Artificial Origin of Rock-Basins. 335 



been completely perforated, while its edge has been left entire, 

 forming an arch which extends over the aperture. Basins of 

 every size, and of every stage of formation and destruction, may 

 be found on almost every earn. The water, collected from the 

 rains, in the basins on the so-called " Sacrificing Stone," as 

 it flows from the upper into the lower cavities, is manifestly 

 wearing for itself a course which, in process of time, will com- 

 pletely unite all the basins into one great irregular cavity. 



These circumstances are clearly indicative of the natural 

 process, still going on, by which these curious excavations 

 have been produced, and by which also they will eventually 

 be destroyed. But perhaps the most palpably-undeniable 

 evidence that they cannot have been artificially formed, ma}' 

 be found in the circumstance, which Dr. Macculloch has not 

 mentioned, that many of the rock-basins on Carnbrea are 

 crossed by the veins of porphyry and porphyritic granite 

 which traverse the earns; and which, offering a much greater 

 resistance to the action of decomposing agents than the gra- 

 nite itself, have been left in the basins, in the form of ridges* 

 their edges only having been rounded by the action of the 

 elements. This fact is obviously conclusive; since the Druidi- 

 cal sculptors, who must have possessed the skill required to 

 render some of the basins accurately spheroidal, if they were 

 indeed the artists of them ; would not have left these unsightly 

 ridges in other basins *. 



The " indications of design," stated to be afforded by " the 

 peculiar form" of these cavities, are all, when strictly ex- 

 amined, evidences that they were produced by the natural 

 process which has been described by Dr. Macculloch, and il- 

 lustrated in the preceding remarks. This is also the case 

 with every particular among those which have been so elabo- 



* It may be added, in further confirmation of the natural process here 

 maintained to have exposed these veins, that similar ridges of porphyry, 

 several inches in height, project from the smoothed surfaces of many of 

 the earns where there are not any rcck-basins, having manifestly been 

 denuded by the same process of weathering ; and that, in some positions, 

 the granite decomposes in a direction perpendicular to the planes of the 

 veins which intersect it, when they become exposed, in such a manner, as 

 to form the face of the rock. 



The writer purposely refrains, in this place, from designating, more parti- 

 cularly than as above, the material of these veins ; (although he is fully 

 aware of the importance and interest of the subject, in the present state 

 of our knowledge and of geological speculation, on the relations of granite 

 to the incumbent rocks, and the origin of elvan dykes, &c.;) because it is 

 not described in the notes from which the observations on rock-basins 

 have been derived, and the specimens collected at the time of making 

 them are not at present accessible to him ; his memory alone, furnishing 

 uierely a general impression of their nature. 



rately 



