of Dairy and Antrim. 113 



nation of their strata, (the same with all the rest) to those 

 approaching from the westward ; their final immersion is 

 lost for want of perpendicularity. 



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 ap- 

 plicable 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* 

 eeptions. 



2. The upper and lower surface of each stratum preserve 

 an exact parallelism, so long as they are covered by another 

 stratum j 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 rec- 

 tilineal ; 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 fa- 

 cades, and our surface itself, are unconnected with, and 

 unaffected by, the arrangement of the strata below them. 



4. 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 sy- 

 stem j or where a whyn dyke cuts through an accumulation 

 of strata; in all these cases the change is always per salt um 

 and never per gradus, the lines of demarcation always di- 

 stinct, and well defined ; yet the different materials pass 

 into each other without interrupting the solidity and con- 

 tinuity of the whole mass. 



6\ The facades on our coast are formed as it were bv vef- 

 Vol. 33. No. 130, Feb. 1609. H ' tical 



