upper boundary defined by

5 triples
GPTKB property

Random triples
Subject Object
gptkb:Stage_10_of_the_Cambrian base of the Ordovician Period
gptkb:Jiangshanian_Stage first appearance of Lotagnostus americanus
gptkb:Stage_3_(Cambrian) base of Cambrian Stage 4
gptkb:Drumian_Stage first appearance of Lejopyge laevigata
gptkb:Jiangshanian_stage First appearance of Lotagnostus americanus