DOMAIN I. S1DEROUS. 



of slate, chiefly near Laferriere in Normandy, 

 and in the neighbourhood of Angers. The last 

 is the most important; it furnishes slate of the 

 most perfect quality; and its extent and pro- 

 digious thickness make it be regarded as in- 

 exhaustible. 



" This bed extends for a space of two leagues, 

 from Avrille to Trelaze, passing under Angers, 

 where the Mayenne, which comes from the 

 north, cuts it at right angles. 



" The town of Angers is not only covered but 

 built with slate, those blocks being employed in 

 masonry which are the least divisible. 



" The quarries which are actually explored 

 are all in the same line, from west to east, as 

 well as the ancient pits; it being in this di- 

 rection that, by the exterior disposition of the 

 soil, the bed of slate presents itself nearest the 

 surface. Immediately under the vegetable earth 

 is found a brittle kind of slate, which, for four 

 or five feet in depth, splits into little fragments 

 of some inches, which have the form of a rhom- 

 boid, or a portion of that figure. 



" A little lower is found what they call build- 

 ing stone, being a pretty firm slate, but scarcely 

 divisible into leaves. This is employed in the 

 construction of houses, after it has been suffi- 

 ciently hardened by^being dried in the open air. 



