ORTMANN I TERTIARY INVERTEBRATES. 
279 
Of these 29 species, 19 have been found at Santa Cruz. This horizon, 
the lowermost in this section, ought to be Juliense, and, indeed, it con- 
tains 5 Juliense species; but this conclusion is entirely upset by the fact 
that 3 Leonense and 4 Suprapatagonian species are also represented here. 
400 above base. 
Only Modiola andina has been collected here. 
600 above base (or 100' below top of marine series). 
* Terebratella dorsata. 
J * Terebratella patagonica. 
*Nucula patagonica. 
*Leda crrazurizi. 
* Glycimeris ibari. 
L * Per na quadrisidcata. 
L & S * Ostrea ingens. 
J& S * Pec ten geminatus. 
Modiola andina. 
* Crassatellites quartus. 
Cardita volckmanni. 
* Cardium philip pii. 
* Venus meridionalis. 
* Venus volckmanni. 
Mactra garretti. 
Panop ea regularis. 
*Panopea quemadensis. 
* Mar tesia patagonica. 
* Solariella dautzenbergi. 
* Gibbida Icevis. 
* Gibbida dalli. 
* Infundibid u m corrugatu m. 
Galerus araucanus. 
L * Turritella ambulacrum. 
Vermetus cf. intortus. 
S * Struthiolaria ameghinoi. 
* Pyrula Carolina. 
J Siphonalis noachina. 
* Trophon patagonicus. 
S Voluta ameghinoi. 
* Terebra costellata. 
* Geryon peruvianus. 
The comparison of this locality with others is very important and inter- 
esting. About half (15) of the number of species are identical with those 
of the lowermost horizon of this section, although both are separated from 
each other by almost 600 feet of deposit. In this locality, out of 32 
species, 25 are common to the type-locality at Santa Cruz, and this shows 
conclusively that the three (Santa Cruz, lower and upper horizon of Rio 
Tarde section) cannot be separated, and further, it shows that at Santa 
Cruz no two or more horizons can be represented, since the latter section 
comprises only about 250 feet, while here, at 600 feet above the base, still 
an unmistakable Patagonian fauna (as found at Santa Cruz) is present. 
Comparing our list with the subdivisions of Ameghino and v. Ihering, 
we see that we have here again, at 6oo' above the base, and ioo' below 
the top, where we should expect a characteristic Suprapatagonian fauna, a 
mixture of 3 Juliense, 3 Leonense, and 4 Suprapatagonian elements, a 
relation that has hardly changed from that found at the base of the Rio 
Tarde section. 
Extreme top of marine series (Rio Tarde section). 
Ostrea ingens has been found here in a form (see p. 109) that corre- 
sponds to O. hate her i, which is found, according to v. Ihering and 
Ameghino, exclusively in the Leonense beds. 
