OF THE ALPS, NORTH ITALY. 861 
exceedingly instructive section. These beds are capped, as shown 
in figure 4, by moraine débris (c); and it is interesting to note 
that this moraine matter is the western limit of the great right 
lateral moraine which was thrown out from the Val d’Orta. On 
passing to the westward of Maggiora no more of such drift is seen ; 
the low porphyry hills at the back of Boca are free from it. Here, 
again, we find the soft Tertiary formation coming in where glacial 
action has been in a less degree exerted, on the margin of the great 
glacier which extended from this point 18 miles without a break, 
to the left lateral moraine on the flank of Monte Grande, near 
Gavirate, onthe Lago Varese. This Tertiary remnant has here also, 
as at the Lago d’Orta, been protected by the steep scarp of the porphyry 
against which it rests. If these beds, as well as those at Boca, be 
proved to belong to the Newer Pliocene, like those at Monte Grande 
and at Strambinello, near Ivrea, then this was somewhere near the 
limit of the coast-line of that later Pliocene sea. Maggiora is more 
than 500 feet above the level of Lago Maggiore, only eight miles to 
the east, so that if during later Pliocene times the sea did not extend 
to the Orta valley, there is every reason for supposing that it did 
extend far up the depression of Maggiore, and its two great branches 
the Toce and Ticino, of which I shall give some further proof. The 
Inferior, or Older, Pliocene of Orta first described, may have had 
even a wider extension northward, further within the mountains 
than the Newer. 
Tur NEIGHBOURHOOD oF IVREA. 
The next and last sections I shall refer to are those I saw first 
in the neighbourhood of Ivrea, especially that at Strambinello, 
referred to by Gastaldi. J am indebted to the kindness of Signor 
Luigi Bruno, a land-surveyor of Ivrea, for calling my attention to 
the section; it was he who recommended me to visit the place, 
as well as several others of geological interest in the neighbourhood ; 
and he also showed me his plans and sections. My best thanks are 
also due to him for his section, which I now produce (fig. 5), made 
in 1870, drawn by him, and subsequently forwarded to me. 
Any one visiting this old town should go to Strambinello; for not 
only is it interesting to the geologist, but the scenery of the Chiu- 
sella valley is very beautiful. As the section may not be commonly 
known to English geologists, and as it is most instructive and bears 
on the previous sections treated of, I give a description of it. 
At the bridge spanning the Chiusella beyond Strambinello, at 
1059 feet above the sea, the base of the Pliocene with marine shells 
is seen, resting horizontally on the diorite rock, through which the 
river has since cut its way some feet below. The difference of 
denudation and its action on the rock is very well displayed here, 
when; first, it was subjected to ice-action and water combined, and, 
secondly, to water-action only, as at the present day. 
On the south bank the Pliocene is broken up and mixed with 
diorite detritus, showing that their destruction was due to their more 
Q.J.G.S. No. 160. 3M 
