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一个白晚垩世的介形类化石组合首次被发现在 Otway盆地的钻孔中。化石产于 Eum eralla组的灰色砂泥岩中。 Eum eralla组是依据孢粉材料而确定其时代为早白垩世 ,即相当于 Barrem ain- Albian阶。介形类化石包括 10属 :Cytherelloidea sp.1,Bairdia cf.austracretacea Bate,B?sp.juv.?,Eucythere?sp.,Cydocypris sp.,Darwinulacf.contracta Mandelstam,D.?sp.1,Cyprois sp.,Talicypridea sp.,Zigiphocypris sp.,Eacyprissp.及 Candonasp.。它们代表一个中、新生代混生的面貌 ;其时代应为晚白垩世。依据生态的差异 ,介形类化石又可分为两个不同的组合 :海陆混合相和淡水—半咸水相。前者包括 Cytherelloidea和 Bairdia见于 Crayfish1A钻孔中 ,而后者 Dar-winula,Ziziphocypris和 Cyclocypris产于 Penola1和 Katnook2钻孔中。海相属 Cytherelloidea和 Bairdia发现在5 40 .4- 5 43.1m(Eumeralla组井深 195 7- 477m在 Crayfish 1A钻孔中 ) ,代表着 Eum eralla组上部发生的一个晚白垩世海侵。
A white Cretaceous ostracod assemblage was first found in boreholes in the Otway Basin. Fossils are found in the gray sand and mudstone of the Eum eralla Formation. The Eum eralla Formation is based on sporopollen materials and is dated to the Early Cretaceous, which is equivalent to the Barrem ain-Albian order. Ostoid fossils include 10 genera: Cytherelloidea sp. 1, Bairdia cf. Austracretacea Bate, B? Sp.juv. ?, Eucythere? Sp., Cydocypris sp., Darwinulacf. Contracta Mandelstam, D. sp. ., Talicypridea sp., Zigiphocypris sp., Eacyprissp. And Candonasp. They represent a mixed Mesozoic and Cenozoic era; their era should be Late Cretaceous. According to ecological differences, the fossils of Ostracoda can be divided into two different combinations: sea-land mixed phase and freshwater-brackish water phase. The former including Cytherelloidea and Bairdia are found in Crayfish 1A boreholes, while the latter Dar-winula, Ziziphocypris and Cyclocypris are produced in Penola 1 and Katnook 2 boreholes. The marine Cytherelloidea and Bairdia were found at 5 40.4-43.3 m (well E 195-7 47m in the Crayfish 1A borehole) representing a Late Cretaceous transgression occurring in the upper part of the Eum eralla Formation.