236 GEOGNOSY OF EAST LOTHIAN. 



stacks rise above the water at some distance from the 

 cliffs. The cliffs, ledges and stacks are formed of red 

 sandstone and red trap-tuff, which are intermingled 

 in various ways. The cliffs continue to be prin- 

 cipally of red tuff, until nearly opposite Sheep 

 Craig, when the colour changes to greenish-grey, 

 and vast cliffs of this variety extend along the 

 coast, and form the rock on which are situated the 

 striking ruins of Tantallan Castle. Veins of tuff 

 of a cotemporaneous nature traverse the tuff of 

 which the cliffs are composed, and in the same rocks 

 there are many veins of calcareous ironstone, vary- 

 ing from a few inches to two feet in width, and red 

 and white zeolite and amethyst*, and jaspers of va- 

 rious descriptions. Tantallan Bay is bounded, on 

 both sides, by lofty cliffs of trap-tuff ; but, on the 

 beach, a number of sandstone strata, in a nearly ho- 

 rizontal position, are to be observed. These strata, 

 where they appear on the north side of the bay, 

 when examined at low-water, can be traced a con- 

 siderable distance, until at length they disappear 

 under the tuff. The tuff on the north side of the 

 bay is sometimes very coarse ; and in it, in one place, 

 there is a mass of yellowish-grey sandstone, several 

 fathoms in extent, and five or six feet thick ; and, 

 in another, a cotemporaneous bed of columnar basalt, 

 terminating on both extremities in the form of 



* Mr Sligo junior of Seacliff, informs me he has collected 

 fine specimens of red zeolite, and also of amethyst, in these 

 cliffs. 



