I90I S. S. BUCKMAN— BRACHIOPODA 265 



vertically ; long, even over-exposure, with a small stop, the 

 plates being developed with much restrainer ;* some uni- 

 formity in regard to the colour of the examples — whereof 

 the eye is not an efficient guide ; elimination of shadows. 



The last detail was not attended to in the photographs 

 which were taken for the plate, hence some of its inferiority. 

 To obviate shadows cast by one specimen on another, it 

 is necessary to place them far enough apart. To obviate 

 shadows on the background, Mr Chas. Upton has suggested 

 an excellent plan, which I take the liberty to mention. 

 Mount the Brachiopods to be photographed on small pieces 

 of clay on a glass plate, support the glass plate by glass 

 legs (tumblers) some distance above a white sheet of card- 

 board. Shadows will thereby be eliminated. I have tried, 

 with success, a modification of this plan in the case of 

 Ammonites. 



X. Appendix II.— A Jurassic (part) Time Table 



Herewith is given an outHne of the Jurassic Time Table 

 explained at the Annual Meeting, 1899. It is important in 

 one respect, as an appendix to this paper on Brachiopods, 

 because it explains the chronological terms used herein. 

 It is hoped that it will be of greater importance later — 

 that it will serve as a basis for making records both of the 

 stratal and faunal sequence ; and that such records, whether 

 made by members of the Club, or by other geologists and 

 palaeontologists, may furnish important technical papers for 

 pubHcation in the Proceedings, to which they would give 

 a very special scientific value. 



The Appendix is divided into three tables : — (y^-J Ex- 

 planatory of the chronological terms. (B.) The stratal 

 sequence. (C.) A list of hemerae, with blank spaces 

 left to be used for registration purposes. 



* In November, 35 minutes with f. 32 gave very good results with Ammonites. 



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