402 REPORT—1890. 
pipernoid tuff is not in contact with the limestone, and could not have 
acted upon it directly, and therefore the probability is that this chemical 
erosion was brought into action by rainwater percolating through the 
tuffs having dissolved out the acids, probably of fluorine, chlorine, and 
sulphur, from the ejectamenta that formed the pipernoid tuff. 
The fragments of scoriz and porphyritic vitreous trachyte that enter 
into the composition of the pipernoid tuff are comparatively very large, 
and would seem to indicate the prevalence of a strong wind. 
Marine terrace of Castellamare.—A proper examination of this is 
prevented to a large extent by talus, vegetation, and buildings; but I 
had the good fortune lately to find a small spot in a private garden near 
‘Sommazzarello’ where there is an entrance to an old tunnel quarry in 
the pipernoid tuff which forms the basis of the cliff. This marine terrace 
is, on account of its height and age, so far as can be made out, contem- 
poraneous with that at Pozzuoli, known as the Starza, and which over- 
looks the Serapeum, and, like it, has been built under, against, and over 
by the Romans, at that time forming part of the town of Stabie. At 
the section in question the base of the cliff is composed of a bank of 
pipernoid tuff, the bottom of which is not visible in the hole 2 m. deep, 
which also forms another 4 m. at the cliff bottom. Superposed upon 
this are traces of the musewm breccia, as indicated by the included rock 
fragments ; but the main mass is a red pisolitic earth, some of the pisolites 
attaining the size of an egg. The appearance of a few well-rounded 
pebbles indicates water erosion, but whether fluviatile or marine I could 
find no certain indication. Associated with the fragments of the nwusewm 
breccia are many pieces of limestone, which of course are to be expected 
in this locality. The main mass of the cliff above is made up of a series 
of beds of limestone pebbles interstratified with bands of tuff and 
tufaceous earth. These tuffs will, I think, by a more careful examina- 
tion, prove to be chiefly of Vesuvian origin. At the top of the cliff there 
is a marked stratum of plinian pumice (Phase VII., Period 1), which 
of course buried Stabiz. This section shows us that the grey tuff was 
ejected before all the other visible components of this cliff, and at a time, 
or possibly previous to the time (if there were several oscillations of 
level), when the sea-surface stood above the level of the platform of this 
terrace, and at no great distance eroded the foot of Monte Barbaro. 
This, therefore, is another link in the chronological chain of the Naples 
volcanic region. 
Erratics on Capri.icMy attention has been devoted to the examina- 
tion of the remnants of volcanic rocks which in places mantle the 
Cretaceous and Jurassic limestones of the island of Capri. These tuffs 
are, no doubt, often a resorted mixture of the ejectamenta from different 
sources, and of different dates, which from time to time have reached the 
island, though much of the fine-grained sanidinic variety is undoubtedly 
to be referred to much decomposed remnants of pipernoid tuff, such as is. 
often met with on the mainland. The principal part of the island, how- 
ever, is covered by a mantle of ochreous argillaceous earth, often a metre 
or more in thickness, and containing nearer its bottom a poorly defined 
band of about 0°10m. thick, composed of rock fragments identical with 
those of the museum breccia associated with the essential components of 
those ejectamenta, viz., the peculiar porphyritic obsidian and wood-like 
pumice. These fragments were of considerable size, and out of some 
pocketfuls collected during half an hour from a spot called Lima five of 
