1832.] On the Gypsum of the Himalaya. 451 



doubted ? In almost every bed of clay, where sulphuret of iron and 

 calcareous matter are present, and the bed is so loose as to allow of infil- 

 tration, the sulphuret is decomposing and the sulphate of lime forming ? 

 Did he not know that the same solution was commonly given and 

 received for the presence of the abundant sulphuric and sulphurous 

 acids, which both rise in vapours from the craters of volcanos and im- 

 pregnate the mineral waters near them ; viz. that they were produced 

 by the decomposition of sulphur and sulphuretted hydrogen. Has he 

 never heard, for instance, of the phenomena of the " Solfatara" near 

 Vesuvius, and the manner in which they are accounted for ? Lastly, 

 when he asserted that " we know of no gypsum actually forming at 

 this day," had he forgotten that gypsum, as well as the tufaceous car- 

 bonate, is actually forming at present ? In proof of this, I will refer 

 him no further than to a popular treatise of the day, LyelPs Geology, 

 (vol. I.) Under the head gypsum springs, he may see a notice of that 

 at Baden near Vienna ; and a little farther back he will find an account 

 of the baths of San Filippo, where three copious springs deposit calcare- 

 ous carbonate, with gypsum and sulphate of magnesia. 



Having accounted for the formation of gypsum, and thus rendered 

 it probable that some gypsum beds are deposited by infiltration, i. e. by 

 the insinuation of the mineral in solution into cracks and fissures, he 

 comes to the general conclusion that all gypsum is produced by infiltra- 

 tion. That gypsum is analogous to calcareous deposits, is certainly true 

 but if he had recollected the manner in which calcareous deposits took 

 place, he would have seen that great part of them could not be 

 said to be caused by infiltration. Thus, when a spring containing 

 carbonate of lime in solution issues to the surface, most of its mineral 

 is carried to a neighbouring river ; by the river to a lake, or to the 

 sea. We have instances of calcareous beds now forming at the 

 bottom of lakes, and, though we can have no direct evidence of what 

 is going on at the bottom of the sea, we have good reason to believe 

 that the same process is taking place there. Now the same reasoning 

 holds with respect to sulphate of lime. It is carried down to lakes 

 and seas, and must be precipitated, owing to the evaporation which is 

 continually taking place. If we examine the deposits of carbonate of 

 lime and gypsum, which together constitute great part of our later 

 strata, we find that they tally with the above supposition ; viz. that 

 they are precisely such as would have been deposited at the bottom 

 of the lakes or shallow seas. The different remains found in them 

 the shells, the aquatic vegetables, the amphibious reptiles, the fishes 

 the mammalia, all point to the same result. Take, for instance, the 



