How many pieces of artwork did Georges Seurat do?

He had two older siblings.

There are 35,000 pieces of Artwork in the Louvre. Source: http://goparis.about.com/od/parismuseums/a/Louvre_Museum.htm

He had one older brother, and one older sister.

There are 215 paintings and 180 drawings of his still in existence.

There are 215 paintings and 180 drawings of his still in existence.The word 'major' is a relative thing. You may call a dozen of his paintings major.