3.28 M. F. J. Pictet on the present state of the question as to 



But the admission of such a fact, opposed to the systematic 

 teaching of the schools, cannot be accepted until it has been freed 

 from all chances of error. It is particularly necessary to ascertain 

 if thosewhich have been referred to the Stramberg limestone really 

 belong to it, and whether they have really lived together at the 

 same time and constituted a single fauna, as is required by the 

 conclusion which we have just indicated. 



Now it must be admitted that the most recent investigations 

 have rendered this contemporaneity to a certain extent doubtful. 

 It appeared very probable a few months ago ; but now it is no 

 longer certain ; and we must explain, before going further, the 

 arguments which may be adduced to modify the ideas previously 

 put forward. But, as will be seen hereafter, the conclusions 

 with which we can replace them present themselves under a 

 curious and unexpected light, and raise questions of quite equal 

 gravity. 



The first doubts were set on foot by the study of the Swiss 

 beds associated with the Stramberg limestone — that is to say, the 

 Corallian stage of Wimmis and that of Mont Saleve. These 

 deposits, notwithstanding evident relations with the Tithonian 

 stage, are nevertheless deficient in several characters which would 

 render this analogy incontestable. Thus neither at Wimmis nor 

 at the Saleve has Terebratula janitor been found, any more than 

 any of the Cephalopoda of Stramberg. If we might suppose 

 that the German geologists have combined into one two distinct 

 beds, of which the more recent is characterized by this Tere- 

 bratula and the Cephalopoda, and the deeper one by another set 

 of fossils, would it not be possible that we should find with us 

 only the inferior fauna, designated by some geologists the fauna 

 of Terebratula moravica, and which would constitute the last 

 term of the Jurassic, period, whilst the true Stramberg would 

 form the base of the Cretaceous formations. M. Hebert gives 

 us the good news that he has commenced a comparative investi- 

 gation of all these faunas. 



These doubts are in great part confirmed by a recent note by 

 M. Coquand, " On the Stages of Provence V*. The analysis of 

 this important document would lead us too far. Its principal 

 result is, that in this region the fauna of Terebratula moravica, 

 entirely destitute of Cephalopoda and probably identical with that 

 of the Coralline limestones of the Saleve and Wimmis, is covered by 

 beds containing Kimmeridgian and Portlandian Ammonites, and 

 consequently is evidently Jurassic. These facts, at least as far 

 as we can judge of them from a first sketch, seem to indicate 

 that there are two different orders of succession according to the 



* Bull, de la Soc. Geol. 1869, vol. xxvi. p. 100. See also in the same 

 Number a note by M. Hebert, p. 131. 



