xii 1 OUS ROCKS 17$ 



I may refer to the Sheets of the Geological Survey of 

 England and Wales, pa 75 and 78, embracing 



nowdon region ; and to Sheets **, 13, 32, 33, 39, 40, 

 and 4 1 of the Geological Survey of Scotland, showing the 

 development of the volcanoes of the Old Red Sandstone, 

 Carboniferous, and Permian periods in the midland 



icts of Scotland 1 



* The Mbject of thu chapter .il I* found more folly 

 in my Anntnt ViUvm* 0f Grttl Britnm, 2 vob. 1897. 



