1855.] HAMILTON — TERTIARIES OF HESSE CASSEL. 141 



anticlinal, and we consequently find the whole country between Frank- 

 fort-on-Main and Cassel studded with basaltic outbursts, whilst to 

 the north they are comparatively scarce, and ultimately north of 

 Gottingen and Miinden cease altogether. 



To repeat then briefly the epochs and phaenomena above described, 

 we find the first evidence of tertiary deposits in North Germany in 

 the brown-coal and its associated underclays of Magdeburg. During 

 the earher tertiary periods, the whole of Germany appears to have 

 been dry land. At the same time, or at the termination of this pe- 

 riod, a vast swampy region, covered with a semitropical vegetation, 

 stretched along the base of the mountains of Germany, from Silesia 

 and the confines of Poland to near the Eocene Ocean, which occupied 

 those portions of Holland and of Belgium where its fauna has been 

 preserved. A gradual subsidence took place, possibly contempora- 

 neous with the period when the accumulations of Flysch or Molasse 

 were being deposited, also in a gradually sinking sea-bottom on the 

 northern flanks of the Alps. This swampy vegetation was then sub- 

 merged beneath the ocean, and was being converted into Brown-coal, 

 while a marine fauna was introduced, and lived and perished in the 

 waters above. This great change, I am inclined to think, marks the 

 limits of the Eocene and Miocene periods, as far at least as this part 

 of the earth's surface is concerned ; for I have already admitted that 

 we must not attempt to introduce such a strict procrustean rule as to 

 assert that the limits of these periods (if we choose to adopt them) 

 must be absolutely applied to the same epoch in all districts. 



The oceanic waters, thus admitted over a portion of Northern 

 Germany, penetrated between the mountains of the Hartz and the 

 Weser Gebirge, round the eastern flanks of the Westerwald and the 

 Taunus, and along that deflexion through which the Upper Rhine 

 now flows, until they reached those portions of the southern or 

 Alpine ocean in which the Flysch and Nagelflue, and perhaps the 

 Older Molasse, were deposited. 



During the period of this connection, the Marine-sands of Wein- 

 heim were deposited, until the subsequent oscillation of the land first 

 cut off the communication with the Southern Ocean, and subse- 

 quently, by the elevation of the Muschelkalk and Bunter-Sandstein, 

 in the north of Germany, raised a permanent barrier between the 

 Mayence basin and the North German Ocean. This separation was 

 subsequently confirmed by the numerous volcanic outbursts which 

 have penetrated the whole surface of the country, from the banks of 

 the Main near Frankfort, Hanau, and the Vogelsgebirg, northwards, 

 to the region of Gottingen and Miinden. 



After this a period intervened, when in the northern plains of 

 Germany, a swampy district, with a luxuriant vegetation, stretched 

 along the mountain coast, covering up the marine formation of the 

 Septaria clay, and giving rise to that upper Brown-coal formation 

 which is now so extensively worked in Mark Brandenburg and the 

 country about Frankfort on the Oder, extending to the frontiers of 

 Silesia and of Posen. Thus those formations which we have endea- 

 voured to identify with the Middle Limburg of Belgium are confined 



