Correspondence — Dr. W. J. Barkas. 431 



In this paper the author described in great detail the geological 

 observations made by him during a journey, in company with Dr. 

 Beke, in the Sinaitic peninsula. 



26. "Giants' Kettles at Christiana." By MM. W. 0. Brogger 

 and H. H. Reusch. Communicated by Prof. Kjerulf, F.M.G.S. 



The authors first refer to the popular notices about Giants' kettles, 

 and describe in detail a number of these pits, which were examined 

 and emptied near Christiania. They then mention the theories 

 concerning their origin. From their own facts and reading they 

 conclude that many of these remarkable pits were made at the 

 bottom of "Moulins" during a glacial period, when the locality was 

 covered with ice on the scale of existing ice in Greenland. The 

 contents of these pits are traced to their parent rocks, which are 

 higher up towards the great valley of Gulbransdal, in which glacial 

 phenomena abound. They are inclined to conclude that moraine 

 matter was washed off the glacier-ico from time to time, and left in 

 the pits at last. 



The Society then adjourned till the 4th November, 1874. 



coI^I^ESI=OI^rxD:EI^T■o:E . 



AMPSIGENTRUM IN A NEW HORIZON. 



SiK, — "While carefully looking over a series of fossil teeth from 

 the Sub-carboniferous Limestone, near Richmond, that had been 

 lying in my cabinet for some time, I discovered two beautiful scales 

 of Megalichthys, and an undoubted jaw of Amphicentrum nearly 

 perfect. It is principally to the jaw that I desire to direct attention, 

 for I am not aware that any remains of Amphicentrum have ever 

 been found in the Limestone itself, though they have been obtained 

 from the shales both above and below it, and are comparatively com- 

 mon in the shales of the Upper Coal-measures. This specimen is 

 larger than the jaws usually found in the more recent formation, 

 being half an inch long and one-eighth of an inch broad at the 

 articular extremity ; it presents two ridges, which are joined for 

 some distance along the anterior portion of the surface of the jaw, 

 but which diverge widely as they proceed backwards ; these ridges 

 are denticulated, and the denticles are most distinct on the posterior 

 portion, where they resemble small rounded tubercles. The whole 

 of the exposed surface is very plentifully covered with minute pores, 

 which give it an irregularly granular aspect. I have no hesitation 

 in ascribing this specimen to the same species as that found in the 

 Coal-measures, and named A. granulosum, Young. The interest 

 attached to this discovery is increased when we remember that the 

 remains found in the Coal-shales must have belonged to fishes that 

 existed in lakes, rivers, or estuaries, while the fishes that lived durino- 

 the formation of the Sub-carboniferor'= Limestone must have roamed 

 in salt water; Amphicentrum must, therefore, have lived both in fresh 

 and salt waters, like some modern fishes. 



