The present paper deals with some 30 square miles of land situated in Caernarvonshire and embracing the drainage area of the River Ogwen and parts of adjacent river-basins. It is doubtful if any part of Great Britain presents in such a small area so many interesting topographical features and such beautiful and diversified scenery as this part of North Wales. It is in part a thoroughly mountainous region accompanied by characteristics that belong to mountains, and it is a glaciated mountain region with typical glacial topography. But adjoining the mountains is an area of entirely different characteristics, and the change from the one to the other is sudden and complete. An upland plain abruptly terminates against a range of mountains without the interposition of foot-hills, the crags and pinnacles rising precipitously from the level land; or, in other words, the plain cuts as it were a shelf in the mountainous masses.
Small-area analyses of bone cancer diagnosed in Great Britain provide clues to aetiology
