3* NATURAL HISTORY. 



Feet fncli 



Brought over 54 6. 



XIX. Very large powdered marie 1 6 



XX. Hard and calcinable stone like marble 1 6 



XXI. Grey and vitrifiable sand mixed with 

 fossile shells., particularly oysters and muscles, 

 which have no adherence with sand, and which 



are not petrified - - 30 



XXII. White vitrifiable sand mixed with 

 shells 20 



XXIII. Sand streaked red and white, vitrifi- 

 able and mixed with the like shells 1 



XXIV. Larger sand, but still vitrifiable and 

 mixed with the like shells - 10 



XXV. Grey, fine, and vitrifiable sand, mix- 

 ed with the like shells - 8 6 



XXVI. Very fine fat sand, where there were 



only a few shells - - - 30 



XXVII. Freestone .... 3 



XXVIII. Vitrifiable sand, streaked red and 

 white -.-...40 



XXIX. White vitrifiable sand -.36 



XXX. Reddish vitrifiable sand - - 15 

 Total depths when they left off digging JQJ g 



Within a trench made at Amsterdam, the earth was 

 dry to the depth of 230 feet, and the strata of earth 

 were found as follows : 7 feet of vegetable or garden 

 earth, 9 feet turf, 9 feet soft clay, 8 feet sand, 4 feet 

 earth, 10 feet sand, on which it is customary to fix the 

 piles which support the houses of Amsterdam ; then 

 2 feet argile, 4 of white sand^ 5 of dry earth, 1 of soft 

 earth, 14 of gravel, 8 argile, mixed with earth ; 4 of 

 gravel mixed with shells ; then clay 1 02 feet thick, 

 and at last 31 feet sand, at which depth they ceased 



