ZONE OF AMALTHEUS IBEX. 



83 



This zone appears to extend into Northamptonshire, as the specimens of Ainal. Ibex, 

 and Ae(/. Valdani in the British Museum, marked from Watford, testify. 



In Dorsetshire I have collected at Lyme Regis fragments of the leading fossils of this 

 zone, as, for example, A. Valdani, A. Maugenesti, in greyish coloured clay beneath a bed 

 with Aec). Davoei, so that the zone of Amaltheus Ibex appears to maintain an independent 

 position above the Jamesoni-heds in the localities I have cited wherever we are able to 

 ascertain the position of its fossils with sufficient accuracy to determine the limits of the 

 zone. 



Foreign Correlations. — In South- West Germany this zone was first separated from 

 the Jamesoni-heds by Dr. Oppel,^ as he found in beds of clay and marl a few feet thick, 

 resting upon the Jamesoni-heds, a group of Ammonites that were constantly associated 

 together, namely, Amal. Ibex, Aeg. Maugenesti, Aeg. Valdani, Aeg. Actcson, and Aeg. Cen- 

 taurus, whilst in the Jamesoni-heds the group of associates consisted oi Aegoceras Jamesoni, 

 Aeg. Masseanum, Aeg. suhmuticiim, Aeg. Taylori, and Aeg. pettos ; and a like distribution of 

 species is found in the two zones in Gloucestershire. The Ibex-heds are much more 

 easily discovered round Cheltenham than the Jamesoni-heds, which are only reached in 

 some deep brick-earth diggings. 



In several of the exposures for obtaining ironstone out of the Middle Lias of North 

 Germany some good sections of the Jamesoni, Henleyi, and Margaritatm-iQxs.es have been 

 discovered. The following section, made by the late Dr. U. Schlonbach,** of a cutting near 

 Oldershauscn shows the relation of tlic Ibex and .Jamesoni zones to each other in that 

 region. 



Section near Oldershausen, between Oldenrode and Echte ; the beds taken in 



descending Order. 



No. 



1 



2 

 3 



Petrology. 



Thick- 

 ness. 



ft. in. 



G 



1 8 

 10 



Organic Remains. 



A dark red-brown ironstone, with very 

 fine oolitic granules, and containing 

 many petrifactions from 4 to 



A greenish-brown marly limestone, very 

 crumbly, and containing many petri- 

 factions 



A bard greyish-yellow limestone, often 

 oolitic 



Phyll. Losconihi, Aey. hijhriduin, Aey. Irei-isphia, 

 Ae(/. .Jamesoni, Aey. Valdani, Aey. Gumbrechti, 

 Amal .Oj}peli,Belemnites clavatns,B.brevifonnis, 

 B. elonyatus, Nautilvs interinedius, I'hola- 

 domya decorata, P. ofjliquata, P. nmhigua, 

 P. IIaxismunni,Avicnlu Sineniuriensis, Gryphcea 

 obliqua, Pentacrinus basaltiformis. 



Lyt. Jimbriatiim, Aeg. Valdani, Phyll. Loscomhi, 

 Belemnites elonyatus, B. breviformis, B. 

 clavatus, B. umbiiicatus, Cryptcenia expansa, 

 Spiriferina rostrata. 



Aey. Capricornus, Belem'.iite.'t elonyatus, B. 

 breviformis, B. clavatus, B. umbiliratus, 

 Millericrinus Ilunsmanni, Pentacrinus nndus. \ 





' ' Juraformation,' p. 122, IS.OG. 



- ' Eisenstcin des mittleren Lias im N.-\V. Dtutscliland,' p. 193, 1863. 



