All along it was thought to be either an act of God or perhaps long, slow climate change, and that really changed in 1980, in this rocky outcrop near Gubbio, where Walter Alvarez, trying to figure out what was the time difference between these white rocks, which held creatures of the Cretaceous period, and the pink rocks above, which held Tertiary fossils.
一直以来，人们认为这或许是上帝的行为， 也或者是长期，缓慢的气候变化。 1980年，在古比奥附近一块露出地面的岩层 确实发生了改变。 Walter Alvarez试图在这儿弄清楚 这些包含着白垩纪时代生物的 白色岩石相差的年代， 还有上方包含了第三纪化石的粉红岩石。