Yol. 51.] CRUSH-CONGLOMERATES OP THE ISLE OF MAST. 569 



into fragments yield a crush-conglomerate very like that in Sulby 

 Glen presently to be described. These rocks I propose to term 

 the 'Niarbyl Flags.' 



They re-appear for a short distance in the coast-section 2^ miles 

 north of Peel. Immediately beyond the northern termination of 

 these flags in the coast-section a huge mass of slaty conglomerate 

 makes its appearance, occupying the whole of the foreshore and the 

 cliff 40 to 50 feet high in the headland south of Gob y Deigan, 3 

 miles north of Peel. It is here that the structure was noticed by 

 Henslow. 1 The section is however rather difficult of access ; and 

 for convenient study the inland exposures of Sulby Glen and of the 

 neighbourhood of Ramsey are preferable. 



About a mile farther north, at Gob ny Creggan Glassey, there is 

 again an exhibition of the brecciated structure, but it is confined to 

 a narrow band of limited extent. From a little beyond this place, 

 the cliffs of the west coast are composed entirely of drift. 



(b) Inland Sections. 2 — The character of the inland exposures is 

 frequently so unfavourable for study that, as Henslow pointed out, 

 the conglomeratic structure is not always easy to discriminate, 

 especially where the breccia is fine-grained, and the inclusions 

 chiefly argillaceous. It is therefore possible that the structure may 

 exist in a few places where I have as yet failed to detect it ; but 

 such cases are not likely to be numerous or extensive. 



In passing inland from the coast in the neighbourhood of 

 Gob y Deigan a belt of about 4 mile of contorted flaggy slates and 

 grits is traversed, and on the farther side, around the head of 

 Glion Cam and in the quarterland of Corvalley and again near 

 Chester, some obscure exposures of the crush-conglomerate may be 

 seen. . On the same line of strike about 2 miles farther north-east 

 similar traces occur, on the slope above the village of Kirk Michael, 

 but no clear section is afforded in any of these localities. It is not 

 probable, however, that the crush-material of this belt is anywhere 

 thick. 



For more satisfactory exposures we must pass 4 miles farther 

 inland, across the hilly ridge which rises in Slieau Freoaghane to a 

 height of 1602 feet. This ridge is composed of a variable series of 

 banded and on the whole rather sandy beds, with broad masses of 

 dark blue, more purely argillaceous slates. From it we.descend into 

 the wide elevated basin of the Sulby River, wherein occurs by far 

 the grandest development of the crush-conglomerate to be found in 

 the Island, and fortunately under circumstances peculiarly favour- 

 able for examination. 



(c) Sulby Glen. — A feeder of the River Neb which takes its rise 

 on the col between Lhargee Ruy and Colden, flows near its head 

 for about 100 yards over a slaty breccia, crowded with subangular 

 and lenticular fragments of fine-grained grit and pale slate, of 

 which the largest are about 6 inches in length. A mantle of 



1 Trans. Geol. Soc. ser. 1, vol. v. (1820) p. 490. 



2 Puller local details of these sections are reserved for the Survey Memoir. 



