Rich silver-bearing lead ores in the Northern Pennines?

The main lead ore mineral within the Northern Pennine carbonate-hosted gale na-fluorite orefield is silver-bearing galena. Numerous reliable assay and recovery records, from the heyday of lead mining during the eighteenth and nineteenth centuries, indicate that silver values in the ores then being mi ned were typically fairly modest, in the range 100-250 ppm Ag. Historical r ecords from the area written during the eleventh and twelfth centuries, alt hough very much less complete and more open to interpretation, indicate lev els of silver production which could not have been sustained from such ores . It is suggested that lead ores with much higher silver content may have b een available in these earlier times. A few scattered occurrences of galena with enhanced silver content may represent the vestiges of these ores.