THE HUMAN SPECIES. 131 



workmen finding sea-shells and animal hair to the depth of 

 132 feet. 1 * The lake Flevo, known to the Romans, was 

 evidently not then ancient, since a great portion of West 

 Friesland, on its banks, sunk down and formed the present 

 Zuyder Zee, leaving of the coast only a chain of islands. The 

 canal of Drusus, now denominated the Yssel, is a further 

 instance of the tendency of rivers to flow northwards ; for this 

 additional outlet of the Rhine was a proximate cause in the 

 formation of the Zuyder Zee, by breaking through the coast 

 more to the north than the ancient channel, which was a river 

 then known by the name of Flevus, whose waters were dis- 

 charged close to the present Flie island. Another great sub- 

 mersion in the south-east of Holland, was felt at the Biesbosch, 

 near Gertruydenberg, in 1421, when the waters of the Meuse 

 and Waal, suddenly overwhelming seventy-two villages, 100,- 

 000 human beings were lost ; but the subsoil must have sunk 

 at the same time, since the whole region has remained beneath 

 the surface, and is now overgrown with huge reeds. 



The principal mouth of the Rhine, during the Roman sway, 

 is all but obliterated, excepting in name, and the whole coast 

 of Holland has much receded from its earlier tide-mark; for, 

 at the spot where the Rhine mouth entered the sea, there stood 

 a fortress, by some ascribed to Drusus, by others to Claudius, 

 intended to guard the entrance. The whole plan of this struc- 

 ture, with walls of hewn stone, still three feet high when it 

 was last seen, is now buried under the waves, and more than 

 a mile from the present shore.! Coins of Postumus, Victo- 

 rinus, and Tetricus, with others, resembling early Anglo-Saxon 



* See Des Roche's Hist, des Pays Bas., vol. i. A learned and exceed- 

 ingly curious work, which the untimely death of the author has left unfin- 

 ished. The Ganges ofTers a similar result, for, on sinking an Artesian 

 well at Fort William, Calcutta, bones of cauidce were brought up from 

 the depth of 150 feet. 



t This place is known by the name of Huis-ten Britten. Here several 

 alto-relievo figures of the goddess Nehalennia, and many coins, have beea 



