Well they're roots from something - are there trees nearby, or very large shrubs?

How deep is this? I'd imagine the only thing you can do is to deep dig the whole area (a bit at a time if its too big to do all at once) and remove the offending stuff as you come to it.

they look like tree roots to me. as already asked are there large trees nearby?

Thanks for replies
They look like roots but it is a reasonable distance to trees
They lie about 3-6 inches below the surface.
Maybe attempting to dig them out is the only option.

Its amazing how far tree roots can spread sometimes

Yea, what's 'a reasonable distance' exactly? If the trees are large ones, and the distance is within 60 feet, it'll be them...