412 OBSERVATIONS ON THE GEOLOGY 



secondly, The nature and relative situation of the minerals in 

 the United States, whilst they are certainly the most extensive 

 of any field yet examined, may perhaps be found to be the 

 most correct elucidation of the general exactitude of that theory, 

 as respects the relative position of the different series of rocks. 

 Without entering into any investigation of the origin or first 

 formation of the various substances, the following nomenclature 

 will be used. 



Class 1st. Primitive Rocks. 



1. Granite, 8. Porphyry, 



2. Gneiss, 9. Sienite, 



3. Mica slate, 10. Topaz-Rock, 



4. Clay slate, 1 1 . Quartz-Rock, 



5. Primitive Limestone, 12. Primitive Flinty-Slate, 



6. Primitive Trap, 13. Primitive Gypsum, 



7. Serpentine, 14. White-Stone. 



Class Id. Transition Rocks. 



1. Transition Limestone, 4. Transition Flinty-Slate, 



2. Transition Trap, 5. Transition Gypsum. 



3. Grey Wacke. 



Class 3d. Flcetz or Secondary Rocks. 



1. Old Red Sandstone or 1st 7. Third Flcetz-Sandstone, 



Sandstone Formation, 8. Rock-Salt Formation, 



2. First or Oldest Flcetz-Lime- 9. Chalk Formation, 



stone, 10. Flcetz-Trap Formation, 



3. First or Oldest Flcetz-Gyp- 11. Independent Coal Forma- 



sum, tion, 



4. 2d or Variegated Sandstone, 12. Newest Flcetz-Trap Forma- 



5. 2d Flcetz-Gypsum, tion. 



6. 2d Flcetz-Limestone, 



Class Uh. Alluvial Rocks. 



1. Peat, 5. Nagel fluh, 



2. Sand and gravel, 6. Calc-tuff, 



3. Loam, 7, Calc-sinter. 



4. Bog iron ore, 



