Grandmother left no will

What is the name of your state? MS.
My grrandfather died 45 years ago with no will. Then my father died in 1968 with no will. They found oil and gas on the family estate. My mother and I received one half each of my fathers part. My grandmother received a child part as well. Then my grandmother dies with not will. Does her part that would have been left to my father get split equaly between my mother and me or being the only blood relative child, do I get this part from my grandmother alone?

R. west

Each successive interest should go to the appropriate parties based on intestate succession law for the state that applies for each decedant.

Was probate done for Grandfather?

Father?

Grandmother?

AS we have no clue about spousal interests or any adopted children, we have no idea what other parties besides "blood" relatives may be out there with all these probate interests that may be entitled to estate shares, if the first probate was neglected and never filed. And then the next.....and the next.....

How is the land in question titled?