I take it that you don't know what your GGrandmother's maiden name is? Is this correct? I certainly understand that, it's hard to track down some of this information. I've come across a pretty cool link recently. I'll see if I can find it, then copy paste here for you.
You might have to sign up once you get there, but it's free. Here's somemore info about Mallon's that came to Philly from Ireland.
Database: Philadelphia, 1800-1850 Passenger and Immigration Lists October 15, 2004
(Name) (Arrival Date) (Age) (Gender) (Port of Departure) (Place of Origin) (Ship Name)
Catharine Mallon Sep 30, 1818 Unknown Halifax Brig Elizabeth Catharine, Jr. Mallon Sep 30, 1818 Unknown Halifax Brig Elizabeth Charles Mallon Sep 30, 1818 Unknown Halifax Brig Elizabeth Edward Mallon Jul 11, 1848 24 Male Ship Damascus Eliza Mallon Aug 05, 1847 7 Female Ireland Ship Susquehanna Henry Mallon Oct 01, 1850 40 Male Liverpool Ireland Ship Kalamazoo James Mallon Aug 05, 1847 65 Male Ireland Ship Susquehanna Jno. Mallon Apr 21, 1831 12 Male Liverpool USA Ship Arab John Mallon Aug 05, 1847 11 Male Ireland Ship Susquehanna John Mallon Jul 25, 1835 16 Male Londonderry Ireland Ship Earl Kellie Michael Mallon Jun 10, 1839 25 Male Liverpool Ireland Ship Chevalier Michael Mallon Jun 13, 1850 70 Male Liverpool Ireland Ship Susquehanna Nancy Mallon May 04, 1846 18 Female Londonderry Ship General Washington Owen Mallon Jul 22, 1828 22 Male St. John, N.B. Ireland Amethyst Philip Mallon Aug 05, 1847 9 Male Ireland Ship Susquehanna Robert Mallon Oct 01, 1850 10 Male Liverpool Ireland Ship Kalamazoo Rose Mallon Aug 05, 1847 54 Female Ireland Ship Susquehanna Rose Mallon Jul 25, 1835 50 Female Londonderry Ireland Ship Earl Kellie Sarah Mallon Oct 19, 1850 21 Female Liverpool Ireland Ship Saranak Sean Mallon May 13, 1822 26 Male Belfast USA Beres
The above didn't exactly copy paste out to what the original chart looks like. But it should give you some idea and hopefully the link works for you.
Good luck Cuzz (smiles) maybe we are related. Let me know what you find out k? Enjoy your day, Bob