THE BIRDS OF THE STOUR VALLEY (ESSEX ONLY). 147
some hundreds present. On 21/12/24 a matter of a thousand
birds were stretched along the mud from Bradfield to Wrabness
Sluice. On 22/3/25, although I searched carefully, I could not
find a single Coot. During both winters I always found the
Coots in the same stretch of the river, in Jacques Bay, and never
saw any farther down the river than Wrabness Sluice. During
the course of a conversation with a local sportsman he stated
that he was of the opinion that the Coots spread southwards
from the Broads. The probability is that these gatherings of
Coots are not composed of native British birds but come from
Southern Scandinavia (see Dr. Eagle Clarke's Studies in Bird
Migration, vol. 1, p. 53). So far as Essex is concerned these
great Coot gatherings are perhaps peculiar to the Stour, they
certainly have no parallel on either the Blackwater or the Crouch.
The lagoons at Parkeston are probable nesting quarters of the
species.
Other species identified :—Jay, Starling, Greenfinch, Linnet,
Bullfinch, Chaffinch, House Sparrow, Yellowhammer, Reed
Bunting, Skylark, Tree-Pipit, Pied Wagtail, Tree-creeper, Nut-
hatch, Great Tit, Blue Tit, Long-tailed Tit, Red-backed Shrike,
Spotted Flycatcher, Willow Wren, Sedge Warbler, Blackcap,
Whitethroat, Lesser Whitethroat, Fieldfare, Mistle-Thrush,
Song Thrush, Redwing, Blackbird, Nightingale, Redbreast,
Hedge Sparrow, Wren, Swift, Green Woodpecker, Cuckoo, Kestrel,
Mallard, Wood Pigeon, Turtle Dove, Lapwing, Redshank,
Black-headed Gull, Moorhen, Partridge, and Pheasant.
Cambrian Rocks under Fobbing.—The Summary of Pro-
gress of the Geological Survey for 1924 (published in September
1925), gives details of a deep boring at Fobbing, carried out by
the Southend Water Company in that year. After passing
through various Tertiary strata, the bore entered the Chalk at
2981/2 ft. depth, and then passed down successively through
5011/2 feet of Upper and Middle Chalk, 112 ft. of Lower Chalk,
33 ft. of Upper Greensand, and 182 ft. of Gault,with characteristic
fossils. At this depth (1,127 ft.), dark shales were entered,
underlain by grey, greenish, micaceous sandstones and thin bands
of hard greenish grey and grey quartzites, of Palaeozoic age :
the shales contained recognizable fragments of the Brachiopod
Acrotreta, apparently of Cambrian type. "The general aspect
of the sandstones and quartzites suggests correlation with the
Lingula Flags." The bore stopped at 1,1521/2 feet depth.
Editor.