4 



THE GEOLOGIST. 



author's idea being that tlie bed of Basalt forming the Canseway ex- 

 tended eastward to Portmoon, a distance of two-miles (page 46), and 

 that the whole of the strata are parallel to each other. These sup- 

 positions are, as far as I am aware of, adopted by all subsequent 

 ■writers on the Causeway ; and as they are errors, a transcript of my 

 notes may not be unacceptable to the readers of the " Geologist f 

 they tend at least to illustrate more fully the structure of the Basaltic 

 deposits to which I allude, and are a few additional facts added to 

 our present information on this interesting subject. 



Proceeding to the Causeway from Portrush, when we arrrive 

 at Dunluce Castle the view^s of the coast are remai^kably 

 striking and instructive. That to the west, from a window in 

 Dunluce Castle (Fig. 1) shows the junction of the Basalt and Chalk 



Lign. 1.— View looking west, from a ^vindow in Dunluce Castle. Chalk Cliffs capped by Basalt. 



most admirably. The Basalt, wliich for the height of some hundreds 

 of feet above the Chalk is quite amorphous, is seen capping all the 

 low chalk promontaries along the coast. Between Portrush strand 

 and the stream adjoining Dmiluce Castle on the west, the absolute 

 junction of the two rocks can be closely studied in many places on 

 the road which passes over the cliffs alluded to, the surface of the 

 chalk on Avhich the basalt rests bemg very uneven, and in some places 

 excavated into wide and deep gullies like the transverse sections of 

 river-courses ; at others it presents bluffs or possibly headlands 

 against wliich the basalt has flowed, and which it eventually com- 

 pletely overlays. In this yiqw the cliff close to the spectator is 



