V.—On the Occurrence of a Black Limestone in the Strata of the Maltese Islands

Abstract

While engaged in the examination of the superficial deposits of the Maltese Islands, I have often met with rounded pebbles and angular fragments of a black, crystalline limestone, either lying on the rock surfaces, or embedded in the Quaternary formations.The late Professor Leith Adams drew attention to the same fact as long ago as 1867, and in a paper which was published in the Quart. Journ. Geol. Soc. he expressed an opinion that the fragments which he had seen lying on the surfaces of the sides and summits of the Gozitan Hills, belonged to a formation that was of a much later age than any of the rocks that are now to be found in situ in the islands.Dr. John Murray, too, notes in his brochure on the Maltese Islands the occurrence of similar fragments in the neighbourhood of Marsa Scirocco, and he further adds that no evidences of the rock having been found in situ in the islands had hitherto been recorded. The remarks of these gentlemen led me to consider the matter attentively, and I have, during the last year, been carrying on investigations with the object of discovering the origin of the black marble, the result of which has been to show that it is but a variety of the Lower Coralline Limestone, the basement bed of the Maltese series, and that it occurs extensively in situ in that formation.