You need to help us by measuring your items, or placing some common object, like a penny, etc., next to the object.
I would keep detecting that area & dig everything . One time I found a small railroad uniform button. I kept searching the area & dug up ALL the buttons to the jacket, that was rotted away, except for a small patch of cloth on one of the buttons. I donated the set of buttons to the small museum of the small, historical town I was in.