202 On the basaltic Surface of the Counties 



this stratum exhibits, as it happens to be disclosed to us ; 

 and by the converse, an attention to these appearances will 

 Gnable us accurately to determine the position of the stratum. 



This stratum, from Bally castle to Solomon's Porch, (about 

 twenty- five miles,) keeps very nearly the level of the sea, 

 often indeed sinking below the surface, but never raising its 

 lower edge above it : but when at Solomon's Porch, the 

 bouudary of our basaltic area begins to deflect to the south- 

 west, and then to the south, the ascent of the stratum to 

 the southward begins to operate, and we perceive the dotted 

 line of its quarries gradually to rise along the face of the 

 mountain from the shore to Monynceny and Seqfin, where 

 is has attained the height of 1500 feet: it is true, the actual 

 stratum has not been opened at these two great elevations, 

 but the white rubble immediately below the basaltic facade 

 proves incontestably that it is close at hand. 



An accumulation of basaltic strata, had in this southern 

 course, as well as on the northern shore, covered the lime- 

 stone up to the summits of the hills or mountains. 



I have already stated how the ridge of mountain is sud- 

 denly interrupted by the valley of the Mayola, from 1600 to 

 1 700 feet deep ; but if we look to the southward, in the 

 rectilineal course of the strata (the positions of which we 

 have been able to ascertain with so much accuracy), wc shall 

 find near the summit of the mountain Slieve gallon a similar 

 white limestone stratum crowned with basalt, cutting it in 

 the very direction the former ought to have reached it, that 

 is perhaps two hundred feet higher, the ascent of the strata 

 to the southward having elevated their planes so much in a 

 distance of four miles, the probable interval between the 

 summits of these mountains. 



We arc now to decide whether this calcareous and basaltic 

 fragment, on the summit of Stievegatton mountain, be the 

 last remnant of the old arrangement we have been tracing, 

 and ascertaining with so much precision, for seventeen or 

 eighteen miles from the sea, aud twenty- five miles along 

 the coast, but now interrupted by the valley of the Mayola, 

 like our former more diminutive interruptions, and also like 

 them resumed at the next elevation, in the same rectilineal 



course, 



