始新世基本上为暖期。莱伊尔爵士曾充分意识到,根据均变论当时的世界较今日的更暖;在北半球,鳄类、棕榈、海生软体动物以及珊瑚化石发现于比其现代同类所曾达到的更高的纬度区。始新世是地壳活动加剧的时代,全球板块重新组合,拉拉米与喜马拉雅全球构造型式间的分界也划在这一时期。 Eocene is basically a warm period. Sir Lear was fully aware that the world at that time was more warmer than today according to the law of uniformitism. In the northern hemisphere, crocodiles, palms, marine mollusks and coral fossils were found at higher levels than their modern counterparts had achieved Latitude area. Eocene is the era of crustal activity intensified, the reorganization of the world plate, Lalami and the Himalayan world structure between the boundaries are also drawn in this period.