1869.] JOASS STJTHEKLAl^D GOLB-FIELD. 323 



pound of felspar and quartz (c), commonly interbedded with, but 

 once apparently intersecting, the strata. 



The more felspathic varieties of this granitoid rock are readily 

 disintegrated, forming either a white plastic clay or a gritty siliceous 

 sand, according to the predominance respectively of felspar or quartz. 

 Towards the head of the stream, this and other granitiform rocks, 

 large-grained, pinkish, and friable, become abundant, forming great 

 slopes of granular grit, from which the locality at the Suisgill forks 

 takes its Celtic name of Feithegaineamhaich, or the Sandy Swamp. 

 The same name, and for a similar reason, is given to the head of 

 one of the streams running into the Langwell Water, in the neigh- 

 bouring district of Caithness. 



In the small stream Allt-an-t'fhionnaraidh, to the soutlf-east of 

 Suisgill, a water-rolled pellet, about | inch in diameter, and con- 

 taining gold in intimate connexion with felspar and quartz, was 

 recently picked up without washing. So far as the origin of the 

 gold may be inferred from such a small specimen, it suggests the 

 binary granitiform layers and grits of the upper Suisgill. 



In Kil-Donnan burn, where, as is now generally known, the 

 Sutherland gold was first discovered by Mr. E. N. Gilchrist, a native 

 of the county, on his return after a seventeen years' residence in 

 Australia, the flaggy rocks are generally quartzose and gneissose, 

 dipping E. and E.S.E., T^ith an occasional veer to the N.E. Quartz- 

 veins of small size occur here, generally encased in chloritic clay. 

 The felspathic rock c is also present, but not in abundance. The 

 drift, which at its contact with the bottom rock, sometimes consists 

 of bluish and yellow clay with light- coloured patches, is most fre- 

 quently, as in Suisgill, a ferruginous gravel with rolled boulders, 

 apparently of local origin. Above occurs yellowish clay, overlain 

 by coarse sand, containing dark flexed earthy lines in section, the 

 whole covered by thin peat moss. Gold is found in the greatest 

 quantity in the lowest portion of the alluvium, but is obtained occa- 

 sionally from wash -dirt immediately under the surface turf (fig. 4). 



In the streams which run into the XlUie from the N.E., between 

 Kil-Donnan and Kil-Pheadar (namely Allt-duible, or the double 

 burn, which runs into one before reaching the river, Allt-bhreacaich, 

 the speckled burn, from the quantity of quartz lying about its slopes, 

 and AUt-torrish, the burn of mounds, from its numerous prehistoric 

 tumuli), the rocks preserve the same character and general easterly 

 dip, with some slight local variations. All these streams are auri- 

 ferous, but not richly so. Xil-Pheadar and Caien burns traverse 

 the granite of the Ord; and no gold has been discovered in them, 

 although their nearness to Helmsdale village, where many of the 

 miners lodge, prompted and facilitated careful and frequent search. 



The same persistence of easterly dip is traceable as we cross the 

 strike to the Old Eed Sandstone at Berriedale, on the Caithness 

 coast. The rocks, however, become more quartzose till they pass 

 upwards into the quartzite mountains of the Sgerreabeinn range. 

 The occurrence of these quartzites, and the fact that prospecting 

 was prohibited within the Berriedale district, probably occasioned 



