The deposits near Caylus and in Quercy occupy fissures and pockets in Jurassic limestone, and have yielded a remarkable assemblage of the relics of Tertiary mammals and other fossils.
The present volcanoes lie along a line (with offshoots) which runs parallel to the west coast, but some distance to the east of the fissures from which the early Tertiary lavas were poured.
It has been suggested that these spurs represent the sites of vents or fissures of eruption.
49); or they extend down the calyx as fissures about halfway, FIG.
Each segment is again divided by lateral fissures, which do not extend quite to the posterior border of the organ; of the central lobes thus cut off, the right is rather the larger, and has two fissures in its free border dividing it into lobules.