604 TIMOTHY WILLIAM STANTON 
Tylostoma sp. Glauconia cf. picteti Coquand 
Glauconia branneri (Hill) Nerinea sp. 
Glauconia cf. helvetica (Pictet and Neumayria? ? walcotti Hill 
Renevier) Stoliczkaia justinae (Hill) 
Excepting the ammonites and the last two species of Tri- 
gonia these forms are all very abundant in certain layers and 
give character to the fauna. The Ostrea is a simple form of 
little diagnostic value mentioned merely on account of its abun- 
dance. The Trigonias represent three groups, two of which, 
scabre and quadrate, are characteristic of the Cretaceous and 
the other, glabre, occurs in both Jura and Lower Cretaceous. 
Requienia and Monopleura are not known outside of the Creta- 
ceous and are found in the Urgonian and higher horizons of 
Portugal and other southern European countries. Watica pied- 
ernalis is very like NV. stmillinus Choffat of the Urgonian of Portu- 
gal, and Choffat speaks of the great abundance of large Naticas 
in that horizon, though similar forms also occur in the Valanginian 
(Lower Neocomian) of the same region. The species of Glau- 
conia are all represented by very similar southern European 
forms ranging from the Urgonian to the Aptian and perhaps 
higher. The two species of ammonites are not well enough 
known to be compared satisfactorily but their nearest relatives 
apparently are Lower Cretaceous species. 
Several other forms have representative species in southern 
Europe but when the comparisons are all made the final result is 
not a definite correlation of the lowest fossiliferous beds of the 
Trinity with any particular horizon of the Lower Cretaceous, 
though the evidence is clear that it cannot be earlier than the 
Lower Cretaceous and that it probably is not the base of the 
Cretaceous. 
*For stratigraphy and related species mentioned in this discussion see, CHOFFAT 
Recueil de Monog. Stratig. sur le Systéme Crétacique du Portugal, Lisbonne, 1885 
Recueil de Monog. paléont., etc., 1886. 
PICTET et RENEVIER. Fossiles du Terrain Aptien de la Perte du Rhone. 
PICTET et CAMPICHE. Fossiles du Terrain Crétacé des environs de Sainte Croix 
Der LorIoL et DE LORIERE. Fossilés du Neocomien superieur de Utrillas. 
CoQuaND, Monographie paléontologique de l’etage Aptien de l’Espagne. 
