Piece in the valley

It would be easier to persuade people not enamoured of knowledge or interested in information, to embrace a nineteenth century curiosity for the natural world, if labelling was not so imprecise. Or, rather, it is hard to reconcile the existing nomenclature.

Take valleys. We picnic in valleys, we rest in their shade and admire their aspect, but we don't give them much more thought. Perhaps the locale of pleasant memories is not the basis for a dry discourse. Or vice versa.

Still, as I'd written on rivers, which run through valleys, and mountains, through which valleys nestle, it seemed reasonable to have a peek down their side.

In its broader sense a valley is identical to a dale. One with a river can be a vale. There are the river valleys, cradle of civilisation - having all that is necessary for the basis of primitive agriculture, and for development beyond that.

The largest valley is the Great Rift Valley. Rift valleys are created by the action of a geological rift or fault.
Not every valley is as clear cut. Capertee Valley is the widest valley. According to one source it is also the "world's largest canyon". Yet, when researching narrow and deep valleys, another source describes deep, narrow valleys as being known as "canyons or gorges", and not even normally referred to as valleys. Now if this is the case, why would a wide valley be known as a canyon at all, never mind the widest valley?

So perhaps there are other conditions under which a valley can be classified as a canyon.

Tiger Leaping Gorge is the longest, narrowest, and deepest gorge in the world.

A correspondent to an online Q and A conjectured that the Mariana Trench is the deepest but probably couldn't be considered a valley since it is underwater.

The premise of measuring valleys accurately to determine whether they are also (or rather) a hollow or a coon is fraught by complication. Even in this day and age.
There are enough glens and ravines to go around, straths aplenty. The earth doesn't lack for terms to describe the bits where it splits.
A dell was a part of the landscape long before it adorned desktops, a gully had nothing to do with cricket,  and kloofs, well what are kloofs?!