396 • Mr. Bennett on the Geology of Madeira. 



break off a piece of it. T'here 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 Fun- 

 chal. From the beach before the town to Illhoo Castle, and beyond 

 it to the land called the Punta de la Cru%^ 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 

 tlie 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 tarious thickness, the 

 deepest appearing to be about 4 feet, and alternating with that stratum 

 which I have called Peper'mo. 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 exceed- 

 ing a few inches in diameter. Their substance is brittle and crumbles 



