Complex sentence: Four such circular structures have been unearthed so far; geophysical surveys indicate that there are 16 more, enclosing up to eight pillars each, amounting to nearly 200 pillars in all.
Split into simpler sentences: Four such circular structures have been unearthed so far. Geophysical surveys indicate that there are 16 more, enclosing up to eight pillars each, amounting to nearly 200 pillars in all.