Geological Society of London. 41 



It is suggestive that all the glacial deposits met with by the 

 author in Arctic and Polar lands (except the terminal moraines now 

 forming above sea-level) should be glacio-marine beds. 



Prof. Bonney in his report describes the rocks brought home by 

 the author. They include granite-gneiss (very like Archaean rocks), 

 grit, chert, limestone with Favosites (Silurian or Devonian), lime- 

 stone with Amphipora ramosa (Devonian), limestone with Litho- 

 strotion irregnlare (Carboniferous), and a fragment of a Jurassic 

 belemnite. The fossils have been examined by Mr. E. T. Newton, 

 F.R.S. 



TL— December 4, 1895.— Dr. Henry Woodward, F.E.S., President, 

 in the Chair. The following communications were read : — 



1. "On the Alteration of certain Basic Eruptive Eocks from 

 Brent Tor, Devon." By Frank Rutley, Esq., F.G.S. 



Two microscopic sections of rocks occurring on the north side of 

 Brent Tor were examined, and a cursory glance suggested at once 

 the idea that they might originally have consisted to a greater or less 

 extent of extremely vesicular basalt-glass. No unaltered vitreous 

 matter, except perhaps mere traces, can now be detected in these 

 specimens, the interest of which lies in the assemblage of alteration- 

 products which they contain. A third section cut from a small chip 

 collected at the southern side of the base of the Tor consists of 

 a highly vesicular lava of a hyalopilitic character, which may be 

 regarded as an amygdaloidal glassy basalt. 



The author gives a detailed account of the microscopic characters 

 of the three sections, and discusses the history of the rocks, com- 

 paring them with Tertiary basic glass, and with the Devonian rocks 

 of Cant Hill, which he described previously. He brings forward 

 evidence in favour of the view that the original alteration of both 

 the Brent Tor and Cant Hill rocks was palagonitic ; and that while 

 in the Brent Tor rocks the subsequent alteration of the palagonite 

 into felsitic matter, magnetite, secondary felspar, epidote, and pro- 

 bably kaolin, and some serpentine and chlorite, was complete, it was 

 only partial in the case of the Cant Hill rocks. We may, therefore, 

 assume that palagonite is not the ultimate phase of alteration in 

 basic igneous rocks. 



2. " The Mollusca of the Chalk Rock : Part I." By Henry Woods, 

 Esq., M.A., F.G.S. 



In the introductory part of the paper the author gives an account 

 of the characters, distribution, and literature of the Chalk Rock. 

 He points out that the Chalk Rock fauna may be recognized at the 

 same level in Northern France, N.W. Germany, Saxony, Silesia, and 

 Bohemia; and on account of the wide distribution and distinctive 

 features of this fauna, he suggests that the Chalk Rock merits 

 a palaeontological rather than a lithological designation, and pro- 

 poses for it the term "zone of Heteroceras reussianum." 



The main part of the paper is devoted to the consideration of the 

 Cephalopoda, Gasteropoda, and Scaphopoda ; and is based largely 

 on the collection from Cuckhamsley (Berks) made by the late 



