Dinosaurs survived into the Paleocene (comparatively modern) era - about 65 million years ago and counting?
Well, EurekaAlert (28 April 2009) offers some suggestions in "Evidence of the 'Lost World' -- did dinosaurs survive the end Cretaceous extinctions?"
The Lost World, Sir Arthur Conan Doyle's account of an isolated community of dinosaurs that survived the catastrophic extinction event 65 million years ago, has no less appeal now than it did when it was written a century ago. Various Hollywood versions have tried to recreate the lost world of dinosaurs, but today the fiction seems just a little closer to reality. New scientific evidence suggests that dinosaur bones from the Ojo Alamo Sandstone in the San Juan Basin, USA, date from after the extinction, and that dinosaurs may have survived in a remote area of what is now New Mexico and Colorado for up to half a million years. This controversial new research, published today in the journal Palaeontologia Electronica, is based on detailed chemical investigations of the dinosaur bones, and evidence for the age of the rocks in which they are found.My caution is, we all want this. We wish the more interesting dinos were alive today. Gee, if we could show off a real T Rex at the Royal Ontario Museum, people would be lined up around the block 18 times. But, like the space aliens, ... they never write, they never phone ...
"The great difficulty with this hypothesis - that these are the remains of dinosaurs that survived - is ruling out the possibility that the bones date from before the extinction" says Jim Fassett, author of the research. "After being killed and deposited in sands and muds, it is possible for bones to be exhumed by rivers and then incorporated into younger rocks" he explains.