Geological Notes from West Galway. 153 



well the effect of the violent earth-movenaents previously 

 referred to. This quartzite makes up more than half the 

 cutting ; it contains much iron pyrites, the decomposition of 

 which causes the water flowing" from the cutting to be highly 

 impregnated with iron, and the face of the cutting is for the 

 same reason much stained. Near the centre of the quartzite 

 is a mass of white granite, which seems to have been brought 

 into its present position by faults, the lines of which may be 

 traced by the highl}- crushed appearance of the rock in them. 

 In this granite are some large picked-up pieces of quartzite. 

 Deep blue fluor-spar also occurs as concretions in this granite. 

 A wedge-shaped piece of dark schistose rock, probably a much 

 altered and crushed hornblende schist, has been thrust into 

 the granite apparently by faults. In this schist are some 

 veins of haematite. There seems to be some hornblende 

 schist mixed with the quartzite in parts of the cutting. 

 •At its farther end the quartzite is traversed by numerous 

 small -granite veins, mostly horizontal ; some of them are 

 very felsitic, and much of the felspar is of a greyish black 

 colour (probably labradorite), and the granite often contains 

 calcite veins which may be due to the decomposition of lime 

 felspars. Opposite the signal, a well-marked fault brings in 

 a dark quartzite with larger granite veins ; these, however, 

 have been so much cut up and displaced by minor faults 

 that the granite seems to occur in patches. The green 

 quartzite is cut off suddenly by a well-marked fault, and 

 about twelve feet farther on is another fault, similar and 

 parallel to the last. Between these fault-planes is a mass 

 of greyish-brown rock without granite veins. Professor 

 Cole, to whom I submitted a specimen, suggests that 

 it may be a m3'lonite, formed by the crushing together of 

 quartzite and granite ; but it would do well for a fine-grained 

 quartzite. The fault-planes bounding this rock are worthy 

 of special description ; they are each about a foot wide, with 

 parallel walls, and are occupied by clayey matter and some 

 fragments of the adjacent rocks. In the clay are curious 

 little spherical masses of the rock included between the faults. 

 These spherules are about the vsize of ordinary shot, and might 

 have been formed by an oscillator}^ movement of the adjacent 

 rocks. The last of the faults just described is bounded on its 

 farther side by a mass of red granite. This granite is much 



