166 Dr. Berger on the Geological Features 



south-west of that town, the mulattoe rests on a slate clay probably 

 of this formation. 



The localities already cited range along the south eastern border 

 of the great basaltic and secondary area ; the same formation ap- 

 pears also to exist towards the northern boundary. From speci- 

 mens which we examined in the collection of the Dublin Society, 

 we had reason to believe that this is the case in the neighbourhood 

 of Ballycastle, but we did not ourselves observe this formation in 

 situ in that point. About half way between Ballycastle and Bush- 

 mills near Ballintoy, the chalk formation rises sufficiently high to 

 disclose its substrata ; a valley opening towards the sea, near 

 White Park, shews that they here consist of the slate clay of the lias 

 formation, with gryphites and ammonites. Farther east the chalk 

 cliffs again emerge from the level of the sea immediately beyond 

 Dunluce Castle, and continue to rise till they are broken off at the 

 commencement of Portrush Strand. As they here exhibit nearly 

 the same thickness which they possess near White Park, we are 

 naturally led to expect the recurrence of similar substrata near this 

 point ; and accordingly, in the peninsula of Portrush, a singular 

 rock is seen, divided by interposed masses of greenstone, but con- 

 taining ammonites and gryphites, and possessing exactly that cha- 

 racter which would be assumed by the slate clay before described, 

 if indurated by the action of heat. In the explanatory notes 

 accompanying the sections of the coast a more detailed account of 

 this peninsula will be found. 



The cabinet of the Dublin Society contains specimens of lias 

 from the neighbourhood of Magilligan, about eight miles westward 

 from Portrush, and close to the north-west angle of the basaltic area. 



