Black beneath the night : a study of ancient Maltese 'cart'-tracks

Abstract

Brian Blouet's image of a "Sandwich" fits the stratigraph of the 'Maltese Rocks' to perfection. The top and bottom layers consist of a bed of hard limestone. Deposits of softer rocks, like greensand and blue clay, fill the space between. Successively from top to bottom the geological make up of the Maltese Islands is as follows : Upper Coralline Limestone (about 530 ft. thick); Greensand (about 50 ft. thick); Blue Clay (about 230 ft. thick); the next 75-680 rt. of Globigerina Limestone are followed, right at the bottom, by over 600 feet of lower Coralline Limestone. The Globigerina Limestone is made up of a 0 thick bed of soft, easily quarried rock" of a deep yellow colour. M.R. House, K.C. Dunham and J.C. Wigglesworth, writing about the geology and structure of the Maltese Islands, analysed the Globigerina Limestone as follows : (in succession). (iii) Upper Globigerina Limestone Yellow-orange fine grained and honey conils weathering Limestone with abundant pterpods and scattered ferugineous nodules. A Light-grey/blue angillaceores nodules. Yellow, friable and jointed fine-grained Limestone with scattered ferrugineous nodules. Yellow limestone as above but with several phophetie seams. (ii) Middle Globigerina Limestone. Phosophatic nodule bed with limestone pebbles and abundant coral, fish teeth and other fossils the whole passing irregularly down into the bed below. Light grey to intensely white-weathering chalky limestone with khaki-hearted charts in the middle portion: several thin nodule seems within it, two well marked ones lie 14ft. and 19ft. above the base. (i) Lower Globigerina Limestone. Phosophatic nodule bed forming a massine ledge with ferugineous and phosphatic nodules and abundant casts of fossils and fish, etc. Fine grained yellow limestone with abundant Pecton spp. and Bryozoa. Bryozoan and Foraminiferan rock [...].