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The Coral Reefs of the Peninsula of Sinai

1888; Nature Portfolio; Volume: 39; Issue: 999 Linguagem: Inglês

10.1038/039172a0

1476-4687

Baoyu Gao,

Cephalopods and Marine Biology

MUCH has been written and said of late on the origin of coral reefs; yet the best authorities, when they have not theories of their own to uphold, are agreed in thinking that the matter is far from being finally settled. For this reason a thorough examination of all coral districts is much needed, and every work which adds to the general stock of knowledge on the subject deserves attention. The present memoir deals with the geology of the peninsula of Sinai, and the dependence of the coral reefs in the Gulfs of Suez and Akabah on the characters of the rocks forming the shores. Herr Walther has undertaken difficult and disagreeable, if not dangerous, journeys in the course of his research, and in point of thoroughness his observations leave little to be desired. Believing that a solution of the question in any given area can only be obtained by carefully studying the relations of the reefs to their basis, he has thoroughly examined the geological character of the western mountains of the peninsula, and gives in the first part of the book a full account of all that he observed. The results of his geological survey are most conveniently studied in the plate giving a series of sections through the peninsula. These show that south of Uâdi Firan there are two parallel lines of granite mountains, running north-west and south-east, and between them lies a basin filled in with sedimentary rocks. As far south as Gebêl Nakûs the granite forms the shore, and the author points out that in this region there is no fringing reef and no coral of any kind. Further south, where the sedimentary rocks form the sea-cliff, the fringing reef makes its appearance, sending out offsets from the shore from place to place, which form barrier reefs and even atolls. The shores of the Gulf of Akabah are granitic, and are devoid of coral reefs. Commenting on this, the author explains that the granite is rapidly weathered out, and that its surface thus constantly undergoing destruction does not afford a sufficiently firm basis for coral growth. Die Korallenriffe der Sinaihalbinsel, geologische und biologische Beobachtungen. Von Johannes Walther Dr. Phil, und Privat-docent an der Universität Jena. Des xix. Bandes der Abhandlungen der Mathematisch-physischen Classe der Königl. Sächsischen Gesellschaft der Wissenschaften. (Leipzig: bei S. Hirzel, 1888.)