1832.] On the Gypsum of the Himalaya. 453 



sition," and that primary rocks u are never found reposing on the 

 newer formations." 



That identity of mineral structure proves formations to he contem- 

 poraneous, and that the order of superposition is invariable, were 

 doctrines laid down by Werner, and for along time received as axioms 

 in geology. But of late years, a further insight into the phenomena of 

 existing volcanos, and a more extended research over the surface of 

 the globe, have brought both these propositions into doubt, and tended 

 to confirm a belief that natural causes at present in operation are 

 adequate to produce all the appearances that are presented to us. I 

 cannot quote an example of quartz veins in secondary rocks from 

 memory, and at this distance in the country having few books to refer 

 to, I must be content with Jamieson's Mineralogy. It is there stated, 

 under the head quartz, that quartz veins are found in secondary rocks 

 as well as in transition. But I could name a locality, in the north of 

 Europe, of granite overlying a transition limestone, and I can refer to 

 Humboldt, as quoted by Daubeny, (on volcanos, p. 350,) for the fol- 

 lowing as an ascending series : No. 1, granite ; 2, Alpine limestone ; 3, 

 granite. To the same chapter of the same work I would refer for a de- 

 scription of the porphyry of South America, not distinguishable from the 

 transition porphyry of Europe, which as well as sienite, gradually ap- 

 proximates to trachyte, and passes into it ; so that Humboldt considers 

 there is no natural line of separation between the transition and modern 

 volcanic formations of America. What then becomes of the doctrine 

 of contemporaneous origin? It maybe matter of convenience to pre- 

 serve the classification of primary, transition, secondary, and tertiary 

 rocks, for want of a better or as indicative of certain organic remains. 

 But it is prejudicial to the cause of truth to ascribe to the opinion 

 more importance than it deserves ; especially in a country as yet almost 

 unstudied, where the disciples of it must go forth predetermined to find 

 analogies to the European formations, and to overlook discrepancies. 



It may appear presumptuous in me to hazard an opinion respecting 

 a rock which I have never seen, but one or two circumstances men- 

 tioned by the writer lead me to believe, that the gypsum beds de- 

 scribed by him in the Himalaya are not posterior to the formations 

 with which they are connected. The first of these is, that they are 

 interstratified with a reddish argillaceous schist. Now although it may 

 be conceived to be possible that liquid sulphate of lime might have been 

 forcibly thrust between two layers of rock of a different nature, as we 

 see is frequently the case with lava, trap, and granite ; there is nothing 

 in the history of gypsum which leads us to believe it would happen. It 



