An abrupt Upper Middle Cambrian faunal change, Christmas Hills, Tasmania

Abstract

Sediments containing two almost entirely different Upper Middle Cambrian faunas are in direct contact near Christmas Hills, Tasmania. Two reasons are advanced in explanation for this faunal change, (a) that there is a disconformity at the position of the faunal change, or (b) that the younger fauna replaced the older fauna due to a change in environment.