On the Fossils of a Boulder-clay in Caithness. 39 



Caithness, run north and south, with deviations to the east 

 and west. I have found them almost all over the county. 



Beds of sand occur in some localities over the clay, and 

 nests of sand are occasionally in it. Cracks, varying from 

 an inch to a foot across, run down the clay to great depths, 

 some vertically, others diagonally, and from these run, hori- 

 zontally, smaller ones ; all these are filled with sand. The 

 sand contained in them was evidently poured in from 

 above, first trickling down the sides mixed with tenacious 

 matter, and which has consolidated there, the centre of the 

 cracks being filled with loose sand. The shells in the sand 

 are of the same kind as those in the clay, but so friable, that 

 on attempting to remove them, they fall in pieces — thus 

 showing that sand is a bad preservative of organisms em- 

 bedded in it. 



In many cases where thick beds of sand occur, clay again 

 overlies it, and above all, beds of stones of all kinds and 

 sizes, which no doubt were left by the after washings to 

 which the clay had been subjected, the clay being carried 

 away to other localities, and in all probability forms the 

 brick-clay, which is said to be younger than the boulder-clay. 



At Pulteney Town, near the harbour, a large block of 

 granite, many tons in weight, rests on the Boulder-clay, 66 

 feet above the level of the sea. All over the county large 

 boulders are met with. The march of improvement is de- 

 stroying them fast. The largest I know is at Reiss, Wick, 

 a conglomerate block ; its cyclopean size makes it a con- 

 spicuous object in the flat field near the farm-house of 

 Kilmster. All the clays of Caithness, or nearly so, might 

 be made into bricks, tiles, &c. ; it, however, would be rather 

 expensive to take out the stones. This could be done by 

 washing when preparing the clay for use. A similar clay 

 is so treated at Peterhead, Aberdeenshire ; the wares made 

 from it are highly prized, and it has been worked profitably 

 for years. In this clay-work I have found similar shells to 

 those of Caithness, but much more comminuted, and in less 

 abundance. It is also very full of stones. 



Some of the Caithness shells are almost perfect, especially 

 the smaller ones ; others, again, for instance the Astartes, 



