ZONE OF AMALTHEUS IBEX. 



85 



Middle Lias of Swabia. 

 Upper part of Middle Lias. Amaltheus margaritatm begins. 





Petrology. 



Thick- 

 ness. 



Organic Remains. 



Henleyi 

 beds 



Hard marly beds, alternating 

 •with bluish clay ; shells cal- 

 careous , 



ft. 

 10, 



Belemnites umbilicatus begins herey Aeg. Davcei, 

 Aeg. Henleyi, Lijt. Jimbriatum ; Aeg. striatum ; 

 Inoceramus ventricosus, Pentacrinus subangu- 

 laris. 



Ibex 

 beds 



Light grey, hard, marly beds, 

 with alternate layers of clay ; 

 organic remains pyritic 



15-18 



Amal. Ibex, Aeg. Maugenesti, Aeg. Valdani, Aeg. 

 Centaurns, Aeg. Actceon, Waldheimia numis- 

 malis, Rhyn. rimosa. 



Jamesoni 

 beds 



Aeg. Jamesoni, Aeg. Masseanum,Aeg .Taylori, Aeg. 

 pettos, Amal. Lynx, Pentacrinus basaltiformis. 



Akmatum 

 bed 



Grey marls 



2 



Aegoceras armatum. 



So that the stratigraphical character of the lower half of the Swabian Middle Lias 

 very much resembles the section I have given of the same beds in North Germany at 

 p. 31 of this work, where the classification of Professor von Seebach, Dr. Schlonbach, 

 and Dr. Emerson are arranged for comparison in {)arallel columns. 



In France this zone has been found in Normandy. Professor E. Deslongchamps^ has 

 described the " Niveau des Ammonites Valdani el des (/rosses A. fimbriatus," which is 

 always well characterised at Bully, Maltot, Fresnay-le-Puceux, and in the environs of Caen, 

 where the Ammonites Valdani strata have a thickness of 3 metres =10 feet. They 

 consist of granular limestones, sometimes sonorous and siliceous, \vhich cleave sometimes 

 into plates, and enclose a great number of fossils. Large and magnificent specimens of 

 Lytoeeras fimbriatum, Amaltheus Engelhardli, Amaltheus Ibex, and Aet^oeeras Taijlori, are 

 here found. The most abundant, and most characteristic Cephalopod of this small horizon 

 is the Ammonites Valdani, of which the rock, especially at Maltot, sometimes consists. 

 Among the Gastropods are Trochus, Chemnitzia, Pleurotomaria suturalis, and P. si?nilis, 

 with a large number of Lamellibranchs, — Panopaa elongata, Pholadomya Hausmanni, 

 Lyonsia unioides, Inoceramus ventricosus, I. substriatus, Ilinnites velatus, Pecten orbicularis, 

 P. ceqidvalvis, Ilarpax Parlcinsoni. Certain Brachiopods are very characteristic of this zone; 

 in the first line are varieties with a ventral groove, as Terebratula subovoides, Spiriferina 



1 ' Etudes sur les Etages Jurassiques Inferieurs de la Normandie,' p. 48, 1864. 



