Outlines of Geology. TI 



respecting the structure, position, and contents, of the strata that 

 envelope our globe. I have said nothing of Buffon, whose the- 

 ories and speculations are much of the same cast as those of 

 Burnet ; nor of Rouelle, who reasoned more correctly, and dis- 

 criminated with greater judgment; wishing to confine myself 

 chiefly to the opinions, as well as to the writings, of our own 

 countrymen. But in the works of this period one very important 

 fact must not be overlooked, relating to the distinction insisted 

 upon chiefly by Lehman, and some other continental authors, 

 which may be made between rocks containing organized fossils, 

 and those which are destitute of such remains ; the former bear- 

 ing evident traces of great revolutions and changes, the latter, 

 apparently of an anterior date, and exhibiting no marks of animal 

 or vegetable relics : the former, in the words of Lehman, owing 

 their formation to partial or local accidents and derangements, the 

 latter coeval with the world. To these which have since been 

 called secondary and primary rocks, he added a third class, in 

 which, as to position and structure, he professed to recognise the 

 operation of the deluge ; he presumed that they must have resulted 

 from some great catastrophe, tearing up and modifying an ancient 

 order of things. But in respect to the classification of rocks, it 

 will be our business to speak more at length hereafter : and ap- 

 prehensive that I may already have fatigued your attention with 

 matters rather curious than useful, and with details historical 

 rather than practical, I shall only further trespass upon it by briefly 

 adverting to the speculations of two comparatively modern theo- 

 rists, whose opinions have divided the geologists of our own time, 

 and who may be called the founders of its once opposed schools ; 

 premising, however, that in their arguments and hypotheses, as in 

 those of their predecessors, we shall find much that is blameful 

 and faulty, mixed up with a body of practical and matter-of-fact 

 information, of infinite use and value : indeed, though it is unfor- 

 tunately my business to adduce many of these theories rather to 

 refute, than to elucidate them ; and though they are, with few 

 exceptions, so many imaginaiy fabrics, displaying rather the fol- 



