J. H. Coolie — Geological Notes on Gozo. 351 



Tt is lenticular in shape, but breaks off abruptly at the lower 

 side, and an escarpment is thus formed, which shows the maximum 

 thickness of the bed to be about 7 feet, while at the extremities it 

 thins out to 18 inches and a foot. 



Its upper surface is extremelj^ hard ; and like the surfaces of 

 the surrounding strata, it has been considerably honeycombed and 

 otherwise weather-worn. 



I'he materials of which it is composed are very uniform, both in 

 general appearance and in arrangement. They consist for the most 

 part of fine detrital matter, the product, apparently of the erosive 

 action of the atmosphere on the Upper Coralline, the Greensands 

 and the Globigerina beds. 



The deposit is divisible into two well-marked zones, the most 

 persistent features of each of which are the irregularity of its 

 divisional planes and its non-crystalline character. 



The top zone consists of an impure, perfectly formed limestone 

 of a whitish colour, and it is usually overlain by a thin, stalagmitic 

 layer of about one inch or less in thickness. 



A chemical analysis showed a sample of this bed to consist of 

 about 80 per cent, of carbonate of lime. 



In many parts of the bed, minute perforations are noticeable 

 traversing the rock in all directions. Tliey vary considerably both 

 in length and in the diameter of the bore. None of them exceed 

 -i\th of an inch in diameter, while many of them are much less. 



These capillary tubes often play an important part in determining 

 the direction in which the rock cleaves. They are, however, not 

 persistent throughout the formation, and are more numerous in some 

 parts than in others. 



This upper division of the deposit is very fossiliferous ; but, 

 owing to the imperfect character of the rock, the Mammalian 

 remains are seldom found in a perfect condition, and even when 

 found entire, they are often so rotten that they fall to pieces under 

 the slightest pressure. 



Besides large quantities of land-shells, and mammalian remains, 

 the teeth and vertebratse of Sharks, Echinoderms, several species 

 of Corals, and other representatives of a marine fauna occur. All 

 of these latter have, however, been derived from the Globisreriua 

 Limestone. 



The following is a list of the organic remains that I have found 

 in this bed. 



Marine. 

 Two teeth. [Oxyrhina hastilis). 

 One tooth. Oxyrhina xiphodon. 



(Both of these species are characteristic of beds 2, 3, and 4.) 

 Flabellnm, Zoantharia, and Corallines. One Echinoderm (ScMz- 

 aster, sp.). 



Land shells.* 

 Selix vermiculata (Miill.) (common). Helix virgata ? Mont. 

 Helix pisana (Miill.) (common). Helix caperata ? Mont. 



Helix striata (Drap.). Pomatias melitensis (Sow.). 



* Kindly identified by Mr. E. A. Smith. 



