Eminent domain laws can be very difficult to interpret. It shouldn't be suggested that ancient artifacts belong to you because they are under your house, but no one should have to have their lives disrupted without consent just because something is located under your living space. At some point, your land is your land until you give it up.
I completely support the fact that If I wanted to go look and dig down in my basement, I could. But I am against the fact that If someone else wanted too, they'd have to come on my property. Even though It would be awesome to find treasures especially if you know where they are, I don't think anyone has a right to dig them up but you!
In the case you are digging a garden & you find an ancient artifact, that artifact should be yours. The reasoning behind my saying is that your property is yours and you can do whatever you want with YOUR PROPERTY!!!!!! So therefore, the artifacts you dig up should be yours.
As you bought the property, I suppose you have a right to change the pipes and all that stuff. You can make underground changes, such as building an underground. Why shouldn't you be allowed to dig up ancient artifacts? It is your ground, property and anything under it. If nobody finds out, you will not go to the Court...
No, I think that digging up ancient artifacts if their under your house should not be illegal, although OTHER people should not be able to come look under YOUR house. If you want to look then go for it, it is your property. But other people searching should not be able to come onto your property to look.
If they're under your own house, I don't think digging up ancient artifacts should be illegal. If you own the land, and own your house, then everything you find there should be yours. It's you land so you should own what's in it. If you find oil on your property that's yours, so why not everything else you find as long as it's not something crazy, like bombs.