1858.] STOW EHENOSTEKBEEG. 193 



of the Carbonaceous beds and the granite further to the south than 

 this point. 



4. On the Structure of some of the Siliceous Nodules of the Chalk. 

 By N. T. Wetherell, Esq., M.E.C.S. 



[Communicated by the President,] 

 [Abstract.] 



The author described several specimens of the peculiar banded 

 flints* found in the chalk and in gravel, and of which he had 

 made a large collection during several years. They usually exhibit 

 a central longitudinal axis or narrow stem, crossed on its middle third 

 by numerous short parallel stripes of alternately light and dark flint, 

 and frequently terminated at each extremity by an irregular mass of 

 flint, often clouded or grey. The axis occurs sometimes isolated, 

 sometimes covered with a thin coating of grey flint only, and some- 

 times associated with only a few cross stripes of the banded structure. 

 In some instances the banded flint has for its axis a sponge, or frag- 

 ments of sponge. 



The author had not found in the banded flint any spongy tissue 

 peculiar to it; in some instances, however, a silicified sponge ap- 

 pears to have been traversed by alternate lines of the light and dark 

 colour analogous to those of the banded flints. In some instances a 

 concentric arrangement of light and dark layers of flint occurs around 

 the two ends of an axis, or around isolated nuclei. 



Mr. WethereU regarded this banded appearance in the flint as not 

 being due to an organic structure, but to have originated in a peculiar 

 arrangement of the siliceous matter around organic bodies, frequently 

 long and stem-like, such as those of the Graphularia, which supplied 

 so many axial nuclei to the concretions in the London Clay f. 



November 17, 1858. 



Augustus Smith, Esq., M.P., 1 Eaton Square, was elected a 

 Fellow. 



The following communications were read : — 



1. On some Eossils /rom South Africa. By C. W. Stow, Esq. 



[In a Letter to the Assistant-Secretary.] 



[Abstract.] 



At the close of 1850 Mr. Stow and his party feU back into the 

 interior to avoid the Kaffirs ; in making the journey he collected 

 largely the fossils on his route, and succeeded, with much trouble, 

 in preserving them on his return. 



* Mr. Parkinson figures and describes a worn specimen of one of these flints 

 in his ' Organic Eemains,' vol. iii. p. 241. pi. 16. fig. 18. 

 t Quart. Journ. Geol. Soc. vol. xiv. p. 30. 



