Abstract.  Three sections of the Pragian/Zlichovian and two sections of the Zlichovian/Dalejan
      boundary intervals, all situated in the vicinity of Prague, are described as possible candidate strato-
      types of the lower boundaries of both chronostratigraphic units.  The lower Zlichovian boundary
      should be placed as close as possible to the upper range of the tentaculite Nowakia acuaria acuaria
      (typical of the Pragian) and close to effects of the basal Zlichovian Event, as it was originally defined.
      The best level for the base of the Dalejan is the lower boundary of the Nowakia cancellata Range
      Zone, which corresponds to the original definition of this stage, and which has support in the gon-
      iatite biostratigraphy (close to the upper range of the Anetoceras fauna and to the onset of Gyrocer-
      atites gracilis), the conodont biostratigraphy (proximity of the lower limit of the Polygnathus
      laticostatus-inversus Zone) and the event-stratigraphy (close to culmination of the Daleje Fvent).