Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne (1867).djvu/99

Rh The main branch of the Aln has its sources on the eastern slope of the Cheviot range near to Alnham, where the junction of a few sikes, or mountain streamlets, forms the Ale-water. The highest hills at the head of the vale of the Aln are the Grey Yade of Coppall (900 feet), and Cochrane Pike (1096 feet), which, like the other Cheviot hills, are bare and grassy, with here and there an outbreak of porphyritic rock. The general course of the river is from west to east, and its length about 24 miles. The upper portion flows in a pretty wide valley, between the porphyritic hills on the north and the great sandstone ridge on the south and south-east. It skirts the base of this ridge for 11 miles till it reaches Brislaw, where it cuts through the ridge which, at the Beacon Hill on Alnwick Moor, attains 808 feet; and after crossing Hulme Park, which extends about 3 miles, and, passing by Hulme and Alnwick Abbeys and Alnwick Castle, it winds its way south-eastward and falls into the sea at Alnmouth.

The drainage area of the upper portion is from 3 to 11 miles wide, the principal affluents on the south being the Coo and Edlingham Burns, which are more than 5 miles in length, and drain the moorlands of the sandstone ridge about Coo Crag (1004 feet), and of Rimside (816 feet), where there is a station for . The ridge is here several miles broad, heathery, and in many places boggy, and extends southward without interruption to the Coquet. On its eastern slope Rugley Burn has its source in Alnwick Moor and in Rugley Old Dene; by the side of this burn grow ', ', and . On the north of the Aln two branch-streams, Eglingham and Shipley Burns, which have a course of about 6 miles, and unite and join the Aln near Shipley, have their sources in the Chillingham and Charlton Moors, which have an elevation of from 600 to 1000 feet. At the base of the Eglingham hills is Kimmer Lough, now about 9 acres in extent, but formerly much larger.