THE BAY OF BISCAY. 147 



dulation of the soil surrounding it marks the extreme 

 boundary of the chain of the Pyrenees. At a few 

 feet from this little bay, the cliffs sink to rise no more, 

 their last rocks dipping below the sea of sand, which 

 extends as far as La Gironde, exhibiting in the midst 

 of our richest provinces a miniature representation of 

 an African desert. Biarritz, with the surrounding 

 district, which is thus situated on the limit of one 

 of those great geological formations which give to 

 our globe its existing configuration, presents very 

 curious problems, regarding whose solution geolo- 

 gists are by no means agreed. We will endeavour 

 to give some idea of this subject, by taking for our 

 guides the magnificent Atlas* and the special Memoirs 

 of MM. Dufrenoy f and Elie de Beaumont. 



* In 1811, M. Brochant de Villiers, professor of mineralogy and 

 geology at the School of Mines, first proposed to construct a 

 geological atlas of France. The execution of this project, after 

 many delays, was resumed in 1822, under MM. Dufrenoy and Elie 

 de Beaumont, who shared in the responsibility and labours of the 

 undertaking. They devoted themselves for nineteen years to this 

 great work, which appeared in 1841. It is unfortunately very 

 difficult to procure copies of this splendid atlas, in consequence of 

 the government having reserved to themselves the absolute monopoly 

 of the work. 



f M. Dufrenoy a member of the Institute, professor at the 

 Jardin des Plantes, and Director of the Ecole des Mines, has raised 

 himself to the first place among contemporary geologists by the 

 publication of numerous works, among which we will only instance 

 those which refer to the geological atlas of France and to Mount 

 Vesuvius, the latter of which is to a certain degree the pendant to 

 that of M. Elie de Beaumont on Etna. M. Dufrenoy has especially 

 endeavoured to restore to mineralogy its character as a science of 

 observation, which it had partly lost by the introduction of almost 

 exclusively chemical methods. His TraitG de Mincralogie, which is 

 L 2 



