Vol. 57.] CRTJSH-CONGLOMEKATES OF AEGTLLSHIRE. 321 



of crush-conglomerate manufacture can be continuously traced 

 from the initial to the final stage, and consequently structures 

 which have' originated in earth-movements have, in some cases, 

 Tjeen confounded with phases of contemporaneous deposit analogous 

 to the Highland Eoulder-bed. 



As the principal physical features of the region correspond both 

 with the strike of the beds and the axis of folding, deep transverse 

 sections showing clearly the passage of one rock into another are 

 far from plentiful. That part of the parish of Kilmartin, however, 

 Tjordering the upper end of Loch Craignish, is divided by valleys 

 which truncate the prevailing surface-features. We consequently 

 find isolated platforms blocked out, so to speak, from the rest of 

 the country, and as these transverse valleys owe their origin to 

 faults, steep escarpments have resulted, displaying sections trans- 

 verse to the strike and to the folding axes. The hill of C reag nam 

 Fitheach, overlooking the head of Loch Craignish, forms one of 

 these platforms, with precipitous slopes on its northern, western, 

 and southern boundaries. The last-named, however, aff'ords the 

 best section, being almost a perpendicular escarpment and bare of 

 vegetation. This truncated platform displays efi'ectively the tectonic 

 arrangement of the country adverted to earlier. While the folding 

 and foliation are everywhere seen to be dipping at high angles and 

 often perpendicular, the escarpment-faces show that the beds, 

 although somewhat undulatory in behaviour, are generally horizontal, 

 in fact, the exact converse of what the surface-features indicate. 

 Examination shows a big mass of limestone interposed between 

 epidiorites. The mapping suggests that both epidiorites form part 

 of a single mass. The nature of the ground, however, does not 

 permit of this being proved ; and it must be admitted that the 

 epidiorite which underlies the limestone is more crystalline and 

 massive than that which rests upon it. So that, notwithstanding the 

 variation shown earlier to exist in the epidiorites of the district, 

 which might sufficiently account for its divergent character, there 

 is just the possibility that we are dealing with two sills which 

 partly overlap, although this supposition is unlikely. The upper 

 igneous mass, with which we are particularly dealing, is of the 

 vesicular type already noted. This epidiorite is a detached portion 

 of the large complex sill that I have already described. Its junction 

 with the limestone is intricately folded, and of as intimate a type of 

 plication as that described earlier from Arichamish (pp. 318-19) : 

 folded limbs of epidiorite, from a few inches to a foot or more in 

 thickness, being packed together at a high angle in a limestone- 

 matrix. In the sections, big blocks may be seen in process of division 

 by the shearing movements which have succeeded the folding. 

 Among the folded limbs lenticles may be observed which have become 

 completely isolated, consisting usually of epidiorite and sometimes 

 of limestone. The limestone, however, seems generally to have 

 played the part of a plastic body, and has accommodated itself as a 

 •matrix to the folded and isolated fragments of epidiorite, between 

 which it has been squeezed. At the south-eastern corner of the hill 



