NATURAL HISTORY. 



587 



them quite hot, so that it was 

 most ])robably iriflaininable ; but 

 we (lid not ascertain this. We 

 heard the boiling thirty yards be- 

 fore we came to the pools, re- 

 sembling in noise a water-fall. 

 The pools did not overflow ; of 

 course the bubbling was occa- 

 sioneil by the rising of air alone. 

 The water of one of the pools ap- 

 peared to contain a mixture of 

 earth and lime, and from the 

 taste to be combined witli alkali. 

 The water of the Bludugs and 

 the lake is used medicinally by 

 the Javanese, and cattle drinking 

 of the water are poisoned. 



Some Observations on the iSult 

 Mines of Cardonu, made during 

 a Tour in Spain, in the Summer 

 of 1814. By Thomas Stewart 

 Traill, M. D. M. G. S. 



(From Transactions of the Geological So- 

 eiely, Vol. III.) 



These celebrated mines occupy 

 the head of a small valley in tlie 

 immediate vicinity of Cardona, a 

 town in the province of Cata- 

 lonia. 



This valley extends about half 

 a mile in length, from the river 

 Cardonero to the mines, in a di- 

 rection from east-south-east to 

 west-north-west. Its north-west- 

 ern side is bounded by a very 

 steep and lofty ridge, the sunnnit 

 of which is crowned by the town 

 and castle of Caidona. The op- 

 posite boundary i.s somewhat less 

 elevated ; but both sides are con- 

 siderably higher than the up])er 

 surface of the fossil salt. On 

 entering this valley, the attention 

 is arrested by bold cliffs of a 

 greyish white coloui-, which are 



soon discovered to consist of one 

 vast mass of salt. The sides and 

 bottom of the valley are conijiosed 

 of reddish brown clay, forming a 

 thick bed, from which heie and 

 there large imiiedded masses of 

 lock salt project in tl;e manner 

 of more ordinaiy rocks ; espe- 

 cially along the winding ascent 

 which leads up to the town of 

 Cardona. The summits of tlic 

 ridges which bound the \allcy on 

 cacii side, are formed of a jel- 

 lowisli grey sandstone of a coar.se 

 texture, and containing many 

 scales of grey mica. 



The great body of the salt 

 forms a rugged precipice, which 

 is reckoned between 400 and oOO 

 feet in height at the upper ex- 

 tremity of tiie valley, a)Kl is co- 

 vered by a thick bed of the clay 

 above mentioned. 



The precipitous form is partly 

 owing to the manner in which 

 the mine has been wrought for a 

 series of ages. There is no ex- 

 cavation ; but the salt has been 

 procured by woi'king down per- 

 pendicularly as in an open quarry. 

 The lowest part of the present 

 woiks has a solid floor of pure 

 salt which is not above the level 

 of the bottom of the valley, where 

 no salt is foiuitl ; but the real 

 depth of the bed of salt has never 

 yet been ascertained. Tiie upper 

 surface of the salt is not level ; 

 but appears irregulaily elevated, 

 according to the general outline 

 of the hill in which it occurs. 



The salt has been usually re- 

 presented as forming an entire 

 mountain : but though it here 

 appears sui)])lying tlie place of 

 common lock, from its being 

 confined to this valley, and not 

 attaining so high a level as the 

 surr{)unding 



