Abyssinian Deposits.—During 1911 an Italian resident in Eritrea discovered a remarkable occurrence of potash salts in the Piano del Sale, near the provisional boundary between the Italian colony and Abyssinia. On account of its equivocal situation, development was somewhat handicapped during the early stages by Abyssinian hostility. Fortunately these preliminary difficulties were successfully overcome, and the deposit proved to be of great assistance to the Allied Powers during the war. The rate of production has gradually increased, and the estimated output for 1918 is stated to be equivalent to 50,000 tons of KCl.

In South Devon the outcrops of Middle Devonian igneous rocks form a series of roughly parallel bands, which broaden out and occupy a continuous area about twelve square miles in extent in the neighbourhood of Ashprington village. No detailed account of the petrological characters of these rocks has been given, although similar types have been described fully in the Plymouth Survey Memoir. For this reason, and also in the hope that further study might explain more completely the cause of the broadened outcrop, I investigated many exposures in the Ashprington area.

It is nearly forty years since Walcott published the well-known memoir which first gave palæontologists definite information regarding the appendages of Trilobites. This work was based on a laborious investigation of Calymene senaria and some other species by means of thin sections. Since then much knowledge has been gained, and, in particular, Beecher's researches on Triarthrus have provided us with a new conception of the Trilobite limb which, in some respects, is not readily to be reconciled with Walcott's earlier results. Now, at length, in this finely illustrated monograph, the veteran student of the Trilobita brings together the results of his own work and that of other investigators and reviews the whole in the light of his unrivalled experience.

The field-work upon which this communication is based was carried out in 1917 and 1918, in preparation for the Geological Survey map of Sheet 86 (Huntly).

According to a strict interpretation of the international rules of zoological nomenclature the generic name Spirifer is wrongly used for the group including Anomites striatus, Martin, and should be restricted to the group including Anomites cuspidatus, Martin, i.e. it should replace Syringothyris, Winchell. My object in pointing this out is not to urge a strict interpretation of the international rules in this case, for it would serve no useful purpose to attempt to displace a name which through a century of usage has become the geological equivalent of a household word, but to show the need for geologists to combine with zoologists in demanding a list of nomina conservanda in zoology.