GLACIATION OF THE SHETLAND ISLES. 785 
line between the conglomerates and the metamorphic rocks. At 
this point it dies out, and the boundary-line southwards towards 
Fladabister is formed by the basement breccia already described. 
At Rovey Head the conglomerates are thrown into synclinal and 
anticlinal folds; but eventually they dip to the south-east, and are 
succeeded immediately by grey sandstones, with blue and grey flags 
passing upwards into the series of the Lerwick Sandstones. The 
dominating members of this series are coarse grits, frequently con- 
glomeratic, with partings of fine red shales. 
In Bressay, however, these arenaceous and conglomeratic strata 
are overlain by a more flaggy series, which is more or less persistent 
till Noss Head is reached. We were struck with the resemblance 
which some of these grey flaggy bands bear to the calcareous flags 
of Orkney and Caithness containing the fish-remains ; but a careful 
search failed to bring any to light. Numerous plant-remains have 
long ago been detected, not only in these strata but also in some of 
the other groups on the eastern shore of the Mainland. 
In the peninsular tract of country which lies to the west of the 
Weesdale district there is a great series of rocks which, with the 
exception of a small tract at Melby, have been hitherto considered as 
forming part of the metamorphic series. The small strip of Old- 
Red-Sandstone rocks at Melby, measuring about a mile and a half 
in length, has been referred to by previous observers. They are 
separated by a fault from the red quartzites and shales of Sandness 
Hill; and on approaching the fault iti is observable that the beds are 
much shattered on account of this dislocation. They consist of red- 
dish sandstones with dark blue flags and shales, dipping to the east 
of south and south-east, from Sandness to near Melby. 
The great series of rocks which occupies almost the whole of the 
remainder of this peninsular tract, and which by their fossil contents 
we have proved to be of Old-Red-Sandstone age, has a somewhat 
different lithological character. Over a great part of this area the 
beds consist of grey and blue altered sandstones, with green and pale 
shales. The altered sandstones are usually traversed in every direc- 
tion by joints, which are coated with peroxide of iron; and in places 
the beds have a marked schistose character. Sometimes the sand- 
stones are converted into genuine quartzites, and the shales inter- 
bedded with them are distinctly cleaved. The strata lie in a trough 
the axis of which runs approximately from Fontabrough Voe east- 
wards by the village of Walls to the head of Bixetter Voe. On 
the north side of the syncline we have a gradually ascending series 
exposed on the coast-line from the cliffs of Sandness Hill south- 
wards towards Fontabrough Voe, the average strike of the beds 
being E. 20° N. 
We discovered the plant-remains on the hills north of Walls, and 
subsequently in quarries by the roadside east of the village, and on 
the hills between Gruting and Bixetter Voes. They have been exa- 
mined by Mr. C. W. Peach, who has kindly furnished the notes on 
the specimens embodied in the Appendix. He is of opinion that the 
plants are identical with those found in the Old-Red formation of 
