OYSTER CULTURE IN FRANCE. 575 



One hundred thousand oysters can be parced in these 

 claires. The specimens fed there are the little oysters 

 gathered on the crassats, which require to grow before 

 fattening, and the spat on tiles, which is only introduced 



*v 



after having remained in the packing cases till the month 

 of April, when the very dangerous tide of the March 

 equinox is over. 



The native oysters of which the growth has been 

 arrested are placed in the reserve claires. In their new 

 abode they return, after a little time, to a normal growth, 

 and gain in six months from 2 to 4 centimetres. 



As it is essential not to lose an inch of the precious 

 working ground, the banks west of the crassat of Lahillon 

 are utilised as free pares ; but to facilitate the access to the 

 higher claires, at every 20 metres a space has been left 

 where boats can moor. 



ILE DES OISEAUX (PARCS OF CRASTORBE). 



L'lle des Oiseaux is the largest crassat in the basin, 

 and the pare owners regard it as the most favourable ground 

 for the cultivation of the oyster. The Ostricultural Society 

 possesses 1 1 hectares of claires there. The -soil of these 

 claires has been made before being used ; it was originally 

 composed of a bottom of mud several metres thick, and of 

 so thin a consistency that it could scarcely be walked on, 

 even with large pattens. 



The consolidation of the soil has been affected thus : 

 A layer of shell-gravel, which is common in the Arcachon 

 basin, was first laid down. On this layer, the thickness of 

 which varies according to the greater or lesser fluidity of 

 the mud, was spread another layer of pebbles, as large as 

 nuts, from the quarries of Gazinet, near Bordeaux. These 

 pares, being in the neighbourhood of strong currents, have 



