198 Outlines of Geology. 



posed, that Staffa, as it now is, was lifted from the bottom of the 

 ocean, with these pebbles and this alluvium lying upon it, we do 

 not diminish our difficulty; we assume changes greater than the 

 former, and adopt causes less consistent with the effect. Whether 

 the forces that have operated have been gradual or rapid, slow or 

 sudden, are questions which perhaps may be answered by an 

 examination of the strata and their arrangements, and as we find 

 these apparently undisturbed, it is not likely that the separation 

 of Staffa from the adjacent islands should have been effected by 

 any great dislocation, or earthquake, or Huttonian force emana* 

 ting from below ; it seems to have been more gradual and tranquil, 

 and to have resulted from powers which have not shaken or dis* 

 turbed the neighbouring parts, but yet have cut and carved away 

 th(B intervening rocks. I must however beg that none of these 

 remarks may be considered as having any reference to tlie origin 

 of the island itself; but merely to the probable source of the 

 matters which lie upon its basaltic strata. 



Jf we now reflect upon the wonderful occurrences which even 

 our most superficial strata record ; upon the extinct species of qua- 

 drupeds, birds, and probably of vegetables, which they contain ; 

 and upon the enigma which the mere inspection of a gravel pebble 

 calls upon us to solve ; we shall not be surprised at the occurrence 

 of greater difficulties, when we descend into those strata of the 

 earth, of an origin more remote and recondite ; and I trust that 

 my hearers, seeing the insufficiency of theories, even when ap- 

 plied to the simplest cases, will not be disposed to consider that 1 

 have judged amiss, if I pass lightly over the speculative part of 

 geology, and limit myself chiefly to its less excursive and enter- 

 taining, but more profitable practical details. 



Art. III. Description q/Psittacus Fieldii, a new species of 

 Parrot from Australia. By William Swainson, F. R. and 

 L. S. 



In my account, recently published, of several additions to the 

 Ornithology of Australia, F liave not noticed a most beautiful 



