REPORT OF THE MEETINGS FOR 1200 231 



by a series of dykes of porphyrite, all the rest of the 

 vast pile of volcanic rocks which formerly covered the district 

 having been entirely removed. These porphyrite dykes are 

 well exposed near the railwaj' station at Burnmouth ; they 

 are admirably represented by a typical example, which crosses 

 the dene leading from the school to Partonhall, and they 

 are equally well shown in connection with the striking 

 coast features known as the Gull Rock and the Breeches 

 Rock, to the north of Burnmouth. Good examples of these 

 porphyrites are also to be seen at Lamberton. 



After a long time the volcanic activity died out, and 

 the old volcanoes were gradually wasted away, leaving only 

 some few disconnected fragments of the lavas and tuffs. 

 Besides the porphyrite dykes there now appear at the 

 surface several masses of granite. These were originally 

 formed at the roots of the old volcanoes, aud they owe their 

 present exposure at the surface to the combined effects of 

 upheaval and denudation, by which all the thick mass of 

 rock which formerly overlay them has been gradually 

 , removed, and washed sea-ward to form newer strata 

 elsewhere. 



There were many periods of disturbance during the 

 development of the events just noticed, which completely 

 altered the face of the country, time after time. 



Near the close of the great desert conditions the Upper 

 Old Red Sandstone was laid down. It was formed in very 

 much the same manner as the older Old Red Sandstone 

 had been before it. Remnants of this Upper Old Red are 

 seen at the foot of the cliff below Burnmouth, as well as 

 at Chesters, Siccar Point, and many other places in the 

 neighbourhood. 



After a time, the land once more began to subside; the 

 sea margin approached nearer and nearer ; rain began to 

 fall in fair quantity, and with increasing regularity ; 

 vegetation gained a footing; and the old desert conditions 

 gradually passed away, giving place to climatal conditions 

 which were as different as they could well be from those 

 which preceded them. It was under these conditions that 

 the Carboniferous rocks were found. First of all, when 

 the climate had really begun to change for the better, th^ 



