J. W. JTJDD ON THE SECONDARY ROCKS OF SCOTLAND. 



673 



strata of the Western Islands from destruction by denuding forces is 

 that afforded by the magnificent section of the Innimore of Ardtor- 

 nish. Here we find a series of lava-sheets poured from the great 

 volcanos of Mull and Ardnamurchan during the Miocene period (the 

 greatly denuded masses of which retain a thickness of over 1200 feet) 

 lying upon a series of strata ranging in age from the Carboniferous 

 to the tipper Chalk. There Secondary and Tertiary strata have been 

 cut across by a fault, probably having a throw of nearly 2000 feet, 

 by which they have been brought into apposition with vast moun- 

 tain-masses of gneiss, probably of Cambrian and Silurian age (see 

 fig. 5). 



Fig. 4. — Junction of Torridon Sandstone and Middle-Lias Strata, as 

 seen a little to the West of Scalpa House, in the Island of Scalpa. 



a. Torridon Sandstones. 



Fault. 

 b. Middle-Lias beds (Scalpa series). 



The dip of the Middle-Lias strata is found to increase gradually, as we appi'oach 



the line of fault, from 3 C 



up 



to 35° or more. 



Fig. 5. — Section exposed at the Innimore of Ardtornish, on the 

 Sound of Mull. 



f. Miocene basalts. 

 ' e. Marls. 



d. Sandstones. \ Poikilitic. 

 _ c. Conglomerates. J 



b. Carboniferous rocks seen in reefs 



on the shore. 

 a. Gneiss and schist (Paleozoic). 



2t2 



