For decades, one of the most abundant kinds of fossils on Earth, numbering in the millions of specimens, was a mystery to paleontologists. But geologists discovered that these mysterious fossils could basically be used to tell time in the deep past.
For decades, one of the most abundant kinds of fossils on Earth, numbering in the millions of specimens, was a mystery to paleontologists. But geologists discovered that these mysterious fossils could basically be used to tell time in the deep past.