Vol. 58, ] AMONG THE JURASSIC ROCKS OF SUTHERLAND. 291 
(1) The breccias are contemporaneous, that is, were deposited at the “same 
general period as the surrounding strata ; 
(2) None of the fragments haye been observed to be striated, but several are 
rounded ; 
(3) The age of the series containing the breccia-beds is exclusively Upper 
Jurassic ; 
(4) The age of the fragments is that of the Old Red Sandstone ; 
(5) A strip of this rock occurs, 77 situ, to the south of Helmsdale, between 
the granite and the Upper Jurassic rocks; and 
(6), confirming Murchison, the granite is separated from the rocks to the 
east of it by a fault. 
To base on these facts any more definite explanation of the mode 
of formation of the breccias, required some more detailed observations 
on them, combined with further knowledge of some agency at that 
time little understood. 
The further observations necessary are in part suggested by the 
facts already obtained, and should be directed to the determination 
of the following :— 
(1) What is the relation, if any can be found, between the breccia-beds and 
the Old Red Sandstone in situ? and 
(2) How are the breccia-beds distributed among the ordinary strata that 
form the presumably long series of Upper Jurassic rocks ? 
We might also hope that some hitherto unexpected feature would 
be discovered which in itself would suggest the method of formation. 
On the other hand, the most hopeful direction in which to seek the 
little understood agency is among the phenomena of ice. 
Il, Tue Inter or Op Rep Sanpsrone. 
In relation to the first of the above questions, I was fortunate 
enough, on a visit to the district in the spring of 1900, to observe 
what appeared to me a very remarkable phenomenon, though it does 
not appear to have been fully noticed before. 
On the reefs a quarter of a mile due south of Port Gower, at 
extreme low water, stands up a long jagged crest, which at this 
time of the tide is singled out from the remaining rocks by showing 
nearly vertical stratification, while all around nearly horizontal beds 
are seen. On a closer approach it is perceived that the jagging of 
the crest is due to breaking-off at different heights of the ends of the 
thin strata of which it is composed ; and, on reaching the mass itself, 
these strata are found to be hard, micaceous, and of a somewhat 
purplish tint, having the character of the Caithness Flags, and, 
therefore, like many of the breccia-fragments. (See fig. 1, p. 292.) 
The length of this crest is divided by the least elevated portions 
into two or three divisions, and extends seaward about 60 yards. 
Transversely it is about one-third as broad as this, and the height 
is between 30 and 40 feet on an average. As may be seen by the 
discoloration of the rocks, the ridge or stack is nearly covered at 
high water, which must be the reason why it has not previously 
been noticed, unless the brief reference by Prof. Judd to a remark- 
able example of a transported block ‘ found on the shore opposite 
Port Gower’ applies to this. It must have been nearly covered by 
Q.J.G.S8. No. 230. x 
