Hi Joann,
I checked the Philadelphia Birth Indexes, however, I did not find any Mary Zur listed. There is a Mary Zura in the indexes. Please note this Mary Zura is not your Mary Zur. Here is the link for the Philadelphia Birth Indexes if you want to view them your self. https://www.phmc.pa.gov/Archives/Research-Online/Pages/Birth-Indices.aspx#.VubWctCb3IA
I had a very dear friend of mine look some information up for your Zur family.
Mikołaj Żur - BIRTH: Abt. 1864 in Księżpol ?, Lubelskie, Poland (church records from this period are missing) Parents: Piotr Zur & Ewa Potocka
DIED: 19.02. 1903 - Record #16 - Księżpol, Lubelskie, Poland
Marriage: 24.07.1888 - Record #9 - Księżpol, Lubelskie, Poland
Pelagia Skrobańska - BIRTH: 1871 - Record # 102 - Józefów, Lubelskie, Poland
Parents: Aleksander Feliks Skrobański & Aleksandra Maria Hetner* - (*In the Russian language, H is often the same as G, so surnames can be read as Hetner or Getner)
Children:
Anastazja Zur -
BIRTH 15.08.1893 in Księżpol, Lubelskie, Poland
Szczepan Zur -
BIRTH 13.02.1896 in Księżpol, Lubelskie, Poland
Adam Zur -
BIRTH 7.04.1897 in Księżpol, Lubelskie, Poland
Błażej Zur - B
IRTH 20.10.1899 in Księżpol, Lubelskie, Poland
Eudoksja Zur -
BIRTH 30.07.1902 in Księżpol, Lubelskie, Poland
DIED 25.08.1902 in Księżpol, Lubelskie, Poland
Mary Zur -
BIRTH 1907 in Pennsylvania
Please note that Mikolaj Zur died in 1903. Therefore, he was not the father of Mary Zur.
I hope this helps some. Have a wonderful day!