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by the labours of those veterans, the late Poulett Scrope and 
Sir Charles Lyell. These freshwater deposits are of the 
tertiary age, and occupy a valley plain of considerable extent 
between the two parallel granitic ranges of the Monts Domes 
and the Farez. 
The order of deposition and the more interesting varieties 
of the limestone with their included organic remains were 
commented on, also the deposits of gypsum and silex in 
various forms. Specimens were exhibited of the indusial 
limestone, which is entirely built up of the larval cases of a 
species of Phryganea or caddis fly, solidified by the deposition 
of lime or travertin. Another variety is composed of the 
valves of that minute crustacean the fresh water Cypris, 
similarly preserved by an incrustation of lime. With these 
were also shown specimens of the shell limestone containing 
Helix beautifully preserved. Other land and freshwater 
shells, as Lymneus, Planorbis, &c., also occur. 
One variety of limestone in a crystalline condition con- 
taining Potamides is quarried as a marble for building 
purposes. 
These limestones are all of chemical origin and due to 
mineral springs, which are still numerous over the whole 
district, but were doubtless more abundant in the past. 
La Limagne is only one of three or four basin-like depres- 
sions which occur in this portion of France. Though now 
totally separated by lofty granite plateaux or volcanic 
mountains, it is very probable that these freshwater deposits 
covered the whole intervening area. Monsieur Julien, 
Professor at the Faculty of Sciences at Clermont, sets forth 
the result of his personal researches as teaching that these 
pretended tertiary basins are but fragments of a continuous 
lacustral formation which covered the whole or part of the 
central plateau and united the great tertiary basins of 
Cantal, Velay, and the Limagne. He demonstrates that 
systems of enormous faults have dislocated these basins, 
