[Reports volI-XIII] . ensive assemblage of fossils, and in a perfect state of preser-vation when collected at the right time. They afford unusualopportunities for both structural and systematic studies, formany of the features commonly not met with are here foundbeautifully preserved. Such are the internal characters ofcrinoids and brachiopods, and the delicate ornamentation ofnearly all groups. Careful comparisons of the fossils from these cherts andthose of the surrounding limestones show that the forms to agreat extent are identical. Moreover, numerous shells andcrinoids are found partly im
[Reports volI-XIII] . ensive assemblage of fossils, and in a perfect state of preser-vation when collected at the right time. They afford unusualopportunities for both structural and systematic studies, formany of the features commonly not met with are here foundbeautifully preserved. Such are the internal characters ofcrinoids and brachiopods, and the delicate ornamentation ofnearly all groups. Careful comparisons of the fossils from these cherts andthose of the surrounding limestones show that the forms to agreat extent are identical. Moreover, numerous shells andcrinoids are found partly imbedded in the chert and partly inthe limestone, with a sharp line of separation, indicating clearlythat the silicious impregnation was acquired long after theoriginal deposition of the beds, and was not due to ft greatersilicity of the waters in which the calcareous deposits weremade, as has been held by many prominent writers. This isin accordance with observations made elsewhere in the Bur-lington limestone, o (3O O. >I ; < < z< 22 O SOME FAtTNAL PECULIARITIES 65 The faunal aspects of the bed in question are particularly interesting. Some of the more common as well as the more important species may be enumerated as follows: Goniatitea osagenBis, Swallow. Pbanerotinna paradoxus, Wlnchell. Capulus paralius, Wnite & Whitfield. Capulus formosus, Keyes. Porcellia nodusa, Hall. LoxoDema prolixa, Whjte & Whitfield. Spaerodoma penguis, (Winchell). Pleurotomaria sp ? Omphalotrochus springvalensis, White. Holopea subconica?, Wlnchell. StraparoUus ammon, White & Whitfield. Euomphaluslaxus?, White. MurchiBonia Bellerophon bilabiatus, White & Whitfield. Alloriema hannibalensis, Shumard. EdmoDdia nuptialis, Winctiell. Edmondia burlingtonensis, White & Whitfield. Conocardiutu * Lithophagus occidentalis, (White & Whitfield). Aviculopecten circulus, Shumard. LiDgula melie, Hall. DiBcina newberryi, Hall. Terebratula rowleyi, Worthen. Productns arcuatus, Hal
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