136 Rev. A. Sedgwick atid Mr. Murchison on Deposits contained between 



tion limestone, which alternate with grauvvacke slate in the north of England. 

 The resemblance must not, however, be pushed too far ; as even the purer and 

 stronger beds, on a cross fracture, give indications of the ordinary texture and 

 foliated structure of the common Caithness schist. The general dip of this 

 part of the system is about N.E. ; not, however, without many interruptions. 

 In the cliffs to the south of Wick Bay it is N.N.E. ; and the flagstone is sur- 

 mounted by a soft, greenish grey, micaceous shale and sandstone. 



About four miles to the south of Wick, the line of bearing of the schistose 

 beds is altered ; and from a point near Ulbster, where they begin to dip 

 westerly or inland, a great change is observed in the physical characters of 

 the country. To the north and west of this point, all the interior parts of the 

 country are composed of one vast, moory, undulating plain, of which the geo- 

 logical structure can be detected only by the occasional outcrop from below 

 the mosses of a few calcareous fissile beds — whilst the southern portion of the 

 country which remains to be elucidated, is hilly, stony, and considerably 

 diversified. In the former region scarcely a rivulet is to be seen, nearly all 

 the superfluous water stagnating in low mosses ; in the latter, the valleys and 

 depressions are occupied by numerous streams. 



An elevated portion of this district rises from a low and knotty promontory 

 on the coast called Clyth-Ness, and forms a number of terraces in the parish 

 of Bruen, which present their escarpment to the east. In the lowest of these 

 terraces, the beds dip westerly or inland, at angles varying from 25° to 30°, 

 whilst, in those nearer the summits, the inclination is only 8° to 10°; and, as 

 the highest beds are not less than 400 or 500 feet above the sea, the total 

 depth of this part of the series would be enormous, were we not to refer some 

 of these terraces to a succession of hitches or breaks in the strata ; — and yet 

 in such a case, their perfect parallelism is almost inexplicable. Near the 

 base of these terraces, the blue calcareous flagstone is burnt for lime, and is 

 overlaid by a series of sandstone beds of considerable thickness, of a very 

 compact structure, much resembling the grauwacke of many parts of Eng- 

 land, being highly compact, siliceous, and micaceous, with colours varying 

 from blue to dark dingy red*. These hills subside towards Clyth ; and the 

 strata of which they are composed are seen upon the coast. Slate and lime- 



* In many parts of the coast to the south of Ulbster, the Caithness flagstone, not merely in 

 hand specimens, but in large sections, puts on the external characters of grauwacke, and, in its 

 structure and mode of weathering, may be compared with the highest portion of the schistose 

 rocks of Westmoreland. These characters, however, often fail ; and on the north coast of the 

 county are hardly ever met with, as the beds from Port Skerry to Duunet Head have a much 

 newer appearance. 



