Experience the Heard’s new exhibit! In May of 1991, avid fossil collector Mike Donovan made an amazing find in Collin County: the partial skeleton of a plesiosaur. In 2015, the bones were donated to the Heard Museum by the Debera Donovan Foundation. Decades after that exciting moment when Mike Donovan first discovered and excavated this epic example of an ancient marine predator, his dream of a museum display has finally become a reality and it is now on permanent display at the Heard. This permanent exhibit is included in general admission and free for Heard Museum members. This exhibit is available during our regular hours of admission. Heard Natural Science Museum and Wildlife Sanctuary is a Texan by Nature Conservation Partner.