28 
THE GEOLOGIST. 
prises the whole of these in various proportions. Melbourne proper, 
with the exception of its extreme 
western portion, which is situate on 
an older volcanic formation, is builfc 
almost wholly upon May Hill sand- 
stones and soft laminated shales. 
The whole of this stratum has evi- 
dently been subjected to immense 
disturbance, it being a matter of no 
little difficulty to discover a patch 
many j-^ards in extent within which 
the beds even approach to a hori- 
zontal position. The general incli- 
nation of the stratification more 
often verges on the perpendicular, 
whilst numerous contortions, folds, 
and doublings — tlieupper edges being 
cut away by denudation, at the same 
time that the lower are hidden far 
below the exposed portion — offer an 
interesting but withal most difficult 
problem to the geological student. 
Very many of these contortions 
Bass 
Strait 
Fig.l. — The shaded portion isSilurian; 
the very dark tiut, Granite ; the dotted, 
Tertiary, and Tertiary cove red by basalt. 
The references are : — 1. Arthur St. 2. 
INlt. Martha. 8. Mt. Eliza. 4. Yowangs. 
may perhaps be explained by the supposition of alternate elevations and 
depressions, but not a few are so intricate as to provoke queries by no 
means admitting of an easy answer. 
In some of the yet unpaved streets of the metropolis, for example, pro- 
truding edges of the shales resemble the piles of slates, seen from above, 
in a stone-mason's yard. Opposite the Supreme Court, several bends in 
the strata suggest the idea of a loosely-bomid book forcibl}^ pressed toge- 
ther from the two ends ; the inner and concave side being jDUckered up, 
whilst the outer curve is correspondingly stretched and fractured. In a 
fine section afforded by a cutting in Studley Park, the beds are nearly ver- 
tical, leaning towards each other above a pretty clearly developed anticlinal; 
such anticlinal, however, would seem rather to have been caused by lateral 
compressionthanby simply uj)heavingforcesacting from beneath. At Keilor, 
a township about tenmiles on the 
i^^^J^Ki:f:^^^^^^\i:^^ii/}^ road to Castlemaine, a natural 
^^<^-'J^fA-,i^^ section displays contortions not 
Fig. 2. — Bend in strata at Keilor, opposite side 
of valley to that represented by PI. II., and near 
the spot whence the latter was taken. 
unlike the letter S reversed and 
placed horizontally (part of this 
curve is shown in the annexed 
sketch, PI. II.), traces of the 
bend being distinctly visible on 
the opposite sides of the valley, 
• — one of denudation, — at least 
200 yards distant. And on re- 
moving the surface of Collins 
Street eight or nine years since, 
arrangements similar to the 
ground plan. Fig. 3, presented themselves, none of which seem capable of 
being accounted for by simple geological forces acting vertically. 
A somewhat remarkable feature of the strata referred to, is tlie frequent 
protrusion of Elvan dykes. Several of these masses are represented on 
the map b}^ waving lines. Prom the condition of the closely adjacent 
