Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/408

 break of a piece of it. There are other rocks where the red lava forms the base, and these are soft.

On our road from Funchal to the Corral we saw a stratum of large nodules or balls of lava, composed of concentric layers similar to the coat of an onion, and lying one above another; the stratum exposed was 30 or 40 feet in depth, and appeared to go down to the bottom of the hill.

We also examined the coast to the westward of the town of Funchal. From the beach before the town to Illhoo Castle, and beyond it to the land called the Punta de la Cruz, the general character of the coast is as follows: the red stone is the apparent base upon which rests a bed of grey prismatic lava, the stratum being sometimes from 40 to 100 feet in depth. At times this grey lava rests upon a deep bed of ashes and pumice, agglutinated together like the Peperino and Puzzolano in the vicinity of Naples. The scoria at the surface is remarkably thick, and all the upper parts of the lava appear to be cellular. The general dip of the lava on the coast near Funchal is to the north, but near the fort of Illhoo, it forms with a mass of pumice that is intersected with slight veins of carbonate of lime and zeolite, a rapid angle or curve of declination to the east. To the westward of the fort, the lava is not found for a little distance, and there is nothing but deep beds of pumice and the agglutinated mass above mentioned. These beds of pumice are of various thickness, the deepest appearing to be about 4 feet, and alternating with that stratum which I have called Peperino. In different cavities of the pumice bed, there are large deposits of black ashes. Towards the extremity of the strata the red stone appears on the surface in a more solid state, and lies in prismatic masses, the prisms being small, and not exceeding a few inches in diameter. Their substance is brittle and crumbles