Re: Why are hills formed?

Your question is both simple and copmplex.  There are two basic ways to 
create a hill.  One is to push or otherwise move the material that makes 
up the hill into place.  Examples of this include everything from huge 
mountain chains such as the Himalaya, which have been pushed up by the 
collision of two continents, to morraines, which have been pushed up by 
glaciers, to coastal sand dunes, which have been piled up by the wind, to 
little piles of dirt that get heaved up by the frost in cold climates.  

The other way to make a hill is to remove all of the material that is not 
the hill.  Erosion is constantly eating away at the landscape and some 
parts erode faster than others.  That could be beacuse they are weaker, or 
because they are acted on by stronger erosive agents, but for whatever 
reason, if some part of the landscape is preferentially removed, what is 
left will likely stick up as a hill.

In England, the latter is probably the case, as there hasn't been much 
tectonics recently, although they could be glacial as well.  I'm afraid 
you'd need a local expert to answer the details (although glacial 
morraines are pretty obviously a mixed up mess of everything from clay to 
boulders).  

Hope this helps,
Dave Smith