In 2019 my partner and I visited Lyon, France for five weeks and during that time spent considerable time in and around Beaune - the spiritual home of wine makers the world over. We hired a tour guide with a four wheel drive who took us to many places and some outstanding vineyards at the tops of steep rocky hills and told us the history of the area.
He described how the whole area had been once under the sea. The sea then retreated but returned 25 million years later, covering only the area south of Beane (the Cote de Beane) so the limestone south of Beane is 25 million years younger. They believe that is the explanation for why pinot noir is mostly grown in the north (the Cote de Nuits) and chardonnay is mostly grown in the south.
The best vineyards (Grand Cru and Premier Cru), are on the slopes because the limestone gives excellent drainage - better then the valley floor and the top of the rocky hills. He also told us that after the French revolution aristocrats and church owners were displaced and the allocation of all wine land was given to the worker's families and what has happened in the subsequent centuries as families have tried to hold onto those precious hectares. Some are only two hectares in size. For instance the picture shows the Romanee Conti vineyards owned by Domaine de la Romanee Conti- in 2018 it produced bottles of wine which retailed for $39,000 each!