Round stones are probably granite: it doesn't cut easily and requires expen$ive equipment. The blades for my sandstone cutter cost $10 each and can cut about 20 feet before they are worn to the nubs.

Find a project that can use what you have, or find flat rocks for the dry stack.

Granite is cut by drilling holes and inserting feathers and wedges. It takes a bit of skill to make anythying usable out of pieces of granite smaller than a fridge.

I guess I,ll have to make my wall out of the rocks I have. I have seen pictures of some walls with mostly oval rock.
It won't be too tall and I,ll have to make it wide- correct?
Thanks for the input lazygardens and bambooo. Paul F B

I have split Wisconsin rock, mostly very ancient hard precambrian rock.

Get a good sledgehammer, heavy gloves, and high quality safety glasses or goggles.

Set round rock on ground and start tapping it. Turn if need be. Hit it harder if need be. Most rocks will crack in half. Some granites are actually pretty easy. Some rocks like marble tend to shatter while balsalt sort of "packs" under the hammer. But the technology is simple so long as you wear eye protection as rock chips will zing off sometimes. Usually not at you but it does happen.

If a rock doesn't break throw it aside and try another one. You can always come back and work on it later.

Try a book called 'The Granite Kiss'. Very instructional, the kind of book you can take with you as you build and you won't mind getting it dirty.