I was disappointed that these black pants are not 99.1% Cotton, 0.9% Lycra Spandex like the denim pants.  The black ones are 75% cotton, 24% polyester and 1% elastane.  Otherwise they fit great like denim 515's.  Rather than go through the hassle of returning them I will keep them.  But I prefer more cotton so won't buy these again unless they change it to more cotton.