the earth was formed by a big cloud that swirled around and around and around and had lots of pressure that it sqused and there floating in space was new born earth
the ocean formed by the volcanos all the times it erupted and all the ash made clouds and it started raining for 4.5 millions of years and all the lava started to dry and it started making crust and once all the rain came in it covered all the volcanos and so only about a million of volcanos have been discovered.