Dr. R. L. Sherlock — Foraminifera of 82')eeton Clay. 255 



EXPLANATION OF PLATE XVII. 



The six microphotographs reproduced in this Plate are taken by reflected 

 light, and illustrate the crystallization-phenomena of the plane surfaces or 

 facets which bound the inclusions. 



Fig. 1. Group of roundish mould-facets showing rhomboidal impressions. 



Oblique illumination, magnified 8 diameters. 

 ,, 2. Knob-facet, with curved cracks and pseudo-striation. Oblique 



illumination, magnified 22 diameters. 

 ,, ;5. Mould-facet, with highly magnified, rhomboidal impression showing 



frayed edge. The perfecting of the outline of the impression in 



the enveloping crystalline material can be faintly seen, as shown 



by the white crosses. 

 ,, 4. Knob-facet showing crystalline structure. A fragment of film is 



marked A- 

 ,, o. Structure of film, a portion of which is shown in Fig. 4 (marked A). 

 ,, 6. Knob-facet showing crystal-shafts and resolution of pseudo-striation 



into aligned dots. 



Figs. 3-6, vertical illumination, magnified 110 diameters. 



II. — The Foraminifera of the Speeton Clay of Yorkshire. 



By K. L. Sherlock, D.Sc, A.E.C.Sc, F.G.S. 



(PLATES XVIII AND XIX.) ^ 



{Continued from the May Number, p. 222.) 



Family LAGENID^. 



Sub-family LAGENIN^. 



Lagena, Walker & Boys. 



Lagena glohom {lAoxita.^vi). (PI. XVIII, Fig. 6.) 



Vermieulum globosiim, Montagu, 1803 : Test. Brit., p. o23. 



Entosolenia globosa, Eeuss, 1862: Sitzungsb. d. k. Ak. Wiss. Wien, vol. xlvi, 



p. 318, pi. i, figs. 1-3. 

 Lacjcna globosa, Burrows, Sherborn, & Bailey, 1890 : Journ. Roy. Micr. Soc, 



p. 555, pi. ix, figs. 1, 2, 4. 



Itemarks. — This species has been recorded in rocks as old as the 

 "Wenlock Limestone and shale (Brady), and is still living in almost 

 every depth of water and in all latitudes. 



Horizon. — Present in C^, Cj, C^q. One specimen from each bed. 



Lagena apiculata, Reuss. (PI. XVIII, Fig. 12.) 



Lagena apiculata,'ReusB, 1862: Sitzungsb. d. k. Ak. Wiss. Wien, vol. xlvi, 

 p. 319, pi. i, figs. 4-8, 10, 11. 



Remarks. — L. apiculata is known from various formations from the 

 Lias to the Becent. It is still abundant in both shallow and deep 

 Avater. It is noteworthy that the specimens from Cj and C^q are very 

 large (see PI. XVIII, Fig. 12). 



Horizon. — Fouiui in B base c, Cj^, ? Cg (broken specimen), C^q. One 

 from each horizon. 



' Plate XIX will appear in the July Number with the concluding part of the 

 author's paper. 



