84 J. A. Birds — On the hie of Man. 



together with a profusion of traps and porphyries, some I believe 

 from the Cheviots, and several specimens of Prehnite (or one of the 

 same family of minerals) which (according to Hall's Mineralogist's 

 Directory) is not to be found in situ nearer than Beith in Ayrshire, 

 or, in abundance, than Kenfrewshire, or the Kilpatrick Hills in the 

 neighbourhood of Glasgow. 



The whole northern plain of the island — as may be seen by sections 

 at Riversdale, on the 'banks of the Sulby river near Ramsey, on the 

 roads to Kirk- Andreas and Kirk-Bride, and between the latter village 

 and Blue Point, in the neighbourhood of Ballaugh, at Turby, and 

 thence south to Kirk-Michael — is composed of similar deposits, all 

 belonging, I believe, to the Lower Boulder-clay and Middle Drift. 

 The same formations, or at least the sands and gravel, are to be seen 

 at Peel in the west, and may be traced for some miles up the central 

 valley of the island. They may be seen again along the railway 

 from Ballasalla to Port St. Mary. A considerable thickness of the 

 sands appears in a cutting of the same railway near Port .Soderick, 

 and they must be or have been present in considerable strength at 

 Douglas, as the sandy shore and beach of the bay has no doubt been 

 formed from tbeir remains ; though it is difficult, now that the land 

 has been built over, to find any good sections. 



If now we quit the shores, and ascend towards the higher ground 

 and the mountains, we come to a totally different kind of deposit. 

 It consists generally of a yellowish-brown, though occasionally 

 bluish, or reddish, loam, containing angular fragments of almost 

 exclusively local rocks, viz. Silurian schist with 'green-ash,' green- 

 stone, and quartz, together with a few fragments of Old Eed Sand- 

 stone, and a very few, if any not-derived, foreign rocks. This I 

 believe to be the true Upper Boulder-clay. It may be traced from 

 the southern extremity of the island, near Craigneesh (probably it is 

 a patch of the same which is marked by Mr. Cumming on the Calf 

 Islet), to the northern corner of Port Erin Bay, and thence along 

 the southern base of the hills by Colby and Arbory, to Ballasalla. It 

 is well seen in the cuttings of the railway thence to Douglas, and at 

 the station there. It covers the cliffs at Douglas Head ; it may be 

 seen at several points along the road from Quai'ter Bridge to Onchan, 

 and capping the cliffs on the northern side of Douglas Bay; it is trace- 

 able along the road above the valley of the Glass river from Douglas 

 to Abbey Lands ; it crowns the quarry at the side of the road from 

 the Lunatic Asylum to Union Mills, is present in strong force there, 

 and may be seen in every cutting of the railway thence almost to St. 

 John's. In the north of the Island, too, one comes upon it directly 

 on leaving the plain, as at the mouth of the Ballure Glen, at Eamsey, 

 and on the left or mountain side of the road thence to Kirk-Michael. 

 It is present also in the banks of the Foxdale river. 



Prom the fact that this clay is found almost always at a higher 

 level than the Middle Drift sands, and from its containing scarcely 

 any but local rocks, and those always angular or in a very slightly 

 rolled condition, I conclude that it is the wash of the mountains to- 

 wards the later part of their rise and in the beginning of their second 



