ON THE BASALTIC COUNTRY IN IRELAND^ ^57 



neat but diminutive hummock culled the Rock of Clogher, Additional evi- 

 above Bushmills. As our time was precious, you took my ^salti^hum- 

 word for its stratification being precisely similar to that of mocks. 

 DunmvlL **■* $ 



There are many other basaltic hummocks scattered over 

 the surface of our area, all of them either stratified or por- 

 tions of strata; two of the most remarkable are the hill of 

 Knock Loughran, near Maghera, and a tall hummock (the 

 name of which I forget) a mile eastward from Lisanoure. 



We meet still more frequently ah imperfect style of hum- 

 mock, a semicircular facade on one side, while on the other 

 it slopes away gradually with the dip of the strata, as if the 

 operation had been interrupted before it was carried quite 

 round; the most remarkable of these are Ballystrone, in 

 Dcmji and Croaghmore, in Antrim, both visible from Dun- 

 mull. 



Regular stratifications on the summits of hills and moun- 

 tains havt; long been a stumbling block to theorists. The 

 historian of the French Academy, for the year 1716, ob- 

 viously ascribing the superficial inequalities of the Earth 

 (like many others) to causes acting from below, and perceiv- 

 ing how incompatible such assemblages of strata were to his 

 theory, thinks it safer to doubt their existence, as they could 

 not have been formed, he says, " unless the masses of the 

 *' mountains were elevated in the direction of an axis per- 

 " pendicular to the horizon : ce que 11 a pu kre que tres 

 " rare. J> 



But as these stratified mounts are in our area by no 

 means uncommon, they lay us under the necessity of sug- 

 gesting another alternative similar to those we have already 

 stated. 



Were these isolated hummocks originally formed as they 

 now staud, (solitary and separate from each other) one by 

 one? or are they the last remaining portions of a vast conso- 

 lidated mass, of which the intermediate and connecting- 

 strata have been carried off by causes, with which we Ire 

 unacquainted ? 



To be able satisfactorily to resolve this alternative, it be- 

 comes necessary, to take a careful view of the contiguous 

 countries, and to try whether their construction,, and the ar- 



Vol, XXII.— April, 1809. S rangement 



