This Pokédex, which was introduced in Generation I, is the first regional Pokédex. The numbering in this Pokédex would serve as the basis for the official listing of all Pokémon introduced, with subsequent generations' Pokémon being added on to the end, with the name of "Old Pokédex" in Generation II and then the "National Pokédex" ever since, starting with Generation III. For more info on this expanded number listing see this list.
List of Pokémon by Kanto Pokédex number
#001 - #051 Bulbasaur - Dugtrio
#052 - #101 Meowth - Electrode
#102 - #151 Exeggcute - Mew