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If we now look at the fossils which have been found in 

 the Coeloma-bed, we see that with the exception of the 

 single beetle-wing we have here a purely marine fauna. The 

 nature of the rock indicates that the deposition took place 

 in comparatively deep water. However, we also sometimes find 

 in the concretions innumerable well preserved imprints of frag- 

 ments of leaves and other remains of plants, which presumably 

 together with the beetle-wing were carried by a river into 

 the sea. The number of the land-organisms in the concretions 

 moreover permits the conclusion, that the deposition took place 

 near the mouth of the river. 



If we now consider the fauna of the Cyrena-bed it is at 

 once evident that it is of a quite different composition from that 

 of the Coeloma-bed. Beside typical salt-water species, such as 

 those belonging to the genera Cyprina, Astarte, Cryptodon^ 

 Ег-усъпа, TelUna, Natica, Fusus, Aporrhais a. s. o. we here 

 find a brackish-water species, namely Cyrena Gravesii Desk., and 

 presumably a land- species Bulimulus sp. That we have to 

 do with a marine deposit here also is plainly proved by the 

 above named salt-water species, but the deposition here took 

 place in less deep water, and nearer the coast. A material as 

 coarse as that which forms the sandstone , in which the 

 fossils mentioned have been found, could hardly be washed 

 very far out into the sea, but would subside near the coast. 

 That this was the case, the bits of shale which are found depo- 

 sited in the sandstone, are also signs of. Another argument 

 for the Cyrena-bed being a shallow-water formation is from the 

 fossils, among which is found such a strongly marked littoral 

 form as a species of the genus Donax. Species of the 

 genus Mytilus, ' and probably also of the genus Psammobia, 

 which are both generally found in shallow water, also occur 

 here. Even if some of the other species belong to genera 

 which are found in somewhat deeper water, there are presu- 

 mably none of these exclusively found at such great depths. 



