Notices of Memoirs— Prof. A. E. Church. 331 



His diagrams, which are intended to illustrate this statement, show- 

 that he believes his Upper Boulder-clay to be posterior to the 

 " Middle Drift " or Kame series. What are the reasons assigned by 

 the author for slumping these Boulder-clays as part and parcel of 

 his upper series? Because "this clay is found almost always at a 

 higher level than the Middle Drift Sands, and from its containing 

 scarcely any but local rocks, and those always angular or in a 

 very slightly rolled condition, I conclude that it is the wash of the 

 mountains towards the later part of their rise and in the beginning 

 of their second submergence in the sea, and due partly to the action 

 of the sea itself by tides and waves, partly to rainfall and an accu- 

 mulation of snow and ice upon the land, combined with the most 

 effective cause of all — the grinding of coast-ice swept along by 

 violent currents." In the absence of any direct evidence of super- 

 position, I fear that these arguments can have but little weight. In 

 Scotland, for instance, true Lower Boulder-clay occurs very fre- 

 quently at higher levels than the Kame series ; and in the Till there 

 always is a preponderance of local over foreign rocks, the number of 

 the latter diminishing in proportion to the distance from the parent 

 source. As to the last of these reasons, my observations enable me 

 to state that such is not the case with reference to all the Boulder- 

 clays included in his upper series. 1 In the case of those Boulder- 

 clays described in my paper as representing true Till, the stones are 

 neither angular nor slightly rolled; on the contrary, they have 

 the smoothed character of ordinary Till stones with well-marked 

 scratches. Mr. Birds indicates localities un visited by me, and, of 

 course, I have nothing to say with reference to these sections. 



The author further says : "As to which is the true order of the 

 formations, the question must be determined, of course, by reference 

 to sections, such as that of which Mr. Home has given a lithograp'h, 

 near the mouth of the Ballure Glen, and by all sections thence along 

 the northern base of the hills to Kirkmichael." Glancing for a 

 moment at this section exposed on the coast cliff, we have here two 

 Boulder-clays, regarded by Mr. Birds as belonging to his upper 

 series, which are separated by sands and gravels and capped by 

 stratified sands and gravels, which appear to stretch northwards to 

 Bamsay, where the "Middle Drift" series begins. This section 

 seems to indicate that these Boulder-clays pass underneath the 

 stratified sands and gravels of the "Middle Drift" series. Other sec- 

 tions might be adduced which seem to point to the same conclusion. 



IsTOTICES OIF 1 IVIIIEIIVCOHEIS- 



Eed Chalk and Bed Clay. By Professor A. H. Church. 

 From the "Chemical News," May 7, 1875. 



SOME years ago I published an analysis 2 of the Bed Chalk of 

 Hunstanton, Norfolk. The specimens which I examined more 

 minutely were those in which the red colour, so characteristic of 

 this variety of chalk, was exceptionally developed. In these speci- 



1 See Trans. Geol. Soc. Edin. vol. ii. part iii. 



2 1863. Journ. Chem. Soc. (2), vol. i. p. 99. 



