If you do utilize the jacks you'll have to make sure the earthen footing is prepared for that concentrated weight IF it's applied. In the picture you can see they are using masonry piers systems. To be honest those aren't allowed in this area by our building inspectors due to the fact they are more for small decks and not designed for heavy loads such as main structures.
Good luck and always get the advice of a licensed inspector before you get started. They can save you their weight in gold (and some of them are pretty HEAVT too
)
Allen