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Each of them typically exists in igneous rock, or rock made from cooled magma.
Fossils, however, form in sedimentary rock -- sediment quickly covers a dinosaur's body, and the sediment and the bones gradually turn into rock.
The first step toward accurately measuring geologic time came at the turn of the 20th century, when French physicist Henry Becquerel discovered the natural radioactive decay of uranium.
Shortly thereafter, building on related work by Ernest Rutherford, American chemist Bertram Borden Boltwood determined that he could use the predictable decay of radioactive elements such as uranium into other elements to keep track of time.
This was dealt with in the chapter by that name (chapter 1).
Second, generation of living organisms from non-living matter, or origin of life.
In the decades that followed, scientists made important new discoveries about the structure and behavior of atoms, and they refined their existing dating techniques."In a billion years [from now], it seems, intelligent life might be as different from humans as humans are from insects . To change from a human being to a cloud may seem a big order, but it's the kind of change you'd expect over billions of years." Freeman Dyson, Statement made in 1986, quoted in Asimov's Book of Science and Nature Quotations, p. [American mathematician.]"Slowness has really nothing to do with the question.