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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    toeevlum^ Eosi)on(jia varians^ Li^afuesquina chanvplainensis., PLesionnisphitjis^ j\lachirites mcKjna^ Pliomerops canadensis^ and several ceplialopods are coiiimon. Piidsion J.—The CaniarotmcJiia plena division is not very well developed along the line of the section at Chazy. Tlie thickness is 153 feet, but a large ])art of the strata is covered with soil. At the base are about 25 feet of grey dolomite with almost no fossils. The I'emainder of the rock, as far as exposed, is an im])ure shaly limestone, abounding in Caniarotmchia plena. Zones 3„, 3^, and 3^. can not be distinguished just at Chazy village, probably because the strata ai‘e so poorly ex- ]:)Osed. About 3 miles southeast of this point, however, in a tield near the lake shore, tine outcro])s of zone 3„ occur, and here Glaphurns pustulatus^ Amphilichas niinganensis.^ Illce- nus globosus^ and the cephalopods are common. Section at Valcour Island. On Yalcour Island, the whole of the Chazy is exposed, with a thickness of 890 feet. In one section along the south end, almost the entire thickness is showm, while nearly all the miss- ing parts may be seen in other sections on the east and north sides of the island. D ivision 1.—The strata of this division are well exposed on the south end. The thickness is 311- feet. At the base is a zone of sandstone and shale in which Lingula brainerdi is the common fossil. Other fossils are rare, Isotelus harrisi and a species of Eccyliopterus being the only ones thus far found. Above this zone is that of Ortliis acutiplicata^ 10 feet in thickness. The Scalites angulatus zone is not exposed on Yalcour Island, the rocks usually containing it being absent at the peb- ble beach on the south end of the island. The Lopliospira subabbreviata zone is not well developed, but may be indicated by a fauna found on the middle of the west side. Division —The strata of this division are 406 feet in thickness and are usually compact, dark blue and grey lime- stones. The fossils are frequently coarsely silicitied, but are almost always difficult to extract. At the base, zone 2«, the Malocystites murcliisoni zone, is well developed, and as the fossils weather out in this locality, some 40 species have been listed. While the rocks of this division iisuall}^ afford poor collec- tions, yet in favoi-able localities tliey are found to be extremely rich in interesting species. Thus, one locality on the east side of the island has yielded 60 species of fossils, among them such rare trilobites as Asaphus niarginalis., Isotelus bear si, and Pernopleiirides canadensis, and many species of pelecypods.