G42 REPORT— 1897. 



lower beds, or the Cambrian proper. The term Potsdam formation in Canadian 

 geology was a comprehensive one like the term Cambrian, and like it included all 

 between the Calciferous formation and the Huronian. The indiscriminate use of 

 the terms has led to much confusion, and as the divisions of the Cambrian have 

 now been properly determined the expression Potsdam formation has practically 

 no meaning in Canadian geology. 



Report on Life-Zones in the British C arbonifermvs Rocks. 

 See Reports, p, 296. 



4. The Stratigraphic Succession in Jamaica. 

 By Robert T. Hill, Geologist, United States Geological Survey.^ 



This paper gives results of a series of stratigraphic, petrographic, and topo- 

 graphic studies made in the island in the years 1895, 1896, and lf<97, under the 

 auspices of Professor Alexander Agassiz, for the purpose of determining a typical 

 West Indian section which would serve as a basis for comparison with the other 

 West Indian localities. 



The work of the officers of the British Survey and other previous observers was 

 taken as a basis and advanced by critical studies and correlations of other type 

 localities, and by observations upon the new exposures revealed in the recent 

 highway and railway improvements. A new classification and nomenclature of 

 the rocks is proposed, and the sequence of the geologic events in Jamaica history 

 is outlined and interpreted. Petrographic data by Cross and palseontologic deter- 

 minations by Agassiz, Dall, Vaughan, and others are incorporated in the paper. 



5. Preliminary Notice of some Experiments on the Flow of Rocks. 

 By Frank D. Adams and John T. Nicolson, McGill University, Montreal. 



These experiments aim at ascertaining whether it is possible, by subjecting 

 rocks artificially to pressure under the conditions which obtain in the deeper parts 

 of the earth's crust, to produce in them the deformation and cataclastic structures 

 exhibited by the folded rocks of the interior of mountain ranges or of the older 

 formations of the earth. 



Three factors contribute toward bringing about the conditions to which rocks 

 are subjected in the deeper parts of the earth's crust: (1) Great pressure from 

 every direction ; (2) high temperatures ; (3) action of percolating waters. In the 

 present experiments the attempt has been made to reproduce only the first of these 

 conditions, in subsequent experiments the endeavour will be made to reproduce all 

 three of them. 



The experiments have been made chiefly with pure Carrara marble. Columns 

 of the marble 2 centimetres, and 2^ centimetres in diameter, and about 4 centi- 

 metres in length, were very accurately turned and polished. Heavy wrought iron 

 tubes were then made, imitating the plan adopted in the construction of ordnance, 

 by rolling long strips of Swedish n-on around a bar of soft wrought iron and 

 welding the strips to the bar as they were rolled around it. The core of soft iron 

 composing the bar was then drilled out, leaving a tube of welded Swedish iron 

 6 millimetres thick, so constructed that the fibres of the iron run around the tube 

 instead of being parallel to its length. This tube was then very accurately fitted 

 on to the column of marble. This was accomplished by giving a very slight taper 

 to both the column and the interior of the tube, and so arranging it that the 

 marble would pass only about halfway into the tube when cold. The tube was 



' By permission of Professor Agassiz, under whose auspices the researches were 

 made. 



