A California couple walking their dog on their own property in 2013 noticed a rusted can poking out of the bank beneath an old tree. It was the first of eight cans holding 1,427 gold coins with a face value near $28,000, and the hoard was valued at about $10 million

Somewhere in the Sierra Nevada foothills there is a dog that has never been properly thanked.

In February 2013, its owners were walking a track they had used for years, on their own land in the part of California still called Gold Country, when one of them noticed a rusted can jutting out of the bank beneath an old tree. It was absurdly heavy. They assumed old lead paint, lugged it back to the house and levered the lid off. Inside, packed in dirt, sat a stack of gold coins.

Then they went back with a shovel.

What was actually in the cans

Seven more canisters came out of the ground, the last one located with a metal detector. Final tally: 1,427 gold coins dated between 1847 and 1894, face value $27,980. Writing in Coin World, Michele Orzano described the bulk of the haul as Coronet double eagles, the twenty-dollar gold pieces struck at the San Francisco Mint, with smaller numbers of tens and fives. The finders, self-employed and in their forties, had long called that corner of their property Saddle Ridge. The name stuck to the treasure.

Oddest detail: the pieces sat in rough date order, the oldest in the first can, the rest running forward through the decades. Somebody was not panicking. Somebody was filing.

Most of the gold had barely been handled. Coins that circulate come back scuffed and softened at the edges, and this lot had gone into the ground close to new, within living memory of the dies that struck them.

The couple have never been identified. They are known publicly as John and Mary. Their identity is concealed because of the sheer size and value of what came out of that hill, as the National Museum of American History, holder of two coins donated from the find, states plainly.

The mint clerk theory

In 1901, Walter Dimmick, chief clerk at the San Francisco Mint, walked six sealed bags of twenty-dollar coins out of the building. Face value, $30,000. He was caught, convicted and jailed, and the gold was never recovered, a set of facts that had been sitting in the record for a century waiting for precisely this moment.

Amateur coin historian Jack Trout put the connection to the San Francisco Chronicle in March 2014, days after the find was made public. The paper ran it and the story travelled fast, because the numbers were close enough to itch. Roughly $28,000 in the ground, roughly $30,000 out the door, both in uncirculated gold from the same city.

Why the coin people said no

“Provably incorrect,” said David McCarthy, the rare coin specialist at Kagin’s who examined the cache, speaking to NBC News. A mint vault, he explained, would have yielded bags of near-identical coins rather than the spread of dates and denominations that came out of those cans.

Richard Kelly and Nancy Oliver, researchers who had worked through the mint’s own records, made the case at greater length in Coin World. Dimmick raided the cashier’s working vault, used for daily business, so everything inside it would have been dated 1900 or 1901. Saddle Ridge starts in 1847.

Two further objections finished it off. Dimmick took double eagles and nothing else, while the hoard carries three denominations from several mints. And a man who knew where $30,000 lay buried would presumably have collected it on release, rather than dying without it.

Officialdom agreed, and that was the part with legal teeth. Adam Stump of the US Mint told CNN the agency had “no information linking the Saddle Ridge Hoard coins to any thefts” at any of its facilities. He put it more bluntly to the Chronicle: federal property would have had federal lawyers moving on it already.

Don Kagin, the dealer representing the finders, has offered the flattest explanation available. In an Associated Press report carried by Global News, he said the couple believe somebody in the mining industry once occupied the land and squirrelled money away over a working lifetime, in a region that had watched plenty of banks fail.

The bill arrived before the money did

How much of a $10 million windfall does a person actually keep?

Under American law, found treasure counts as ordinary income in the year the finder takes undisputed possession of it. That principle was settled in 1969, when a couple who paid $15 for a second-hand piano discovered about $4,500 stuffed inside it and lost their argument with the taxman. CBS News reported at the time that the same reasoning would land on Saddle Ridge, with roughly half the value owed whether or not a single coin had been sold.

Top federal rate plus California’s state rate came to something near 47 per cent, as The Motley Fool laid out, leaving open whether the lower collectibles rate could be argued instead. Valuation was its own headache, since nobody knows what a coin is worth until somebody buys it.

Where the gold went

Kagin’s took about 90 per cent of the hoard to market in May 2014 through an exclusive arrangement with Amazon, a company that had circled the coin trade for years without finding a way in. CoinWeek put first-day sales across both channels at around $3 million, with Amazon outselling the dealer’s own store two to one and everything priced under $3,000 cleared out.

Star of the collection was an 1866-S double eagle struck without the motto In God We Trust, graded Mint State 62, the finest known example of its type and date, valued by Kagin’s at about $1 million on its own. More than a dozen pieces in the group rated finest or equal-finest for their year and mint.

Whoever filled those cans made exactly one error, and it was not the hiding place. They kept the secret too well, and then they kept it too long.