378 NATURAL SCIENCE. 



JULY, 



Helm' as follows: — Carbon, 78-63 %; hydrogen, io-4b%; oxygen, 

 10-47%; and sulphur, 0*42 %. Its specific gravity is from 1-05 to 

 1-09, and hardness from 2 to 3 ; slightly brittle, and with marked 

 conchoidal fracture. 



From the days of Phoenician traders up to the present time, the 

 Baltic coasts have supplied by far the largest quantities of Amber ; 

 the present annual yield in Prussia alone being estimated at a value 

 of three million marks (6, p. 828). 



The Baltic Amber occurs in a rolled condition in lower Oligocene 

 strata. Credner, in his " Elemente der Geologie" (i, p. 700), quotes a 

 typical section from Runge, giving the following succession, in des- 

 cending order — (i) Surface soil, (2) "Diluvium," (3) Brown-coal, (4) 

 Glauconitic Amber-bearing beds. The strata rich in Amber have an 

 average thickness of 1*3 to 1-7 metres, and are for the most part 

 below sea-level. Along with the rolled pieces of Amber in the glau- 

 conitic sand and clays occur various marine moUusca whose remains 

 became embedded in the sediment, mixed with the hardened resins 

 and vegetable debris carried down by rivers which flowed through the 

 Pine Forests of Scandinavia and Finland. Washed out of the cliffs 

 by marine denudation, the Amber is picked up at ebb tide or collected 

 in nets, and by other means at high tide ; in some localities it is 

 obtained by mining. 



From the abundant occurrence of this fossil resin in the drift 

 of Jutland, Denmark, Sweden, Holland, and other districts, it is 

 considered probable that the amberiferous strata formerly extended 

 over a wide area in Northern Europe. 



Although the Konigsberg district is much the richest, other 

 localities and other geological horizons have yielded Amber in greater 

 or less abundance. From the Greensand of North America, from 

 Miocene beds in Sicily, from Tertiary strata of France (Loire 

 Department and Paris Clay), from Basle, Galicia, Roumania, Green- 

 land, the shores of Spain, and other regions, Amber has been 

 obtained in varying quantities. 



In England this fossil resin has been found in the Cambridge 

 Greensand, the London Clay in the neighbourhood of Kensington, on 

 the shores of Sussex and Essex, and in the Pliocene beds of Norfolk, 

 no doubt, as Mr. Clement Reid has suggested in the case of the 

 Cromer " Forest bed " (10, p. 451), washed out of older strata. 



The various fossil resins were orginally poured out from the 

 tissues or sealed up in the cells and resin ducts of coniferous trees 

 which covered a wide area of Northern Europe during the Eocene 

 period. 



Of this " Amber vegetation " we find an abundant supply of 

 samples, both in the form of incrustations and petrifactions. In 



^ References to papers referring to Amber may he fcurd in the woiks cf 

 Goeppert, Menge, and Conwentz, mentioned at the end of this paper. 



