The Principles of Stratigraphical GeologyMarr, J. E. (John Edward)
Science
The Principles of Stratigraphical Geology
Marr, J. E. (John Edward)
Geology, Stratigraphic
Accompanying these changes in the earth's crust were others which
affected the climate, at any rate locally. The warm climate of Eocene
times gradually gave way to a cooler climate in Oligocene times, and
this lowering of temperature was still further advanced in Miocene
times, though there is evidence that the temperature of those parts of
Europe which have strata representative of the Miocene period was
higher than it is at the present day.
Owing to the changes which occurred in Miocene times, the area of
sedimentation was extensively shifted to our present oceans, and
accordingly we find that the times subsequent to those of the Miocene
uplifts are marked by scattered accumulations of continental
character, with a few insignificant marine strata seldom found far
inland from the present coast-lines.
CHAPTER XXVI.
THE PLIOCENE BEDS.
_Classification._ The Italian Pliocene Beds which have long been known
have been divided into three stages, to which names have been applied
which are somewhat widely used, though the division of the British
deposits into the same three stages has not been made. The stages
are:--
Astian.
Plaisancean.
Zanclean.
The classification of the British deposits may be made as follows:--
Cromer "Forest" Series.
Weybourne Crag and Bure Valley Beds.
Chillesford Crag.
Norwich Crag and Red Crag.
Upper Coralline Crag.
Lower Coralline Crag.
As the English deposits are somewhat scattered it is difficult to make
out the exact order of succession, but the above shows the
classification which is adopted by the best authorities, the Norwich
Crag (or Fluvio-marine Crag as it is sometimes termed) being now
supposed to represent the upper portion of the Red Crag.
_Description of the strata._ The British deposits are chiefly found in
the counties of Norfolk and Suffolk, but isolated patches have been
detected in Kent and at St Erth in Cornwall; while the inclusion of
Pliocene fossils in the glacial deposits of Aberdeenshire and on the
west coasts and islands of Great Britain suggests the occurrence of
Pliocene beds beneath sea-level, around the British coasts, at no
great distance from the land.
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