What is "effigia"

Effigia was an archosaur that lived in what is now New Mexico, south-eastern USA. The 2 meter (6 ft) fossil was collected by Edwin H. Colbert in blocks of rock from the Ghost Ranch Quarry, which were excavated in 1947 and 1948. However, Colbert did not think any large vertebrates besides basal theropod dinosaurs were present in the quarry and as such did not even open the jackets of most of the blocks that were returned to the American Museum of Natural History.