STRATIGRAPHICAL GEOLOGY. 451 



of the Carboniferous system into two main groups, in the way 

 that had been proposed by D'Omalius d'Halloy, was almost uni- 

 versally accepted, and on the suggestion of Dechen the upper 

 group was very often called the Productive Coal-formation. 



With the fauna and palaeontological sub-division of the 

 Carboniferous limestone De Koninck occupied himself for 

 more than fifty years. His monographs of the fossil fauna 

 of the Belgian Carboniferous limestone (1842-44), together 

 with MacCoy's work (1844) on the fossils of the Irish Car- 

 boniferous limestone, and the somewhat older monograph by 

 J. Phillips (1836) on the Yorkshire Carboniferous limestone, are 

 still the basis of all European research on the faunas of the 

 Carboniferous limestone. De Koninck began a revision of 

 the Belgian fauna (1878-88), but unfortunately this handsomely 

 illustrated work was not completed. In his first monograph 

 De Koninck drew attention to the difference of the faunas at 

 Tournay and Vise, and thought it might be explained on the 

 assumption that they had belonged to two separate basins of 

 deposition. Afterwards he ascribed the limestone of Vise to a 

 slightly earlier period than that of Tournay, whereas Dumont 

 had in 1830 supposed the strata of Tournay to be the older 

 group. 



Gosselet in 1860 distinguished three divisions of the lime- 

 stone : a Lower group, with Spirifer Tornacensis as the leading 

 fossil type; a Middle group, with Spirifer cuspidatus and 

 Goniatites sphceroidalis as the typical fossils ; and an Upper 

 group, with Productus giganteus and undatus as the typical 

 fossils. The palaeontological researches of Dupont (1865-71) 

 have confirmed Dumont's view regarding the relative age of the 

 Carboniferous limestone at Vise and at Tournay, showing that 

 the Tournay limestone is the older. 



In England, Phillips had sub-divided the Carboniferous lime- 

 stone of Yorkshire into three groups : (a) a Lower series of 

 Limestone Shales or Sandstones; (b) a Middle series, represented 

 by the Mountain Limestone, 2000 feet thick, and containing a 

 rich marine fauna; and (c) an Upper series, called the Yoredale 

 Beds of limestones, shales and sandstones, and occasional local 

 coal-seams. In the Harz, in Thuringia, in the Fichtel moun- 

 tains, the Sudeten mountains, and in the Rhine provinces, the 

 Carboniferous limestone division is almost wholly represented 

 by the mixed Culm facies of shales, greywackes, flagstones, and 

 thin beds of limestone. 



