378 Reports and Proceedings — 



is more sensitive to weathering than potash. The rocks contain more 

 combined as well as uneombined water on their surface than when 

 sheltered from atmospheric influences. 



The paper was accompanied by an appendix on the microscopical 

 structure of some of the varieties of rocks by Prof. Bonney. 



4. " On the so-called Midford Sands." By James Buckman, Esq. 

 The author quotes from the works of Professor Phillips and other 



authors certain passages, in which the sands below the Oolitic Lime- 

 stones of the Cotteswold Hills and Dorsetshire are correlated with one 

 another, and the name of "Midford Sands" is applied to the formation 

 represented by these strata. 



In opposition to these authors' views Prof. Buckman maintains that 

 two distinct Ammonite bands have been by them confounded with one 

 another; that the sandy beds in the Cotteswolds really belong to a 

 much lower horizon than do the similar strata in Dorsetshire and 

 Somersetshire ; and that while the former lie quite at the base of the 

 Inferior Oolite series, the latter represent a great part of that forma- 

 tion. In support of this view Prof. Buckman points to the fact that 

 a representative of the true Cephalopoda-bed lies at the base of the 

 so-called Midford Sands of Somersetshire ; he illustrates the rapid 

 transitions which take place between sandy and calcareous strata in 

 this part of the series ; and in conclusion he shows, by the study of 

 the somewhat fragmentary fossils found in the sands of Dorsetshire 

 and Somersetshire, that they are the true equivalents of several different 

 divisions of the Oolites of the Cotteswold Hills. He admits, however, 

 that some Liassic forms range upwards into these beds. 



5. "On the Physical Geography of the North-east of England in 

 Permian and Triassic Times." By E. Wilson, Esq., F.G.S. 



In this paper the author seeks to utilize the information he has 

 acquired from the study of the Permian and Triassic rocks of the 

 above district, towards solving some of the difficult and much-debated 

 questions as to their origin. With this end in view he traces the 

 various members of the Magnesian Limestone formation between 

 Notts and Northumberland, noticing in particular the amplification of 

 that group of rocks in northerly and easterly directions, incidentally 

 attention is called to the increased importance of the Marl Slates as a 

 distinct and characteristic series. One of the main objects of the 

 paper is to establish the pre-Permian origin of the Pennine Chain. 

 The nature and relative values of the stratigraphical breaks which, in 

 the district in question, occur between the Carboniferous and Permian, 

 the Permian and Bunter, and the Bunter and Keuper formations, are 

 severally dealt with. The author concludes by speculating as to the 

 general conditions under which the Permians may have been formed, 

 and the physical fluctuations that may possibly have brought about the 

 succession in one geological epoch of rocks so distinct in mineral 

 constitution and in fossil contents as the Marl Slates, Magnesian 

 Limestone, and Permian Marls. 



6. " The Formation of Rock-basins." By J. D. Kendall, Esq., C.E. 

 The author discusses the mechanical difficulties involved in the 



glacier-excavation theory of lake-basins, and suggests that they are 

 due to the action of falling water engulfed in the crevasses of the 



