160 Proceedings of Boy at Society of Edinlv^rgh, [fee. 20, 
3. Contact-Phenomena of some Scottish Olivine-Diabases. ^ 
By Ernst Stecher, Ph.D.,' Leipzig. Communicated hy * 
Archibald Geikie, F.R.S., Director-General of the Geological ^ 
Survey."^ 
In the second and third numbers of the ninth volume of R 
I 
TscliermaP s Miner alogisclie und petrographische Mittlieilungen^ I 
published the results of an examination of some “ dolerites ” from 
the Carboniferous basin of the Firth of Forth, the material for which | 
I obtained through the kindness of Prof. Archibald Geikie. It is 
true most of the “ dolerites ” are already well known through the 
valuable writings of Professor A. Geikie t and Mr Allport, J but a 
special study of the modifications of the rock in the different parts 
of any one volcanic mass has not yet been the subject of any paper. 
Having elicited many facts of petrological interest, I purpose giving- 
in this communication a short account of my investigations. At 
the outset, I may state that the specimens which I have examined 
were obtained from the following localities : — Salisbury Crags, 
Hound Point, Stewartfield (near Broxburn), head of Aherdour 
pier, Hawk-Crag (near Aherdour), Colinswell, the coast west of St 
Monan’s Church, Dodhead Quarry and Kilmundy Quarry (near 
Burntisland), Simnyhank Quarry (near Inverkeithing), and FTew- 
halls (near Queensferry). These rocks have all been grouped hy 
Mr Allport under the common name of dolerites. Professor Geikie, 
however, assigned them partly to the dolerites, partly to the diabases. 
My conviction, arrived at hy the study of the rocks to he described. 
* My friend Professor Zirkel, having told me that he was often at a loss for 
a subject of original investigation to prescribe as a thesis for the doctorate at 
Leipzig, and having asked me for assistance in the matter, I suggested the 
contact-metarnorphism and connected phenomena of the eruptive rocks in the 
basin of the Firth of Forth, which had never been fully investigated. He 
accepted the suggestion, and I forw-arded to him a series of specimens collected 
as material for the purpose of working out the subject. The thesis was eventu- 
ally taken up by Dr Stecher, and the results of his investigations are con- 
densed in the present paper. — A. G. 
d Arch. Geikie, “ On the Carboniferous Volcanic Rocks of the Basin of the 
Firth of Forth,” 1879, Text- Book of Geology, p. 535, &c. 
d S. Allport, “On the Microscopic Structure and Composition of British 
Carboniferous Dolerites,” Quart. Jour. Geol. Soc., 1874, vol. xxx. p. 529, 
&c. 
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