216 



STRATIGRAPHICAL GEOLOGY 



has yielded Homalonotus Rmmeri, Spirifer Mercurii, Pterin<xa ovalis, 

 and Tentaculites ; elsewhere remains of Pteraspis have been found. 

 This group of beds, of which the slates of St. Hubert are the 

 highest member, are known as the Gedinnian. 



The higher stage of the Lower Devonian is called the Coblentzian ; 

 this has 1500 feet of white sandstone (Gres d'Anor) at its base, 

 followed by the greywacke of Montigny, the black sandstone of 

 Vireux, the red slates of Vireux, and the Burnot conglomerate, the 



IKiren 



Cambrian. Silurian. 



Carb. Coal- 



limestone, measures. 



Fig. 70. MAP OF THE ARDENNES (drawn and lent by Professor J. Gossclet). 

 Scale about 35 miles to an inch. 



whole being from 5000 to 6000 feet thick. The Anor sandstone 

 has a special fauna, including Spirifer primcevus, Renssellceria crassi- 

 costa, R. strigiceps, Avicula lamellosa, and Kochia capulifortnis, and 

 appears to represent a series of beds which are more fully developed 

 near Coblentz, and are known as the Taunus quartzite. The grits 

 and mudstones above this white sandstone are characterised by 

 Spirifer paradoxus, S. primcevus, Rhynch. daleidensis, and Athyris 

 undata, while the higher beds contain Spirifer paradoxus, Chonetes 

 sarcinulata, Sp. hystericus, and Leptcena Murchisoni. 



The whole series becomes thinner toward the north, and along 

 the northern side of the basin it is represented only by the 

 variegated slates of St. Hubert and the Coblentzian Beds in a 



