A. E. Ortmann — Climatic zones in Jurassic times. 257 



Akt. XXX. — An examination of the arguments given by 

 Neumayr for the existence of climatic zones in Jurassic 

 times ; by Arnold E. Ortmann. 



In a recent publication (Principles of marine Zoogeography)* 

 the present writer incidentally indicated the reasons why Neu- 

 mayr's theory of climatic zones in the Jurassic period cannot 

 be accepted as correct. It may be allowed to enter into details 

 in the present article, since my views differ so widely from 

 these of Neumayr, and especially since many prominent geolo- 

 gists have adopted his views more or less completely. 



It is very important to examine closely the arguments of 

 Neumayr himself and his defense against the objections made 

 by other scientists. Although the arguments are collected in a 

 special paper (1883), the detailed palseontological investiga- 

 tions and the conclusions derived from particular cases are 

 scattered through a large number of publications, and there- 

 fore it would be perhaps desirable to give here a list of the 

 papers referred to. 



1871. Jurastudien, 5. Der penninische Klippenzug. — Jahrb. 

 K. K. Geol. Reichsanstalt, vol. xxi, p. 503-526. 



1876. Die Ornatenthone von Tschulkowo und die Stellung des 

 russischen Jura. — Benecke's geogn. palseont. Beitrsege II. 



1877. Bemerkungen tiber den russischen Jura. — Neues Jahrb. 

 Min. Geol. Pal. 1877. 



1883. Ueber Klimatische Zonen wsehrend der Jura — und Kreide- 



periode. — Denkschr. K. K. Akad. Wiss. Wien., vol. xlvii. 

 1885. Die geographische Verbreitung der Juraformation. — ibid., 



vol. 1. 

 1887. Ueber die Beziehungen zwirchen der russichen und west- 



europaischen Juraformation. — Neues Jahrb. etc. 1887, 1. f 

 1890. Kritiscbe Bemerkungen ueber die Verbreitung des Jura. — 



ibid. 1890, 1. 

 1890. Erdgeschichte, vol. II. 



The supposition, that in the Jurassic time climatic zones 

 were developed on the earth, was first made by Marcou, but it 

 attracted no attention until Neumayr attempted to prove this 

 theory by palseontological and geological evidence. The dem- 

 onstration given by him proceeds in the following manner. 



He investigated the different faunas, especially of the mid- 

 dle and upper Jura in the different localities of Europe, and 



*Grundzuge der marinen Tiergeographie, Jena, 1896, p. 62, 63. 

 f This is a reply to a paper under the same heading published by Nikitin in 

 1886 in the same periodical. 



