332 Correspondence—Mr. A. J. Jukes Browne. 
sion seemed to me open to doubt in 1868, but subsequent discoveries 
compelled me fully to accept it in 1878 (Q. J. G.8. vol. xxxv. p. 138). 
Since that time repeated discoveries leave no room for doubt about 
the matter. It is accepted by the late Professor Leith Adams, in 
his work on the Mammoth (Pal. Soc.), as well as by Mr. EH. T. 
Newton in his valuable memoir on “The Vertebrata of the Forest 
Bed of Norfolk and Suffolk” (Geol. Survey, 1882), who may be 
supposed to have ‘matured opinions,’ and a right, if not “the best 
right to decide such a point.” Its Pre-Glacial age is further con- 
firmed by the discovery of one of its teeth in the gravel beneath the 
boulder clay of Northwich, Cheshire, as I pointed out in 1878 (Q. J. 
G. S. vol. xxxv. p. 141). Surely the view which I retracted against 
the Pre-Glacial Age of the Mammoth, although it be supported by 
Dr. James Geikie, cannot be said to balance the testimony of these 
independent witnesses which Mr. Howorth either does not know, or 
thinks fit to ignore. Whether or no my opinion is sufficiently 
‘matured’ by the 25. years during which I have been working at 
the Pleistocene Mammals, to count in the controversy, may be left 
to those interested in such questions. 
Mr. Howorth’s method of disposing of evidence against his views 
may perhaps be allowable to an advocate fighting a case in the law 
courts, but it is not likely to advance the knowledge of the facts. 
We are not in a court of law, but in a court of science, where the 
wig and the bands of the special pleader appear to me to be out of 
place. Into the controversy as to the Glacial Period, or into the 
last revival of the old diluvial doctrine given up some fifty years 
ago by its great preacher in this country, Dr. Buckland, I must 
decline to enter, believing that the only satisfactory method of deal- 
ing with such matters is not merely to compile opinions at home, 
but to test them by years of patient work in the field, after the 
fashion of our prea leaders, Lyell, Evans, and Prestwich. 
W. Boyp Dawkins. 
OVERLAP AND OVERSTEP. 
Srr,—Mr. Goodchild’s article on “Overlap and its related Phe- 
nomena,” contains a useful suggestion, though I think the ambiguity 
arising from the use of the term overlap in a twofold sense and the 
desirability of limiting its application may be stated without import- 
ing further confusion into the subject or wrapping it up in the 
elaborate phraseology which Mr. Goodchild has employed. 
In the first place I never myself met with a person who applied 
the term overlap to a case of thinning out, whereby the higher mem- ~ 
ber of a conformable series comes to rest upon a lower member of 
the same series in consequence of the alternation of an intervening 
stratum. Ifthe term has ever been used to express such a relation, 
I think the precedent may safely be disregarded, since it is obviously 
unnecessary to confuse such a simple matter as the thinning out of 
a bed with the more complicated phenomena of overlap. 
Secondly, I fail to see in what particular Mr. Goodchild’s definition 
of overlap (p. 226) differs from that ordinarily given (see Jukes’ 
