Geological Society. 73 



Headon of Headon Hill ; for the Brockenhurst bed is entirely absent 

 from the west of the island. The authors maintained that Prof. 

 Judd has assigned a false position to this bed in his vertical section 

 of New- Forest beds, and that instead of being higher than the 

 Yenus-bed horizon, it is plainly below it, since at Whitley Ridge it 

 lies on the Lower Headon, being succeeded by the Yenus-bed and then 

 by the Upper Headon. The palaeontological evidence was then dis- 

 cussed; and it was objected to Prof. Judd's lists that he has mixed up 

 the Colwell Bay and Brockenhurst fossils in one list, thereby begging 

 the question. In opposition to his statistics the authors maintained 

 that the Brockenhurst bed has about 48 per cent, of species which 

 pass up from the Barton beds, while the Yenus-bed series of either 

 Colwell Bay or Headon Hill have only 29 per cent., suggestive of the 

 lower position of the former. 



Further examination of the lists of fossils prepared from an ex- 

 amination of the Edwards collection shows that the Colwell-Bay 

 and Headon-Hill marine beds have thirteen times more species 

 common to themselves alone than either of them have in common 

 with the Brockenhurst bed. The palaeontological evidence is there- 

 fore in accord with the stratigraphical ; they both occupy a higher 

 zone than the Brockenhurst bed, which, when developed, occupies 

 the base of the Middle Headon. The authors therefore reject Prof. 

 Judd's term Brockenhurst series, and revert to the classification and 

 nomenclature of the Geological Survey. 



December 15. — Eobert Etheridge, Esq., E.R.S., President, 

 in the Chair. 



The following communications were read : — 



1. " On the Constitution and History of Grits and Sandstones.'' 

 By John Arthur Phillips, Esq., E.G.S. 



In the first part of this paper the author described the micro- 

 scopic and chemical structure of a large series of grits, sandstones, 

 and, in some cases, quartzites, of various geological ages, noticing 

 finally several sands of more or less recent date. The cementing 

 material in the harder varieties is commonly to a large extent 

 siliceous. The grains vary considerably in form and in the nature 

 of their enclosures, cavities of various kinds and minute crystals of 

 schorl or rutile not being rare. The author drew attention to the 

 evidence of the deposition of secondary quartz upon the original 

 grains, so as to continue its crystal structure, which sometimes 

 exhibits externally a crystal form. This is frequently observable 

 in sandstone of Carboniferous, Permian, and Triassic age. Pelspar 

 grains are not unfrequently present, with scales of mica and minute 

 chlorite and epidote. Chemical analyses of some varieties were also 

 given. The author then considered the effect of flowing water upon 

 transported particles of sand or gravel. It results from his in- 

 vestigations that fragments of quartz or schorl less than -^" in 



