I thought this was just a London maker with incomplete marks.
But I couldn't find an appropriated OC mark anywhere. The second mark could be anything. The second spoon has an illegible mark. They are 10.8 cm long.
Maurice
That is the only OC in Jackson, but it looks like the Cassidy mark has a pellet. Also he seems a bit late for the style. Finally the cartouche on the second mark doesn't seem to fit.
It seems I have seen similar style in America, but I may be wrong, as memory is a funny thing.
Maurice
Well trying to follow up, on Owen Cassidy, someone gave his working dates as 1753-1816. I am not sure where that came from or whether it is accurate. I also tried to find a American spoon in that pattern, but had no luck. Many Irish silversmiths ended up in Baltimore, but nothing there. Of course I actually had no luck finding any examples of that pattern anywhere. I tried image search of Irish Georgian shell spoon, but came up with nothing. I also realize my mistake trying to read the marks. I would have thought the second mark would be a lion, date letter, Hibernia, or something that would help. The cartouche is squared off on the end with a loop showing. It doesn't seem to fit anything. Then I realized it could be just the same OC mark pinched on the sides, to reform the stem after striking. So the mark alone doesn't rule in or out anywhere. Then I tried to find marked works by Cassidy. For a silversmith with such a long working period I could only find less than a handful of items with marks attributed to him. None of the marks are the same. However if he did work as early as 1753 he could have made the spoon, which I would date c. 1755. So I guess any silversmith with a long working period might have several marks over the years. I would think the proof would be finding the same pattern spoon. Without examples to the contrary I would lean towards Trev's experience of seeing similar patterns of Irish origin.
Maurice
If he really worked until 1816, and started before 1753 he ought to get some kind of award if not for longevity, then at least unproductiveness. One dealer evidently called the pattern shell-front and shell-back, but he might have been the only one who did. He showed to very similar examples both made in London. Which opens up the search area, but doesn't help much as OC doesn't come up in London anyway.
Maurice
This is a very worn example of the result of the use of a similar, or perhaps even the same, die. This one is of a spoon by Michael Keating of Dublin. The use of such dies is fairly uncommon in Irish work of the period, simply because a vast majority of Irish smiths could not afford such dies. It would be of no surprise if such a die was shared between several smiths.
Keating started work in the 1760's, he was recorded as a Quarter Brother in 1766.
Hi Trev & Maurice
A pair of Cassidy tongs for comparison to your spoon shell bowl decoration.
I make them Dublin 1769 as marks still very crisp.
He must have been a very accomplished silversmith judging by the various skills used on this pair.
A top quality example, a shame so little is known of him.
Initials on the inside of the arm instead of bow end.