SECTIONAL TRANSACTIONS— C. 329 



orthophyre (Lundyite), and basaltic or doleritic types, all of which are par- 

 ticularly interesting in relation to the granites. Basic dykes have been 

 mapped magnetically in several cases. 



A hybrid junction-rock with xenoliths separates the sediments from 

 discordant plutonic intrusions. 



Chemically the granitic types are mainly alkaline, with relatively little 

 lime, magnesia, or iron, but some rare earths. 



Texturally these rocks range from porphyritic varieties to microgranites, 

 granophyres, and fine-grained granite-aplites. 



They are also characterised by pegmatite facies and junction-zones 

 involving drusy cavities lined with a distinct assemblage of accessory 

 minerals. 



Both in the field and under the microscope it is possible to recognise in 

 these rocks the effects of thermal and mechanical stress, differentiation, 

 assimilation and pneumatolysis. 



Mr. C. W. Peacock and Dr. H. C. Versey. — Glacial gravels along the 

 margin of the Yorkshire Wolds. 



A number of isolated gravels occur between the Vale of York moraines 

 and the Humber, at levels ranging from 175 ft. above O.D. down to 50 ft. 

 The composition of these gravels is recorded, and they are correlated with 

 the Purple Clay and Hessle Clay episodes of the Yorkshire coast. Their 

 mode of formation is grouped under (i) marginal drainage gravels ; (2) out- 

 wash gravels from Ferriby moraine ; and (3) deltaic gravels round Market 

 Weighton. Their relation to the Bielsbeck deposits is also discussed. 



Dr. D. A. Wray. — The physiographic evolution of the southern Pennine area 

 in the Upper Carboniferous period. 



The Millstone Grits have been shown by the researches of Sorby and 

 Gilligan to be deltaic deposits derived from a large continental mass which 

 extended from what is now the North of Scotland towards Scandinavia. 

 There is a remarkable similarity in character and thickness of the formation 

 along both the eastern and western slopes of the Pennines, but a pronounced 

 south-westerly thickening in the higher beds has been proved by Tonks 

 and Wright to take place in south Lancashire, where a maximum thickness 

 for these beds is recorded. 



The distribution and character of the Lower Coal Measure sediments 

 indicate that a marked change in physiographical conditions took place at 

 the close of the Millstone Grit period. These sediments were laid down 

 in a sinking area extending in an east and west direction across the Southern 

 Pennines with the maximum depression taking place in the west. There 

 are clear evidences of a slight though pronounced line of contemporary 

 uplift along an east and west axis in Yorkshire, and this line of uplift, which 

 became more marked at a later period, has produced effects of far-reaching 

 economic importance in the higher Productive Measures. 



A thick series of sandy sediments devoid of coals form the upper limit of 

 the Lower Coal Measures, and the present writer has endeavoured to show 

 this horizon marks a faunal and floral break of some importance in the 

 Coal Measure succession. Recent researches appear to confirm these 

 conclusions ; while it is at this stage important physiographical changes 

 occurred within the Southern Pennine area. 



The major subdivisions of the Middle or Productive Coal Measures can 

 now be broadly correlated by means of their non-marine fauna from the 

 west of Manchester right across the Southern Pennine area almost to the 



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