22 



Ketton stone lengthened out, as the broken ends plainly 

 show. They vary extremely in their forms, and when 

 large are sometimes perforated on the outside, apparently 

 by some marine insects ; which may have contributed to 

 the idea of the whole being of animal construction. Nature 

 ever allotting certain bounds to every species of her pro- 

 ductions, permits them to separate from one another in 

 many nice and curious ways. Thus calcareous earth in 

 this instance is separating from the clay in the form of 

 opaque branching corals ; in others we shall find different 

 modes of separation or division of calcareous earth and 

 other substances. 



The small specimens are very much branched, and mostly 

 white, but somewhat softer to the touch. The larger are 

 often more coloured with iron, perhaps some animal sub- 

 stance, as the place in which they are found contains 

 many dead shells. Sometimes they contain some salt, which 

 is readily perceived by the taste, and remains after drying in 

 the cabinet. Some have no saline taste. 



