The Lake District takes the form of a roughly circular upland massif deeply dissected by a broadly radial pattern of major valleys whose present character is largely the product of repeated glaciations over the last 2 million years. However the apparent radial pattern is not from a central dome, but from an axial watershed extending west-east from St Bees Head to Shap. Most of these valleys display the U-shaped cross-section characteristic of glacial origin, and often contain elongate lakes occupying sizeable bedrock hollows, with tracts of relatively flat ground at their infilled heads, or where they are divided by lateral tributaries (Buttermere-Crummock Water; Derwent Water-Bassenthwaite Lake). Smaller lakes known as tarns occupy glacial cirques at higher elevations. It is the abundance of both which has led to the area becoming known as the Lake District. The mountains of the Lake District are also known as the Cumbrian Mountains, although this name is less frequently used than terms like the Lake District or the Lakeland Fells. As the highest ground in England, Scafell Pike (978m/3210') naturally has a very extensive view on a clear day, ranging from the Galloway Hills of Scotland to the Mourne Mountains in Northern Ireland, the Isle of Man, and Snowdonia in Wales.