Here again is what the source you cited stated: George F. Dodwell your source said it was a GRADUAL change. Now you try to quote another source who claims it was rapid. yet the one man who did a systematic study says it was not rapid but gradual. If this is how the conversation is going to go with you ignoring rebuttals then please count me out.
SC: "...no other proof other than..." So, yes - we have proof. Thank you.
Present it please.