280 PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 



Punta Arenas, horizon V (uppermost). See the description of the 

 Punta Arenas section, given by the writer, according to Hatcher's observa- 

 tions, 1898, p. 481. 



Ameghino (1899, p. ? 13) has completely misunderstood, and arbitrarily 

 changed the account the writer has given of this horizon. Hatcher 

 labelled some oysters collected here: "below" and "above" V. This 

 means only that this horizon begins, at the base, with an almost solid 

 layer of oysters, then follows a layer of dark-greenish sand that contains 

 the other fossils, which ends again, at the top, in a similar layer of oyster 

 shells. This whole horizon, including both oyster beds, is a unit, and 

 there is no break at all. Nevertheless, Ameghino constructs an hiatus 

 between the upper oyster layer and the rest, and correlates the former 

 with his Tehuelche formation, the latter with the Suprapatagonian part of 

 the Santacruzian formation. This assumption of an hiatus within our 

 horizon V is entirely unwarranted, and characterizes Ameghino's manner 

 of trimming facts to suit his theories, even without having seen the origi- 

 nal locality. 



We must take together all the fossils found here, and may mention only 

 that Ostrea ingens occurs everywhere in this horizon (also in the sand be- 

 tween the two oyster beds), and that Sigapatella has been found only in- 

 side of oyster shells of the upper oyster bed. The latter consists of a 

 form of Ostrea ingens, that resembles much the Cape Fairweather variety : 



*Glydmeris ibaria. Venus chiloensis. * Sigapatella amcricana. 



L & S * Ostrea ingens. S Meretrix iheringi. 



S *Lucina promaucana. * Crepidula gregaria. 



Although very small, this list contains 5 species that are found at the 

 type-locality at Santa Cruz (marked *). For the rest, so-called "Supra- 

 patagonian" species prevail. Ostrea ingens is a Patagonian (Leonense) 

 and Suprapatagonian species, and it is to be remarked, that the form 

 hatcheri, which is said to be characteristic of the Leonense beds, has also 

 been found here. 



In conclusion, I add here a list of those species which have been ascer- 

 tained to be present both near the base and near the top of the Patagonian 

 series (as understood by us). 



(base : San Julian. 



I. Ciaans antarctica. . - ~. _,. 



(top : 30 miles north of Rio Chalia. 



