2 O i 
of the Counties of Derry and Antrim. 
I shall now proceed to select from the great mass of facts 
that are exhibited on the face of Bengore promontory, and 
occur in the contiguous basaltic country, such as seem appli- 
cable to geological questions, and likely to throw light on 
such subjects. 
Facts applicable to geological Questions. 
1 Every stratum preserves accurately, or very nearly, the 
same thickness through its whole extent, with very few ex- 
ceptions. 
2, The upper and lower surface of each stratum preserve 
an exact parallelism, so long as they are covered by another 
stratum ; but when any stratum becomes the superficial one, 
its upper surface is scolloped, or sloped away irregularly, 
while the plane forming its base continues steady, and recti- 
lineal ; but the parallelism of its planes is resumed as soon as 
another stratum is placed over it. 
3. The superficial lines bounding the summit of our fayades, 
and our surface itself, are unconnected with, and unaffected 
by, the arrangement of the strata below them. 
y. Nature, in the formation of her arrangements, has never 
acted upon an extensive scale in our basaltic area, (at least 
on its northern side, where our continuous precipices enable 
us to determine the point with precision, ) but changes her 
materials, or her arrangement, or both, every two or three 
miles, and often at much smaller intervals. 
5. Wherever there is a change of material, as from one 
stratum to another in a vertical line ; or where the change is 
in a horizontal direction by the introduction of a new system ; 
or where a whyn dyke cuts through an accumulation of 
MDCCCVIII D d 
