66 



not here eater into the consideration, whether, in 

 point of origin, it is prior or posterior to these ; 

 that question appertains purely to that part of its 

 geological history, of which this work does not 

 pretend to treat. 



The position of Serpentine, on the contrary, 

 which is the only other rock contained in this 

 division, is not necessarily inferior to that of the 

 stratified rocks of the primary class. It occurs in 

 every part of the series, from granite upwards, 

 even to the confines of the secondary strata. As 

 an unstratified rock, however, it is necessarily 

 placed in this division ; and it will soon be seen 

 that, in the uncertainly of its position with re- 

 spect to the stratified substances, it is by no means 

 a solitary instance of irregularity. 



The stratified division requires here no ex- 

 planation beyond that which its name will sug- 

 gest ; and its several characters are fully ex- 

 amined in that chapter which is appropriated to 

 the structure of rocks, and in the preliminary re- 

 marks to the primary class. 



