Jan., 1891. 
A TRIP TO ORKNEY AND SHETLAND. 
13 
cliff, beyond which the ground is covered with grass, and 
rises gently for a mile or two further inland. The stratum is 
a light-coloured sandstone, split up at the surface into thin 
layers of an inch or two thickness, which are broken up and 
lie scattered as loose shingle in irregular groups over the solid 
rock. These loose pieces are seen, at some parts, to have a 
more finished and symmetrical appearance, with moulded 
edges, and further on an exposed surface of the rock is seen, 
marked out with irregular crossing lines, ready for splitting 
up into the loose pieces seen ; and at last a place is met 
with where these markings become definite moulded grooves, 
dividing up the surface of the rock into approximately 
symmetrical figures, and presenting a striking resemblance to 
a tesselated pavement, with tiles of about four to eight inches 
in size, and sometimes as large as a foot in length. This 
resemblance to an artificial pavement is rendered still more 
striking by the several “ tiles ” being separated by very regular 
jointing lines of about an inch in width, of a lighter colour than 
the “ tiles,” and depressed about a quarter of an inch below 
them, giving so distinct an appearance of a cement joint that 
it is very difficult at first to conceive the whole is not an 
artificial pavement of tiles, set in cement. This difficulty is 
increased by the circumstance that each “tile” is bordered 
by a really well finished moulding, which is carried uniformly 
round all the edges of the “ tile,” and in several cases there is 
a second moulding parallel to the first one, and sometimes a 
third smaller one. A section shows the lower one with two 
mouldings, and the upper one with three mouldings; a 
marked correspondence is shown between them as regards 
the two outer mouldings, and the third inner one has the 
appearance of being formed out of the edge of the main 
centre portion, suggesting a successive formation of these 
parallel mouldings from the outside inwards. 
The more general form of the “ tiles ” approximates to a 
lozenge shape, most frequently with one of the angles 
rounded off; but one example is a nearly perfect lozenge, 
having sides of from 3 inches to 4J inches in length; and 
a general feature of them is that the “tile” is darker 
coloured than the intervening “ cement ” portion. Some of 
the “ tiles ” are darker than the others, and in those the darker 
portion generally stands out more prominent, and has rounded 
edges, with a deep groove cut in all round, and separating it 
from the first moulding. Then in other specimens that may 
be termed further advanced, there is seen a tendency to the 
dark centre portion becoming undercut at the edges, and at 
last specimens are found where the centre has become actually 
detached, and has the appearance of a “nodule of ironstone;” 
