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Approaching the end of the Cretaceous period, where on the planet (latitude and longitude) was Cornwall, England? .. Approximately.

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    $\begingroup$ I don't think defining the historical longitude is very meaningful. What do you want to do with historical longitude information? Relative longitude compared to certain other features would seem more relevant? $\endgroup$ – gerrit Apr 10 '17 at 9:21
  • $\begingroup$ "I don't think defining the historical longitude is very meaningful" Gerrit's comment is interesting and it points to an underlying premise in the OP's question: that you could derive some sort of meaning by taking a current location of any land-point on earth, along with all associated current local geography, and simply walk it back to some global position it might have occupied tens of millions of years ago. Sure, you could do that, but it tells you nothing if surrounding context is missing. Certainly more meaningful is, "How far below sea level was Cornwall during the late Cretaceous?" $\endgroup$ – Knob Scratcher Apr 12 '17 at 4:09
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The rocks that make up Britain have been slowly drifting north over geologic time. About 700 million years ago it was near the South Pole!

I paused this Youtube video at 75 mya, held the end of a toothpick over Cornwall, then played it to the end keeping the toothpick steady over that point, under which the approximate location of Bilbao, Spain eventually slid itself. Bilbao is at 43°15′25″N according to Wikipedia.

So now, think of how longitude is defined: Relative to the meridian through Greenwich. A cursory glance at the video I linked to shows the rocks that make up Great Britain have moved as a unit and haven't rotated appreciably over the last 75 million years. So the longitudes associated with Cornwall haven't changed much in that time.

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  • $\begingroup$ Don't forget, any part of Cornwall has moved many hundreds of feet vertically since that time. $\endgroup$ – Knob Scratcher Apr 12 '17 at 4:13

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