MARINE BIOLOGICAL STATION AT PORT ERIN. 65 



coast near Ramsey, and is practically continuous to the 

 south-western coast north of Port Erin, but is broken 

 across in one place by a deep transverse valley, which 

 intersects the Island between Peel and Douglas. Xorth 

 Barrule, with an altitude of 1,840 feet, forms the north- 

 eastern extremity of this ridge, which culminates 3^- miles 

 farther south-westward in Snaefell, the highest point of 

 the Island, with an elevation of 2,034 feet, while Cronk- 

 ny-Arrey-Lhaa overhanging the south-western coast, is 

 1,449 feet in height." 



" Most of the larger streams of the Island rise in the 

 vicinity of Snaefell and fall outward in different direc- 

 tions to the sea, the Sulby river and Grlen Aldyn water 

 draining northward, the Coma and the Laxey rivers east- 

 ward, the Grlass and the Baldwin south-eastward, and the 

 Xeb south-westward. The drainage of the smaller tract 

 south of the transverse valley is radial from a separate 

 centre in the south-western portion of the hill-chain, 

 whence flow the Grlen Rushen waters north and , north- 

 westward, the Foxdale river northward, and the Santon, 

 the Silverburn, and the Colby southward." 



During the Great Ice Age which terminated geological 

 as distinguished from recent times the Island was buried 

 under the mass of conjoined glaciers which filled up the 

 basin of the Irish Sea. In post-glacial times, as the ice- 

 sheet retreated from Xorth-western Europe it left the 

 configuration of the Island much as we see it at the 

 present day.* Its main valleys were in existence long 

 before that period ; its hills were doubtless somewhat 

 higher, the volume of water in the streams was greater, 

 and there were lakes of some size, especially in the Xorth, 

 where the broken remains of a large body of water, formed 

 * See Map, fig. 1, on back of title-page. 



