Ch, XV.] FALUNS OF TOURAINE. 203 



before enumerated as containing monuments of the era under 

 consideration. 



Touraine. We have already alluded to the proofs of super- 

 position adduced by M. Desnoyers, to show that the shelly 

 strata provincially called the Faluns of the Loire ' were pos- 

 terior to the most recent fresh-water formation of the basin of 

 the Seine. Their position, therefore, shows that they are of 

 newer origin than the Eocene strata, more recent, at least, 

 than the uppermost beds of the Paris basin. But an exami- 

 nation of their fossil contents proves also that they are refer- 

 rible to that type which distinguishes the Miocene period. 

 When three hundred of the Touraine shells were compared 

 with more than eleven hundred of the Parisian species, there 

 were scarcely more than twenty which could be identified ; 

 and, on the other hand, the fossil shells of the Touraine beds 

 agree far less with the testacea now inhabiting our seas than 

 does the group occurring in the older Pliocene strata of 

 northern Italy. 



The Miocene strata of the Loire have been observed to 

 repose on a great variety of older rocks between Sologne and 

 the sea, in which line they are seen to rest successively upon 

 gneiss, clay- slate, coal-measures, Jura limestone, greenstone, 

 chalk, and lastly upon the upper fresh- water deposits of the 

 basin of the Seine. They consist principally of quartzose 

 gravel, sand, and broken shells. The beds are generally inco- 

 herent, but sometimes agglutinated together by a calcareous or 

 earthy cement, so as to serve as a building-stone. Like the 

 shelly portion of the crag of Norfolk and Suffolk, the faluns 

 and associated strata are of slight thickness, not exceeding 

 seventy feet. They often bear a close resemblance to the 

 crag in appearance, the shells being stained of the same ferru- 

 ginous colour, and being in the same state of decay ; serving 

 in Touraine, just as in Norfolk and Suffolk, to fertilize the 

 arable land. Like the crag, also, they contain mammiferous 

 remains, which are not only intermixed with marine shells, but 

 sometimes encrusted with serpulse, flustra 5 and balani. These 



