>>50902333this.
look at gen 1 moves / pokemon to see why.
gen 1 ground moves are all related to the ground/dirt/earth: sand attack, fissure, earthquake, bone club, bonemerang, and dig.
gen 1 rock moves are: rock throw, rock slide.
gen 1 ground pokemon: various monsters either living in the ground/on the earth or ground-related pokemon such as moles.
gen 1 rock type pokemon: mostly creatures which look like they are wholly or in part made of rock/stone or have a significant portion of their body made of hard minerals (fossils, onix the rock snake, geodude which is just a fucking rock with fists, etc).
don't think too deeply about it, OP. it's a kid's game with an elemental system.
also if you can't tell the difference between rocks and the ground then idk what to tell you.
