Pliocene Epoch, the geologic epoch that began about 6,000,000 years ago and lasted about 4,000,000 years. It is a subdivision of the Tertiary Period of the Cenozoic Era. Great uplifting occurred in the mountains of the northwestern United States during the Pliocene Epoch. Pliocene formations in California are sources of petroleum.
Diamond engagement rings. Diamond anniversary bands. Diamond earrings and necklaces. And now, the right-hand diamond ring! The four Cs -- cut, clarity, carat and color. Find out what the fuss is all about.
Every time a new fossil is found, one of the first things scientists determine is how old that fossil really is. But how do they determine it, and how can they be completely accurate?