374 SECTIONAL TRANSACTIONS.— H. 



able to show that certain definite stone-age culture phases belong to the different 

 periods. Where the cultures are represented by series of tool types indistinguishable 

 (save in material) from well-known European stone-age cultures we use the European 

 terminology but prefix the word ' Kenya.' Where an East African culture is similar 

 to, but not identical with, one of the European ones, we use new names unless we can 

 find parallels in South Africa, in which case we use the South African name with the 

 prefix ' Kenya.' In using culture names already used elsewhere we specify that we 

 do not intend to suggest any contemporaneity of the European and East African 

 cultures, the former may be earlier or later. 



It is obviously unwise to use similar stone-age cultures in areas so far from each 

 other as Europe and East Africa as evidence of contemporaneity of the periods in 

 which they occur and, therefore, all thought of correlation on the basis of the cultures 

 is out of the question. Rather we must seek some other data upon which we can 

 attempt to determine whether any given culture is earlier or later in East Africa than 

 it was in Europe. 



At first one turns naturally to fauna, bearing in mind the value which has always 

 been placed on fauna in Europe as a means of dating any deposit. 



But here again one is immediately foiled because fauna, like man, is not the same 

 all over the world at any one time. Fauna may well be an index of temperature and 

 climatic conditions, but is no good for long distance correlation. 



Turning from fauna we seek a solution to our problem in climatic correlation. 

 Meteorologists to-day tell us that such great climatic changes as the advances and 

 retreats of the ice-sheets in the Northern and Southern Hemispheres during the 

 Pleistocene, cannot but have been accompanied by very marked climatic changes in 

 other parts of the world which were not glaciated. Dr. C. S. Simpson and Dr. C. E. P. 

 Brooks have done a great deal of work on this subject and, on theoretical grounds, have 

 shown that the glacial phases should have been accompanied by periods of increased 

 rainfall and the interglacial periods by periods of less precipitation. Their views 

 may be summarised briefly as follows. The changes in climate which resulted in the 

 glacial periods were due to fluctuations of solar radiation. The glacial maxima were 

 in pairs Giinz and Mindel, Riss and Wiirm separated by a long Mindel-Riss inter- 

 glacial. Each pair of glacial maxima would have been accompanied by one major 

 Pluvial period in non-glaciated parts of the world. 



Secondary causes, such as the shifting of storm belts, &c., probably also played a 

 part so that each of the main Pluvial periods, which correspond to two glacial maxima, 

 may have sub-divisions. Tlie minor climatic fluctuations, such as the Achen retreat, 

 the Biihl advance, &c., were probably not due to the primary cause of change of solar 

 radiation, but secondary causes such as polar shift, storm belts, &c. The bigger of 

 the minor oscillations would afiect the climate of the other parts of the world to a less 

 extent than the true glacials, but probably enough to be recorded in lake basins without 

 outlet. The first major Pluvial is thus correlated with the Giinz and Mindel glaciations 

 of the Alps, and the second major Pluvial with the Riss and Wiirm glaciations, the 

 long interval being the equivalent of the Mindel-Riss interglacial. In many parts 

 this Mindel-Riss interglacial was marked by earth movements on a large scale. 



Blanckenhorn gives an identical sequence for the Jordan valley : — 



(Minor Pluvial fluctuations.) 

 Aridity. 

 Second Diluvial, two terraces with a dry period between. 

 Period of aridity. Rift Valley faulting and earth movements. 

 First Diluvial. 

 He also suggests that the First Diluvial=Gunz and Mindel and the Second, Riss 

 and Wiirm. On grounds of climatic correlation, therefore, it would seem that we 

 have the following table for the major climatic fluctuations : — 



Europe. East Africa. Jordan Valley. 



Giinz and Mindel . . Kamasian . . . Older Diluvial in Jordan 



Valley. 



Long Mindel-Riss . Rift Faulting, &c. Dry . Rift Faulting, &c. Dry. 



Interglacial 



Riss and Wiirm . . Gamblian II and Younger Diluvial, 



Gamblian I two peaks. 



Achen retreat . . Dry period . . . Dry period. 



