ZONE OF AMALTHEUS SPINATUS. 



109 



Annelida. 



Ditrypa circinata, Tate. 

 — capitata, Phil. 



Pentacrinus, sp. 



Cidaris amalthei, Querist. 



Ditrypa quinquesulcata, Munst. 

 Serpula limax, Goldf. 



ECHINODERMATA. 



Rhabdocidaris, spine. 



Foreign Correlations. — Dr. Oppel ^ has shown that the upper half of the Swabian 

 Middle Lias admits of the following division : 



Upper Lias — Posidonomya-heAs. 



Horizons. 



Petrology. 



Thick 



NESS. 



Organic Remains. 



Amaltheus 



spinatus 



beds 



Light argillaceous marly 

 strata, alternating witli 

 clays 



feet. 

 G— 8 



Amal. spinatus, Belemnites breviformis, B. crassus, 

 Lima Hervianni, Spiriferina rostrata, Rhyn- 

 chonella quinqueplicata, Wald. punctata, Wald. 

 subovoides. 



Upper 



Margaritatus 



beds 



Blue clay with geodes, pyri- 

 tic nodules, and separate 

 argillaceous marly strata 



45 

 10 



Atrial, margaritatus, Phrjlloceras zetes, Belemnites 

 paxillosus, Bel. compressus, Chemnitzia undu- 

 lata. Turbo paludince/ormis, Leda acuminata, 

 Pentacrinus Iccvis. 



Under 



Margaritatus 



beds 



Bluish clay, with argilla- 

 ceous marls 



Lyt. fmbriatus, Aey. (jlobosus, Harpoceras Nor- 

 mannianum, Belemnites umbilicatus, B. elon- 

 gatus, B. longissimus. 



Amaltheus margaritatus begins here. 



H enleyi-hed. Aetjoceras Henleyi. Inoceramus ventricosus. 



The Petrology of the Spinatus -hed in Svvabia differs from the blue clays of the 

 Margaritatm-ho.'S. on which the lighter argillaceous Marls rest, and the organic remains 

 have enabled Dr. Oppel to define their limits, as he has done in the above profile. 



In North Germany, Dr. U. Schlonbach " adopted a division of the upper portion of 

 the Middle Lias, which closely resembles the preceding section of the South German 

 series, and this careful observer has given a very instructive profile of an Ironstone 

 exposure near Liebenburg, where the spinatus were found to be very distinct from the 

 margaritatus beds. 



' 'Jura Formation,' p. 139, 1856. 



- "Den Eiseustein des mittleren Lias N.W. Deutscbland," ' Zeitsch d. Deutscben geol. Gessellsch. 

 .Tahrg.,' vol. xv, p. 489, 1863. 



