84 



TAB. XXXIX. 



The upper figure is chiefly composed of irregular whitish 

 grains of quartz, cemented to each other by a sort of agglu- 

 tination of its own particles, and in some parts with oxide of 

 iron, which gives it the brownish tinge : it has a few specks 

 of mica, and a very little decomposed feltspar. This was 

 sent me by the Rev. Mr. Harriman from Durham. 



The lower figure is perhaps the coarsest sort of sandstone, 

 of much the same ingredients, but of a looser texture, with 

 more decomposed feltspar, and was given me by Lady Wil- 

 son, who brought it from Walmington in Cumberland. 

 The coarseness of the stone shows plainly that it could not 

 have been formed by human contrivance with the present 

 beautiful ornament, but that it is a natural production, 

 which equals in simplicity and elegance some of the m'ost 

 admired ornaments of antiquity, and may, like them, give 

 an useful hint to modern architects. 



The impressions seem to be like the leafy scales of the 

 stem of some plant yet unknown to us. They are most 

 like some foreign Euphorbia or Cactus. 



TAB. XL. 



The lower figures in this plate are of the finest texture; 

 the particles in the right hand figure, are so fine as scarcely 

 to be discerned without a magnifying glass : the fracture, 

 which is a little shattery as well as earthy, in some parts 

 readily shows the sand-like texture. It is more strongly 



4 



