In 1836, when the subjects of palaeontology and geology were in their infancy, the Newburgh clergyman John Anderson was rewarded with his most important discovery, the fossil fish of Dura Den. We can imagine the sense of excitement and wonder from his later description:
'This peculiarity of entireness, and even of freshness in these olden denizens of the waters, is so remarkable that, when first exposed to view on the newly split-up rock, there is a life-like glistering over the clear, shining scaly forms, that one can scarcely divest himself of the idea . . .he is looking actually upon the creations of yesterday, the relics of things that had just ceased to breathe. "Here is a living one!" exclaimed a workman, as he raised from the bed of the river a large flagstone on which were counted upwards of fifty fishes, one eminently beautiful, full, and rounded in its form. Indeed, the most splendid representations of an Audubon, a Gould, or a Landseer, on their glossy canvas, will shrink in comparison beside these pictures of nature-painting, brighter than the dyes of the artist as set in their stony tablets, and contrasting finely with the rich saffron-coloured rock in which, uninjured and unstained, they have hung for ages.'
The first Old Red Sandstone fossil fish scale from nearby Drumdryan quarry had been brought to light in 1827 by Mr. Spence, a student at St. Andrews University. Anderson, whose curiosity had been aroused by this and similar finds from Clashbennie, Perthshire, began his explorations. He found fossilised fish scales, teeth and bones in the sandstone of Parkhill, Birkhill, Dairsie and Strathmiglo, and had alerted the stonemasons working on Mr. Yool's new mill at Dura to look out for similar remains. Called out of his presbytery meeting, Anderson could hardly believe his eyes when he saw one of the masons holding an entire stone fish, which had 'leaped into his hands'.
This first exciting discovery was reported in the Fifeshire Journal in 1837. Soon, several types of fossil fish entirely new to science had been discovered on the site. Some of the specimens were sent off for the opinion of the world expert, Louis Agassiz.
Next to emerge was a 'shoal of frog-like creatures' blackening a layer of rock fifty feet above the valley floor. It was suggested that these bizarre creatures, which were new even to the experts, might be large beetles or perhaps crustaceans, before they were recognised to be placoderm fish.
These early finds were described by Anderson in Fife Illustrated (1840) and the fame of Dura Den soon spread, to amateur and professional enthusiasts alike, who came to see for themselves these '. . . legends inscribed on the rocks beneath, of creatures that battled in their hard scaly armature . . . now entombed in their marble sepulchres'. The eminent geologist Charles Lyell visited in 1842 as did Dr. John Grant Malcolmson who made comparisons with the fossiliferous Morayshire sandstones, while Dr. George Buist and Professor John Fleming were frequent explorers of the locality.
The 16th of September 1858 was especially memorable in the annals of Dura Den, when, '. . . in the presence of Sir Roderick J. Murchison, Lord and Lady Kinnaird, and a distinguished party from Rossie Priory, the largest fossil Holoptychius ever discovered was exhumed from the rock, in full and perfect outline and entireness, and measuring upwards of three feet in length'. Lady Kinnaird painted this specimen of Holoptychius andersoni which entered Lord Kinnaird's collection at Rossie Priory. It was during this visit that Murchison, the Director of the Geological Survey, became convinced that the fish-bearing yellow sandstone layer was part of the Old Red Sandstone formation. That very evening Dr Anderson wrote beautifully descriptive letterof that day to his grandchildren, Maggie and Johnny.
A couple of months later, '. . . nearly a thousand fossil fishes were lifted from their stony bed of ages' by the proprietors of Dura, Mr and Mrs Dalgleish. These included the new types Phaneropleuron and Glyptoloemus.
Successive investigations of Dura Den, some funded by the British Association, produced hundreds of fossils and made it a site of world importance.