I’d assistance - Two rocks from two locations

[Vnaz50]

San Antonio, Tx 78023

The rock in the left was found behind my sisters house about 30 yards from a dried out creek bed. It was found about 8 in down while metal detecting. So far we have pulled about six various size rocks from this hole. It looks like it hard a corn, on the top right of that rock. 
 

The rock on the right is just another one from my back yard. 

[ClearLake]

Yes, those are rocks, limestone. Your area is underlain but Cretaceous aged limestones which weather into all sorts of shapes, some unusual and interesting, some not so much. Often they may contain fossils, but I don’t see any in these two.