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Contents
In this book 190 marine to brackish bivalvian species mainly from the
Longzhaogou Group and the lowermost Chengzihe Formation of Jixi Group
together with 23 freshwater species from the Chengzihe and Muleng Formations
of Jixi Group in the eastern Heilongjiang Province were described .These
bivalves comprise 32 species and 1 new genus and species in the Palaeotaxodonta
,1 species in the Cryptodonta,95species (7 species new )and 1new genus
in the Pteriomorphia ,12 species in the Palaeoheterodonta ,59 species
in the Heterodonta, and 13 species in the Anomalodesmata. Based on Jupiteria
(Ezonuculana) aff. mactraeformis (Na-geo), Portlandia aff. sanchuensis(Yabe
et Nagao)and Thracia (Sow.)in the upper marine member of the Peide Formation
and Aucellia aptiensis(D' Orb.), A. caucasica (v.Bicj) , Expgura ? erecta
Gu sp. nov . , Amphidonte subhaliotoidea (Nagao0, Aetostreon aff . xouloni
(Defrance), Owtrea spp. , Arctica cf . saussuri(Brongn .)and Thracia rotundata
(J. de C. Sow.)in the Yunshan Formation to Aptian and principally Aptian
. The Longzhaogou and Jixi Groups could be correlated with each other.
Aucellina and Arctica together with Pinna ,Isog-nomon and Filosina indecate
a temperate climate in the region of the Groups .The ingressed Late Early
Cretaceous sea from the east in the ancient Wanda and Jixi areas as well
as theLate Jurassic sea in the Suibin area appeared not of great depths
,yet most probably of embaymental palaeoenvironment. The freshwater species
of the Jixi Group belong to Jehol or Witim faunas, entirely of Asian or
Holarctic nonmarine faunas ;they are of late Early Cretaceous instead
of Late Jurassic age as held for a long time.
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