478 Ortmann — Some new marine Tertiary horizons. 



Art. XLTX. — Preliminary Report on some new marine Ter- 

 tiary horizons discovered by Mr. -/. B. Hatcher near Punta 



Arenas, Magellanes, Chile ; by Arnold E. Ortmann, Ph.D. 



Having arrived in Punta Arenas in December, 1897, Mr. 

 J. B. Hatcher directed his attention first to the study of the 

 Tertiary deposits found near the Coal Mines of Punta Arenas. 

 He collected a lot of specimens from these beds, and about the 

 middle of February, 1898, his first shipment of fossils reached 

 Princeton, together with a letter giving stratigraphical notes 

 and a rough sketch of a section of the locality under discus- 

 sion. The writer has examined the marine fossils of this col- 

 lection, and thinks it important to give a preliminary report on 

 these beds, since this collection shows that there are represented 

 two new horizons different from and older than the Tertiary 

 beds known in Patagonia (Patagonian and Suprapatagonian 

 beds), which contain a marine fauna that is to be regarded as 

 completely new to science. 



Although Philippi* has described a couple of species from 

 Punta Arenas and the surrounding country, nothing was known 

 hitherto as to the stratigraphical relations of these fossils. 

 Now, Mr. Hatcher's collection contains a number of Philippi's 

 species, and his notes show conclusively that they are not 

 found in one and the same bed, but belong to three different 

 horizons, one of which is apparently identical with Patagonian 

 deposits, while the two others are different and older. 



While I do not propose to give a complete geology of these 

 parts — leaving this task to Mr. Hatcher — I may describe the 

 general succession of the beds under discussion, in order to 

 show their relations to each other. 



The locality is situated on the bluffs of the northern banks 

 of the Rio de las Minas, which cuts through the strata in a 

 west-easterly direction. The dip of the beds seems to be to 

 the west — quite different from that observed by Mr. Hatcher 

 farther north. f 



Mr. Hatcher distinguishes in his notes five principal horizons. 

 The first (the lowermost) contains only plant-remains (leaves, 

 etc.), the second and third contain marine shells, the fourth 

 represents the Punta Arenas coal, and the fifth (the uppermost) 

 contains again marine fossils. He did not send any measure- 

 ments of the thickness of the respective beds : only the verti- 

 cal distance of the outcrop of the fifth bed on top of the hills 

 from Punta Arenas is given approximately as 700 feet. Thus 



* Die tertiaeren und quartaeren Versteinerungen Chiles, 1887. 

 fThis Jourual, vol. iv, November, 1897, pp. 334 and 338. 



