452 On the Gypsum of the Himalaya. [Oct. 



Paris basin, as it is called. Here we have gypsum interstratified with 

 beds of sand, marl, and carbonate of lime ; now what reason have we 

 1o suppose that the gypsum was deposited by infiltration any more 

 than the carbonate of lime, or indeed than the sand and marl ; for 

 they too may be held in suspension by springs, as the others may be 

 held in solution. Do not the remains found in each prove that they 

 are all of the same era ? The writer talks of the absence of vegetable 

 remains in gypsum. Did he never hear of any in the gypsum near 

 Paris ? Moreover, if we must suppose the process of infiltration to have 

 taken place for the gypsum, and for that alone, we must also suppose 

 that the place it now occupies was once a hollow. That is, in the 

 country round Paris a subterraneous cavity existed, a few feet in depth, 

 but occupying an area of many miles in extent, covered by a roof 

 composed of loose beds of sand and gravel. The writer may have 

 seen, in examining mines, the great difficulty of driving a tunnel 

 through soft strata, wide enough even for a man to creep through, and 

 the artificial supports it must receive. What could have supported 

 the cavity, we just now supposed, before the infiltration was completed? 

 I forbear from extending these arguments to the gypsum of the earlier 

 secondary formations, but they are equally applicable to them. The 

 writer states that all geologists are agreed as to many beds of gypsum 

 being secondary. One would have thought that circumstance might 

 have made him hesitate before propounding his theory, and conclude, 

 they had some good reasons for doing so. As I have never examined 

 the gypsum of the Alps, I cannot enter into that part of the question ; 

 there are one or two other points, however, which I cannot pass over, 

 as they seem like a revival of the obsolete doctrines of Werner. The 

 writer esteems it almost matter of certainty, that the origin of all gyp- 

 sums is contemporaneous, from the u exact resemblance both in texture 

 and crystallization that they all bear, whether Alpine, or those varie- 

 ties found with the secondary rocks : a similarity that does not exist 

 in any of the limestones formed at different periods." To refer him 

 no further than the same chapter of the same book, I have already 

 quoted (Lyell), we find there that a rock is now depositing in Italy 

 from a spring, " which cannot be distinguished, in hand specimens, either 

 in grain, colour, or composition from statuary marble." I have myself 

 seen on the continent of Europe a secondary limestone, not distinguish- 

 able in texture and crystallization from the primitive marbles which 

 are usually found in beds in mica-slate. Many other instances might be 

 cited to the same effect. Nor is the writer more fortunate in two 

 other assertions he has made, viz. that li quartz veins are the type of tran- 



