23£ GEOGNOSY OF EAST LOTHIAN. 



has the usual characters. Nearly in the middle of 

 the tract, there is a pyramidal mass of trap-rock, 

 which appears to rise through the sandstone strata. 

 It is partly tuff, partly basalt inclining to green- 

 Stone. 



The strata of sandstone immediately in contact 

 with the mass of trap, are curved, and inclined to- 

 wards it. This fact, of a mass of trap rising through 

 the strata of sandstone, will he viewed by some as 

 favourable to the volcanic theory of its formation, 

 while others will be inclined to consider it as illus- 

 trative of its Neptunian origin. 



The rocks and cliffs of trap-tuff continue along 

 the shore, until they are succeeded by cliffs, and 

 then by ledges of red and white sandstone. The 

 tuff is in general fine granular, here and there 

 formed into concretions, from the size of an apple 

 to that of a man's head, and upwards. These con- 

 cretions are, in general, round ; and at first sight 

 appear like balls of basalt. It is sometimes travers- 

 ed by veins of very hard and compact tuff, several 

 inches wide, and also by veins of compact felspar, of 

 the same magnitude. In some places the tuff is 

 quarried for oven-stones, and is known to the quarry- 

 men by the name of Leckstone. It is worthy of re- 

 mark, that varieties of tuff are quarried for the 

 same purpose, in other parts of Scotland; and in some 

 districts on the Rhine, this stone is quarried to a 

 vast extent, and is exported to Holland, and other 



