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106 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Dec. 5, 



ments of the mountain, and repeated with equal distinctness in the 

 corresponding precipices on the other side of the valley. It is im- 

 possible to give verbal details ; but the figure, imperfect as it un- 

 avoidably is, represents the facts more distinctly than words. It is 

 clear that the quartzite is mere fragments of the upper formation, 

 brought down repeatedly by faults, and in some cases even forced in 

 below the inferior red sandstone by enormous lateral pressure. This 

 very clear natural section thus tells us the structure of the N.W. 

 Highlands, and the true nature of those apparently anomalous 

 sections which have puzzled observers in other parts of the line of 

 junction. 



The most critical point of the section is at the eastern extremity, 

 where the red sandstone and quartzite meet the gneiss or, rather, 

 mica-slate. Near this point the quartzite, still resting on red sand- 

 stone, is thrown down some hundred feet below its former level. 

 Repeated slips take place, still further depressing the quartzite and 

 red sandstone, the latter dipping at about 15°, until near the line of 

 junction, where both the quartzite and sandstone dip at 33°, to S. 

 55° E. An irregular, but nearly vertical, line of favdt here separates 

 them from the mica-slate, dipping on the whole at 40° or 50°, to S. 

 or S.E., but in some parts ranging from 15° to 60°, and dipping in 

 various directions from N.E. to S.W. It forms but a mere coating, 

 as it were, on the front of the hill, and is in part intermixed with 

 compact syenitic rocks, which may explain the irregularity in the 

 dip and direction of the beds. In this place, therefore, there is no 

 overlap of the gneiss on the quartzite, but the two formations meet, 

 end to end, along a line of fracture. It is also noteworthy that in 

 this section the red sandstone does not thin-out before the quartzite, 

 as in some of the northern localities, but comes up almost into con- 

 tact with the gneiss. 



Another section in the hills between Loch Carron and Loch Kees- 

 horn (fig. 14) exhibits the same relation even more clearly. In this 



Eig. 14. — Section near Loch Carron. 



Roustag. Meal-na-Damb. 



c 1 . Quartzite. b. Red sandstone. 



a. Talcose or chloritic schist, with granitoid veins. 



place the quartzite, resting on the red sandstone, rises into some 

 lofty mountains. Near the line of junction it dips at 50° to 60°, to 

 E. 2U° S.. but is fractured and broken, and small fragments of the 

 limestone are involved between it and the talc or chlorite-slate. 

 This rock is much intermixed with veins of red granitoid matter, 

 and dips very irregularly at angles of 20° to 30°, to E. 15° to 45° S., 

 but in part at low angles nearly north. A small stream, running 



