Yes you can tell from the name Jerseyanthus is another member of the Calicanthaceae just like Idiospermum.
From fossils described as recently as 2004 and discovered not long before that in the Raritan formation of New Jersey in The USA, Jerseyanthus dates back to the Late Cretaceous (about 90 million years ago).
It has been placed as a sister group to the genus Calycanthus which still inhabits the USA. In fact Jerseyanthus really only has very minor differences from modern day Calycanthus and Chimonanthus (the number of tepals being the main one).
We have both Chimonanthus praecox and Calycanthus floridus as representatives of the Calycanthaceae in the fossil garden.