Dozens of species that are unknown to science are included in a collection of fossils bequeathed to the National Museums Scotland in Edinburgh.

They are the earliest stages of the evolution of birds.

The collection is said to be one of the most important of its kind in the world. It will take several years to describe all the specimen, but initial analysis shows at least 50 new species.

The principal curator of the NMS told the Observer that the collection was exciting. Different modern bird families have some of the same characteristics.

In the UK, there is no comparable site for bird fossils, so the importance of the collection cannot be underestimated. Despite being buried in clay for millions of years, the specimen are still preserved in 3 dimensions. They are usually found at other places.

Daniels died last September at the age of 90. Daniels worked as a cabinet-maker and locksmith, but his passion was palaeontology, which led him to fossil sites outside London and elsewhere in southern England. He was interested in the period after dinosaurs became extinct. He moved to Holland-on-Sea so that he could pursue his interest in the London Clay formation.

He struck up a friendship with Kitchener after moving to Edinburgh with his wife and daughter.

Kitchener told them he wanted to see their bird collection. I wanted to show you it, but we don't have any. He told me about his large collection.

Kitchener remembers him as a friendly man who was largely self-taught but knew his subject and had a special skill in looking for fossils from unprepossessing clumps of clay. Previously, only occasional stray bones had been found there, but Michael discovered hundreds of more or less complete skeletons.

Michael Daniels, an amateur palaeontology enthusiast, makes another discovery at Walton-on-the-Naze.

Michael Daniels, an amateur palaeontology enthusiast, makes another discovery at Walton-on-the-Naze. Photograph: Handout

Daniels walked 1,590 miles to collect 15 tons of London Clay. It was difficult to process and dry the residues. He was able to extract the middle- ear bones of tiny birds by marrying the relevant finds and fragments into some coherence with the help of a binocular microscope, probes and tweezers.

Several of the world's leading natural history museums had offered to provide a permanent home for the collection.

He trusted me that we would take care of the collection. We work with Dr Gerald Mayr in Germany to get the collection done.

The importance of Michael Daniels' collection cannot be overstated. It is comparable to other bird rich sites in the US, China and Germany.

This is one of the most important collections of its type in the world because of the number of preserved specimen.

The Danielsraptor phorusrhacoides is a large ancient falcon with a narrow beak and long legs, which looked more like a caracara from the Americas than a kestrel.

Unlike today's diver, the Nasidytes ypresianus did not have a narrow bill and its jaws were wider.

The huge diversity of bird species at Walton-on-the-Naze may be due to the fact that the climate was much warmer in the past.

The NMS wants to stage an exhibition with reconstructions of the birds as they were 55 million years ago.