the Nomenclature of the Foraminifera. 223 



P. 457. (Wind-dust, Paster-Thai.) 



PL 6 I. figs. 82, 83. Spiroloculina. Young Comuspirai or 

 Miliola ? 

 P. 460. (Wind-dust, Silesia and Austria.) 



PI. 6 III. fig. 59. Textilaria globulosa? T. gihhosa, D'Orb. 

 fig. 80. Textilaria globulosa? T. globulosa, ^hx. 



§ 3. We now proceed to study the ' Mikrogeologie ' (1854), 

 beginning with the first plate that contains figures of Forami- 

 nifera. 



I. Marl\7\, or clay from, ^gina, Greece. (" Plastischer 

 Thon " in tlie explanation of the plate ; " Mergel-Fels. als 

 plastischer Thon. aus ^gina " on the plate.) (Abhandlungen 

 der Berliner Akademie der Wissenschaften, 1838 ; Griechen- 

 land no. 5. Monatsberichte Berl. Ak. Wiss. 1838, p. 176; 

 1842 ; 1844, pp. 62, 73, &c. ; 1847, p. 43.) 



This certainly appears to be a Tertiary* clay containing 

 Diatoms, spicules, and Polycystines in abundance, and with 

 so little calcareous matter {Foraminifera) that it can be used 

 for terra cotta. Its position is thus described by Herr Fiedler 

 in Dr. Ehrenberg's memoir : — " Ueber einen plastischen Krei- 

 demergel von ^gina aus mikroskopischen Organismen und 

 iiber die moglichkeit, durch mikroskopische TJntersuchung des 

 Materials den Ursprung gewisser alter iichtgriechischer Kunst- 

 denkmaler aus gebrannter Erde (Terracotten) mit bislier un- 

 bekannter Sicherheit zu bestimmen." (Monatsber. 1842, 

 pp. 263-268.) 



" In ^gina there is much chalk-marl [?], particularly in 

 the valley north of the town. A little peaked hill in the 

 middle of the valley, on which stands a small chapel to St. 

 Demetrios, is overlain by pale-red trachyte two fathoms 

 thick ; under this, down to the base, the hill consists of yel- 

 lowish-white and greyish chalk-marl [?]. The upper, yellowish 

 marl contains Venus shells ; the lower, pale-pellow marl, with 

 greenish streaks, has Pecten shells and rusty specks, and there 

 only is soft to the nail. This lower portion in particular forms 

 [hildet) a plastic clay which is worked" (p. 263). 



Clays rich in Diatoms have been used for brick-making 

 and ceramic purposes in England, Europe, Asia, and North 

 America. 



Plate xix. figs. 1-80 comprehend Diatomacese, Polycystina, 

 Spongoliths, &c. Fig. 81, Nodosaria monile (1844, p. 93), 

 is N. fliformis, D'Orb. Fig. 82, Grammostomum depressuni 



* It is referred to aa of Tertiary age by Elirenberg, * Abhandlungen,' 

 185G, p. 127. 



