416 NOTES ON THE GEOLOGY 



Will the facts above stated throw any light upon the general 

 subject of the origin of rock salt ? That this substance in Asia, 

 as in other parts of the world, is usually connected with rocks of 

 rather recent igneous origin, seems fully established. But do not 

 the facts respecting the exceedingly salt lakes of Oroomiah, Elton, 

 and others, render it extremely probable that beds of salt, alternat- 

 ing with beds of earth, may have been formed, — indeed, are now 

 forming ? So that, although originally of volcanic origin, subse- 

 quent alluvial agency may redeposit it. And \vill not this double 

 origin of the substance best accord with facts ? 



I will refer in this place to an interesting specimen of marble, 

 obtained by Rev. Mr. Merrick, in the ruins of Persepolis. It is 

 a dark gray, argillaceous, bituminous limestone, with casts of 

 univalve shells. (No. 202.) In dissolving this stone in hydro- 

 chloric acid, it gave off a strong bituminous odor ; but the quan- 

 tity of bitumen in it is not very large. I found in one hundred 

 parts, 



Earthy residuum, .... 2.33 



Carbonate of magnesia, . . . 2.21 



Carbonate of lime, .... 95.46 



100.00 

 It would be strange, if such limestone would not form a good 

 hydraulic cement. But the locality of the quaiTy from whence 

 it was talvcn, I do not know. It is not a rock, however, that 

 would be carried a gi-eat distance, because not handsome ; and, 

 therefore, we should expect to find the quany not far from 

 Persepolis. 



No. 216 is an exceedingly rich ore of copper, from a mine 

 about sixty miles northeast of Tabreez ; and of course not far 

 from Georgia. It is mainly native copper, incrusted with the 

 green and blue carbonates, and mixed with the red oxide. The 

 native copper exists in some of the cavities in crystals. This 

 mine is extensively worked by the Persians, and is said to be very 

 rich. A large number of cannon have been cast from it for the 

 Persian government. 



