496 J. G. Goodchild—On Drift. 



possible to hazard a conjecture as to the period in years since the 

 formation of the Burwell peat commenced, but we know that — 

 except in the dykes — it ceased when the Fens were drained, less 

 than a century ago, and the occurrence of this skeleton proves 

 positively that the district was so far drained as to be traversable 

 at the time this ox was killed, and there is no evidence of any 

 subsequent long-continued submergence; for undoubtedly the greater 

 portion of the peat found above the skeleton was not formed upon 

 it, but was the result of the carcase having sunk into it when in a 

 moist state. 



Indeed such few facts as we possess all tend to warrant the con- 

 clusion that this specimen need not be referred to any very remote 

 period in time. It is of interest not with reference to the antiquity 

 of man, but as affording evidence of the contemporaneity of man with 

 Bos primigenius, as a proof of one especial purpose to which celts 

 were applied, and as rendering it probable that this ox lived, and 

 that the early inhabitants of the Cambridgeshire Fens continued 

 primaeval habits, to a much more recent period than has been 

 generally supposed. 



The celt (Fig. 1) is figured one-third less than the natural size. 

 Fig. 2 as seen in profile. Fig. 3, section as shown at the broken 

 proximal end. 



III. — On Drift. 



By J. G. GooDCHiLD, F.G.S. 

 of H.M. Geological Survey. 



N a letter to Nature for 14th May, 1874, Mr, Belt has expressed 

 his belief that the presence of shells in glacial deposits, at what- 

 ever elevation they may be found, does not necessarily constitute a 

 proof that the land has been depressed to that extent relatively to 

 the level of the sea ; but that in such cases as those of the drifts of 

 the basin of the Irish Sea the shells occur in their present positions 

 because they were thrust thither out of the bed of the sea by the ice- 

 sheet which was advancing from the North. 



Somewhat similar views with regard to other drifts had been pre- 

 viously advanced by Messrs. Croll and Tiddeman; but up to the 

 time of the publication of Mr. Belt's letter no one had ventured, in 

 print, to extend this theory to such deposits as those of Macclesfield 

 and Moel Tryfaen. 



The communication referred to gave rise to an instructive dis- 

 cussion, which was brought to a close by a letter from Prof Green, 

 in which attention was recalled to the fact that the drifts in question 

 were finely stratified, and that, therefore, they could not have origi- 

 nated in the way suggested. 



As no one since has ventured to re-open the discussion, I propose 

 to take advantage of the renewed interest in the subject likely to be 

 occasioned by the publication of Mr. James G-eikie's paper on " The 

 Occurrence of Erratics at Higher Levels than the Kock Masses from 

 which they have been derived," which I have just read, to re-state 

 some of the arguments used in a paper read to the Geological Society 

 on the 24th of June last, in which I have sought to establish a new 



