12 
POPULAR SCIENCE REVIEW. 
govia some years ago, soon after some excavations had been 
made, on the occasion of the visit of Napoleon III., when many 
Bornan and Celtic relics were discovered. The best plan to 
attack Gergovia from Clermont is to drive by Beaumont and 
Aubieres to the base of the hill. The superficial drifts of Beau- 
mont have furnished the bones and teeth of mammoth and 
Spermophilus, a kind of marmot. The best sections of fresh- 
water beds are on the northern and north-eastern flanks of Ger- 
govia; and we recommend the searcher for fossils to walk up the 
stream from Bomagnat by Clemensat, and then strike across for 
Gergovia. At the base of the series there occur the fossil snail 
shells {Helix) that are so abundant at the base of the Puy 
Dallet; and here M. Lecoq obtained freshwater mussels ( Unios ) 
while above rest the indusial limestones full of the cases of the 
larvae of caddis flies, surrounded by minute freshwater shells. The 
■eastern face of the camp is perhaps the best for seeing the posi- 
tion of two outflows of basalt and the deposition of lacustrine 
silts and fossil remains between the basaltic outflows. To the 
southward is a dyke through the freshwater beds, and this seems 
to be the site of a chimney by which volcanic materials were in- 
jected into and over the lacustrine silts. 
On reaching the summit of Gergovia we arrive on a plateau 
about a mile and a half in length from west to east, by perhaps 
half a mile in width. It exhibits now no trace of the old Gaul- 
ish city, although the plough frequently turns up coins, and 
pieces of coarse pottery are often met with. The south face of 
the hill is evidently scarped, and the remains of a rude stone 
rampart of basaltic blocks may be traced. It would seem that 
the north face was sufficiently protected by the abrupt and pre- 
cipitous character of its basaltic rocks. The platform is pene- 
trated from north to south by five narrow rude roads, probably 
the ancient Vise. 
The prospect from Gergovia is truly grand and interesting, 
not merely on account of its extent, but from the variety of 
form, colour, and contrast due to the geological configuration 
of the country. On all sides rise isolated hills, some of them 
surmounted by fortresses, built in almost inaccessible places, by 
the feudal lords who were ever ready for warlike and violent 
deeds. These unruly barons were at last put down by Louis 
XIII. and Bichelieu, and their strongholds destroyed. Such 
was Montrognon, which is close to the N.E. ; and Montredon, 
which lies a little W. of the great basaltic platform of La Serre, 
of which it is an outlier. 
The best descent from Gergovia is by the S.E. side of the 
camp, where a dyke of volcanic ash, scoriae, and masses of lava 
have been ejected through a fissure in the freshwater beds, and 
through the lower basalts ; and the protrusion of this dyke has 
