Notes and Comments. 243 



to the Leeds Art Gallery Committee, against the closing of 

 their gallery, and the Council is glad to say that the Leeds 

 Committee decided to re-open their institution. A memorial 

 has also been addressed to the Prime Minister, on behalf of 

 the Association, with regard to the appropriation of part of 

 the Victoria and Albert Museum to provide offices for the 

 Board of Education. 



CORRELATION OF JURASSIC CHRONOLOGY. 



At a recent meeting of the Geological Society of London, 

 Mr. S. S. Buckman read a paper with the above title. He 

 stated : — One of the principles utilized in this paper to ascertain 

 or to surmise faunal sequence where precise information is 

 defective, is that of what may be called ' faunal dissimilarity ' — 

 that is, if the deposits of two neighbouring localities A and B, 

 supposedly isochronous from their sequential position, show 

 differing faunas, it is a reasonable inference that the faunas 

 are not of the same date. Theoretical stratigraphical correla- 

 tion has usually worked along these lines, but the principle 

 involved has not been recognized by name. Now the principle 

 is utilized, not only in regard to neighbouring localities, but 

 even more widely, with suggestive results. The paper is 

 chiefly concerned with the Liassic Ages hitherto known as 

 Domerian, Charmouthian, Sinemurian. In all of them there 

 is proposed a considerable increase of the number of faunal 

 horizons indicative of consecutive time-intervals, or hemerae. 

 In the case of the first no change of name is made ; but in 

 regard to the other two, subdivision seemed necessary, and 

 each is apportioned into three Ages, as follows : — 



Proposed Names. Old Terms. 



Hwiccian. ) 



Wessexian. Charmouthian. 



Raasayan. ) 



Deiran. ) 



Mercian. Sinemurian. 



Lymian. J 



THE ARMATUM ZONE. 



These, with the Domerian, each contain on an average 

 about ten hemerae, the grouping being controlled by the dom- 

 inance of ammonite families or phases thereof — thus, Domerian : 

 Age of Amaltheids ; Raasayan : Age of Deroceratidae and 

 Echioceratidae. It is obvious that, with this increase in the 

 number of local non-sequences is greatly increased. Some 

 comparative diagrams illustrate this. One of the most inter- 

 esting discoveries which has resulted, partly from the great 

 thickness of Scottish strata investigated and collected from, 

 partly from comparisons with other areas, is that the so-called 

 ' armatum Zone ' of the English Midlands and that of the 

 Radstock district, of Yorkshire and of the Scottish Isles, are 



1917 Aug.l. 



