Here are a couple excerpts from the article (by Emil Silvestru): "The evolutionary paradox of the Roraima pollen of South America is still not solved."
Microfossils have been reported from the Roraima Formation (RF) in British Guiana as early as 1964, soon after its Paleoproterozoic age was ‘established’. They were described as sponge spicules and possible remnants of foraminifera and radiolaria. The previous year well-preserved pollen and spores were found in rocks from Cero Venamo (composed of the same RF rocks) by botanist Dunsterville. His discovery was treated with suspicion, given the Precambrian age for the formation. Then in 1966, Stainforth6 announced the discovery of pollen and spores (henceforth called ‘microfossils’) in the same formation at Paruima. The microfossil assemblage is described as different from the present local floral association and is most likely ‘Tertiary’ (Stainforth mentions some authors who place it in the Miocene). Although no palynological inventory is presented, angiosperm pollen must be included.
And the second quote:
With all the above in mind, since according to observational science contamination is the least probable of all possibilities (a Holmesian ‘impossible’), there seem to be only two solutions:
1. The whole evolutionary biostratigraphy which places the first angiosperm pollen in the Early Cretaceous is wrong, angiosperms being in fact present throughout the entire geologic column (does that sound like something you have already read about?). This would of course be the equivalent of Haldane’s rabbit and mortally wound the ‘evolutionary elephant’.
2. The CF is Tertiary in age and not Paleoproterozoic, completely rejecting radiometric dating. If so, the very concept of radiometric dating and particularly its reliability needs to be questioned.
Either possibility is simply unacceptable to the evolutionary establishment, hence the escape into the improbable: contamination. A concept that has already served to settle similar problems before: when radiometric dating is clearly at odds with the established biostratigraphy, contamination (‘radioisotope contamination’) is invoked. Or, when accepting contamination would challenge the very concept of radiometric dating, ‘out of place fossils’ (‘fossil contamination’) are invoked.