true Carboniferous Nummulite. 223 



quior^ Rouillier, from the Carboniferous limestone of Miatscli- 

 kovo ( Orohias aniiquior^ d'Eichwalcl), would fonn a remarkable 

 exception if its complete agreement with NummuUtes should 

 be confirmed. I have not liitherto disceraed any important 

 distinction. The often-quoted living forms belong in part to 

 Amphi'steginaj in part to Operculina.^^ 



Professor Seguenza, in a table of the geological range of 

 the various genera of fossil Foramininifera* published almost 

 simultaneously with tlie two works already quoted, gives with 

 even greater decision the Eocene as the age of the ap])ear- 

 ance, the Miocene as that of the extinction of the true Num- 

 mulite. 



It would be easy to add quotations of exactly similar im- 

 port from the works of other palreontologists ; but it is scarcely 

 worth while to cite individual authorities for what, by its ge- 

 neral acceptance, had come to be looked upon almost in the 

 light of a geological dogma. 



GiimheVs Researches. — Doubts as to the entire accuracy of 

 this view have been raised from time to time, but they have 

 not, until quite recently, been based on evidence sufficiently 

 circumstantial to obtain much credence. Two years ago, 

 however, Dr. C. W. Giimbel of Municli, in the preface to his 

 memoir on certain " Jurassic precursors of the genera Num- 

 muUtes and Orhituh'tes^^'[, reviewed the whole question of tlie 

 existence of prsetertiary Nummulites as it then appeared to 

 stand. In his analysis the various published notices of Num- 

 mulites supposed to be of earlier geological age tlian the be- 

 ginning of the Tertiary epoch are recounted, the cu'cum- 

 stances on which they are founded criticised, and in some 

 instances tlie results of a reexamination of the original speci- 

 mens detailed. I ])ropose to summarize the conclusions arrived 

 at by Dr. Giimbel on this head, rather than venture upon an 

 independent commentary, for which I should have but insuffi- 

 cient data. 



Turning first to the Russian Carboniferous specimens al- 

 ready alluded to. Dr. Giimbel accepts Prof. Reuss's estimate 

 of Rouillier's Nummulina antiquior\ — that is, that it may be 

 a Nummulite, but that there is no sufficient evidence to jirove 

 the fact. 



D'Eichwald's adoption of Rouillier's species, and his de- 



• Forani. Monotal. di Messina, parte seconda (18G2), p. 25. 



t " Ueber zwei jurassische VorlJiufer des Foraminif'cien-Geschlechtes 

 Nummulina und Orbitulites," von Ilerrn Obeibergratli ])r. C. W. Giimbel. 

 Neues .Jahrbuch fiir xMin., Jahrjr. 1872, p. 241, pis. 7 & 8. 



X Rouillior and ^'osin^kv, '" Etudes progressive sur la Gt'ologie de Mos- 

 cou," Quatrieme Etude, bulletin Soc. Imp. des Naturalistes de Mcscoii, 

 1849, vol. xxii. p. 337. 



16* 



