THE fourth part of the sketch of the geography and geology of the Himalayas is entirely the work of Mr. H. H. Hayden, and is devoted to a review of the present state of our knowledge of the Himalayas.

Sketch maps, satellite images, photos, GIS maps and geology maps are all useful, too. This video shows how to use an OS map, using scale and grid references. Find out more about GCSE Geography .