ABSTRACT
THESCRAPPINESSOFthestratigraphicrecordofthePleistoceneperiodislargelyduetoitshavingbeenaperiodof denudationanderosionratherthanoneofaccumulationand sedimentation,exceptincertainoceanbasinsorgeosynclines. Oneofthemethodsofsubdividingtheperiodandcorrelating thestagesonaglobalbasisdependsonthefactthatthelandmasseshavebeenslowlyandintermittentlyrisinginrelation tosea-levelthroughoutUpperTertiaryandQuaternary times. 37Asaconsequencetherehavebeenphasesofactive down-cuttingbyriverswhenthelandwasrising,andphases oflateralerosionbyriverandseawhentherelativelevelwas static.InthestablepartsofSouthernBritaintherearethree erosionalplatformsprobablycorrespondingtoprolongedpauses intheupliftoftheland.Theseare,indescendingorderofage: 6oo-ftplatformcappedbyOlderRedCrag38 400-ftplatformcappedbythePebbleGravelandoldestlocal
glacialdrift(Giinz?)39 2oo-ftplatformcappedbytheFinchleyBoulderClay(Mindel
II?)'O Inadditiontotherisingoftheland-masses,throughout
Quaternarytimestherehasbeenanupanddownmovementof sea-levelreflectingchangesinthevolumeoftheworld'sicesheets.Alterationsofsea-levelwhichareindependentofany movementofthelandareknownaseustatic.Accordingtothe nowwidelyheldtheoryofglacialeustasy,41highsea-levels correspondtointerglacialstages,whentherewasmoreorless
One of the most important events in the history of the Mediterranean shores was the 'Great Regression' sometimes known as the Roman or Romanian regression11 which followed the 'Milazzian' (or as some prefer, Sicilian II) and preceded the Tyrrhenian stage of high sea-level. The fact that it coincided with a very striking change in the composition of the marine molluscan fauna is of considerable interest because the Mindel Glaciation, with which this regression proba:bly corresponded, was a time of equally dramatic change in the continental mammalian fauna (Zeuner, 1959a, p. 285).
