Madeira and Porto Santo. 319 
I took a boat and went to the small island of Baxo : it is only 
half a mile distant from the south-west end of Porto Santo, (en- 
tirely composed of cliffs of tufa with dikes), from which it has 
been evidently separated. To get at all the strata in succession, 
I was obliged to climb up an almost perpendicular height of 
about 220 feet on my hands and knees. I first ascended about 
100 feet of the same tufa, which I have described at Porto San- 
to ; then twelve feet of limestone, of a granular sandy structure, 
glimmering lustre, and emitting an alliaceous odour when 
struck ; it contained no fossils, or at least none that I could dis- 
cover, after examining and breaking away its surface in various 
directions, and after splitting numerous large fragments ; it is 
of a buff-ground, sprinkled with grey and red spots or grains. 
Above this I found about fifty feet of a conglomerate of nodules 
of basalt, or rather of wacke, (from its colour, fracture, and 
specific gravity), which I need not describe particularly here. 
I then climbed over from eight to ten feet of a conglomerate 
limestone, generally of a chalky white, soiling the fingers, some- 
times of a whitish blue, and containing large nodules of wacke 
and imbedded masses of agranular, sandy limestone, resembling 
that before described. The white part of this limestone presented 
great masses of Lamarck’s Cateniporse, (Tubipora catenulata, 
Lin. Gm.) ; and with much difficulty I chiselled out some perfect 
moulds of a large Cardium, Fig. 83, of the Cardium edule ; one 
end of a Solen ; of a Solenemya, Fig. 55 ; moulds of various sized 
Yenuses; a Voluta, Fig. 54; a Turritella; a Conus, like that at 
Lisbon, Fig. 27 ; the Pecten multiradiatus, and the Pecten gla- 
ber, (neither of which species I believe have before been found in 
a fossil state), and the fragment of a large white Pecten, Fig. 59. 
Above this shelly limestone was about six feet of a fine-grained, 
indurated sandstone, deposited in layers, with projecting ledges, 
and acquiring a scoriaceous appearance, and dark grey colour, 
on the outer surface, from exposure to the atmosphere, but pre- 
senting an orange-brown within, and effervescing. On this rest- 
ed a conglomerate, about fifty feet deep, of nodules of wacke, 
of a lesser portion of the orange-coloured ferruginous sand, and 
of small fragments of wacke, emerging like nail-heads, and 
coated (with the exception of the upper surface) with an indu- 
rated grey clay, which also lines small cavities in a mamillated 
2 
