jDESCklPTION Of TlNTO. 



125 



.entirely satisfactory, from the sniallness and in- 

 frequency of the rocky masses which remain 

 uncovered, was such, I trust, as has enabled me 

 to ascertain the formation of the mountain, and 

 to convey a tolerably accurate conception of its 

 structure. 



From these remarks, it may in general be pre- 

 sumed, that Tinto is of secofidary formation. The 

 eastern extremity of its base, forms the lowest 

 boundary of the mountain-valley along which 

 the Clyde flows. From this level, the base springs 

 with considerable steepness, to the height of about 

 400 feet, where v/e arrive at the first stage or 

 rounded back : and after ascending another height: 

 of perhaps 500 feet, a second platform., with an 

 inclination towards the west, brings us to the ac- 

 clivity, from which the elevation proceeds to the 

 summit without interruption ; exhibiting the ele- 

 gant conical or rather ellipsoidal figure of this 

 noted mountain. From the foot of the western 

 acclivity, Tinto stretches into a long and appa- 

 rently unbroken ridge, which penetrates the coun- 

 try for several miles to the south-west. 



The sketch which accompanies this paper, 

 though very imperfect, will enable the Society to 

 follow the description I am now to give. 



Tinto, then, in the language of Werner, may 

 be described as a flcetz mountain superincumbent, 

 I conjecture, on grey-wacke. For, of this rock, 

 which is known to extend like a zone or belt 

 across the country, from St Abb's Head on the 



