129, 30] AGE OF THE ORANGE SAND. 17 



FOSSILS OF THE ORANGE SAND FORMATION ; ITS GEOLOGICAL AGE. 



Extensive and minute examination, which I have bestowed on the 

 various stages and facies of tlie Orange Sand formation of Mississippi 

 have failed to satisfy me that it contains any fossils whatsoever 

 characteristic of itself. It usually contains the fossils, as well as the 

 materials, more or less modified, of the underlying* formations ; and 

 although silicified wood is of very common occurrence in the 

 Orange Sand strata generally, the circumstance of its occurrence 

 with any degree of frequency being either confined to the territory 

 of the lignitic formations, or to water-worn fragments, seems to 

 indicate that this fossil, also, is derived from more ancient deposits 

 and owes its presence within the Orange Sand to the destruction of 

 the former by denudation. It is true that the coarse sands which 

 compose the main mass of the formation, are a material unfavora- 

 ble to the preservation of fossils ; but the fine sands, as well as 

 the impalpable clays which so frequently occur, could not but have 

 preserved traces at least of the proper fossils of the Orange Sand 

 period, had any such existed. The black clay deposit on the 

 Memphis and Charleston Railroad, previously described, is the 

 only instance in which, to my knowledge, there is strong evidence 

 of fossils (leaves) being found within the Orange Sand in their 

 original place. The shape of this mass renders it difficult to believe 

 it anything else than a deposit formed in loco ; but we shall see that 

 even thus, it might be supposed to belong to the underlying lignitic 

 tertiary, and not properly to the Orange Sand. 



29. Devonian and Silurian fossils in the Orange Sand. — Corals 

 are the most commonly occurring among the pebbles of the 

 western belt (IF 17) ; e. g. Lithostrothion basaltiforme, Calamopora, 

 Astrcea, Millepora, Catenipora, Chcetetes, Cyathophyllum, Petraia. 

 Next to these, stems of Cyathocrinus and other Crinoidea are 

 most abundant. I have also found an Atrypa, and a fragment of a 

 Trilobite. 



30. Carboniferous fossils in the Orange Sand. — The pebble beds 

 on the territory of the carboniferous formation, in Tishomingo 

 county, consist chieflyof chert, hornstone and sandstone, containing 

 fossils identical with those of the underlying carboniferous strata 

 — Cyathophyllum, Fenestella, Gorgonia, Pentremites, Productus, 



*Not always of those underlying in the same locality ; but commonly^ at 

 least, at no great distance. 

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