Toad found in Coal at St. Helen's... or Was It? (sources)
- The Swiss Cross: a monthly magazine of popular science, Vol. V, No. 1, January, 1889 New York, USA. Pg. 20. Online at: https://books.google.com/books?id=tEUoAQAAIAAJ&pg=PA20&dq=Swiss+cross+monthly+hartlepool&hl=en&sa=X&ei=_8b0VKbcCYa4oQTh_oGABw&ved=0CCsQ6AEwAA#v=onepage&q&f=false