1868.] Amber; its Origin and History. 178 
because upon the Danish Islands the deposits of that formation still 
form zones which follow one another in the order of their age from 
the north-east to the south-west. Add to all this that Cretaceous 
beds now crop out in the East of Prussia on the banks of the 
Niemen near Grodno, and that in the south Cretaceous beds to the 
thickness of 800 feet were bored through, in sinking a well near 
Thorn on the Vistula, and scarcely a doubt can then remain that the 
Tertiary deposits were accumulated in a sea-bed, which was formed 
by a great depression of the strata belonging to the Cretaceous 
formation. 
The discovery of the parentage of the “ Glauconitic Sand ” also 
furnishes us with that of the Amber of Samland. The trees which 
yielded the Amber-resin must have grown upon the Greensand 
beds of the Cretaceous formation. Even as in North America at 
the present day the Taaodium distichwm especially delights in the 
low and frequently inundated marsh-lands lying along the lower 
portion of the Mississippi, so during the Tertiary period may tho 
Amber-trees haye flourished best on the boggy coast which then 
surrounded the great continent of Northern Europe. 
We can still more exactly draw the boundaries which then 
existed between sea and land, and with the assistance of a few 
hypotheses we can picture to ourselves the conditions under which 
the Amber was deposited. 
We know not, indeed, how far in Prussia the beds of the 
“ Glauconitic Sand” extend, as they are exposed only on the coast 
of Samland; but as we know that the beds of the Brown-coal 
formation were deposited immediately upon them, we can conclude, 
from the expansion which these beds possess in Prussia, what were 
the general boundaries of the old Tertiary sea, namely, that the 
whole of West Prussia, a neighbouring portion of Pomerania, and 
the western half of East Prussia, extending to about the thirty-ninth 
degree of longitude (from Ferro), formed the bed of a bay connected 
in the south-west with the great Tertiary sea, which covered the 
larger part of Northern Germany. ‘The northern boundary of this 
bay left Samland at some distance, and was continued westward 
with some irregularity to Riickshéft, which lies at the foot of the 
peninsula of Hela, and where thick Brown-coal beds crop out on 
the coast of the Baltic. The bay was, as we have seen, a basin in 
the Cretaceous formation, and was bordered by widely expanded 
flat coasts, which mark the last upheaval of the district. Number- 
less rivulets with small discharge emptied themselves into the bay, 
and carried solid matter into it; but a larger stream from the 
north-west, which flowed through the southern portion of the 
Cretaceous land, algo discharged itself here. 
_ We have no knowledge of the oldest deposits which were formed 
in the bay; we can only conclude from the corresponding form- 
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