164, REPORT—1862. 
ralogical composition of the granites of Donegal, and the minerals associated’ 
with them.” In furtherance of this object, Mr. Haughton and Mr. Scott re- 
paired, last Easter, to the northern part of the county, as they had visited the 
S.W. portion of the district in the summer of 1861. They were accompanied 
on their tour by Mr. Jukes, Local Director of the Geological Survey of Ireland, 
who gave them the valuable benefit of his experience and assistance throughout 
the tour. The exploration commenced at Moville, on the E. shore of Innis- 
howen, whence a section was carried along the N. coast of that peninsula 
nearly as far as Malin Head. This section exhibited a great thickness of 
“primary rocks, consisting of quartzite and mica-slate, accompanied by several 
beds of limestone, and a number of beds of igneous rocks, which appeared to 
de contemporaneous with the sedimentary rocks. These are best exhibited at a 
place called the Mintiaghs or Bar of Inch, where there are several alternations 
of quartz-rock and syenite exhibited in an escarpment of several hundred feet 
in height. This locality is situated about five miles N. of Buncrana. From 
Buncrana, the granite of Urrismenagh, near Dunaff Head, was visited. 
From Milford an excursion was made to the extremity of the promontory 
of Fanad, lying between Lough Swilly and Sheep Haven, in order to visit the 
granite of this district. This patch of granite is not a continuation of that 
which traverses the country in a N.E. and 8.W. direction, as it lies to the 
N. of that axis and exhibits a slight difference in composition from the granite 
of the central axis. From Milford the route lay to Dunfanaghy ; anda section 
was made across the northern end of the granitic axis of the county at Glen, 
in which its gneissose character was very strongly exhibited. This was 
marked in a most decisive manner between Lackagh Bridge and Creeshlagh, 
where the rock might be observed changing from gneiss, by almost insensible 
gradations, on the one hand into granite, and on the other into hornblende slate 
and crystalline syenite. The latter is most highly crystalline at Horn Head, 
where it contains large quantities of titaniciron. On the return-journey from 
Dunfanaghy to Letterkenny, it was determined to make two sections across 
the granite ; so that Mr. Haughton and Mr. Scott took the road from Creesh- 
lagh through the Gap of Barnesbeg, while Mr. Jukes took that by Owencarrow 
Bridge, about four miles higher up the valley. 
It having now been found necessary to compare the facts observed with 
those which were to be observed in other countries, Sir R. Griffith repaired 
to Scotland in the month of July. Mr. Haughton traversed the centre of 
Scotland, and paid a visit to Sweden, Finland, and Russia. Both these gen- 
tlemen discovered facts strongly confirming the views propounded at the 
Manchester Meeting, of the similarity of the geological structure of Donegal 
to that of the Scandinavian peninsula and of Scotland. For this latter fact 
the Committee had been prepared by the examination of a series of specimens 
of Scotch granites which had been furnished to them by Sir R. I. Murchison, 
in accordance with his kind promise made at the last Meeting. 
While these tours were in progress, Mr. Scott repaired, for the third time, 
to Donegal, and spent the month of July in the re-examination of ‘several 
points connected with the geology of the southern district. He visited the 
granite of Barnesmore, near the town of Donegal, which is essentially non- 
gneissose, and is penetrated by numerous pitchstone dykes, some of which 
are amygdaloidal. Numerous minerals were discovered here, which were in 
some cases new to the district. In the neighbourhood of Glenties, a consi- 
derable quantity of andalusite was found in the mica-slate—a mineral which 
is replaced near Barnesmore by kyanite, and in the Rosses, near Dungloe, by 
a white variety of kyanite. 
