Chancery Lane, curiously enough, still exists as part of Mascher Street, running from Coomb's Alley (now Cuthbert Street) to Arch Street. To my mind the old names were better. According to Robert Alotta's book on Philadelphia street names (see the bibliography), it was renamed Mascher in 1895 after 1850s city councilman John Mascher, who in that decade proposed and established the less charming but much more sensible numbering system we have today. Chancery Lane's early buildings are all gone, but quite a run of 18th century homes still exist on old Coomb's Alley.
Chancery Lane appears to have been one of those small alleys in which Clement Biddle followed the same numbering system as MacPherson, though not always applying it the same way.
(1785) #1, Hoborn, Widow
(1791) #1 Chancery Lane, Hoover, Margaret, widow
(1785) #2, Wilson, George
(1785) Wilson, George, merchant, Chancery Lane between Coomb's Alley and 2nd
(1791) #2 Chancery Lane, Wilson, George, grocer
(1785) #3, Honeyman, William
(1785) Honeyman, William, hatter, Chancery Lane near Arch
(1791) #3 Chancery Lane, Botner, Joseph, saddler, also at 3 S. Front St.
(1785) #4, Hermitage, Benjamin
(1791) #4 Chancery Lane, Wharton, Thomas, mariner
(1785) #5, Lynn, Joseph
(1791) #5 Chancery Lane, Lynn, Joseph, merchant
(1785) #6, Norton, George
(1785) Nortan, George, cooper, Chancery Lane between Coomb's Alley and Arch
(1791) #6 Chancery Lane, Mollineux, John, hairdresser
(1785) #7, Hink, James
(1785) #7, Hynk, James
(1785) Hilbks, James, rigger, Chancery Lane between Coomb's Alley and Arch
(1791) #7 Chancery Lane, Nixon, Jane, widow
(1785) #8, vacant or residents would not give name
(1791) #8 Chancery Lane, Justice, James, taylor
(1785) #10, vacant or residents would not give name
(1791) #9 Chancery Lane, Crawford, Samuel, porter
(1785) #11, Walker, Joseph
(1791) #49 Chancery Lane, Snyder, George, coach maker
CHANCERY LANE, UNKNOWN LOCATION
(1785) Kean, John, gentleman, Chancery Lane between Coomb's Alley and Arch
(1785) Walker, Emanuel, china merchant, Chancery Lane near Arch