The issue of the features of planet Earth’s features way back in geological times interests but I have not systematically taught myself about them. Evidence in the rocks has been analysed by geologists and paleontologists to the extent that standard maps have been drawn showing the Earth’s surface in the Ordovician geological era (s.p.b.). At that time the planet’s surface was made up, as today, of seas/oceans and continental landmasses although back then the latter had been far less impacted orogenic movements in the Earth’s crust. Most, perhaps all, early lifeforms back then were aquatic, see above, these mostly concentrated in shallow seas around continental blocks. Such lifeforms had evolved in the ‘Cambrian Explosion’ (in the bulk and diversity of lifeforms), Cambrian being the earlier geological era. In contrast, the late Ordovician Era was to witness on of Planet Earth’s four major ‘Extinctions’, when many previously recorded lifeforms cease to exist thereafter. The reasons for mass extinctions are hotly debated amongst scientists, and may have varied in each episode. Also debated is whether there was life on land 450 million years ago, an earlier hypothesis being that there wasn’t. The bulk of the ocean then was mostly in the Northern Hemisphere and, compared to today, there may have been a greater proportion of the Earth’s surface covered in water. I am unsure as to whether plants existed on the land, but I suspect only in a limited way.
Presumably at a given point on the Earth’s surface back then there must have been day and night, weather, seasons and atmosphere, although with less oxygen then it may have been hostile to the evolution of animals with lungs.
How fascinating it is when walking anywhere today one is on bedrocks created in a world so different from that of today. How insignificant the here and now sometimes seems.