upon which it reposes without crumbling, to a hardness so considerable as to require a very violent blow from a hammer to break it;[80] indeed holes are actually bored in some parts for the purpose of admitting cables with which vessels are moored. Buildings are here commonly constructed of it, and the church of Crantock is entirely built with it. By the inhabitants the stone is employed for various articles of domestic and rural oeconomy." "The Geologist, who has previously examined the celebrated specimen from Guadaloupe, enclosing a human skeleton, and which is now in the British Museum, will be forcibly struck with the great similitude which this stone bears to it; and suspecting that masses might be found containing human bones imbedded, if a diligent search were made in the vicinity of those cemetries which have been overwhelmed, I made an excursion with my friend Sir Christopher Hawkins, for that purpose; but time and patience failed us, and the discovery is reserved for some more persevering and fortunate member of the society." "Such then is the nature and situation of this most interesting formation. In the next place, we have to enquire into the causes which have operated in thus consolidating the sand, and into the peculiar circumstances under which the operation has been conducted." "It will appear that there are at least three distinct modes by which the _lapidification_ of calcareous sand may be effected, and that the present formation is capable of affording characteristic examples of each." "The three species of cementing matter to which I allude, are all deposited from water in which they either exist chemically dissolved, or mechanically suspended. The water deriving them from the substances through which it percolates; thus is the first species of cement obtained-- 1. _By the percolation of water, through a stratum of calcareous sand, by which it becomes impregnated with carbonate of lime._ 2. _By the percolation of water through strata containing decomposing Sulphurets; by which it becomes impregnated with Sulphuric salts._ 3. _By the percolation of water through decomposing Clay-slate, or any other ferruginous strata; by which it becomes impregnated with Iron, Alumina, and other mineral matter._