the wood occupies as 
Browncoal chiefly the uppermost place in the series of deposits 
can perhaps be explained only by supposing that it floated about 
on the surface of the water until the trough under it was filled 
up, and it was pressed downward into the Sand. 
About this time the coarse Quartzsand on both margins of the 
trough lay dry; but, as it 1s covered by the beds of the uppermost 
division of the Browncoal-formation, it is clear that a depression 
again followed the upheaval of the country, during which the deposits 
of the argillaceous ‘“ Micaceous Sand,” of the “ Coal-sand,” and of 
the Browncoal, were accumulated. The “ Micaceous Sand” of the 
upper division contains, however, no Glauconite, and as we are 
unacquainted with its origin, the influence of the river on these 
beds is also unknown, and the mode of their formation cannot 
be pursued any farther with certainty. No doubt the forests of 
an extensive shore-line again perished, and furnished the wood 
to the Browncoal-beds. Finally, the Prussian Bay of the North- 
German Tertiary sea was filled up, and while numerous deposits 
were formed in other parts of this sea, Prussia was laid dry by 
an upheaval of the rocks, and thus ended for a time the history 
of the country, but only to commence again after many centuries, 
when a harsher period of destruction succeeded to the clemency of 
the Tertiary Epoch. 
This new period in the history of Samland began with the 
depression of the continent of Northern Europe. This region, 
which had endured since the oldest period of the earth’s formation, 
was depressed first of all in the north-east, then in the south; 
and the Polar sea was enlarged as gradually, the valleys and 
deeper portions of the land being overflowed towards the south. 
The climate and all the conditions of the country were thus com- 
pletely changed. ‘The mountains projecting out of the sea were 
covered with glaciers, which extended down to the water. Icebergs 
and ice-flakes laden with the débris of rocks and with blocks of 
stone were detached from these glaciers and drifted towards the 
