A small Hudson's Bay Co. post at mouth of Isonglass or Old Factory river, James Bay, about 30 miles north of East Main river. Built before 1665, probably abandoned in 1686 temporarily when Forts Rupert, Moose and Albany were captured by the French. A mica mine was discovered on the river bank and was worked by the Company for some time, but unprofitably. The river, which empties into Moar's Bay, was called Mica, Isonglass, or Old Factory river. Shown on map No. 24 and the river on map No. 63.