Old Chimney and Attic

1910 home. Old chimney no longer used as it was for an old heating system in the basement. Improper flashing above, thoughts on the dark wood and white scale around it? Unable to get up in the attic through the scuttle hole from the closet which was full.20190810_130203-2507504 20190810_142557

Likely a fungi growth of sort from getting & staying wet. Efflorescence+fungi on the brick.