ISLE OF MAN. GEOLOGY. SANDSTONE, 549 



as the elevated position of this latter appears to demon- 

 strate; but the causes which led to that change of 

 position have been such as to extend their action, whether 

 chemical, mechanical, or both united, through the primary 

 to the secondary strata. 



The mineral character of the sandstone now described, 

 presents little variety. It is more commonly of a compact 

 than a loose texture, and not unfrequently possesses the 

 hardness and crystalline appearance of the primary 

 sandstone, or of quartz rock. It is formed of sand 

 intermixed with ferruginous lay, and is generally of 

 a deep purple-brown. Occasionally it displays those 

 white spherules so frequently occurring in the sandstones 

 of this description, and already noticed in the account 

 of Arran. The beds are often divided by seams of 

 red or blue shale, or of clay, generally very thin ; and 

 they occasionally present that undulated surface which 

 so accurately resembles the effect produced on hard 

 sand during the retiring of the tide. Rare and thin 

 beds of the coarser grit and breccia usually associated 

 with this rock, are also to be seen, intermixed with 

 the finer variety, and mica is not an unfrequent ingre- 

 dient. The clay found in the seams has often the 

 character of ironstone, and lumps of genuine red iron- 

 stone, apparently detached from some of the beds, are 

 scattered on the shore in its vicinity. Two or three 

 insignificant beds of white sandstone are also found 

 alternating with it. 



The last and most remarkable substance occurring 

 in this sandstone, is magnesian limestone. This is highly 

 crystalline, white, and of a pearly lustre, the scales, 

 of which it is composed, being of considerable size and 

 presenting curved surfaces. It forms flat masses of 

 inconsiderable dimensions, which, being parallel to the 

 stratification of the sandstone, might be considered as beds, 

 but, as they frequently ramify into small filaments, they 

 ought rather perhaps to be viewed as parallel veins. 



