Hello. I have an area in my yard that was covered in stone (inch triangular grayish blue stuff) many years ago, probably 4 inches deep. Over many years, things decayed over the stones, and now there is an inch or so of soil, and the area is covered with pachysandra and other plants that creeped over from a garden area.

I'd like to put grass there, and prefer not to take the stones up. What do you suggest? Shall i add an inch or two of soil and seed and call it a day? or any reason i should remove the stone? if money were no object i would remove them, but just trying to understand my options. thanks