290 REV, J. F. BLAKE ON 4 REMARKABLE INLIER [| May 1902, 
17. On a Remarxasre Inuier among the Jurassic Rocks of SurHEr- 
LAND, and tts Beartne on the Ortein of the Brueccra-Bups. 
By the Rev. Joun FRepsrick Brake, M.A., F.G.S. (Read 
March 26th, 1902.) i 
ConTENTS. 
Page 
Ts. -Tntroduction : cccicice cca cetled badencae oh tae 290 
IT. The Inlier of Old Red Sandstone, «..4..02.2-5-o eee eee 291 
IIL. The Distribution of the Breccia-Beds in the Upper Jurassic Series. 297 
IV. Summary of Results 2... [..0).-.cacesdouss rece eee 303 
V. Comparison of the Breccia-Beds with the Work of an Ice-Foot. 304 
VI. Consideration of Difficulties: 2 s.0.0..0sc000c: ssc banescke eee 307 
WII. Concluding Remarks, 5... 50522474 506056 03 poealeaas + Cone ee ee 309 
I. InrRopUCTION, 
‘Tne remarkable deposits, consisting of large angular and rounded 
stones, that skirt the western shores of the Moray Firth, on either 
side of Helmsdale, have already attracted the attention of two 
eminent geologists. 
Sir R fierce Murchison, who was the first to describe them in 
1826,' considered them to be the result of the upheaval of the 
neighbouring granite. This upheaval of the granite, in his view, 
broke up the Jurassic rocks along its south-eastern border, and 
scattered their fragments haphazard in the neighbourhood of the 
fault. In the phraseology of some modern writers he considered 
them to be crush-conglomerates, but his own name for them was 
‘brecciated beds.’ This name and his explanation assumed the 
exclusively Jurassic age of the fragments, and both were therefore 
rendered untenable by the discovery in some of these fragments of 
Old-Red-Sandstone fish-remains. | 
Prof. Judd, who, in 1873,7 first determined the general age of the 
rocks as Upper Jurassic, and described them in far greater detail, 
would not bind himself to any definite theory of their origin, but 
hoped that at some future time the question would be elucidated by 
the discovery of analogous phenomena elsewhere—a hope which the 
preseut communication aspires to fulfil, Meanwhile he suggested 
as the most probable hypothesis at that time, that the blocks com- 
posing the breccia had been carried by floods in a large river that 
aid not reach the sea-shore in the form of a glacier. 
At the present time, the only possible explanation before the 
world is still that given by Prof. Judd, who, whatever modifications 
his hypothesis may require, has clearly laid the following foundation 
of fact :— 
1 Trans. Geol. Soc. ser. 2, vol. ii, pt. ii (1827) p. 293 
> Quart. Journ. Geol. Soc. vol. xxix (1873) pp. 97-195, 
