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Part III. — Tenth Annual Report 
substratum is always mud, which is covered by from an inch or two to 
nearly a foot of sand in some places. Here and there, on the Port- 
Glasgow side, ballast stones have been deposited, but these ultimately 
become silted and buried by mud. Around the perches are stones, but 
the area covered by these is very small. 
The Pillar Bank dries at lowest springs from an inch or so to about three 
feet. With a prevalent south-west wind, not nearly so much of the bank 
dries, and conversely with north-east to south-east winds the dry area is in r 
creased. The tide ebbs for half an hour longer on the Port-Glasgow side 
of the bank than on the Cardross side ; so that, when the bank is drying 
on the south side, it is being covered by the inflowing tide on the north. 
While the above description holds for the general shape and size of the 
Pillar Bank over a number of years, yet the quantity of silt in the water of 
the river, and tidal currents alter in time the configuration and size of the 
bank. In recent years, between the Pillar and the upper end of the Cockle 
Banks, a small bank about 600 yards long and 200 yards broad has risen. 
When the last corrections were made on the Admiralty Survey, water 
covered this bank at low springs to the depth of one foot. This bank, 
included in the map in the Pillar Bank, lies immediately opposite Port- 
Glasgow Harbour, its upper end being about 200 yards on the north side 
of the navigable channel of the Clyde. 
As to the present condition of the Pillar Bank, the supply of mussels 
on the portion that dries is small for the size of the ground capable of 
fattening mussels. The sand on the lower end, and towards the Cardross 
side of the dry area, is not suitable at present for a vigorous growth of 
mussels, but under a system of bed cultivation much of it in time could 
be utilised, especially in places where but a few inches of sand covers the 
underlying stratum of mud. Nearly one-half of the dry area might be 
stocked with mussels, and, with all the other areas stocked, even a portion 
of the other half might be utilised as a store for mussels afterwards to be 
shifted to lower ground. During the present season only some 50 tons 
of mussels have been lifted from the Pillar Bank, but 400 tons have been 
taken from the fiats and the deep off Ardmore. Unfortunately, for an 
exact representation of the present condition of the flats and deeps, the 
data are not so easily obtainable as for banks which become dry. However, 
an examination of the bottom and stock on it by sounding and by raking 
shows that, while mussels are plentiful in some places, they have been 
fairly gathered from other submerged areas. 
Cockle Bank. 
This bank is also on the north side of the navigable channel, and the 
whole bank, viz., the dry and submerged portions, is fully a nautical mile 
in length. The upper end of the bank is near the check, or No. 1 
buoy, off Port-Glasgow Harbour, and the lower end is opposite No. 6 buoy, 
opposite the middle of the new breakwater for the Great Harbour of 
Greenock. The north-east boundary runs alongside the deep channel 
between it and the Pillar Bank, and the lower, or north-west limit, is 
sinuous in outline from opposite No. 6 buoy till it joins the north-eastern 
boundary. The bank is nearly triangular in shape, with the apex directed 
up tne stream. 
About one-half of the bank dries at low springs. The dry area is also 
triangular in shape, above three-quarters a mile long, and about 600 yards 
broad. For fully half-a-mile the Cockle Bank — as might be expected 
from the name — is composed of sand. This sandy area is also triangular, 
