MR. A. HARKER ON THE OVERTHRTJST 



[May 1903, 



The strata imme- 

 diately below show 

 to the eye no sign 

 of extraordinary dis- 

 turbance. They are 

 red sandstones, of 

 fine to medium 

 grain, with a north- 

 westerly dip of 15° 

 to 25°, agreeing 

 with the normal in- 

 clination through- 

 out the northern 

 part of Rum. 



Immediately above 

 the surface of over- 

 thrust comes a re- 

 markable band com- 

 posed largely of 

 crushed limestone. 

 This is mingled with 

 sandstone, usually 

 in a bleached con- 

 dition, and the two 

 rocks are brecciated 

 and in part ground 

 down together ; but 

 there are numerous 

 unbroken lenticles 

 of limestone, some 

 many feet long. 

 They contain abun- 

 dant cherts, and 

 undoubtedly belong 

 to the Cambrian 

 (Durness) Limestone 

 Series, which has 

 not been found in 

 place on this island. 

 The nearest known 

 outcrops are in the 

 Ord district of Skye, 

 about 17 miles away 

 to the east-north- 

 east ; but the lime- 

 stone - material of 

 Monadh Dubh has 

 presumably come 

 from a south - 

 easterly direction. 

 The calcareous band 

 does not usually 



