274 



THE GEOLOGIST. 



"massivea," or incompletely-separated basins; the southern termed the 

 basin of Condroz, the northern the basin of Namur. The former is 

 remarkable for the thickness of its strata and the undulations which bring 

 the same beds so often to the surface ; the latter, of which the different 

 series are much thinner, presents only one flexure of each, constituting the 

 axis of the coal-field. It offers then a symmetrical series in a disjointed 

 basin, of which faults sometimes obscure a portion on one side and some- 

 times on the other. The beds now investigated by M. Dewalque corre- 

 spond to those which M. Dumont described in 1830 under the names 

 of " systemes quartzo-schisteux inferieur et calcareux inferieur ; " and 

 which were subsequently united in the ' Carte geologique de la Belgique ' 

 under the title of " Systeme eifelien," corresponding to w^hat is generally 

 known as Middle Devonian. 



Admitting the exactitude of the fundamental points of Dumont's classi- 

 fication, M. Dewalque considers the observations of palseontologists must 

 cause some modifications of details, and that it is necessary to lower the 

 boundary between the Eifelian and Condrusian formations, tne division of 

 which, Dumont, having only mineralogical character as a guide, has gene- 

 rally set too high. 



Dr. C. Malaise, of Gerabloux, having collected a series of fossils from 

 the fossilifcrous beds of Grand Manil, regarded by Dumont as belonging 

 to tlie " terrain Ehenan," but afterwards assigned to the Silurian system 

 by M. Gonelet, who stated the occurrence there of Trinucleus allied to or- 

 natus, a Calymene near to incerta, Leptceyia depressa, and five species of 

 Orthis. The fossils found by Dr. Malaise have been determined by Pro- 

 fessor De Koninck, and are all of Lower Devonian species, Orthis Mur- 

 ehisonii and O. orhicularis being the predominant forms. The clay-slates 

 and fossiliferous quartzites of Grand-Manil and those of Houffalige and 

 Ardenne, Dr. Malaise believes to belong to the Systeme Coblentzien of 

 the "terrain Hhenan," these fossil fauna being purely of Lower Devonian. 



It is well known that the coal-field of Mons is prolonged subterrane- 

 ously into France, covered by more recent geological formation, towards 

 Valenciennes, Douai, and Bethune. Of late years researches have been 

 made in the opposite direction, to the north of the basin, in the hope of 

 finding coal. It is not clear on what grounds the probability of the exist- 

 ence of a coal-basin to the north of Lille has been founded ; but although 

 five years since, when the subject was brought before the Geological So- 

 ciety of France, this opinion was contested by Dormoy, Delanoue, and 

 Gosselet, a boring was undertaken at Menin, about four leagues from 

 Lille ; and this has now been stopped, after having penetrated without 

 success 306 metres of rock, of which the last 20 consisted of blackish-blue 

 schists. 



It is thus clear that further search to the north of the Menin is hope- 

 less. The borings would come upon the Coblentzian rocks towards Thielt, 

 or they would probably meet with the underlying or Gedinnian beds of 

 the llhcnan formation. 



EEVIEWS. 



Further Discoveries of Flint Implements in the Drift. By John Evans, 

 F.S.A. (Extract from * Archaologia,' 1862.) 

 The prominent part which Mr. Evans took in a brave and consistent 

 manner at the beginning of the discussion on the important topic of the 



