Early radioisotopic age constraints around the Campanian formations of the WIB consisted of K–Ar analyses of biotite and feldspar from interbedded bentonites115,116, with assumed uncertainties about the purchase of ± 5%, and these analyses are usually not discussed further in this article. Biotite ages, especially, are thought of of questionable https://wildbookmarks.com/story13252196/facts-about-what-is-fossil-record-revealed