ZONE or AMALTHEUS SPINATUS. Ill 



Dr. Emerson found the SpinatusSchichten well exposed at Liithorst, near Markol- 

 denclorf, and in a soft, greyish, shaley clay he collected Amalt/ieus spinatus, Brug., 

 Belemnites clavatus, Mill., Turbo paludinafonnis, Schub. The rich Ammonite -iron stone, 

 which was formerly worked between Liithorst and Hiinnesriick, probably belonged to 

 this zone. 



A. von Strombeck^ described the upper beds of the Amaltheenthone with Amal. 

 spinatus in the Helmsted Jura ; and Senator H. Romer found the same in his 

 garden near Hildesheim with Atnal. spinatus, Gresslya ventricosa, Limea acuticosta, 

 and Pecten aqwivahis. Other localities described in the works of Ewald, Bornemann, 

 and Wagener, might be enumerated to show that this upper portion of the Amaltheen- 

 thone is widely distributed in North Germany. 



In France Professor E. Deslongchamps" gives a good profile of the Lias a Belemnites 

 near Caen, in which wc find (No. 4) the thick limestone separated by thin argilo- 

 calcareous layers with Aegoceras Bechei, Lytoceras jimhr latum, Belemnites clavatus^ 

 Grypltaa cymbium, Terebratula subovoides, Wald. punctata, Jthyn. tetraedra, Rhyn. rimosa, 

 and Spiriferina rostrata. This bed is overlain by (No. 5) a bank of sandy limestone, in 

 part finely oolitic, containing Amal. spinatus, Amal. margaritatus, Belemnites niger, 

 B. arcuarius, IHeurotomaria suturalis, Pecten cequivalvis, P. disciformis, Gryphaa 

 cymbium, Terebratula quadrifida, T. punctata, T. Edwardsii, Bhyn. tetraedra, and 

 Spiriferina rostrata. This appears to be the equivalent of the Marlstone rock-bed of 

 English authors, as it is overlain by (No. 6) the Couche a Leptaena, which, as we shall 

 presently learn, forms the lower bed of the Upper Lias. Amaltheus spinatus is collected 

 in other localities in Calvados ; and is found likewise at Avesnes, Doubs, at Saint- Amand 

 Cher ; at Grundcrshofen and Selzbrunncn, Bas Rhin ; in the Departments of Meurtlie, 

 Moselle, Lozere, Haute-Saone, and Aveyron. In the Jura Department Marcou 

 separated his " Marnes a Plieatules," with Amal. spinatus, Belemnites Bruguerianus, 

 Lima Hermamii, PUcatula spinosa^ Gryphcea cymbium, from the underlying beds 

 containing Amal. margaritatus, and was the first to point out the important dift'erences 

 which exist between these two zones. 



In Luxembourg Amal. spinatus has been collected from the " Macigno d^Aubange," 

 near Athus, which is considered by Chapuis and Dcwalque* as the equivalent of the 

 Marlstone and ironstone of English authors. 



Dumortier^ says that Amal. spinatus is found only in the uppermost portion of the 

 Middle Lias, in the horizon of Limea acuticosta, where it is accompanied by Avicula 



' " Die Liasmulde von Markoldendorf ;'' ' Zeitsch. d. Deutscben geol. Gessellsch.' Jahrg., 18/0, p. 303, 

 vol. xxii. 



2 ' Geognost. Karte des Herzog. Braunschweig,' 1856. 



^ 'iitudes Jurassiques Infer, de Normaudie,' pp. 59 — GO, 1864. 



* * Fossiles des Terr, second, de Luxembourg,' p. 12, 1853. 



5 »£tudes Faleont. du Bassin du Rhone,' toni. iii, p. 213, 1869. 



