182i.] Dr. Macculloch's Geological Classification of Rocks. 65 



Primary Class. 



{Stratified continued.) 

 Hornblende schist, Diallage rock, 



Actinolite schist Limestone, 



Quartz rock, Serpentine, 



Red sandstone, Compact felspar. 



Argillaceous schist, 



Secondary Class. 



Stratified. 



Lowest (red) sandstone, Limestone, 



Superior sandstone, Shale. 



U/tst ratified. 



Overlying (and venous) Pitchstone. 



rocks, 



Occasional Rocks. 

 Jasper, Gypsum, 



Siliceous schist, Conglomerate rocks, 



Chert, Veinstones. 



Appendix. 

 Volcanic rocks, Alluvia, 



Clay, marie, sand, Lignite, 



Coal, Peat. 



For the purpose of describing these different families consist- 

 ently with his plan, a geological preface, a history of the rela- 

 tions and general geological characters of each, is* given. This 

 part of the work contains the elements of geology, as far as it 

 relates to rocks ; those parts which relate to actions and events, 

 and to geological causes or theories, being reserved for a general 

 system of geological science, which the author, in his preface, 

 insinuates to be nearly ready for publication. 



The geological history of each family is followed by a synop- 

 tical table of all the varieties or species usually included under 

 it, in which the author has introduced minute descriptions of all 

 those which he professes to have thought deserving of notice, 

 and within his reach. These descriptions are of such a nature 

 as to enable a student to verify such specimens as he may have 

 to examine, and to refer thein to their generic place, or to that 

 which they hold among the families here adopted. 



A specimen of this work; namely, that part which belongs to 

 gneis, will be found in his work on the Western Islands ; and 

 as our limits will not now admit of a* more full detail of his plan 

 and its execution, we shall defer it to some future number ; but 

 m the mean time recommending this work as highly worthy of 

 the notice and examination of geologists. 



New Series, v o L . 1 1 . f 



