104 T. Mellanl Reach — Post- Glacial Geology. 



cases of beetles. When the Post-Glacial deposits rest on Boulder- 

 clay, as is commonly the case, and a section displays both, the 

 difference of the deposits are so striking that a novice may at once 

 pronounce upon them. It is noticeable that the surface of the 

 Boulder-clay under the Post-Glacial deposits is deeply eroded by 

 subaerial action, indicating that the land was at that time at a higher 

 level than now with respect to the sea. The silt and Scrobicularia 

 clays containing the profusion of Foraminifera detailed in the pre- 

 ceding lists are equally a sign of the subsequent submergence of this 

 Boulder-clay surface to a depth marked generally by the 25 feet 

 contour-line. The Superior Peat-and-Forest Bed is again a sign of 

 following subaerial conditions succeeded by a depression, for much of 

 it is now washed over by the tides. 



The last movement of the land was downwards at Formby and 

 Leasowe, and it appears to me to have been the same in Belgium. 

 As I have before observed, the Bruges Canal or Heyst silts lie above 

 the peat, whereas the Leasowe silts lie below. If the Heyst peat is 

 of the same age — and it is certainly not older than the Superior Peat- 

 and-Forest Bed at Leasowe — the Belgian silts I have described are 

 not so old as those at Leasowe, but they nevertheless belong to the 

 same series of beds.^ This group of beds is a geological object- 

 lesson of a comparatively recent date, showing that geological periods 

 are records of a similar kind, but on a larger scale of widely pre- 

 vailing physical conditions. 



Eelative to these conditions it is interesting to find that the 

 Boulder-clay on which the group rests, though so markedly different 

 in physical constitution, possesses a foraminiferal fauna of much the 

 same character, though of a more stunted growth. Even in this little 

 surface exposure one of the specimens of Boulder-clay yielded eleven 

 species of Foraminifera, and if it were possible to get specimens from 

 a depth of 10 or 20 feet it would no doubt yield them in the same 

 profusion as the Boulder-clay at Great Crosby, Lancashire, or Eiver- 

 side, Seacombe, Cheshire.^ The species found in the Leasowe Beds 

 have doubtless lived through the Glacial seas, nevertheless the two 

 periods or episodes are so physically different that no geologist could 

 mistake one for the other. 



The artistic figures given in the Plate accompanying this paper 

 are by Mr. Eobert Welsh, of Belfast, and 1 am greatly indebted to 

 him and Mr. Wright for enabling me to illustrate the leading species 

 in such a satisfactory manner. Being photographs of the actual 

 specimens obtained from the Leasowe deposit, they are instructive as 

 showing the relative sizes of the different species as they occur in 

 the deposit. 



^ There is a very good engineering description of the works of the ne-^- Bruges 

 Ship Canal by Mr. Vernon Ilarcourt in the Minutes of Proceedings of the Institute 

 of Civil Engineers, vol. cxxxvi (1899), pp. 283-295, with plans and sections. 



2 " The Gypsum Boulder, Great Crosby" : Proc. Liverpool Geol. Soc, 1898-99, 

 pp. 347-356. "Foraminiferal Boulder-clay, Riverside, Seacombe, Cheshire": 

 ibid., pp. 357-364. 



