126 Prof. C. Lapworth—The Secret of the Highlands. 
Quartzites pierced by innumerable vertical worm-holes (the Pipe 
rock). 
This last-named band is the highest bed exposed on the western 
side of the Loch, the superior beds having been removed by denuda- 
tion. 
VI.—Sections East of Loch Eriboll. 
On the opposite side of the Loch, however, a magnificent section 
of the naturally succeeding strata is exposed in the cliffs of Hielem 
roadstead or Camas Bay. In this section, which occurs at the little 
headland of Ant-Sron, the strata are thrown into a long and broad 
arch, the beds dipping in opposite directions at a very gentle angle. 
They are laid bare in a continuous exposure nearly a quarter of a 
mile in length, in the cliffs and in the coast platform below, and 
every bed admits of easy study and admeasurement. Here we 
are presented with the following section, in ascending order :-— 
I. (d). Lower or Eriboll Quartzite, chiefly the highest zone (or 
Pipe rock), a series of flaggy quartzites, often iron-stained, and filled 
with hosts of vertical annelide tubes—3Oft. 
Il. Mielem or Fucoid Beds.—50 to 60ft. 
(a) Flaggy grey shales covered with Fucoids (branching worm 
castings)—Fucoid zone. 
(b) Calcareous shales and flags (an impure dolomitic cement- 
stone) —Fucoid Limestone. 
(c) Quartzose flags, with occasional Annelide holes, and a re- 
markable zone of dark blue shale at the summit— Upper or 
Hielem flags. 
Ill. The Salterella Grit or Quartzite—10 to 15ft. 
A conspicuous zone of Quartzite, often gritty with small pebbles 
of quartz, riddled with empty wormholes, and crowded with casts of 
Salterella Macullochit. 
IV. The Friboll or Durness Limestone—150 to 200ft. 
(a) A thin zone of impure dolomitic limestone of a yellowish- 
buff colour, graduating upwards from the Salterella Grit, 
through a conspicuous transitional zone of calcareous grit, 
which weathers into a ragged scoriaceous rock of a most 
remarkable aspect (Scoriaceous-bed). This transitional band 
afforded me Orthoceras, Linguloid shells (?) and the usual 
Salterella Macullochi.' 
(b) Dark (almost black) flaggy Limestones and calcareous shales 
(the latter cleaved) filled in patches with hosts of Salterella 
Macullochii, ete. 
(c) Grey, white and mottled Limestones of great thickness, 
arranged in several well-marked zones, identical with those 
in the Limestone series of Durness. These are the highest 
beds discoverable at this locality. 
1 Between the base of the Fucoid or Hielem beds and the top of the Scoriaceous 
hed the rocks all weather to a yellowish-buff colour upon exposure to the weather, 
forming a striking contrast to the white quartzite below and the dark limestone above. 
