Arkell.1956.Jurassic..

PORTUGAL 239
bukowskii (Choffat) (pi. vi, figs. 19-26; also in bed 3), Idoceras montejuntense
Dacque (Choffat, pi. xi, 2), Aspidoceras aff. cyclotum (Oppel)
(xv, 5), Prorasenia aff. witteana (Oppel) and P. sp. (xv, 6, 7), Sowerbyceras
loryi (Mun.) (xvi bis, 1; also bed 3) and various Taramelliceras (xvi, 12-17)
and other Oppeliids. The absence of Pictonia, Rasenia, Ringsteadia and
Aulacestephanus from Portugal make close comparison with NW. Europe
precarious, but so many species, especially the local Perisphinctids, are
common to beds 3 and 4 that no stage boundary could be drawn between
them.
UPPER OXFORDIAN
Middle Lusitanian pro parte (Lower Montejunto Beds). Bed 1 of the
Montejuno Beds (10 m.), with Perisphinctes (Orthosphinctes) tiziani
(Oppel) var. occidentalis Choffat and allies (1893, pi. v, 5-10) is assignable
with confidence to the Bimammatum Zone.
Lower Lusitanian (Upper Cabaco Beds, 300 m.). Beds with numerous
pelecypods and corals in lenticles; ammonites rare, except in a thin bed
near the base. From this Choffat obtained ammonites which he rightly
recognized as 'indubitably Oxfordian' and of the age of the Transversarium
Zone. His plates ii-iv show Perisphinctes (Arisphinctes) spp.
extremely close to some of those in the Plicatilis Zone of England and NW.
Europe, also Dichotomosphinctes spp. (pi. v, 1, 2), ? Kranaosphinctes (v, 4),
Mirosphinctes (vi, 4), Cardioceras (Plasmatoceras) sp. (vi, 1, 2) of the style
of those in the Arngrove Stone, Euaspidoceras cabassoense Spath (type,
Choffat, pi. 1), which is close to E. crebricostis Arkell, and Ochetoceras
spp. According to Choffat Ochetoceras and Glochiceras (Oppelia subclausa
Oppel sp.) have long ranges, the former from the Transversarium Zone
into the Kimeridgian.
? LOWER OXFORDIAN
Lower Lusitanian (Lower Cabaco Beds, 200 m.). The minimum thickness
of beds (limestones) between the Transversarium Zone and the Upper
Callovian Athleta Zone is 200 m. The only fossils recorded are pelecypods
of a few species without dating value.
UPPER CALLOVIAN
In the Montejunto Range and in Algarve this is represented by marly
limestones with Peltoceras athleta, P. arduennense, Grossouvria spp.,
Kosmoceras spinosum (Sow.) (d'Orbigny, pi. 161: see Choffat, 1893, p. 80),
Paralcidia subcostaria (Oppel), Hecticoceras punctatum, Horioceras baugieri
(d'Orb.), Sowerbyceras tortisulcatum (d'Orb.), etc. (Choffat, 1880, p.
51; 1887, p. 254; 1893, pp. 2, 80).
MIDDLE AND LOWER CALLOVIAN
At Cape Mondego and other places north of the Tagus Choffat (1880,
pp. 50, 69) records numerous Lower and Middle Callovian ammonites
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