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Note on Mr. Henry Keevil's Section of Flint. 

 PLATE XVIII. 



Mr. Henry Keevil, of Batli, has kindly sent for examination 

 a section of flint, wliicli contains several interesting objects. 

 Mr. Keevil found the stone, which measures 1| by 1^, in some 

 road metal ; he broke it with a hammer, and its fracture shows 

 a considerable thickness of white material round a pale brown 

 core ; one of the brown splinters, which he ground down and 

 polished, forms the section in question. A microscopical 

 examination of the slide reveals, first, a number of small 

 spherical bodies, fairly uniform in size, with a diameter of 

 •0016 inch. There are two separate patches crowded with 

 these bodies in the section. 



Two of these spherical bodies, as seen under an apochromatic 

 J of 1'4 N.A. with polarized light, are represented in Plate 

 XVIII. 



The next figure is that of a flask-shaped body full of similar 

 spherical bodies. Its size is as follows : Major axis '0217 inch, 

 minor axis '016 inch. 



The third figure is that of a sector-shaped body, the length 

 from its apex to the centre of the arc being '0068 inch ; it is 

 apparently divided into segments. 



The slide also contains some small fragments of sponge struc- 

 ture, but its chief interest centres in those objects which Mr. 

 Karop has kindly figured in Plate XVIII. 



It was thought desirable to submit the slide to those who 

 had made this subject a special study. We are informed, first, 

 that the small spherical bodies are not organic, but are a part 

 of a process of crystallization, similar bodies being found in 

 " chert ; " secondly, that the flask-shaped body is a pseudo- 

 morph of a foraminifer of the species Lagena, and, thirdly, that 

 the sector-shaped body is an oblique section of another species 

 of foraminifer Cristellaria. We are indebted to Prof. T. Rupert 

 Jones, F.R.S., for so kindly naming these Foraminifera. 



