I guess most likely it will be in a box with 35x40 cm and the depth it depends on the soil some time when there are rocks it wil be from 2-3 m as you know it is very old civilizations and most excavation they found some tools in 1.8 m under ground.
If the items small than the medium jars .
Most time i search in desert and there is no much trash .
Most of times the ground is not have much mineralized but there are some rocks have some minerals .