Though this view is still widely accepted, in the 1980s a group of Dutch paleontologists used Dubois's collection of more than 20,000 animal fossils to reassess the date of the layer in which Java Man was found. Using only fossils from Trinil, they called that new faunal assemblage the Trinil H. K. Fauna, in which H. K. stands for "Haupt Knochenschicht", or "main fossil-bearing layer". This assessment dates the fossils of Java Man to between 900,000 and 1,000,000 years old. On the other hand, work published in 2014 gives a "maximum age of 0.54 ± 0.10 million years and a minimum age of 0.43 ± 0.05 million years" for Ar-Ar and luminescence dating of sediment in human-predated shell material from Trinil. Work continues on assessing the dating of this complex site.