GEOLOGICAL CLASSIFICATION 



OF 



ROCKS, 



WITH DESCRIPTIVE SYNOPSES 



OF 



THE SPECIES AND VARIETIES, 



COMPRISING 



THE ELEMENTS 



OF 



PRACTICAL GEOLOGY. 



BY JOHN MACCULLOCH, M.D. 



F.R.S. F.L.S. Vice Pres. Geoi. Soc. &c. &c. &c. 



Eontron : 



PUBLISHED BY 



LONGMAN, HURST, REES, OR ME, AND BROWN, 

 PATERNOSTER ROW. 



1821. 



