﻿]48 CARBONIFEROUS AND PERMIAN EOR AMIN IEER A . 



authors, adopted their specific term, added a description of an allied symmetrical variety, 

 and formed of the two a new genus Orobias, the representatives being named 0. antiquior 

 and 0. aqualis respectively. The separation from the genus Nummulina was grounded 

 on the non-tubulation of the shell and the absence of any indication of a canal-system. 

 Through the courtesy of General G. von Helmersen of St. Petersburg, I have had the 

 opportunity of studying these and other allied forms existing in large numbers in the 

 Russian white Carboniferous limestones, and can confirm in great measure d'Eichwald's 

 observations, though I hope at a future time to be able to show that, not only the 

 unsymmetrical specimens described by MM. Rouillier and Vosinsky, but also M. 

 D'Eichwald's symmetrical discoidal form, so like a Nummulite in external appearance, 

 are in reality true Fusulina. 



Turning to the Secondary epoch Buvignier 1 has described and figured an Upper 

 Jurassic Nummulite (N. Humbertina) from the Astarte-marl of the north-east of France, 

 and, though more detailed illustration would have been acceptable, there seems little 

 reason to doubt the correctness of the diagnosis. More recently Dr. Giimbel 2 has 

 entered the field with a well-marked member of the genus (N. jurassica) from the 

 Ammonites tenuilobatus and A. dentatus zones of the Upper Jurassic formation of 

 Franconia, instancing at the same time a fossil with similar characters from the Jurassic 

 Beds of Mosskirch in Baden. Passing to the Cretaceous system — as early as 1847, 

 Prof. Zeuschner 3 mentions the occurrence of Nummulites in large numbers in a dolomite 

 of Neocomian age in the Carpathian Mountains, but without entering into any particulars. 

 In 1867 Fraas 4 obtained from the Cretaceous formation of Palestine a number of 

 Nummulina-Yikid fossils, which he assigned to the genus under three specific names. One 

 of these at the least, N. Arbiensis, Conrad, appears to be a true Nummulite, though 

 about the other two there may be considerable doubt. The few cases which have been 

 quoted form, perhaps, the entire record of the occurrence of specimens of the genus 

 Nummulina previous to its enormous development in the early part of the Tertiary 

 epoch, and, as will be seen, they are so few in number that, whilst they scarcely affect 

 the general truth of previously accepted views as to its distribution, they impart 

 a new aspect to its life-history. The structural relationship which exists between 

 Nummulina and Fusulina, that is to say, between the great rock-building genera of the 

 Tertiary and the Palaeozoic epochs is one of extreme interest. Hitherto Fusulina has 

 been regarded morphologically as little more than a Nummulite drawn out at its 

 umbilici, and so assuming the long, fusiform, tapering contour presented by the familiar 

 type F. cylindrica ; but if it can be shown that oblate and even discoidal specimens, such 

 as those already alluded to as contained in the limestone of Miatschkovo near Moscow, 

 are true Fusulina what becomes of the zoological distinction between the two types ? 



1 ' Stat. Geologie d. Dep. de la Meuse,' 1852, p. 338 ; ' Atlas,' p. 47, pi. xxx, figs. 32—35. 



2 ' Neues Jahrb. fur Min., Jahrg. 1872, p. 241, pis. vii and viii. 



3 ' Verbandl. Russ-Kaiserl. min. Gesellscbaft, St. Petersburg,' Jabrg. 1847, p. 105. 



* ' Geol. Beobacbt. am Nil, auf der Sinai-Halbinsel u. in Syrien,' 18G7, s. 82—84, Taf. 1, fig. 8. 



