Reference for Sanhedrin 99:16
אפילו הכי פושט ידו בעיקר עדיף:
[In his view] burning is severer than stoning, since it is the punishmentof a priest's adulterous daughter, the enormity of whose offence lies inthe fact that she profanes her father. On the contrary, is not stoning severer,being the punishment of a blasphemer and idol-worshipper, the gravity ofwhose offence lies in that they reject the fundamental tenet of Judaism?— R. Simeon's view here is in accordance with his other opinion, viz., thata priest's adulterous daughter, whether an arusah or a nesu'ah, is excepted[from the punishment meted out to an Israelites' daughter], in that her penaltyis burning. Now since the Divine Law varied the punishment of an arusah,if a priest's daughter, from that of an Israelite's daughter, from stoningto burning, it follows that burning is a severer penalty.