Charles Darwin spent five years 1831-1836 in his early 20s circumnavigating the World in HMS Beagle. He was on the books as 'naturalist' and was able to go ashore whenever the ship was near enough to land and the calls of naval duty allowed. In one of his memorable excursions from Valparaiso in Chile, Darwin hired horses and took off into the hinterland towards the Andes. He was forcibly struck by finding fossil sea-shells several hundred meters above sea-level. He wouldn't have been surprised at this evidence of a restless Earth, because he had a copy of his mentor Charles Lyell's Principles of Geology. But actually seeing the evidence made him start to wrestle with the idea of [im]mutability. On the same expedition Darwin was famously bitten by a barbeiro beetle Triatoma infestans which possibly delivered a load of parasitic Trypanosoma cruzi to his bloodstream. This infection may have developed later into Chagas' disease. some of whose symptoms the great man displayed: "spasmodic daily & nightly flatulence: occasional vomiting, preceded by shivering, hysterical crying, dying sensations; copious very pallid urine; singing of ears, rocking, treading on air; vision focus & black dots . . ." Other people are convinced that Darwin was a pampered neurotic who was a bit of a hypochondriac.
get us a date on the eruption at Thera that wiped out the Minoans . . . or may not. Come to think of it, piecing together lots of small data-strings because their ends overlap is how we assemble genomes.
there are huge gaps in the continuity of the geological record in N Arizona. I've zoomed [R] into a detail of the picture (which you should check out) of the geological periods exposed in the Canyon. It's the two pinky-grey sections which are most interesting to fossil hunters: the lower, narrower one is from 600-500mya, at the base of the phanerozoic which is also the base of the Cambrian period (another! chunk of the record named from Welsh rocks). Phanerozoic means 'apparent/visible/evident animals". Before that there was life but it wasn't in the form of neat trilobites and ammonites that you'd be proud to have on your mantle-piece. The two lower grey bits in the chart [R] are very old but also very empty fossil-wise. The unconformities in the [pinky-grey] record arise because for 100 mya the area which is now Northern Arizona wasn't a shallow sea or a swamp but one of the many sorts of habitat which never allows fossils to get laid down. It's just as well that we have lots of other exposed rocks in Mississippi and Pennsylvania to fill in the gaps.