The Collaborative International Dictionary
Successional
Successional \Suc*ces"sion*al\, a.
Of or pertaining to a succession; existing in a regular
order; consecutive. ``Successional teeth.''
--Flower. --
Suc*ces"sion*al*ly, adv.
Wiktionary
successional
a. Of, related to or caused by succession
Usage examples of "successional".
Anyway, whether you call it a successional trend or an evolutionary trend, the species selectionists may well be right to believe that it is this kind of trend that they, as palaeontologists, are often dealing with in successive strata of the fossil record.