Mr. Forster's Observations on Ratcheugh Crag. J5 



'No. XII. — Observations on the Geology of Ratcheugh Crag, near Aln- 

 •wick. J3y Mr. Francis FoRSTER, Colliery Vie*wer. 



Read May 18, 1830. 



In offering to the Notice of the Natural History Society the following 

 observations on the geology of Ratcheugh Crag, I have to regret that want 

 of time prevented me from examining the course of the Basaltic Rock, 

 of which it is chiefly composed, beyond the immediate neighbourhood. 

 The limited observations, however, which T was enabled to make, have 

 very strongly impressed me with the idea, that the Basalt of Ratcheugh 

 Crag is a continuation of the same bed which forms the Dunstanborough 

 Castle Cliff, as well as the bold escarpment extending southward behind 

 Craster Sea Houses. I have been induced to form this opinion by the 

 conformity in the inclination of the strata on the coast and at Ratcheugh, 

 by the surface of the country, which appears to rise from the sea at the 

 same angle and in the same direction as the strata, and by the similarity 

 in the strong Limestone bed with which the Basalt is, in both cases, ac- 

 companied. 



Ratcheugh Crag is situated at about two miles and a half E. N. E. 

 from Alnwick, and at about the same distance west, from the sea, at 

 Boulmer. It forms a cliff, facing to the west, and rising about ninety 

 feet above the level of the country, extending towards Alnwick. A 

 tower, built on its summit, commands a most extensive prospect over 

 the surrounding district. Before referring to the section of the Crag 

 itself, which evidently owes its peculiar structure to a Dyke in the vi- 

 cinity, it will be necessary to subjoin the following section of the strata 

 sunk through at Dunsheugh Coal pit, situated at about four hundred 

 yards to the S. E. of the Crag, and set off from the surface in the Lime- 

 stone, underlying the Basalt, and at about two hundred yards beyond 



