It was warmer there than it is today.I finally got around to reading the relevant passages in Lamb's book. The picture in question is bound with the other photographic plates between pages 352 and 353 of volume 2. The photo is mentioned in a section dealing with surface wind currents near large ice masses, such as the receding North America ice dome. The author referred to previous work of his describing winds near the edge of ice in Antarctica. He proposed that during the existence of the North American ice, winds were channeled between the ice and the Rocky Mountains, drawing "warm moist Pacific airmass in Julys of those times" (V2, p 228). That explains why that particular area (McKenzie River Delta) was warmer than it is today. He also pointed out other scientists' work explaining warm föhn winds that blow down from glaciers, heating as they descend in a manner similar to how our local Santa Ana winds heat up as the come down.
What was it you were told about that photo that led you to post it here?
That was my point.
Im happy we agree.
Im reading another of Lamb's books now.
I'll be sure to consult you if I have any questions.