THE HUMAN SPECIES. 61 



THE RHINE. 



THE whole delta of the Rhine, by the many changes 

 that have occurred in its several arms within the his- 

 torical period, through West Friesland, Holland, and 

 Zealand, prove the unconsolidated condition of the de- 

 posits ; and the depth of alluvial was shown at Amster- 

 dam, in 1604, when a well was sunk, in an abortive 

 attempt to obtain pure fresh water, the workmen find- 

 ing sea-shells and animal hair to the depth of 132 feet.* 

 The lake Flevo, known to the Romans, was evidently 

 not then ancient, since a great portion of West Fries- 

 land, 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 oi rivers to 

 flow northwards ; for this additional outlet of the Rhine 

 was a proximate cause in the formation of the Zuyder 



final effect would have terminated long before our historical 

 era. It is more likely to synchronise with the changes in 

 the Polish and Russian inland seas, when a very consider- 

 able alteration must have resulted in the currents and tides 

 on the west coasts of Europe. 



* See Des Roches Hist, des Pays Bas., vol. i. A learned 

 and exceedingly curious work, which the untimely death 

 of the author has left unfinished. The Ganges offers a 

 similar result, for, on sinking an Artesian well at Fort 

 William, Calcutta, bones of canidse were brought up from 

 the depth of 150 feet. 



