93 . Reports and Proceedings — 



the above, of some veiy fragmentary remains, apparently belonging 

 to a Labyrintbodont, a portion of which have already been described 

 by Prof. Miall in the 'Quarterly Journal' (vol. sxx. p. 775). 

 These remains consist of parts of the head and of one hind limb. 



2. " Petrological Notes on some North-of-Engiand Dykes." By 

 J. J. H. Teall, Esq., M.A., F.G.S. 



The author described the stratigraphical relations and the struc- 

 ture, macroscopic and microscopic, of a number of dykes which 

 occur in the north-east of England, giving analyses. He pointed out 

 that they fell into four more or less distinct groups : — 



(1) The Cleveland dyke and that of Acklington. 



(2) The Heth and its related dykes. 



(3) The dykes of Hebburn, of Tynemouth, of Brunton, of 



Hartley, and of Morpeth. 



(4) The High Green dykes. 



Groups (1) and (3) resembled one another in specific gravity and 

 chemical composition, as did (2) and (4), the percentage of silica 

 in the first two (except in the Morpeth dyke) varying from 67 to 59, 

 and the specific gravity being about 2-7 or 2*8, while the others had 

 a silica percentage of from 51 to 53 and a rather higher specific 

 gravity. The former present some microscopic differences, the latter 

 are very closely related. The Cleveland, Acklington, and Hetb 

 dykes have been examined at intervals far apart, and exhibit no 

 variation or relation to the surrounding rocks ; so that evidently 

 they have not taken up any appreciable portion of the material 

 through which they have broken. The dykes of Group (3) being 

 probably Pre-tertiary (the author does not himself find it possible 

 to distinguish igneous rocks by their geologic age) would be termed 

 melaphyres on the continent ; but those of (2) and (4) are nearer 

 to the group of diabases. The Cleveland dyke (Group 1) is almost 

 certainly of Tertiary age, and its structure and composition entitle 

 it to the name of an angite-andesite. 



3. "The Droitwich Brine Springs and Saliferous Marls." By 

 C. Parkinson, Esq., F.G.S. 



The author referred to the effects of the pumping of brine from 

 beneath Droitwich in producing insecurity in the buildings, and 

 proceeded to discuss the possible source of the brine-water system-. 

 He referred to the probable existence of extensive beds of rock-salt, 

 lower than the present brine-cavities, towards the north-east of 

 Droitwich — a conclusion which receives support from the deeper 

 borings carried on at the Stoke works. Full details of these and 

 other recent borings were given by the author. 



IL— January 9, 1884.— J. W. Hulke, Esq., F.K.S., President, in 

 the Chair. — The following communications were read : — 



7. " On the Volcanic Group of St. David's." By the Eev. Prof. 

 J. F. Blake, M.A., F.G.S. 



The result of the author's examination of the rocks in the district 

 of St. David's which have been designated Dimetian, Arvonian, and 



