Glocker, I could be wrong, but without knowing the dimensions, it looks similar to me to an early Australian colonial pattern known as a Dover knife.
The Dover knife was popular here, it seems, from the early 1800s to the 1890s. It was a basic springback clasp knife, usually with a four or five inch spearpoint blade, with a swedge that was sometimes sharpened for piercing, that extended from the tip back to about a quarter of the length of the blade.
I only know of one surviving example, which is in the Maritime Museum of Tasmania. However, there are many references to the pattern by name in shipping records, criminal court cases and archaic Australian slang and bush ballads.
Here's some references from an early Australasian dictionary.
There were well plied shipping lines between England (where they would probably have been made - possibly in Sheffield), Australia and the US during this time and earlier, related to whaling, the general mercantile trade, and the 1850s gold rushes and their aftermath.
Of course, it would have been an easy enough pattern for any regional working cutler to replicate in different sizes, once he had seen one. To my eye, it appears to be an intermediate pattern that harks back to the earlier gully knife and predates the more sophisticated patterns that developed with the widespread use of crucible steel.
Can you post some more details on the dimensions and top and bottom views? And there's no hint of any markings on the blade or tang, you say? Is there any maritime or gold rush migration history in your family?
I've been compiling what information I can find on the Dover and another type of knife for a future post on Australian traditional patterns - I don't know how much interest there would be in it though!
