On the Calton Hill and its relation to the rocks in the neighbourhood

Abstract

My original intention was merely to bring before the notice of the Society a small section recently exposed in making a drain at the Low Calton, where the lowest portion of the traps of the Calton Hill was exposed, but seeing that a good deal of interest is centred on the hill at present owing to the making of the tunnel and other alterations going on in connection with the North British Railway, I have taken the liberty of calling attention to a few facts and theories connected with the hill. The Calton Hill has not received so much attention from geologists as its larger neighbour, Arthur's Seat. This is no doubt due to the fact that its structure is much simpler than that complicated and puzzling series of rocks included in the Queen's Park. Still a number of well-known geologists have described its structure, and others have noted the minerals connected with it. Cunningham, in his “ Geology of Midlothian,” describes the rocks of the Calton Hill as a series of traptuffs and porphyries dipping to the east, and he seems to have considered them all intrusive. He also mentions certain sandstone strata dipping under the traps of the hill that were exposed in excavations made for the foundations of the Waterloo Bridge. He likewise calls attention to the stratified beds that overlie the strap at the eastern end of the hill. Maclaren, in his “ Geology of Fife and the Lothians,” gives a description along with a diagram