Handbook of Birmingham: Prepared for the Members of the British Association, 1886British Association for the Advancement of Science
History
Handbook of Birmingham: Prepared for the Members of the British Association, 1886
British Association for the Advancement of Science
Birmingham (England); Natural history -- England -- Birmingham
Resting upon the Bunter Sandstone, about 480 feet above the sea level,
is a _Lower boulder clay_, containing erratic boulders of slate,
felsite, quartzite, intermixed with blocks and stones of local origin.
Many of the erratics are angular, and some (especially the slates) are
finely striated. The whole deposit is unstratified and compact, and the
boulders are roughly pressed together, in every variety of position,
without any orderly arrangement. This boulder clay is succeeded by the
_Middle Sands and Gravels_ which are irregularly stratified and show
false bedding. Fragments of coal occur among the pebbles. The sands
and gravels dip rapidly to the S.W., and pass under an Upper boulder
clay. _The Upper Boulder Clay_ consists of a compact mass of clay with
erratics scattered through it; but the erratics are neither so abundant
nor so confusedly pressed together as in the lower bed. Granite has
been found, although rarely, associated with the travelled felsites and
quartzites, together with a few flints; and local stones and blocks
are also mixed up with the clay--the clay itself however largely
preponderating and being available for brick making.
The series is capped by a mixture of clay, sand, and gravel in
varying proportions, which fills many hollows that have been washed
out of the upper clay; and must be regarded as Post Glacial. Taking
the general divisions indicated by the California section, attention
may be directed to the following illustrative facts and sections.
Glacial striæ upon the surface of the rock have been noticed at Weoley
Hill Quarry close to California. The removal of a mass of clay, sand,
and gravel exposed a distinctly striated surface of hardened Bunter
Sandstone. The polished surface dips towards the south west, in which
direction the principal striæ run, although there are several cross
striæ. The complete section shews (_a_) striated and polished Bunter
(altitude 520 feet above sea level); (_b_) thin bed of marl; (_c_)
sands and gravels (Middle Glacial); (_d_) clay (Upper Boulder Clay).
A very large number of well-marked and finely smoothed and polished
grooves occur upon the blocks of native rock which are strewn over
the irregularly shaped mass of basalt constituting Rowley Hill,
Worcestershire. Isolated grooved blocks rest upon the surface of
the hill, having been carried by external force into their present
position; but there is also, at Rowley Hall Quarry, a kind of platform,
capping the solid mass of basalt, which is almost entirely composed of
blocks with smoothed and grooved surfaces, stiffly imbedded in clay.
Public-domain text, read in full here on John Shaqi.
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