274 
THE GEOLOGttST. 
"raassivea," or incompletely-separated basins; tlie 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 what is generally 
known as Middle Devonian. 
Admitting the exactitude of the fundamental points of Dumont's classi- 
fication, M. Dewalque considers the observations of palaeontologists 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 Gembloux, having collected a series of fossils from 
the fossiliferous beds of Grand Manil, regarded by Dumont as belonging 
to the " terrain E.henan," but afterwards assigned to the Silurian system 
by M. Gonelet, who stated the occurrence there of Trinucleiis allied to or- 
natus, a, Calymene near to incerta, Leptcena 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- 
chisonii 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 S^'Steme 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 E-lienan formation. 
EEVIEWS. 
Further Discoveries of Flint Implements in the Drift. By John Evans, 
F.S.A. (Extract from ' Archaeologia,' 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 
