462 AMERICAN SPIDERS AKD THEIR SPINNINGWORK. 



genei'ically, and some probablj^ even specifically, from the spiders which 

 now inhabit our continent. 



VII. 



Since most fossil spiders known to us are preserved enclosed in amber, 

 it is important in our study of the life of ancestral araneads to know 

 something of the history and character of this important sub- 

 , _ stance. Amber is a product of the prehistoric world, a hard- 

 ened resin which issued from the bark of certain trees. The 

 chief geographical source of the amber wood is in the bottom of the 

 Baltic Sea in the neighborhood of what is now called Samland, near Pil- 

 lau. The amber tree is known as Pinites succinifer GiJpp. and Ber., and 

 has been described from various vegetable inclusions — wood, blossom, fruit, 

 and needle leaves — along with various insects and araneads. The species 

 Succinifer rightly belongs to the genus Pinus, although that name is really 

 a collective name, inasmuch as included needle leaves and other vegeta- 

 ble formations show there must have been at least four species of pine 

 in the amber fields. Since it cannot be determined which one of these 

 actually secreted the resin, the specific name must be a comiarehensive 

 one. The trees which produce the amber are not now known to exist, 

 but Berendt says that the Balsamea most closely resembles it.^ 



Every gale from the north still throws uji, as for unknown ages it has 

 done, masses of amber on the shore of the Baltic Sea, and each point of 

 the coast is said to receive a jmrticular kind so peculiar that practiced 

 cutters are able, when looking at a rough piece, to decide whetlier it came 

 from a quarter to the east of Danzig or from the west on the coast of 

 Pomerania ; they are therefore probably the product of different trees. 



The sources of amber are submarine forests which, in the middle epoch 

 of the Brown-coal, as Berendt conceives, covered the shores of an island 

 continent that occupied the northern portion of the great Ter- 

 Sources [y^ny gga that covered most of Germany. This island, or group 

 a , J oi islands, had its geographical centre in the southeastern part 

 of the present sea basin, under the fifty-fifth degree of latitude, 

 and its northwestern border extending higher than the present north- 

 western point of Samland. . 



The name Samland will not be found upon many maps, and it may, 

 therefore, be defined as distinguishing that part of Prussia bounded on the 

 west by the Baltic Sea ; on the north in part by the same sea, the Ku- 

 rische Nehrung, and Kurische Haff. The southern boundary is the river 

 Pregel and tlie Frische Haff; while the eastern boundary is an arm of 



^ Berendt, G. K., Die im Bernstein beflndlichen Organischen Rests der Vorwelt gesam- 

 iiK'lt in Verbindung mit Mehreren Ijearbeitet und herausgegeben, von C. L. Koch und Dr. 

 (ieorg Karl Berendt. Band I., Abth. II., page 28, Berlin, 1854 (1845). 



