In the Encyclopedia of Paleoclimatology and Ancient Environments,The Encyclopedia of Paleoclimatology and Ancient Environments by Vivien Gornitz (2008, Springer) it is found that
50My ago the sea temperature was +-13ºC above present value 50 My ago the sea temperature was about 13ºC above the present value.
AFAIK the several proxies gave consistent answers.
Why is the temperature is always decreasing ?