O. H. Morton— Geology of the Isle of Man. 2 1 3 



what obscured by stones and sea- weed. I, however, found without 

 difficulty a spot on the shore, north of the copper mine, where the 

 Old Bed Conglomerate clearly dips below the Carboniferous Lime- 

 stone, and trap-dykes traversing both alike. I found the boulders 

 and pebbles in the Conglomerate to be quartzite instead of limestone 

 — at least all I could find were quartzite, and many I tried with acid 

 so as to be perfectly sure about them. In colour they certainly 

 resemble the limestone in the vicinity, but they still more nearly 

 resemble the quartzite interstratified with the Silurian in close 

 proximity. 



Mr. Howorth says he found no Old Eed Conglomerate, but the 

 limestone resting directly on the Silurian at Cushnahavin, but Mr. 

 Cumming describes how the limestone is faulted against the Silurian 

 at that place so that the appearance may easily be explained, and he 

 states that the Conglomerate occurs at a little distance, about 10 feet 

 below high- water mark. I found the top of it under the limestone 

 just as described, and have great confidence in the correctness of Mr. 

 Cumming's sections, though I had not time to follow them across 

 the whole area. I need scarcely remark on the improbability of 

 trap- dykes intersecting Boulder-clay, and volcanic vents in the 

 British Seas in Post-Tertiary times. 



Mr. Howorth says he was not at Peel, and that his arguments only 

 apply to the south of the island; but I visited that locality and found the 

 Old Bed Sandstone to be interstratified with a conglomerate in steep 

 cliffs dipping towards the sea at a considerable angle. Mr. Cumming 

 refers to numerous blocks of limestone thrown up by the waves along 

 the shore, and concludes that there are beds of it on the dip at no great 

 distance from the land. He also states that limestone was formerly 

 obtained and burnt in kilns, though unable to determine whether it was 

 an interbedded cornstone or an overlying limestone. However, there 

 seems no doubt that the Bed Sandstone with conglomerate at Peel is 

 of the same age as the Conglomerate about Castleton. Mr. Howorth 

 states that he is only an amateur geologist, and had only three days 

 in the district ; but Mr. Cumming resided in the island, being Vice- 

 Principal of St. John's College — within gun-shot from the Old Bed 

 Conglomerate — and it is very improbable that he made any mistake 

 in its geological position — however nearly it may resemble some local 

 Boulder-clay. It is surprising that Mr. Howorth's paper has not 

 been noticed ; for, being the most recent communication on the 

 subject, it tends to throw doubt on the stratigraphical order of the 

 Carboniferous series in the Isle of Man — and the Old Bed Con- 

 glomerate must be considered to be the base of it. 



In conclusion, I recommend those interested in the subject to read 

 Mr. Home's paper, for he very fully describes the Old Bed Sandstone 

 of Mr. Cumming, which he considers to represent the Calciferous 

 Sandstone series of Scotland, and consequently can entertain no 

 doubt as to its position being beneath the Carboniferous Limestone. 



Liverpool Geol. Soc, Fd. 10, 1879. 



