268 S. HAZZLEDINE WARREN,
The Deperet System.—This has been ably explained for
English readers by Sollas (Nature, March 10, 1923 ; Geol. Mag.,
1923, p. 1). It is based upon a succession of raised beaches
in the Mediterranean, dating from between the Pliocene and
the present time. The beaches themselves occupy discontinuous
fragments of Pleistocene time, but the epochs named after
them are extended to continuity. The following is a scheme
averaged from the varied views of different authors :—* (1).
1.—Sicilian. Raised beach at 300 feet, with very cold
marine fauna. Correlated with the Gunzian
glaciation and the Weybourne Crag,
1a.—Emergence of land, with temperate climate ;
including the Cromer Forest Bed.
2.—Milazzian. Raised beach at 200 feet. Temperate
climate. Correlated with the Leda [Yoldia] myalis
bed of Cromer.
2a.—Emergence, Mindelian glaciation. Correlated
with the North Sea Drift, etc.
3.—Tyrrhenian. Raised beach at 100 feet, with
the warmest climate of the Pleistocene.
3a.—Emergence, with Rissian glaciation.
3b.—Temperate climate ; Early Chellian industry.
4.—Monastirian. Raised beach at 60 feet. Temperate
climate. Late Chellian.
4a.—Acheulian.
4b.—Mousterian.
4c.—Upper Palaeolithic, or Cave Age.
4d.—Holocene.
The Penck system starts in the Alpine area, it correlates a
succession of glacial moraines with the deposition of the river
terrace gravels, from the moraine itself all down the course
of the river to the sea. The gaps between the gravel terraces
represent the interglacial periods of erosion due to the flood-
waters of the melting ice.
The Deperet system starts on the sea-board. The suc-
cessive marine platforms determine the base-levels of the rivers,
and consequently the deposition of the river gravel terraces is
independent of the glacial episodes. In fact Sollas makes the
* Views on the Deperet system are so diverse that it would need a separate table to
represent them adequately. The scheme given by Sollas in the 3rd edition of Ancient
Hunters is appended.
Periods. Deposits. Industries.
Sicilian ? .. .. .. .. Norwich Crag
Milazzian ? . . .. .. Weybourne Crag, etc.
Lower Tyrrhenian .. .. Cromer Forest Bed, etc. .. Chellian
Acheulian I.
Upper Tyrrhenian . . . . Leda Myalis bed, etc.. .
Lower Boulder Clay .. .. Acheulian II.
Lower Monastirian .. .. Middle Glacial Sands . . .. Acheulian III
Mousterian I.
Upper Monastirian .. .. Upper Boulder Clay .. .. Mousterian II.
(and later) (and later)