Two beds containing relatively thick and highly concentrated oyster shell banks occurring in the densely fossiliferous Wadi Al Abraq outcrop (Upper Eocene Maadi Formation, Cairo-Sukhna Road, Egypt). Such shell beds are almost monospecific. The upper level consists mainly of Ostrea clotbeyi Bellardi, topped by a considerable concentration of Carolia placunoides Cantraine, while in the lower level occurs Ostrea multicostata Deshayes. In both beds, the upper contact with the overlying marl bed (about 2 m thick) is sharp and sometimes erosive. Similarly, the contact with the underlying shale (1.5 m thick) is sharp and erosional. The shell beds are composed mainly of loosely packed oyster shells and their fragments (usually with a high proportion of disarticulated specimens) set in the sandy limestone matrix. The collected oysters show bioerosion and skeletobiont assemblages. Bioerosion trace fossils comprise ten ichnospecies while skeletozoans comprise five taxa. In general, shells of O. clotbeyi show a higher incidence of bioerosion than O. multicostata. The shells' chaotic orientation and their moderate fragmentation indicate that the shell bed formation was associated with high energy events. On the other hand, the low frequency of articulated specimens suggests that the shell beds are parautochthonous oyster banks' remnants. The taphonomic features of the studied assemblage indicate deposition in a shallow-water, wave-dominated environment.

两个含有相对厚和高度集中的牡蛎壳库的床层出现在富含化石的 Wadi Al Abraq 露头（上始新世 Maadi 组，开罗 - 苏赫纳路，埃及）。这种壳床几乎是单一的。上层主要由Ostrea clotbeyi Bellardi组成，顶部是相当浓度的Carolia placunoides Cantraine，而下层则出现Ostrea multicostata德沙耶斯。在这两个层中，与上覆泥灰岩层（约 2 m 厚）的上部接触面尖锐，有时具有侵蚀性。类似地，与下伏页岩（1.5 m 厚）的接触是尖锐的和侵蚀性的。贝壳床主要由松散堆积的牡蛎壳和它们的碎片组成（通常带有高比例的脱节标本），它们位于砂质石灰岩基质中。收集的牡蛎显示出生物侵蚀和骨骼生物组合。生物侵蚀痕迹化石包括十个鱼类物种，而骨骼动物包括五个分类群。一般来说，O 的壳。clotbeyi显示出比O更高的生物侵蚀发生率。多重数据. 贝壳的混沌取向和适度的碎裂表明贝壳床的形成与高能事件有关。另一方面，铰接标本的低频率表明贝壳床是原地牡蛎库的残余物。所研究组合的土壤学特征表明沉积在浅水、波浪主导的环境中。