GOSSELET DEVONIAN ROCKS. 23 



mannstatter's figures when etched. Their chemical constitution is 

 9_LH iron, °*L nickel, ^ arsenic, °-2i graphite. 



100 ' 100 100 100 b r 



M. Neumann's investigations, and those of Prof. Reuss, prove the 

 Chotzen iron to be a natural production, and not artificial ; nor can 

 it be the result of a reductive natural process undergone by any fer- 

 riferous mineral substance. M. Neumann considers it to be meteoric 

 iron which had fallen to the surface during the cretaceous period, 

 and similar in every way to the iron which has frequently fallen in 

 modern times. The native iron discovered (October 1852) by M. 

 Borneman in the argillaceous Keuper coal of Muhlhausen (Thu- 

 ringia) differs essentially from the Chotzen native iron, having been 

 found associated with black magnetic oxide of iron. [Count M.] 



On the Devonian Rocks, near Avesnes. 

 By M. J. Gosselet. 



[Bulletin de la Societe Geologique de France, torn. 14. pp. 364-373.] 



The limestones of Oetrceungt, near Avesnes, have hitherto been re- 

 garded as Carboniferous, and are so coloured in the great Geological 

 Map of France. M. Gosselet, at the request of M. Hebert, has 

 investigated them, and confirms the suspicions of the latter as to 

 their Devonian character. By careful sections, and tables of fossils, 

 he has enlarged our acquaintance with the middle rocks of this 

 series, and, by connecting his researches with the labours of M. 

 Dumont, has thrown some additional light on the still vexed question 

 of correlation among the Devonians. 



There are quarries of undoubted Carboniferous limestone at 

 Oetrceungt with Productus sublcevis ; but their relations with the lower 

 strata are nowhere displayed in visible contact. 



The section of the great lower limestone at the Pare Quarries, 

 shows fourteen well-characterized beds with occasional Clymenice, and 

 constantly-recurring Terebratula concentrica and Spirifer aperturatus. 

 These beds may be grouped into four divisions : — 



1 . The first from above, characterized by Pentamerus aculolobatus. 



2. The next, by large Spirifer aperturatus. 



3. Grey limestones, with Terebratula pugnus. 



4. Slates of Notre-Dame-des-Monts. 



M. Gosselet then examines other quarries on the line of strike, and 

 shows the persistence of the subdivisions eastward as far as Givet, 

 and establishes distinct fossil horizons in the great Eifelian limestones 

 round that picturesque town. The line of String 'ocephalus Burtini 

 (elswhere typical) passes at the base of the frowning cliffsof Charlemont. 

 He then carefully alludes to sections down the Meuse towards the 

 mountain-limestone of Dinant, and upwards towards the Ardennes 

 slates of Meziers. We left M. Gosselet near the latter, verifying 

 the singularly accurate work of Dumont in his local divisions. The 

 Ahrian, which succeeds the Eifelian, appears to be a gritty repre- 

 sentative of our Plymouth limestones. The Coblentzian series is a 

 more solid form of the Looe slates, with occasional plants ; whilst 



