570 Geological Society : — 



mathematical application which the average English schoolboy finds 

 unpalatable enough. At this point a welcome relief is afforded by 

 some simple qualitative experiments illustrating the transfer of 

 energy from one form to another, and especially from the mecha- 

 nical form to heat, electricity and light ; these not only serve to 

 introduce the principle of conservation of energy, but they also 

 indicate that a relation exists between the various forms of energy. 

 It must not be supposed from these criticisms and suggestions 

 that the treatise is not a valuable text-book : Professor Crew is 

 an excellent teacher and gives lucid explanations of all the subjects 

 of which he treats. If in some portions of the work the usual 

 order of treatment has not been followed, it may at any rate be 

 said that the author's treatment is equally consecutive and logical. 

 He has aimed at setting forth what he, quoting Dickens, calls 

 " the universal dovetailedness of things," apparently forgetting 

 that some preliminary preparation is necessary before the dove- 

 tailing process takes place. J. L. H. 



LXI. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued, from p. 400.] 



June 21st, 1899.— W. Whitaker, B.A., F.R.S.,President,in the Chair. 

 r PHE following communications were read : — 

 -*- 1. 'On a Series of Agglomerates, Ashes, and Tuffs in the 

 Carboniferous Limestone Series of Congleton Edge.' By Walcot 

 Gibson, Esq., F.G.S., and Dr. Wheelton Hind, F.R.C.S., F.G.S. 

 With an Appendix on the Petrography of the Igneous Eocks by 

 H. H. Arnold-Bemrose, Esq., M.A., F.G.S. 



After referring to the discovery of volcanic rocks in the upper 

 part of the Carboniferous Limestone Series at Tissiugton, the 

 authors proceed to describe evidence of volcanic action of the same 

 age on the western slopes of Congleton Edge. This ridge is capped 

 by two beds of Millstone Grit separated by black shales. Below 

 the lower grit (the ' Third Grit ' ) is a narrow dome of limestone 

 lying in the midst of so-called ' Yoredale Shales ' and exposed in an 

 old quarry. The upper beds of the Limestone consist of thin shales 

 and limestones containing one important and some minor seams of 

 tuff and agglomerate, and certain evidence points to the probability 

 that a ' neck ' occurs in the quarry. A brook-section north of the 

 quarry exposes beds of ash aud tuff interstratified with shales and 

 limestones, the thicker beds being presumably equivalent to those 

 seen in the quarry. A brook-section south of the quarry displays 

 the beds between the Limestone and the ' Third Grit,' and a small 

 quarry yields a varied marine fauna. 



In the Appendix it is stated that the igneous rock of the quarry 

 is either a volcanic agglomerate filling a vent, or a thick deposit of 

 very hard, coarse ash, probably formed not far from a vent. Ashy 

 material in the Limestone indicates that the volcanic action was 

 contemporaneous with the deposition of the Limestone. Two kinds 

 oflapilli occur — one palagonitic, without crystals, and a second dole- 

 ritic, free from vesicles, and containing felspar, olivine, and often 

 augite ; the latter type, though common in the agglomerate, is rarer 

 in the bedded tuffs. The fragments are freqiiently altered into calcite. 



