Early radioisotopic age constraints about the Campanian formations of the WIB consisted of K–Ar analyses of biotite and feldspar from interbedded bentonites115,116, with assumed uncertainties about the order of ± 5%, and these analyses are certainly not discussed additional listed here. Biotite ages, especially, are regarded of questionable accuracy by https://mnobookmarks.com/story13177512/facts-about-fossil-definition-for-kids-revealed