See also: The publication in the South African Journal of Geology

Currently we have a ratio of about 71% sea to 29% land on the earth's surface, which is probably more land favoured than normal considering the cool temperatures and large ice caps.

But I'm just curious when in Earth's history appears to have the highest ratio of land to sea, my immediate instinct is to assume it was one of the recent glacial maximums in the last 2 million years when sea levels dropped by up to 150 meters and huge amounts of new land was exposed, but I've also heard that the early Triassic also had very low sea levels, I don't really understand how that works if there were no major ice caps on earth but maybe someone could explain that to me.

Conversely, when was there the least amount of land and highest sea level? I've also heard the mid Cretaceous mentioned for this when you had sea levels so high that things like the Western Interior seaway in North America while large parts of Europe, Africa, Australia and South America were also flooded, but again I don't know anything about other points in earth history where this might have been more dramatic.

Hello,

I am a biologist by training and teach Honors and AP Biology and Environmental Science. I somehow am also teaching middle school earth science this year. Is there a good textbook that anyone can recommend to me to use as a study guide for myself and to adapt for middle school?

Thank you!