1826,] Sir James Hall on Hie Consolidation of the Strata. 503 



in a manner fit to be laid before this Society. This must be my 

 apology to those who hear me, and to such of my friends as 

 take an interest in these investigations, for having so long de- 

 layed the publication of a set of facts, some of which had pre- 

 sented themselves to my view many years ago. 



Whoever, indeed, has had any experience in the prosecution 

 of new subjects of experimental inquiry, knows that, owing to 

 his ignorance of the requisite adjustment of the proportions of 

 the ingredients, and of other similar arrangements, he must de»- 

 pend, in a great degree, upon chance for the success of his first 

 results, and that he must often submit to spend much time and 

 labour upon a subject, even after it has been made out to his 

 own satisfaction, before he has acquired sufficient command 

 over its details to answer for the result of any particular experi- 

 ment, so as to be able to produce it with confidence to the 

 public. 



It may be interesting, in the first place, to describe, in a 

 general way, the geological structure of the country, in the 

 neighbourhood of the singular scene which gave rise to these 

 speculations. 



On different occasions I have laid before this Society obser- 

 vations made on the rugged shore which occupies the southern 

 entrance of our estuary the Firth of Forth, which, from being 

 frequently washed by a very boisterous ocean, presents to view 

 a distinct exhibition of its internal structure. The eastern part 

 is occupied by the promontory of Fastcastle, composed entirely 

 of the elder quality of strata, called by the Germans Grey 

 Wacke. Further to the west it consists of cliffs formed of 

 Sandstone, nearly in a horizontal position. These two meeting 

 in the crag called the Siccar Point, afford the most distinct view 

 we any where have of the peculiar relation and mutual history 

 of these two rocks. 



More inland, on the borders of Lammermuir, a set of hori- 

 zontal beds occur, consisting of a loose assemblage of rounded 

 stones, intermixed with sand and gravel, which bear every ap- 

 pearance of having been deposited by water, and which, as to 

 their general history, seem to have undergone no change since 

 the overwhelming, though transient, agitations of water, of which 

 I have frequently had occasion to speak in this Society. 



In the summer of 1812, as I was returning from visiting the 

 granitic range which occurs in the water of Fasnet, in the hills 

 of Lammermuir, and riding down the little valley of Aikengaw, 

 which deeply indents this loose collection of gravel and shingle, 

 about two miles above the village of Oldhamstocks, and at the 

 distance of eight or ten miles from the sea, I was struck with 

 astonishment on seeing one of these gravel banks, formed, as 



