The excavation work will continue next season

The remains were found between June and September this year in the Fort Peck Reservoir area of Hell Creek, Montana. The area is a famous dinosaur hunting ground.

It has rocks that cross what is known as the K-T boundary, the layer where dinosaurs vanish from the geological record about 65 million years ago.

Horner and his team are involved in a five-year survey of the dinosaurs, mammals, invertebrates and fossil plants found in the region.

But they deliberately set out to look for creatures that lived long before the mass extinction - well below the K-T boundary.

Largest ever

"Most people have been interested in the extinction of dinosaurs, but I'm more interested in how they lived and evolved," he said.

Other creatures, such as this turtle, were also unearthed

Most of the Tyrannosaurus remains have not yet been fully uncovered. Only the parts of three skeletons and most of a fourth have been removed so far. The rest will be extracted next summer.

There is great excitement about one of the specimens in particular. This was discovered by Horner's wife, Celeste, in July.

The skeleton is only partially intact, but the jaw and a few cervical ribs removed late in the digging season seem to indicate that C-rex (as it has been dubbed) could be the largest T. rex ever found - bigger even than Sue, which drew huge crowds to the Field Museum in Chicago when it was put on full public display for the first time in May.

All images courtesy of the Museum of the Rockies