1040 REPORT—1885. 
tions are mechanical, or are due partly to chemical action, as this question is still 
undetermined. THe suggests that Fuller's earth might be advantageously placed 
with other materials in filter beds, or otherwise used as a water purifier on a 
large scale. 
WEDNESDAY, SEPTEMBER 16. 
The following Papers and Report were read :— 
1. On the Glacial Deposits at Montrose. By Dr. Hownen. 
These consist in order of age, first, of the non-fossiliferous boulder clay, derived 
chiefly from the denudation of the great conglomerate. Second, a glacial marine 
clay, containing the remains of the Arctic seal (Phaa hirta), Arctic birds, fishes, 
star-fishes, mollusca, and foraminifera, besides pieces of ice borne chalk, flint, coal, 
and other rocks foreign to the district. Third, deposits of peat, in which are found . 
remains of the reindeer, trees, and bog plants, including the buckbean; a grain of 
the common barley was also got in this peat. Fourth, a thick bed of estuary, or 
scrobicularia silt, containing shells of species found living in the present estuary 
basin of the South Ksk. In this deposit at the Redfield Railway cutting, nine feet 
below the surface, the skull of an ox, Bos longifrons, was found beneath an un- 
disturbed deposit of sand and coarse clay. Fifth, a bed of apparently glacial 
eoarse clay. These deposits terminate on a great ridge or storm beach consisting 
of pebbles and small boulders derived from the boulder clay. This ridge divides 
the town of Montrose into two halves, known to builders as the clay half and the 
sand half. In the sand half, slightly above the level of the present sea beach, 
marine shells are found of species now living on the coast, but a much larger size. 
The diagrams and specimens exhibited indicated repeated alternation of climate and 
level since the earlier glacial period. 
2. Notes on the Rocks of St. Kilda. By Auuxanvrr Ross, F.G.S,. 
On a visit to St. Kilda in 1884 I collected a few specimens of the rocks of 
which the island is composed, and which are now presented for inspection to the 
members of the British Association. 
The island has been described as being in the form of the letter H, the northern 
limb being represented by Connacher and Oschival, and the southern by the 
Mullach More. These limbs are connected by a ridge which forms the cross bar of 
the H, and divides the north from the south bay. The latter bay is nearly circular, 
the hills sloping in all directions and forming an almost perfect amphitheatre. 
The land rises to a considerable height on the west side of the island, which is 
bounded by cliffs from 800 to 1,000 feet high. 
The island is composed of granite and gabbros, which meet in a line running 
from the west side of the village at the south bay to the centre of the glen at 
north bay. ‘The portion to the north of this line is composed entirely of cream- 
coloured granite, while that to the south consists of greenstones and gabbros. 
In the course of a walk extending from the landing-place on the north side, 
along the summit of Oschival and Connacher down into the valley at north bay, 
and along the north shoulder of Mullach More back to the south bay, I picked up 
the specimens now exhibited. 
Passing along the top of the ridge between Oschival and Connacher and over the 
top of the latter, I found as I began to descend towards the line of junction the 
granites becoming finer grained and more compact. Along the line of junction the 
change is very marked, and on crossing it, we come on the gabbros and greenstones, 
on the southern side of the glen. Some of the specimens illustrate this walk, 
