Gegebi alawodudu akoko to gba baseball ni idije na lati eyin ewadun 1880, o kopa koko ninu mimu iwa ipinsoto eleya wa sopin ninu ere baseball, eyi to ti fa awon agba boolu alawodudu si pe ki won o mo gba boolu ni Negro leagues nikan fun ogota odun.Itokasiawon ojoibi ni 1919Awon ojoalaisi ni 1972Awon ara AmerikaAwon omo Afrika Amerika.. 
As with other deleologic Periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several million years.. 