260 ANNALS NEW YORK ACADEMY OF SCIENCES 



have a longer diameter of six inches. The difference in form as well as 

 in the composition of the pebbles enabled Bergeron, Jardel and Picandet 

 to determine that the stream giving this deposit entered the basin at the 

 northeast near the Pont de Bourran. The dip of these beds, though 

 slightly interrupted at times, is southwestward or south of west at not 

 far from 30 degrees, until one passes the summit at les Estaques, some- 

 what more than a mile north from Decazeville. 



At barely 750 feet from the fork in the road at les Estaques, a con- 

 glomerate is shown dipping south of west at 30 degrees; but there the 

 dip is reversed to north of east. At 300 yards farther the southwestward 

 dip is resumed, and it is retained until one is directly above the entrance 

 to the Bouquies mine. There a deep side cut shows a sharp fold with 

 steeper dips on the northeasterly side, the beds being almost vertical ; but 

 this decreases to 20 degrees within a few rods, and that rate continues as 

 far as the beds were followed. The exposure at this place shows between 

 sandy and conglomerate beds, a mass of shale almost 25 feet thick and 

 containing some thin streaks of coal. No other trace of carbonaceous 

 material was observed at any exposure along this line; this exposure is 

 more than 200 feet above the Bouquies mine. No closer determination 

 was made, as atmospheric conditions rendered the aneroid useless. The 

 coal at this mine was not measured ; it is reported as being 48 feet thick. 



The Campagnac deposits show only slight differences in type, and such 

 as are shown are due mostly to the sources whence the materials were 

 derived. They were made by streams from the southeast and northeast, 

 and the physical structure of the deposits shows that practically similar 

 conditions of flow existed contemporaneously on all. The thickness of 

 the Campagnac system varies. A cross section constructed by Saint- 

 Martin of the Campagnac company seems to make the interval between 

 the Campagnac and Bourran coal beds not far from 175 meters at the 

 bottom of the syncline west from Cransac. But A. Jardel, director of 

 the Decazeville company's mines, states that in the Puits de Decazes, near 

 Cransac, he reached the Campagnac coal at about 200 meters below the 

 surface, and he is inclined to think that the interval between the beds is 

 nearly 300 meters, the dip of 27 to 30 degrees being ignored. Tt is 

 wholly probable that each determination is correct for its locality and 

 that the interval between the beds decreases toward the west. A trial pit 

 was sunk below the Bourran coal bed near Decazeville, but the test was 

 not continued directly; at the bottom of the pit a horizontal entry was 

 driven in the direction of the dip and a new pit was sunk at its end near 

 the bottom of the syncline. It is difficult to determine accurately the 

 relation of the two pits to the Bourran bed, but beyond doubt the test 

 was carried to approximately 1000 feet without reaching the Campagnac 



