562 MULL. GEOLOGY. 



singular manner ; the rock being often crystalline, and com- 

 monly so highly indurated as to be difficult to recognise, 

 while the parallel aspect resulting from stratification fre- 

 quently disappears. I no where observed any indications of 

 organic remains, although it is probable they exist among 

 those beds which have undergone the least alteration. 



The peculiar situation of these strata renders it impos- 

 sible to ascertain their dip with correctness, the more 

 so as they are often considerably undulated. Yet there 

 is a general tendency toward the north-west in the only 

 places where the form of the ground permits observations 

 of that nature to be made. It is almost superfluous to 

 add that they are traversed and intersected in every direc- 

 tion by innumerable veins of trap. The appearances 

 hence produced are highly interesting ; but the remarks 

 already made on the coast of Trotternish in Sky have 

 exhausted all that could be said on this subject. 



The next portion of the secondary rocks to be noticed 

 is found near Achnacrosh, forming a small hill and extend- 

 ing to the sea shore, where the directions and inclinations 

 of the beds can readily be traced. These consist almost 

 entirely of limestone, presenting two or three different 

 varieties of colour and texture. The predominant colour 

 however is smoke grey passing into a paler grey, and 

 the general character is argillaceous. In one or two 

 places, where trap veins interfere, the beds assume a 

 darker colour and a crystalline aspect ; while in others, 

 under similar circumstances, both the colour and texture 

 remain unaltered, although the regularity of the beds 

 is interrupted, and a confused structure takes place of the 

 regularly stratified disposition. The general direction of 

 these beds is N. N. W. and their dip easterly, at angles 

 varying from forty to sixty degrees. They contain gry- 

 phites, terebratulae, and belemnites, the former being by 

 much the most abundant. I must remark of this fossil 

 that it is a different species from that found in the lowest 

 limestone of Sky ; the specific distinction being strongly 



