The original age assignment of Triassic was based upon the recovery of only one type of fossil pollen, striate bisaccates, from the sample submitted as 63ARr 58. The determination was correct based upon the evidence at hand.

I did not know at that time a significant fact which has since developed from the study of a large number of Alaskan pollen samples: striate bisaccates are widespread as reworked contaminants in younger rocks. In most cases they are well preserved, so that they are not readily distinguishable from the indigenous pollen flora. Striate bisaccate pollen is durable, and may out-last the indigenous pollen under degradative conditions, which were the norm for the Alaskan material. This situation creates a misleading and unavoidable trap for the palynologist; I fell into it in the earlier report.

The sample from the same locality submitted as 66ATr 175 contains better preserved material. In addition to the reworked striate bisaccate pollen, other genera, such as Tauracosporites, Cicatricosporites, Tasmanites, and Tythodiscus, are present. The assemblage is that associated at numerous other localities with the “tasmanites” oil shale. Its age, though not yet accurately determined from palynomorphs, is in the Jurassic-Early Cretaceous range rather than Triassic as earlier reported.