I disagree. Language is a good thing to have on your A-Levels and Math you will need as you need to calculate, measure and analyse data and the preciseness needed in math is useful if this is the path you want to take. However geology would be excellent to do. To be an archaeologist you need to do the degree in university. To be completely honest i debt know if they will actually care what subjects you do as long as you are good at the core ones because no specific gcse's or a-levels are required to take the course alone.