Correspondence — 0. W. Lainj)lugh. 237 



of drift has been found beneath the mass. It is supposed to have 

 been sHced off exactly at the base of the Gault, and, like a pancake, 

 to have been tossed over cleanly back into its bed, without breaking 

 and without entangling any extraneous matter. By this overturn, 

 it is assumed that a thin band of limestone originally at the top of 

 the Gault and a similar thin band of limestone and breccia at its 

 base have been everywhere brought directly into contact within 

 a belt never more than 2 feet thick, and usually less, as shown in 

 Fig. 2 of my critics' paper. Glacialists have been accused at times 

 of expecting too much from ice-sheets, ))ut they have never expected 

 such a feat as this. 



4. Reason is shown in our paper of 1903 for believing that the 

 thin irregular layer of iron-grit or ironstone which covers the lenticles 

 of limestone, and to which they appear to owe their preservation, 

 was in existence before the deposition of the Gault. The fresh 

 evidence accumulated during my later investigations has, I think, 

 placed this point beyond doubt. It is, of course, fatal to the 

 hypothesis of my critics, and they are compelled to put forward 

 the argument that the ironstone floors have been formed in Post- 

 Glacial times, after the beds had been overturned, though they tacitly 

 admit that the ironstone fragments between the floors are of pre- 

 Upper Gault age, at least. 



But I feel that it is really useless to enter into a lengthy verbal 

 debate in this matter ; the evidence speaks for itself in the whole 

 section, and I will ask anyone who is doubtful upon it to make a 

 personal examination of what is to be seen, even though the 

 exposures visible at any particular time can hardly be expected to 

 give the cumulative impression which I have received year by year 

 in seeing one section after another. I feel sure that it will be found 

 easier, on the spot, to believe in an extension of the range of the 

 anomalous fossils than to believe that the bed had been brought 

 into its present position through a gigantic inversion by glacial or 

 other agency. 



As regards the Gault, for the present I will only say that my 

 colleagues may possibly be right in claiming that the Upper Gault 

 alone is present under Shenley Hill, though there are several factors 

 which call imperatively for a^ suspension of judgment in this matter, 

 pending further investigation. I may be permitted to point out 

 that in our paper of 1903 we explicitly stated that the Gault exposed 

 at that time contained no discriminative fossils, and that the presence 

 of the Lower Gault was inferred solely on the evidence of the fossils 

 recorded by Jukes-Browne from a neighbouring pit. But whether 

 Upper or Lower Gault, the statement that it is inverted runs 

 counter to so many points of evidence recently considered in the 

 field, that I have no hesitation in rejecting the supposition as 

 unwarranted. 



G. W. Lamplugh. 

 St. Albans. 



April 5, 1920. 



