Nice block of 36 (6X6) imperf (watermarked loops) 2p (orange red on light blue paper) stamps from 1855 featuring Queen Isabella II.  Possibly used as revenue or postage receipt as still has gum (aged) and cancelled in pen lines.  Paper is brittle, gum is smeared, there is some tears on some stamps on top row.  Been in storage for many generations, sheets are fragile.  See scan!  This collection has been sitting untouched for nearly 100 years.  The scans show them as they are, I make no claims as to identification or genuineness.