338 ORTMANN — DISTRIBUTION OF DECAPODS [April 3, 



existence of such a line would in a large degree facilitate the 

 imagination of such a connection, and would force us — if we have 

 other evidence pointing to a former connection of these parts — to 

 construct this old land-bridge nowhere else but along the direction 

 of this line. That is to say, the connection of Australia and New 

 Zealand with South America, which is probable on account of cer- 

 tain facts in the distribution of life, was across the Pole, and not 

 in lower latitudes in the southern part of the Pacific Ocean, as 

 accepted by some authors. 



The tectonic connection of Graham Land with Terra del Fuego, 

 indicated by Gregory, is much emphasized by Fricker. 1 Accord- 

 ing to him, it is formed by the arc of islands running from Terra 

 del Fuego over South Georgia and the South Sandwich Islands to 

 Graham Land. This line, however, again indicates only the 

 general direction of this possible connection, but does not give any 

 hints as to its actual existence, nor to the poss'ble time of it. 



We know that a large part of South America (the Brazilian 

 Plateau, see below) is a very old continental mass, which ex- 

 tended southward into northern Argentina, but not into Patagonia. 

 What is now the chain of the Cordilleras was certainly ocean dur- 

 ing Mesozoic times, since here we find Jurassic and Cretaceous 

 deposits largely developed, and the latter have been traced far to 

 the south and over almost all of Patagonia; the Tertiary beds of 

 southern Patagonia rest, wherever this has been observed, upon 

 Cretaceous deposits. 2 The Patagonian Cretaceous, in its upper divi- 

 sions, consists of rocks formed apparently under continental condi- 

 tions (littoral, freshwater, or eolian), and these latter (Guaranitic 

 beds) were subject, after their deposition, to erosion, indicating a 

 land period at the close and after the Cretaceous. Thus, there 

 seems to have been an upheaval, beginning at the end of Mesozoic 

 time and continuing into the Tertiary ; during the Eocene these 

 regions probably were land to a large extent. 3 



West of the Mesozoic beds known in the tract of the Cordilleras 

 there are, in the so-called Coast Cordilleras of Chili, rocks of 

 another character ; they are apparently metamorphic, but their age 

 is disputed. According to Steinmann, 4 they are Mesozoic ; snd 



1 The Antarctic Regions, London, 1900, p. 140 if. 



3 See Hatcher, J. B., in Amer. Jour. Sei., Vol. ix, 1900, p. 95 ff., and 

 Ortmann, Rep. Princeton Exped. Patagonia, Vol. iv, Part 2, 1902, p. 285. 

 8 See Ortmann, /. c, p. 317. 

 * Neues Jahrb. f. Mineral., etc., Beil., Bd. 10, 1895, P- 6- 



