Webster on Calton Hill. 23* 



extensive and indurated. On the shore opposite to Godreyy 

 Island, an immense mass of it occurs, of more than a hundred 

 feet in length, and from twelve to twenty feet in depth, con- 

 taining entire shells and fragments of clay slate ; it is singular 

 that the whole mass assumes a striking appearance of stratifica- 

 tion. In some places it appears that attempts have been made 

 to separate it, probably for the purpose of building ; for several 



old houses in Gwythian are built of it." " It is around the 



promontory of New Kaye that the most extensive formation 

 of sandstone takes place. Here it may be seen in different 

 stages of induration ; from a state in which it is too friable to 

 be detached from the rock upon which it reposes, to a hard- 

 ness so considerable, that it requires a very violent blow from 

 a sledge to break it." — ^" But it is on the western side of the 

 promontory of New Kaye, in Fistril Bay, that the geologist will 

 be most struck with the formation ; for here no other rock is 

 in sight. The cliffs, which are high, and extend for several 



miles, are entirely composed of it." " The beach is covered 



with disjointed fragments, which have been detached from the 

 cliff above, many of which weigh two or three tons." 



There are three modes by which Dr. Paris conceives the 

 lapidification of calcareous sand may be effected. 1st. " By 

 the percolation of water through a hill of calcareous sand, by 

 which it becomes impregnated with carbonate of lime." 2d. 

 " The percolation of water through strata containing pyritical 

 substances, by which it becomes impregnated with sulphuric 

 s^lts." 3d. " The percolation of water through decomposing 

 Viate, or any ferruginous strata, by which it becomes impreg- 

 nated with iron alumina, and other mineral matter." 



