Intelligence and Miscellaneous Articles. 75 



and of Castel Nuovo, are made to cross argillaceous limestone beds, 

 and with such abundance that their formation may be fully tested. 

 Action also takes place at the same time upon the walls of fractures 

 and the fissures of the soil which open a passage to the subterranean 

 vapours. Thence it extends gradually into the interior of the masses, 

 and it ends by gypsifying whole circles whose radius is generally 

 that of the lagoons themselves. Pure limestones are converted into 

 a lamellar sulphate of lime, but of a loose texture and free of cel- 

 lules. This structure is probably due to the expansion they undergo 

 from the addition of new materials, and perhaps also by the passage 

 of the gas at the moment of the crystallization of the salt. The cal- 

 careous formations below the argillaceous, preserve after their trans- 

 formation their primitive position, and they present an alternation of 

 gypseous beds, and of argillaceous beds which the acid has freed 

 from the soluble bases. When this influence is exerted in the direc- 

 tion of the thickness of the strata, it is very common to see towards 

 the limits where the metamorphic influence ceases, a mass of rock 

 strikingly calcareous at one of its extremities, terminating at the 

 other extremity in a gypsum which the inhabitants use for buildings. 

 The resemblance to the gypsum beds, occurring in the midst of the 

 secondary formations, is . exhibited even in the reddish tint with 

 which oxidation marks the associate clays of the alberese. But a 

 peculiarity which has given me the solution of a problem which had 

 embarrassed me thus far, deserves mention ; for we have reproduced 

 here certain phenomena of which the enormous deposits of the Pro- 

 vencal Alps present many examples. I had noticed at Roquevaire 

 and at Digne, irregular argillaceous incrustations in which are found 

 entangled without order, angular fragments of sulphate of lime of 

 various sizes. In admitting the transformation of the Jurassic lime- 

 stone of these countries posterior to its consolidation under the in- 

 fluence of the acid vapours, it was difficult to explain the mode of 

 formation of these breccias and the manner in which these fragments 

 were introduced. In all these cases they seemed to indicate an 

 overflow of waters, but the theory opposes the intervention of waters 

 for the accomplishment of the facts relative to the conversion of the 

 limestone, or it leaves in doubt the part which they must have acted. 

 But, observe what is apparent at the lagoons of Monte Cerboli and 

 of Castel Nuovo. At the same time that the limestone is changed 

 into gypsum, by the contact of sulphurous agents, the fragments of 

 alberese which waters had brought down from heights above to the 

 midst of the miry and boiling lakes, are thus changed into sulphate 

 of lime, and constitute, with the clays in which they sink, brecciated 

 argillo-gypseous beds without stratification. That this fact should 

 be equally apparent in the ancient beds under analogous circum- 

 stances, is at least what might be inferred from the examination 

 of that which passes in the lagoons. We should also observe 

 the analogous positions of the boracite of Luneburg, which is found 

 in crystals disseminated in gypsum intercalated in the midst of a 

 cretaceous bed, and the boracic acid and borates of the Tuscan 

 lagoons. 



These different facts well confirmed, establish in my view an inti- 



