362 Memoir relative to [May, 



employed in defraying the expenses incurred in bl^ilding the 

 arsenal at Genoa, was the produce of the island of Sardinia. 



The great extent, and the irregular shape, of the excavations 

 formed for the purposes of mining in Sardinia excite surprise ; 

 and the appearances of what seems to have been an unprofitable 

 waste of money and labour give rise to doubts as to what has 

 been the actual cause of these works of the early miners. To 

 suppose that the enormous excavations which remain have at 

 any time been filled with solid masses of ore is impossible ; and 

 it is equally difficult to believe that vast chambers, some of 

 them formed in the shape of domes, and others as extensive 

 square and circular apartments, should have beeii constructed 

 without a view to gain. That these chasms are natural is an 

 idea which cannot for a moment be entertained; and perhaps 

 the most satisfactory way in which to account for their existence 

 is to concur in a tradition prevalent in the island, that constructed 

 at first for the purposes of the miner, these caverns served in 

 after times as a residence for the natives, when domestic feuds 

 of a political nature, or when hostile invasion, desolated the 

 country. For these purposes it is conjectured that the mines 

 have been gradually enlarged and altered till they assumed their 

 present form ; and that, like the Gothic inhabitants of Spain, 

 who are known to have sought a similar species of shelter to 

 escape the tyranny of their Moorish conquerors, the Sardinians 

 were wont to seclude themselves in these subterraneous dwell- 

 ings to preserve the freedom, the inheritance of their northern 

 ancestors. 



The entrances to these caverns are constructed upon several 

 difi^erent plans ; in some it is merely a horizontal creek in the 

 rock ; in others, it is wide enough to admit two coaches abreast ; 

 and in some it is a door of about seven feet six inches in height, 

 and four feet three inches in breadth. 



In most of these excavations, the ore appears to have been 

 thoroughly wrought out, as hardly the least spark of it can be 

 detected at present; and if the great number of mines in different 

 districts of the island be considered, the wealth which the ancient 

 possessors of the mmes must have derived from them must have 

 been inm3ense. 



The high grounds of Sardinia are composed of granite;* under 

 this is a stratum of limestone, of the great thickness of 80 or 90 

 fathoms, of a compact and brittle texture, and of a whitish 

 colour ; and under this is generally a stratum of a brownish 

 coloured schistus, frequently intermixed with some of a blue 

 colour. In this limestone are situated the lead veins in a matrix 



* Tlie granite on the summit of the mountains liere shows considerable appear- 

 ances of stratification, which gives rise to a conjecture, that it rests in a stratum 

 nbove tlie limestone, and does not penetrate through the strata of limestdne and 

 jchistns, and thus form the base on which llic last mentioned strata rest, according 

 fa the received opinion of geologists respecting the nature of granite raountains. 



