256 Proceedings of the Royal Physical Society. 
a number of Microbrachit, but from careful examination 
I feel convinced that this species is practically confined to 
one or two of the beds worked at present. Beside these 
fishes, no other fossils occur except drifted and broken 
fragments of plants, from a few inches to 2 feet or more 
in length, and sometimes 3 inches in breadth. These 
fragments are common in the Orkney flagstones generally, 
and are mostly undecipherable. I visited two other quarries 
in adjoining fields, one being somewhat above, the other 
somewhat below the level of the Microbrachius quarry. Both 
yielded a similar rock to that described, the upper containing 
also a few thin shaly beds, under which are some beds of 
sandstone, each 6 to 8 inches thick. Both quarries yield 
D. macropterus in abundance, but badly preserved and 
readily decomposing on exposure, and plant remains. In 
neither did I find Microbrachius. The dip is the same as in 
the first-mentioned quarry. 
To ascertain the nature of the rocks at this particular 
horizon, I made an examination of the coast section exposed 
in the cliffs at the south side of Deerness parish. The narrow 
neck which joins the peninsula of Deerness to the mainland 
of Orkney is crossed by a fault which runs in a northerly 
direction out the bay. The downthrow is probably to the 
east. The first beds met with on the Deerness shore are yellow, 
somewhat coarse sandstones, in beds 4 to 8 inches or more 
thick, dipping E.S.E. at a low angle. Followed along the 
shore, they are succeeded by reddish sandstones, with red 
clay beds and thin layers of grey shales. At the Mermaid’s 
Rocks, these are cut by a trap dyke running nearly north and 
south, and, as seen in the shore, about 25 feet broad. A little 
farther on, they are overlain by beds of red clay, with here 
and there sandstones, and over these a series of thin brittle 
calcareous flags, alternating with grey shales and layers of 
yellow sandstone. These are well exposed on the western 
shores of Newark Bay, and their dip varies a little, but is 
generally 8.E. and E., at angles of 4 or 5 degrees. From their 
character and their strike there can be no doubt that they 
are the beds which yield Microbrachius in the quarry a 
mile or so inland. They are succeeded by soft dark brown 
