278 
PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
Of these 19 species, 16 (marked *) are found at Santa Cruz, which 
would make these beds identical with those of the type-locality. The 
fact, that Juliense, Leonense, and Suprapatagonian species — although 
only a few of each category — are associated here, is in so far interesting, 
as it shows that these three supposed different divisions are condensed 
here into only 100 feet. 
Lake Pueyrredon. 
East end of Lake Pueyrredon; horizon not ascertained. 
J * Rhynchonella plicigera. L& S* Ostrea ingens. * Cardium philip pii. 
* Terebratella dorsata. J & S * Pec ten geminatus. 
All of these 5 species have been recorded from Santa Cruz, and, 
although the number of species is very small, we have a mixture of 
Patagonian and Suprapatagonian forms. According to the matrix and 
the species found, this horizon seems to correspond to the lowermost of 
the Rio Tarde section (see below). 
High bluffs , S. IV. of Lake Pueyrredon ; horizon not ascertained, but 
about 1000' below Santacruzian beds. 
J * Rhynchonella plicigera. Magellania lenticularis. Gryphcea cf. tarda. 
Rhynchonella squamosa. J * Terebratella patagonica. 
This horizon also seems to correspond to the lowermost of the Rio 
Tarde section. 
Lake Pueyrredon, Rio Tarde section, 700' thick (see Hatcher, 
1900 a, p. 100). 
Base of marine Tertiary: The lowermost beds of the Rio Tarde sec- 
tion, immediately overlying a basaltic deposit that lies on top of the 
barren Cretaceous sandstones. 
* Cidaris antarctica. 
J Scutella patagonensis . 
Cyrtoma posthumum. 
J * Rhynchonella plicigera. 
Rhynchonella squamosa. 
Magellania lenticularis. 
* Terebratella dorsata. 
J * Terebratella patagonica. 
J Bouchardia zitteli. 
* Glycimeris ibari. 
L *Perna quadrisulcata. 
L & S * Ostrea ingens. 
J & S *Pecten geminatus. 
Modiola andina. 
Crassatellites longior. 
* Cardium philippii. 
* Cardium pisum. 
* Venus volckmanni. 
* Panopea regularis. 
* Pan op e a quemadensis. 
* Dentalium sulcosum. 
*Gibbula Icevis. 
S *Scalaria rugulosa. 
L * Turritella ambulacrum. 
S * Struthiolaria ameghinoi. 
* Trophon patagonicus. 
Urosalpinx pyriformis. 
Balanus cf. psittacus. 
Balamis varians. 
