The ruins in the direction of Uxma were those of Xlapak on the Puuc route. They are after Labná towards Uxmal and before Sayil. They are badly deteriorated so you can´t see much but it´s well worth a stop on the way to take a look. As most of the ruins sites on the Puuc route, there aren´t any tourists. So, you´ll have the place to yourself.