13 



TAB. CVIII. 



IERRUM argillaceum. 



Argillaceous Oxide of Iron. 



My very good friend the Rev. J. Harriman sent me this 

 from the banks of the river Tees, which place seems to 

 abound in a great variety of curious petrifactions. It appears 

 to be a fragment of a large flat piece of a confirmed Iron- 

 stone, and, I should suspect, a very good one of the kind. 

 It is however rendered additionally curious, as it includes 

 Carbonate of Lime, or Calcareous Spar, in the form of 

 Echinus spines, but different from any before noticed. 



