although there is no clear ending to the 7th day of Genesis listed in the Bible...the closest we come is the verse at Revelation 21:1.
The listing of the heavens the earth and the sea does closely correspond to the listing at the start of Genesis of the heaves and the earth and the deep/waters
There could be a strong case to be made that Revelation 21:1is the official ending of the 7th day of creation and the beginning of the 8th day of God's creative work.