1859.] 



SCEOPE CONES AND CBATEKS. 



531 



Fig. 14. — The '' Mamelon Centrdle ;^^ a boss of vitreous lava on the 

 summit of the Volcano of Bourbon. (After Bory de St. Yincent.) 



Fig. 15. — Ideal section of the Mamelon Centrale. 



Fig. 16. — Ideal section of the Puys de Sarcouy and Goule, Monts 



de Dome (fig. 13). 



