Photo File:The Quarterly journal of the Geological Society of London (

bhl | titre the quarterly journal of the geological society of london. | source https://www.flickr.com/photos/biodivlibrary/12961147895 | description 242 1.r0ceedings of the geological society. .maicll 24, 2iid. santonian stage: the lower part with ostrea acutirostris, 0. santonensis, spondylus truncatus, janira quadricostata, sjphceruutes coquandi, and radiolites fissicostata. the upper part, of fluviatile origin, with unio, cyclasy omphalia coquandi (zekeli), and 7 beds of lignite, cyrena glohosa and ferussaci, math., melanopsis rugosa, math., and m. gdllo-provincialis. plan d'aups, near sainte baume, and the environs of mar- tigues. this corresponds to the upper portion of the chalk of gosau. 3rd. campanian and dordonian stages, from 400 to 500 metres, equal to from 1333 to 1666 feet, of lacustrine limestones, with cyclas gardanensis, brongniartina, and gallo-provincialis, math.., ampullaria prohoscidea, math., paludina angulata, math., lymnea longissima, math., &c., and containing 18 layers of lignites, very different from those which are worked lower down, in the santonian stage (fig. 3). it is evident that these lacustrine limestones correspond with the "upper chalk " and with my dordonian stage ; for they are covered by other lacustrine limestones, which , are referred to the level of the ^ig- '^.?section of the freshwater limestone of rilly, and there- upper cretaceous beds of fuveau. fore to the base of the eocene. thus in lower provence it is evident that a complete change must have been wrought in the nature of the waters of the cretaceous sea, which, after the conclusion of the santonian period, from being salt became brackish, and afterwards, from brackish, fresh ? a circumstance which favoured the develop- ment of a population of flu- viatile shells, entirely unknown elsewhere, and which were con- temporary with the gigantic eudistes of the charente, and those of provence, which lived in the immediate vicinity of the lake, at the bottom of which the carbonaceous deposits were pre- cipitated. the classification of these lacustrine sediments had been, until very lately, the cause of great confusion and serious errors. they had been attributed at one time to the miocene period, at another to the eocene, without a single reliable argument, or a single fossil in support of this opinion. the new method of determining their chronological order is justified, not only by their position, but also by the very important fact that in the neighbouring alps, as well as in algeria, where the upper chalk is exclusively of marine origin, we observe, above the santonian strata, ostrea vesicularis and belem- nitella mucronata^ species wanting in the corresponding strata of the bouches du rhone, which, as we have seen, having been deposited in a lake, can only contain lacustrine shells. my friend m. mathe- ron is occupied at the present time in making out a catalogue of this | pageid 36103087 | itemid 111288 | titre id 51125 | pagenumbers page 242 | pagetypes text | volume v.25 | pageurl https://www.biodiversitylibrary.org/page/36103087 | date 1869 | auteur geological society of london | names namefound:ampullaria nameconfirmed:ampullaria eolid:10718936 namebankid:241026 namefound:brongniartina namefound:cyclas nameconfirmed:cyclas eolid:13750058 namebankid:4131942 namefound:cyrena nameconfirmed:cyrena eolid:4757476 namebankid:4134596 na

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