MODE "**. BASALT. 23 



in size, being about six feet in diameter. Many 

 of these huge columns, which have fallen down, 

 are now lying at the bottom of the hill; one in 

 particular, sixty feet in length, has been thrown 

 across a deep gulley, with its ends resting on 

 each side, so as to form a bridge over it*." 



It also appears from Dr. Richardson's recent 

 observations f, that the basalt in the north of 

 Ireland occurs on the tops of hills, at a great 

 distance, while the intervening space has been, 

 as it were, scooped out by some exterior agency, 

 with which we are at present totally unacquaint- 

 ed. But whether some comet has approached 

 the earth, or some small planet, like one of those 

 recently discovered, has fallen into it, and occa- 

 sioned appearances altogether inexplicable upon 

 our small scale of observation, most probably 

 may ever remain a matter of theory +: and in 

 natural, as well as in civil history, there are 

 many objects of which the best judges choose to 

 remain in what Mr. Gibbon emphatically calls 



A LEARNED IGNORANCE. Nor ITlUSt it be for- 



gotten, that masses of sandstone and limestone 



* Landt, 39. 



t Ph. Tr. 1803. 



J Dolomieu, J. de Ph. 1 791, p. 385, thinks that an exterior 

 shock has broken the crust oi' the globe, and raised parts on others. 

 The like ideas may be inferred from the REFOULEMENT of Saussure 



