GEOLOGICAL HISTORY OF SERPENTINES. 203 
strata, along their border, to dip towards or beneath the older rock. These overlying strata, 
where they abut against their marginal limit, which was the ancient shore-line, will, in 
the conditions supposed, assume, according to local circumstances, either an anticlinal or a 
synclinal form. In the former case, the inclination of the strata towards the older mass, 
which forms a resisting barrier, follows necessarily, even though the elevation of the arch 
be slight. In the case of a synclinal fold or inverted arch, we have the strata dipping 
away from the older rock at a greater or less angle, as seen at the eastern base of 
Monteferrato; the strata appearing in their natural order of superposition. When, as is 
frequently the case, this inclination passes beyond the vertical, giving rise to an overturned 
synclinal, the same strata will appear to pass in reversed order beneath the overhanging 
mass of older rock, as along the western border of Monteferrato. It is hardly necessary to 
recall the fact that sharp or inverted folds, whether synclinal or anticlinal, are often 
attended with dislocations and vertical displacements. 
It may seem superflous to insist upon these obvious principles of geological dynamics, 
but I have had occasion to notice that they are sometimes overlooked or misunderstood 
even by teachers of the science to-day. 
§ 105. Prof. Bonney who, as we have seen, holds to the igneous origin of ophiolites, 
finds in the manner in which portions of the stratified silicious rock rest upon the serpen- 
tine near Figline what he regards as a “complete proof” of the eruptive nature of the 
serpentine, placing “the intrusive character of the latter beyond all doubt,” while he 
is also satisfied that the great mass of euphotide (included by him under the name 
of gabbro) is “intrusive in the serpentine.”* Whatever view may be held of the origin 
of these two rocks and their relations to one another, the occurrence of the layers of recom- 
posed ophiolitic rock (arenaria ofiolitica and conglomerato ofiolitico) interposed, as already 
described, between the ophiolitic mass and the beds of phthanite, and even, as I observed 
in one section along the southeast base of the hill, the presence of fragments of serpentine 
in this latter, forces us to the conclusion that these sedimentary strata were deposited 
upon the ophiolite, so that the theory of the eruption of the latter since the deposition of 
the eocene beds is untenable. 
§ 106. The examinations which I have been able to make of the ophiolitic rocks of 
Eastern Liguria, where I spent a little time near Sestri Levante, under the guidance of 
Prof. G. Uzielli of Turin, was such as to leave no doubt in my mind that we have here, 
as maintained by Gastaldi, portions of an ancient stratified series rising out of the over- 
lying eocene. In addition to the varieties of serpentine, and of euphotides, diorites, 
diabases, (the amphimorphic rocks of Issel and Mazzuoli) we find eurites, jaspers, epidotic 
and steatitic rocks, with occasional limestones, and various types of argillites, including 
the hypophthanites of these authors. The whole series, including its masses of pyrites, 
more or less cupriferous and niccoliferous, presents a close resemblance to the group of 
strata accompanying the serpentine of the Huronian series in Eastern Canada, with which 
I have long been familiar. These rocks are well seen along the valley of the Acqua- 
fredda, near which I found in an eocene limestone grains of the underlying serpentine, as 
also evidences of a considerable dislocation since the deposition of the eocene strata. My 

* Geol. Magazine, Aug., 1879. vol. vi., p. 362. 
