The genus Cyclus contains a number of small Arthropoda which are found in the Carboniferous rocks of Europe and the United States. As a rule the fossils are small, less than an inch in diameter, and very often they are enclosed in ironstone nodules. Consequently they are generally overlooked and are rarely found in collections.

Chloritoid-Bearing schists have so far not been recorded from the State of South Australia, though such are known from the Pre-Cambrian rocks of the Broken Hill area. The chloritoid rocks now to be shortly described occur interbedded with quartzites, forming the meridional ridge of the “Frenchman”, on the western coast of southern Eyre Peninsula. In a previous paper (l)1 the rocks of this area have been referred to, as comprised within two groups, a sedimentary series—the Warrow series, and the Dutton series, a group of acid granites of gneissic habit with associated aplites and pegmatites, often rich in tourmaline and carrying garnet, and beryl. These rocks invade the sediments of the Warrow series.

The fossil which forms the subject of this note was thought, when first found by me, to be a new genus of Tabulate corals. Since it may puzzle, and indeed has puzzled, others in a similar manner, it will perhaps prove useful to describe it.