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By J. L. Usher

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Additional resources for Ammonite Faunas of the Upper Cretaceous Rocks of Vancouver Island, British Columbia

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T h e c o n t a c t with the overlying thinbedded shales and shaly sandstones of the Spray formation is gradational on the north shore of the island but abrupt on the south shore. In the area intervening between the north and south shore of the island o u t c r o p s are rare, and this upper c o n t a c t is only approximately located. It id in this central part of the island that the formation reaches its greatest thick­ ness of at least 1,100 and possibly 1,300 feet. N o r t h w a r d s and southwards it thins to about 700 feet.

N o r t h w a r d s and southwards it thins to about 700 feet. T h e formation is finer grained and less c o n ­ glomeratic in the northern outcrops than it is t o the south. T h e Geoffrey conglomerate occurs in massive beds up t o 300 feet thick separated b y beds and lenses of sandstone. In general, it is unsorted, and contains pebbles and cobbles, and boulders up to 2 feet in diameter. The texture is finer grained t o w a r d s the t o p of the formation. T h e c o m p o n e n t s of the conglomerate are m o s t l y well rounded, and comprise fragments of trap, quartz, quartz diorite, diorite porphyries, granite-like rocks, gneisses, schists, chert, argillite, sandstone, and rare, calcareous concretions.

Jacquoti, it is probable that the C e d a r District-Trent R i v e r faunizone is part (and possibly the upper part) of the C a m p a n i a n Stage. T h i s p r o b a b i l i t y is strengthened b y the contiguity of the overlying Maestrichtian fauna in the N o r t h u m b e r l a n d and L a m ­ bert formations. The Northumberland-Lambert Faunizone A n entirely new g r o u p of a m m o n i t e species appears in this zone. Baculites chicoensis, B. occidentalis, and Gaudryceras denmanense are the o n l y forms that survived from the lower beds, the Baculites species ap­ parently with difficulty, for it is greatly reduced in numbers, and Gaud­ ryceras denmanense with a sudden flourish.

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Ammonite Faunas of the Upper Cretaceous Rocks of Vancouver Island, British Columbia by J. L. Usher


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