STEVENSON, GOAL BASIN OF DEGAZEVILLE, FRANCE 251 



pletely and a definite measurement of the bed cannot be obtained now; 

 but A. Jardel states that the bed is double, divided by a thick clay part- 

 ing, and in all about 16 feet thick. The strike of the bed has been 

 changed to almost north-south, for the openings are along the stream 

 which flows toward the north. There is in this space a fold with sharp 

 northward pitch, there being easterly dips on the Auzits side, northerly 

 dips where the coal was first reached, and now on the western side dis- 

 tinctly westerly dip, so that the Soulier bed has an elongated curved out- 

 crop. The thickness is such that one should expect to find the bed in a 

 boring at a considerable distance north from Eiou Vieux. 



Separated from the coal bed by a sandstone rich in feldspar is an extra- 

 ordinarily coarse conglomerate, broken by thin shales and, at its maxi- 

 mum, almost 400 feet thick as determined by A. Jardel. This, the 

 feldspathic conglomerate of Bergeron, Jardel and Picandet, is persistent 

 eastward to where it passes under Eiou Vieux and equally persistent 

 southward along the western side of the exposed area. It consists mostly 

 of microgranulite pebbles, thoroughly rounded and varying from one inch 

 to upwards of one foot in diameter, those of the largest size being very 

 numerous. Pebbles of other rocks occur locally. Study of these frag- 

 ments enabled those investigators to determine finally the source of the 

 materials ; the microgranulite came from the areas indicated on the map, 

 the most distant being, at its southern termination, barely four miles 

 south from Eiou Vieux. This conglomerate seems to become less coarse 

 east and west from the first coal opening observed. The sandstones and 

 shales enclosing the I'Estang coal beds have been taken by Bergeron, 

 Jardel and Picandet as being most probably equivalent to the upper part 

 of the conglomerate, which has its full development at half a mile toward 

 the west. Those students have worked out the details of the area so thor- 

 oughly by investigation of the fragments as to prove beypnd question that 

 three little streams entering near Auzits, Haute Serre and Lugan, con- 

 tributed to the formation of these deposits, now exposed in an area of 

 about three square miles, and that the course of the main or central 

 stream during deposition of the later beds is marked distinctly by distri- 

 bution of the larger fragments. 



The feldspathic conglomerate is succeeded by conglomerates and shales, 

 in all about 600 feet as determined by A. Jardel, which continue to the 

 top of the system; they are exposed here and there beyond Eiou Vieux. 

 The extreme thickness of the Auzits system is not far from 1800 feet, the 

 measurement being made along the line of maximum development, near 

 the supposed course of the Haute Serre stream. The average thickness 

 is very much less. 



