266 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 7, 



Fig. 4. — Section at Keiss Harbour. 

 E, w. 



1. Eeddish -brown stony clay. 



2. Dark-grey pebbly silt with broken shells. 



3. Sandstone, iceworn. 



At Keiss harbour, which hes seven or eight miles further to the north, 

 the character of the section is very much the same as at Wick. 

 The total thickness of the drift near the harbour is about 40 feet. 

 The lowermost 23 feet consist of an unstratified mass of dark sandy- 

 mud, with a few broken shells and some stones dispersed through 

 it, which reposes directly upon the ice-worn surface of a red sand- 

 stone rock, without the intervention of any other deposit. The 

 scratches and grooves point W. 35° to 40° "W., and some of the 

 imbedded stones are likewise scratched. The upper 17 feet of the 

 bank consists of a browner coarse mud with more stones, and, so far 

 as I observed, no shells. Although the lowermost sandy portion of 

 the drift at Keiss and Wick has no distinct stratification, it is never- 

 theless more like an ordinary marine deposit than what I saw in the 

 other sections throughout Caithness. 



3. Character of the Stones imbedded in the Drift. — The stones 

 imbedded in the Caithness Drift consist for the most part of the debris 

 of the Caithness flags — those beds which Murchison terms the middle 

 division of the Old Eed Sandstone of this part of Scotland — and 

 accordingly the general hue of the drift closely resembles the pre- 

 vailing dark bluish-grey tint of these strata. There is, however, 

 always a mixture of other sorts ; fragments of quartzose mica- schist, 

 and granite occur, so far as I observed, very frequently in the drift 

 of all parts of Caithness. I noticed them at the Burn of Freswick, 

 which is only a few miles from Duncansby Head, also at Keiss, and 

 all about the neighbourhood of Wick, and along the whole of the 

 Thurso water. There are likewise generally some fragments of 

 sandstone and conglomerate, and occasionally one of hornblende- 

 schist ; this latter, however, is not common. Mr. Peach also 

 mentions the occurrence of porphyry, gneiss. Oolite, Lias, and Chalk- 

 flints. Mr. Dick told me that fragments of OoHte are not uncommon ; 

 I myself observed many pieces of it in the drift at the mouth of 

 Berriedale. 



I did not see many large erratic blocks, but Mr. Peach tells me 

 that some big ones of conglomerate are scattered across the country, 

 more particularly between Weydale and Stoneguu, near Thurso. 

 He saw veri/ few on the Scarabin hills. Mr. Dick told me he had 

 not observed any large blocks which might not have been derived 



