200 DOMAIN X, TRANSIHENT. 



of stone enclose, in the middle of their thickness, 

 another stone in which are contained kernels of 

 flint. 



" Each of these beds, whose thickness varies 

 from one inch to five or six, is therefore com- 

 posed of three different substances: 1. White 

 stone ; 2. Brown stone ; 3. Flint. 



" White stone, No. 1, forms the upper and 

 lower part of each bed; it is calcareous, of a 

 white approaching to red; it breaks in irregular 

 uneven fragments, with obtuse angles; its frac- 

 ture presents a mixture of grains, more or less 

 small, shapeless, earthy, and without any lustre. 

 It is rough to the touch, and stains the hands a 

 little ; it is soft, but however less so than chalk. 

 It therefore differs from this by being a little 

 more hard, and by a coarser grain. It dissolves 

 in acids with considerable effervescence, and 

 leaves behind a small argillaceous sediment. 



" The brown stone, No. 2, which occupies 

 the middle of the beds of that kind of chalk, is of 

 a clear Isabella-brown ; it breaks in conchoidal 

 fragments with sharp edges, and whose angles 

 and small scales are translucent ; its fracture is 

 compact with scales, being sometimes very 

 small, sometimes pretty large. Its lustre is 

 weak, a little shining ; its streak is of a whitish 

 grey; its hardness rather more than that of 



