ANNIVEESAKY ADDEESS OF THE PRESIDENT. liil 



some years ago, it was supposed to be an insect ; but more careful 

 investigations recently made, particularly by M. Brongniart, whom 

 he consulted, have proved it to be of vegetable origin. M. Brong- 

 niart concluded that it was a portion of an Equisetum, very analogous 

 to E. infundihuli forme, of the Carboniferous period, but possibly a 

 new species. From these considerations Prof. Sismoncla concludes 

 that the gneiss in question is a metamorphic rock of the Carboni- 

 ferous period, and suggests the propriety of further search for fossil 

 remains in these crystalline rocks of the Alps. 



M. Barrande has published, during the past year, a second volume of 

 his important work on the Silurian System of the centre of Bohemia. 

 It is the first series of the Cephalopoda, and consists of 107 plates with 

 corresponding explanations. In a short preliminary noticeM. Barrande 

 states that the Silurian Cephalopoda of Bohemia will occupy 350 

 plates ; this large quantity of matter renders it necessary to publish 

 them in separate large numbers or livraisons. The present number 

 forms the first series of the plates devoted to this class. It contains 

 about 200 species, repiesenting the ten following genera: — Goniatites, 

 Noihoceras, Trochoceras, Nautilus, Gyroceras, Hcrcoceras, Lituites, 

 Fhragmoceras, Gomijlioceras, and Ascoccras. The two other genera, 

 Orthoceras and Cyrtoceras, which complete the family of the Silurian 

 NautiKdai of Bohemia, are much richer in species, and will fully 

 occupy the plates of the second and third series, with the exception 

 of such as will represent the features of the general study of the 

 Nautilidae. The text belonging to these ten genera will be shortly 

 published ; the author has therefore confined his observations on 

 them, for the present, to a tabular statement pointing out their ver- 

 tical distribution in the different formations and their principal sub- 

 divisions. 



One of the most remarkable results of an examination of this ta- 

 bular statement is the great preponderance of forms which are 

 characteristic of the formation, or Stage, E. Of 202 species here 

 figured, 155 belong to this formation, and only 47 to Gr, 8 to F, 

 and 2 to D, and at the other end of the series only 2 to H. Looking 

 at individual genera, out of 70 species of Gomplioceras, 61 belong 

 to the formation E. The only remarkable exception to this rule is 

 the genus Goniatites; out of 17 species, 15 belong to the formation Gr, 

 which, with the formations E, E, and H, belong to the Upper Silurian 

 System, and constitute M. Barrande's ^' faune troisieme." Besides 

 this wonderful development of Cephalopoda in this Upper Silurian 

 System of Bohemia, their rapid diminution is no less surprising. 

 Only two species remain in etage H, a Goniatite and a Gyroceras, and 

 these are only found in the lowest subdivision of the etage. 



M. Barrande has also published during the past year a third 

 part of his work entitled ' Defense des Colonies,' comprising a 

 general consideration of the Stages G and H, with special refer- 

 ence to the neighbourhood of Hlubogep, near Prague. The ne- 

 cessity for this publication is stated to be the erroneous views en- 

 tertained by MM. Lipoid and Krejci respecting the stratigraphical 

 conditions of the neighbourhood of Hlubocep and Litten. I shall not 



