60 Prof. T. G. Bonney and Miss Catherine Raisin— 
de lOuest,' close to St. Heliers, for they felt doubts as to the 
correctness of M. Noury’s view of its origin, and were struck by 
its occasional resemblance to some of the rock at Bardon Hill, 
Leicestershire, on the study of which they were then engaged. In 
hopes that it might throw light on some of the difficulties presented 
by that rock, specimens were collected, slides from which were 
examined by Prof. Bonney soon after his return to England. So 
far as concerned the immediate purpose the result was disappointing, 
for the resemblances proved to be comparatively superficial and the 
structures presented few difficulties. He was, however, convinced 
that M. Noury’s interpretation was erroneous. A brief notice would 
have been published almost immediately, but more pressing work 
has again and again obliged him to leave the slides untouched in 
his cabinet, for want of time to search through the literature of the 
subject and to study the more minute microscopic details. So they 
would be still lying, were it not for the kindness of Miss C. A. 
Raisin, who has undertaken that, the more laborious part of the 
work. 
In the walls of gardens on the northern outskirts of St. Heliers 
blocks of ‘‘spilite” are common, one being a conspicuously porphyritic 
variety. In this, erystals of plagioclase felspar, rather tabular in 
shape, sometimes about ?” in length, occur in a dark purplish matrix. 
Prof. Bonney was informed that this variety was obtained from a 
quarry situated, as nearly as he can place it, on the east side of a 
valley to the south-east of the Town Mills Road, which is now 
enclosed and converted into a very pretty shrubbery to the grounds 
of a villa. He was unable to procure a specimen, but the rock 
appeared only to differ from some of that about to be described 
in the rather greater size of the felspar crystals. 
The “‘spilite ”’ is quarried in more than one part of Mont de l'Ouest, 
a rather conspicuous eminence overlooking the sea on the north- 
western side of St. Heliers. The principal pit is on the south-eastern 
side of the hill, close to the part which is called the People’s 
Park. It is an oblong excavation with the longer side facing 
roughly east. The northern side consists of a breccia, the fragments 
being a purplish “spilite,” rarely amygdaloidal, separated by a 
compact green material. This rock much resembles one of the 
brecciated rocks which occur at Bardon Hill. At the northern end 
of the western side isa solid purplish “spilite,” without amygdaloids. 
The cliff is then cut by a dyke a few feet thick, resembling a fine- 
grained diorite. After it comes “spilite” containing apparently 
many fragments, up to about 2 inches in diameter, distinguished by 
a pale green speckling due to abundant epidote. This rock on the 
whole suggested flow-brecciation. Then follows a slightly amygda- . 
loidal “spilite.” The southern wallis formed by a purplish “‘spilite” 
with rather numerous porphyritic felspars up to about 4” long 
and amygdules. Some of the latter are approximately spherical ; 
these also seldom exceed 1” in diameter. Others are elongated and 
irregular in outline, but they are occasionally as much as an inch long. 
1 or ‘‘Gallows Hill,”’ as it is named on some maps. 
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