The fauna of the Chazy limestone / by Percy E. Raymond.

  • Raymond, Percy Edward, 1879-1952.
Date:
[1905]
Catalogue details

Licence: In copyright

Credit: The fauna of the Chazy limestone / by Percy E. Raymond. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Tims far, the following' fossils have been found only in this division, and most of them in but one locality : Gamarotmchia pristiua sp. nov., CtenodonUi didruiforoiis sp. nov., (Jl'idop]>- orus obscorus sp. nov., Cyrtodonta cxpanm sp. nov., End.o- desma undid at urn. sjn nov., Scenelia rohusUt sp. nov., Rapliis- tonid unduhituni sp. nov., llelicotoma miyrans S)). nov., Bucania bidorsataf^ Trochonema diy)ar s}>. nov., Subulites p)i'ohmyata sp. nov., llolopea scrutator sp. nov., Eoharpes ottaicaensis^ Asaphus margined is^ hotel us angusticevuda^ Isot- elus ? bearsi^ lllamus punctatus^ Cybele 'valcourensis^ Cerwu- rus poinpilius^ C. hudsoni^ and Pseudosplicerexoch us approx- im us. This middle division is marked by an abundance of pelec- ypods, gastropods, and trilobites, and in this respect is sharply contrasted with the lower division. Of the 16 pelecypods, 13 are represented here. Of 35 trilobites. 27 are present. Species of Stroinatocerium and Strephochetus are common in these rocks, but are also abundant in the lower zone of the next division. Zone 2„. The Malocystites murchisoni zone. Tims far, only one subfaunule has been detected in Division 2, and that is at the very base. It is best developed at Yalcoiir, but occurs also on Yalconr Island. The zone is characterized by the great abundance of cystid fragments. The characteristic fossils are : (jlaphurus prhmis^ Eoharpes antiqtiatiis^ Lonchodomas halli.^ Cybele valcourensis., Malocystites murchisoni^ Af. emmonsi^ Glyptocystites forbesi^ Palaeocystites tenuiradiatus^ Raphis- toina stamineum, ALaclurites magna., Ploesiomys strophome- noides^ and Camarella varians. Division 3. The Camccrotcechia plena Division.—The strata of this division are rather thin bedded, light grey, coarse- grained limestones, al)Ounding in fossils. Near the base thei*e are always butf-colored, pure, fine-grained dolomites and heavy bedded, coarse-grained blue limestones. The only fossil which is found throughout this division is Camarotmehia plena. Otlier characteristic fossils are: Camarotmehia major sp. nov., Orthis ignicida sp. nov., ALodiolopsis fabaformis sp. nov., and Glaphurus jmstulatus. There is here a decided fallino- off in the number of ^astro- pods and pelecypods, only 6 of tlie former and 5 of the latter being represented. There are about as many trilobites (16) in this division as in Division 1, and 8 of these are found in all three sections. The number of species of brachiopods is about the same in each of the three divisions, but they dominate the fauna in the first and third. In the former, one of the Pro- tremata {llebertella) is most abundant, while in the third divi- sion one of the Telotremata {Camarotmehia) predominates. Am. Jour. Soi.—Fourth Skries, Vol XX Xo. 119—November, 1905. 25