North Island Explorer: Guide to North Vancouver Island









































Idonearca truncate: A Cretaceous Bivalve


Photo 1: Three views of a large Idonearca truncate. (Specimen found at Willow Point Reef)




Well-preserved specimens  of these thick shelled Cretaceous bivalves can be found at numerous locations on Vancouver Island. The umbo is raised and one edge is heavily truncated while the other edge tends to 'flare' upwards.. Slanted grooves in the ligament area (photo) form a 'V' in the direction of the umbo.





Photo 2: Idonearca truncate exposed in matrix

These bivalves exhibit both radial lines and concentric growth rings giving them a checkered pattern.

Other Images:

View of the Idonearca Umbo

Another Large Idonearca Truncate in Matrix.