﻿1848. EDIBLE CLAY. 191 



but in the general character of their venation they 

 resemble the Aceririece. Some portions of the clay 

 was semi- vitrified, and so hard as to receive no im- 

 pression from a file ; and I gathered pieces of this 

 kind, composed of blue semi-vitrified layers, alter- 

 nating with others of a rich buff colour. All the 

 indurated clay, containing leaves, splits easily into 

 thin layers, in every one of which there were 

 impressions, so that the various kinds of leaves 

 must have been deposited thickly above one another 

 at this place. The fossiliferous clay is covered by 

 one hundred and forty feet of sand and sandstone, 

 and by some thin layers of conglomerate. 



A pipe-day is very generally associated with the 

 coal beds, and is frequently found in contact with 

 the lignite. It exists in beds varying in thickness 

 from six inches to a foot, and is generally of a 

 yellowish-white colour, but in some places has a 

 light lake-red tint. It is smooth, without grittiness, 

 and when masticated has a flavour somewhat like 

 the kernel of a hazel nut. When newly dug from 

 its bed, it is plastic, but in drying becomes rather 

 meagre and adheres to the tono;ue : its streak is 

 less glistening than that of ordinary English ^^ipe- 

 clay. As the natives eat this earth in times of 

 scarcity, and suppose that thereby they prolong 

 their lives, I requested Dr. Davy and the late Dr. 

 Prout to examine it, but neither of these able 



