Complex sentence: They wear a black grosgrain gown, with facings down each side in front and a square collar at the back of the same material, edged with gold lace; the differences being in the placement of the lace on the sleeves.
Split into simpler sentences: They wear a black grosgrain gown, with facings down each side in front and a square collar at the back of the same material, edged with gold lace. The differences being in the placement of the lace on the sleeves.