with the fork tines pointed down and to the left, on the back are the following marks:


(I realized this is difficult to see, I have shot it several times with not much better results.
Then the words "Manahan Chicago" and then these last two stamps:

"Manahan Chicago" is inconsistently placed along the length of the fork, although it's consistently positioned on the knives. An Internet search for "Manahan Chicago" turned up nothing with regard to silver flatware."
Thank you in advance for any help/insight anyone can provide.
Polly