Grape Escape Languedoc – Rousillon. Travelling across the Catalan border into Southern France, we encounter Rousillon. One of the most unique wines of this region is Maury, a type of sweet vins doux naturels that reflects the winemaking tradition that sets Rousillon apart from the more northern regions of France. 
Maury wines are produced from the Grenache grape variety, ranging in color from white to red and rosé. The wines, fortified from the presence of schist in the soil, are incredibly sweet and tend to have an intense and aromatic fruit flavor.

” The wines, fortified from the presence of schist in the soil,”?
Do you understand what fortifying wine means……?
Yes Pete I see what you mean. I’m afraid the author is no longer with us but I suspect it is something lost in translation.