4 
PATAGONIAN EXPEDITIONS PALAEONTOLOGY, 
2. The Lower conglomerate , 20 feet in thickness, yielded occasional 
pieces of petrified wood filled with boring Mollusks ( Turnus dubius )} 
3. The Belgrano beds , conformably overlying the lower conglomerate, 
consist of 300 feet of soft greenish sandstones and clays replaced toward 
the top by several layers of harder sandstones and impure limestones. 
These beds, especially in the upper portion, are rich in Cretaceous inver- 
tebrates and at the two localities have yielded all the species described 
in this paper except those just mentioned. The list of species will be 
given later. 
4. The Upper conglomerates , forming the highest member of the Pueyr- 
rydon series, consist of 330 feet of hard, fine-grained, red and variegated 
sandstone with occasional layers of clay, ending above in a series of very 
hard fine conglomerates, which have not yielded any identifiable fossils. 
Resting unconformably on the upper conglomerates are the Variegated 
sandstones , 1350 feet in thickness, referred to the upper Cretaceous on 
stratigraphic grounds. Overlying these is a very thick series of Tertiary 
beds characterized by both vertebrate and invertebrate fossils. 
From this brief description it is seen that all the Cretaceous fossils 
under discussion came from the lower 420 feet of the Pueyrrydon series, 
and a very large proportion of the species were collected from the upper 
part of the Belgrano beds about the middle of that series. All the speci- 
mens from the Gio beds and the lower conglomerate were obtained at 
the locality near the mouth of the canon of Rio Tarde. The Belgrano 
beds at the same locality yielded the following species : 
Lima sp., 
Pecten (Camptonectes) pueyrrydo- 
nensis, 
Pecten argentinus, 
Pecten octoplicatus, 
Avicula (Oxytoma) tardensis, 
Gervillia hatcheri, 
Mytilus (?) argentinus, 
Leda (?) corbuliformis, 
Solecurtus (?) limatus, 
Pleuromya latisulcata, 
Corbula crassatelloides, 
Martesia argentinensis, 
Pleurotomaria tardensis, 
Lunatia pueyrrydonensis, 
Aporrhais (?) sp., 
Hatchericeras patagonense, 
Hatchericeras argentinense, 
1 The specimens of Tubulostimn pupoides have the same field label as this species but Mr. 
Hatcher states that the lower conglomerate yielded no other fossils except the wood with boring 
Mollusks and it is almost certain that the Tubulostium came from either the Gio beds or the Bel- 
grano beds, as the appearance of the specimens would indicate. 
