388 ilr. H. J. Carter 07i the " Tuhulations Sableuses " 



Grayi^ are gathered into short, broken, circular lines. (This 

 form is equally common to the Ventriculites and Gceloptychium, 

 but with long spines) . 



LiTHiSTiNA. Among the remains of the siliceous skeletons 

 of the Lithistina, which are by far the most abundant and 

 most perfect in species and different forms of spicules respec- 

 tively (Rutot, figs. 9-11, 22-26, 43, 45, and 46), is one (fig. 9) 

 which is very like the surface or dermal large spicule of 

 Corallistes [Dactylocalyx) Bowerhanhii ] while the more com- 

 plicated stellate forms (figs. 43, 45, and 46), each of which 

 has a short pointed vertical shaft, indicative of its surface- 

 origin (generally broken off), are equally numerous, varied, 

 and beautiful in their forms. 



Geodina. Small siliceous balls (Rutot, figs. 36 and 37), 

 " zone-spicules " (figs. 12, 13, and 20, 21), " forked " and 

 "anchor-heads" respectively (figs. 16-18), and "body-spi- 

 cules" (figs. 1-4), indicate the presence of Geodia, as well as 

 that of Stellettina, of which, respectively, there are, in all 

 probability, the remains of several species. That form of 

 " zone-spicule " (figs. 20 and 21) which has a curved shaft in 

 addition to produced furcate arms expanded florally and fre- 

 quently veiy unequal in length, abounds also in the Upper 

 Greensand of Hal don Hill, near Exeter, to which, together with 

 the other spicular elements of Geodia, I have given the name 

 of Geodia haldonensis ('Annals,' 1871, vol. vii. pi. x. figs. 67 

 and 68). It is equally common also in the cavities of English 

 chalk-flints ; but I have never seen any sponge of the present 

 day bearing the zone- or large furcate spicules like it ; so this 

 species may have ceased to exist. 



DoNATiNA. The globo-stellates of two kinds of Donatia 

 appear to be present^ as indicated by their forms respectively — 

 of which fig. 35 is one ; and the other is like the globo-stellate 

 of the present day in D. lyncurium^ which is also common in 

 the cavities of the chalk-flints in England. 



Ophioehaphidites is also common here (Rutot, figs. 5 

 and 29), as well as in the Upper Greensand of Haldon Hill, 

 and existing at the present day ('Annals,' 1876, vol. xviii. 

 p. 458.) 



DiATOMACE^. The disks of a cycloid diatom are very 

 abundant (figs. 38, 39, and 39 a, h), presenting two forms, viz. 

 one simple like a flat drum, and the other the same, but with 

 depressions on it, in the form of a " Maltese cross," extending 

 from the centre to the circumference on both sides, in such a 

 way that the prominent or raised parts on one side correspond 

 to the depressions on the other, thus giving the edge, when 

 viewed laterally, an undulated appearance like Cychtella 



