professor Jameson on Secondary Greenstone and Wache. 141 
4. Transitions from greenstone, through wacke and slate- 
clay, into sandstone. 
5. The earthy character of the greenstone. 
But in what manner are these facts connected with the Vol- 
canic and Neptunian hypotheses ? 
The parallelism of the greenstone-beds with the thin layers of 
slate-clay resting upon and lying immediately under them, is not 
easily reconcileable with the volcanic hypothesis; because, had the 
greenstone been forced, in the state of lava, amongst the slate- 
clay, it would have presented a very irregular intermixture at the 
line of junction, and not the perfectly regular meeting every 
where visible in this section. But perfect parallelism is what we 
would expect according to the Neptunian view. The alterna- 
tion of beds of highly crystallized sandstone (highly indurated 
sandstone of the Plutonists) with slate-clay, and the circum- 
stance of masses of unaltered slate-clay and marl occurring in 
the most highly crystallized sandstone, immediately over the 
greenstone, prove that this crystallization (liardening) is not 
produced by heat flowing from greenstone in a state of fu- 
sion, otherwise the slate-clay ought also to have been melted. 
Lastly, The transitions from greenstone into wacke, wacke into 
clay, clay into sandstone, prove that the same agent must have 
presided at the formation of these different rocks, — an explana- 
tion irreconcileable with the Volcanic, but in perfect unison with 
the Neptunian hypothesis. 
Section (^Alternations Wacke, Bituminous Shale, i^c. at the 
Calton Hill, Edinburgh. 
There is another fine display of stratification, highly illustra- 
tive of the mode of formation of greenstone and wacke, at pre- 
sent exposed on the north-east side of the grand road which 
leads across the Calton Hill. 
The following description contains an enumeration of the 
principal features of this fine section. 
The Calton Hill, in a general view, may be considered as a 
vast bed of porphyry rising above the surrounding rocks of the 
coal formation. This bed dips towards the east under an angle 
of 20®, and the direction is north and south. 
