Marshall. — Relations between Cretaceous and Tertiary Rocks. Ill 



The first really detailed description of these beds and of those at 

 Coquimbo, near Valparaiso, was written by Steinmann and Moricke,* who 

 classed the former as Miocene and the latter as youngest Miocene or 

 Pliocene. 



The Tertiary beds of New Zealand are quoted as a parallel because of 

 the occurrence of Natica solida Sow. and of Limopsis insolita Sow. in both 

 countries, and of the closely related forms in New Zealand to Scalaria rugulosa 

 Sow. and Crepidula gregaria Sow. which occur in the South American beds. 



The comparison by Wilckens of the Quiriquina beds of South America 

 with the New Zealand strata is, however, of greater importance. These 

 Quiriquina beds were first fully described by Steinmann and Moricke, but 

 later, with the aid of more abundant material, by Wilckens. The collections 

 were obtained from two neighbouring localities on the mainland, as well as 

 the Island of Quiriquina itself. The fauna from the three localities is practi- 

 cally identical, and is also of very similar age to that of Algarrobo, 210 miles 

 farther north, near Valparaiso. Wilckens compares the gastropods of these 

 beds with those of other Cretaceous strata in the Pacific region. Pugnelhis 

 uncatus, however, is not found at Quiriquina, which has the species Pug- 

 nellits tumidus Gabb. Eriptycha chilensis d'Orb. comes near to Cinulia 

 ohliqua Gabb, and Pyropsis hombnana d'Orb. is related to Pyropsis species 

 from the Foxhill beds of Chico. PugneUus is here stated to be verv 

 characteristic of the Senonian of the Pacific coast. It ranges from the 

 Turonian to the Senonian. Emphasis is laid on the absence of knowledge 

 of the Waipara fauna of New Zealand. 



Wilckens continues with the statement that it is obvious that a sea 

 united all those regions with a similar Upper Cretaceous fauna on the margin 

 of the Pacific. This sea overflowed its coasts in later Senonian time, and 

 laid down such deposits as those at Quiriquina. Finally he states that 

 '' The descendants of the Quiriquina fauna are found in the Patagonian 

 Tertiary. An important problem lies in their relationship to the Eocene 

 fauna of central Europe, as shown by the many similar species that occur 

 in both." 



The Indian Cretaceous contains in the Ariyalur group a formation gene- 

 rally similar in its fauna to the Quiriquina. The gastropod genera PugneUus, 

 Gyrodes, Pyropsis, and Eriptycha are again represented. Kossmat classes 

 with these Indian strata the Cretaceous beds in Natal, Madagascar, Assam, 

 Borneo, Yesso, Vancouver, and Quiriquina. 



(3.) Patagonia. 



A highly important formation in respect of the relationship of the Upper 

 Cretaceous of the Pacific region to the Tertiary is found in Patagonia. For 

 much of our knowledge of this we are again indebted to Wilckens. f He at 

 once states that this horizon is distinctly higher than that of the Cretaceous 

 of Columbia, Peru, and the Chilian and Argentine Cordillera. Though on 

 the east side of the Cordillera, and resting on a great thickness of Older 

 Cretaceous sediments, instead of crystalline rocks as at Quiriquina, it is 

 still the case that the nearest afiinities of the fauna are with the Quiriquina, 

 though there is also a distinct resemblance to the Patagonian Miocene. In 



* G. Steinmann and W. Moricke, "Die Tertiarbildungen des nordlichen Chili und 

 ihre Fauna," Neues Jahrb. fiir Min., &c., Beil.-Band x, 1896, pp. 533-612. 



to. Wilckens, "Die Lamellibranchiaten, Gastropoden, &c., der oberen Kreide 

 Siidpatagoniens," Ber. der. nat. Ges., Freiburg, Bd. xv, 1907. 



