The wines of Sancerre are getting better and better, which can largely be attributed to two things: better viticultural practices, and a more Burgundian approach to terroir, i.e. single-vineyard or soil-specific cuvées. To get a better look at these changes, there's no better place to look than the flinty (aka "silex") soils on the eastern edges of Sancerre.
Our Q&A should give you a good idea what Sancerre on Silex is all about!