644 SCIENCE PROGRESS 



deny, is as a matter of fact denied by all the prominent Mendelians of my 

 acquaintance, and it is the crux of the whole Lamarckian doctrine. No 

 doubt in nature changes in the sizes of organs are due to adaptation of 

 function, but to observe these we should need in most cases to be endowed 

 with the years of Methuselah, and the brilliant result obtained by Guyer 

 opens up a short cut which enables us to see the change in a few generations. 

 I should like to say, in conclusion, that I, for one, am strongly disposed 

 to believe in the chromosome mechanism for segregation, and further to 

 believe in the hypothesis put forward by Bateson in 1914, that the cause 

 of Mendelian "mutations" is probably to be found in irregularities in the 

 separation of sister chromosomes, so that one daughter cell receives too 

 little chromatin, and becomes the parent of the mutant. Further, it is 

 obvious that before any functional adaptation can become firmly engrained 

 in the hereditary constitution it must affect the constitution of the 

 chromosomes. But I repeat that the mutations due to abnormalities of 

 division appear to me to have played no part in the evolutionary process, 

 which, there is every warrant for believing, must have been slow, functional, 

 and continuous. 



Yours faithfully, 



E. W. MacBride. 

 February 7, 1921. 



THE GEOLOGICAL AGE OF THE PALEOLITHIC FLINT 



IMPLEMENTS 



I. From J. Reid Moir, F.G.S., F.R.A.I. 



Dear Sir, — In Science Progress for January 1921 (No. 59, pp. 387-9) 

 there are pubUshed some brief notes upon some of the papers appearing in the 

 Proceedings of the Prehistoric Society of East Anglia (vol. iii, pt. 2). The 

 writer of these notes refers especially to the Presidential Address delivered 

 by Prof. J. E. Marr, F.R.S., and to a paper from the pen of Mr. M. C. Burkitt. 

 Both these papers deal with the question of the geological age of the palaeolithic 

 flint implements, and their relationship to the East Anglian glacial deposits. 

 And in both papers an attempt is made to correlate these deposits with those 

 existing in the Alps and described by Penck {Die Alpen im Eiszeitalter). 

 It is now many years since similar attempts were made, and those of us who 

 are dealing with this question make no claim to be the first to have published 

 speculations upon the possible contemporaneity of the Enghsh glacial beds 

 with those upon the Continent of Europe. But I think I may accept the 

 responsibility for having been the first person to pubUsh a detailed account 

 of the glacial and interglacial deposits (and their contained flint implements) 

 of East Anglia, and their possible relationship to others described by Penck. 

 My correlation, based upon numerous discoveries made by me in East Anglia 

 was first made public on January 17, 1920, and appears in the number of the 

 Proceedings of the Prehistoric Society of East Avglia (vol. iii, pt. 2, pp. 238-43) 

 dealt with by the writer of the anthropological notes in Science Progress. 



Prof. Marr's Presidential Address [Proc. P.S.E.A., vol. iii, pt 2, 

 pp. 177-90) was first made public on March 17, 1920, and Mr. Burkitt's 

 paper {Proc. P.S.E.A., vol. iii, pt. 2, pp. 311-14) was read on April 12, 1920. 

 In both these papers the authors fully acknowledge my work, which formed in 

 part the basis of their respective correlations. I notice, however, that in the 

 notes in Science Progress my researches — no doubt through inadvertence — 

 are not mentioned, and I feel that, altogether apart from any personal motive, 

 this should be rectified. 



I would wish also to comment very briefly upon the note (Science 

 Progress, No. 59, January 1921, p. 389) deahng with Prof. SoUas's paper 



