… because the skirt and draping had lost the look of an oval shaped crinoline, in favor of a tiered draped and frilled train. The front became plainer, with the entire skirt silhouette much less symmetrical. The trains got more and more ornamented with frills, pleats, ruffles, braids, and fringing
The 1875 bustle evolved out of a gradual transition from draping to a soft “polonaise” style reminiscent of the 18th century.
(Photos: Differences were subtle, but you can see the front getting flatter and more vertical, and the drape becoming higher and fuller towards the small of the back – but all the fringe and decoration was quite the same between 1870 and 1873)