﻿Henry S. Hoivorth — Geology of the Isle of Man. 411 



of a conglomerate, and occasional pockets and layers of consolidated 

 fine red mud. The whole thickness is not more than twenty feet at 

 any point. The conglomerate consists of a very closely packed 

 series of boulders, some of them rounded and some with their 

 edges sharp, imbedded in a matrix of consolidated red mud, similar 

 to that just mentioned. 



The boulders just referred to are of various sizes, from a foot and 

 a foot and a half in diameter to small pebbles, and, so far as a careful 

 and prolonged examination could discover, consist almost entirely of 

 pieces of limestone and quartz, the limestone forming about -i% 

 of the whole. These limestone boulders are some of them of the 

 natural colour of the limestone, and others are deeply coloured with 

 iron. These boulders are most clearly of Mountain Limestone, and of 

 the same character as the bedded limestone close by, and but for the 

 colour of a number of them, there would never have been any doubt 

 that they were formed out of the disintegrated limestone. Again, 

 the muddy matrix in which the boulders are imbedded, as well 

 as the intercalated pockets, consists of a paste made up largely of 

 pulverized limestone. 



These facts seem to admit of but one conclusion. A conglomerate 

 consisting almost entirely of limestone boulders, imbedded in a 

 matrix of pulverized limestone, lying immediately in contact with 

 beds of limestone, cannot well by any process of reasoning be made 

 into an " Old Eed Conglomerate." Unless there be some reason of a 

 very marked kind to the contrary, the conclusion is inevitable that it 

 has been formed of the disintegrated beds of Mountain Limestone, 

 and is posterior in date to them. 



Thirdly, as to the position of these beds. Mr. Gumming says they 

 underlie the limestone which rests conformably upon them. I have 

 searched carefully the various points where they appear at Langness, 

 on the banks of the river Santon, at Cushnahavin, and in Derby- 

 haven bay, and nowhere can I find evidence to support this state- 

 ment. The sections exposed are nearly all on the coast, and are 

 much obscured by the overgrowth of sea-weed, and by discoloura- 

 tion, etc., etc. There was only one place where the sequence of the 

 beds seemed to me unmistakable, and that was in the beds lying 

 almost horizontally between high and low water mark in Derby- 

 haven bay, and there, certainly, as far as I could make out, the grey 

 and dai^k coloured limestone was overlain by beds of an ochreous 

 colour, still unmistakable limestone, and in every respect bedded 

 like the grey limestone just mentioned; above this red-coloured lime- 

 stone again lay the beds of red conglomerate. Nowhere, as I have 

 said, could I see any evidences that the conglomerate was overlain 

 by the limestone, nor do I believe, after having tested the position 

 carefully, that such a succession of the beds can be seen anywhere in 

 this part of the island. On the contrary, north of the Santon 

 brook, where, by the violence of the great discharge of traj), the 

 beds are torn and twisted in an extraordinary fashion, a bed of 

 limestone has been thrown up on end, and its lower surface has been 

 bared, and we can examine very easily both its upper and lower 



