570 ISLE OF MAN. GEOLOGY. BRECCIA. 



found alternating with some of the upper beds, or superior 

 in position to the whole of them. 



Of such beds, posterior to the calcareous deposit, I only 

 remarked two. One of these is visible at Derby haven, 

 and also in the neighbourhood of Pool vash. It consists 

 of fragments of schist, quartz, and limestone, united by a 

 calcareous base, and is of a coarse texture. It does not 

 seem to extend far beyond the boundary of the schist, 

 and the explanation of its origin cannot be attended with 

 much difficulty. The fragments of limestone serve to 

 distinguish it from those already enumerated, even where 

 its true position cannot be discovered. 



The other is far more obscure, while it is perfectly dissi- 

 milar from all the rest, and indeed from any rock of this 

 description with which I am acquainted. It consists of 

 minute fragments of schist cemented by a basis of clay, 

 but varies slightly in different places. The fragments are 

 sometimes conspicuous, and, at others, the whole is re- 

 duced to a scaly powder. In certain cases it also contains 

 fragments of limestone, as well as of quartz, and the argil- 

 laceous base is occasionally more or less calcareous. 



It is found extending interruptedly from Scarlet point 

 to Pool vash, being almost every where visible at the 

 surface of the limestone, but alternating also with some of 

 its beds. The confusion, which prevents it from being 

 easily understood, arises partly from the action of the sea 

 in an unequal manner on a substance so tender, but still 

 more from the general irregularity of the calcareous sub- 

 stratum where the trap veins are found, and from the 

 apparent disturbance produced at the places of their 

 intersections. 



Although it is not easy to explain in a satisfactory 

 manner the formation of this rock, I may still point out 

 the resemblance which it bears in its materials to the rub- 

 bish and clay which result from the action of the atmo- 

 sphere on the present exposed surfaces of the schist, and 



