The Floyd E Risvold collection has completed its sale in New York City, bringing a total of $8.6m.
Amongst its many fine autographs (such as the photograph of Kit Carson) and covers, both with rare stamps and stampless, we made note of the Snowshoe Express covers, which bore a postmark indicating that an intrepid cross-country skier had carried them over the mountains.
The original version, Thompson's Carson Valley Express, was established by 'Snowshoe' Thompson in 1857, and the cover bearing his stamp beat its estimate of $10,000-15,000, selling for $18,000.
However, this was not the item from the short section which most excited bidders.
A unique cover bearing the postmark with a picture of a skier and 'Cook's Express' overlaid had been given the modest guide price of $5,000-7,500. Newspaper reports suggest that the Express started up in 1866 but was short-lived, not lasting beyond 1870.
A flurry of bidding ensued when the piece reached the stage, and it was only taken away for an impressive $36,250.
The Nugget Express cover also beat its guide price, bringing $16,000 against a top estimate of $15,000.