138 . III. DIST. CHAR. Substance. 



Tuffstone. Calc Tuff. James, p. 531. Tophus 

 crustans, Gmel. Syst. Nat. T. 111. p. 88. This 

 stone frequently forms the matrix, but rarely 

 the substance, of extraneous fossils It some- 

 times, however, assumes the place and figure 

 of the moss, reeds, &c. which,, in the first in- 

 stance, it had merely incrusted. 



Marl. 



Indurated. Kirw. p. 95. F. An. and Veg. 

 abounds in vegetal remains, of which it 

 frequently forms the substance. 

 Earthy. Kirw. p. 94. F. An. and Veg. 

 Often forms the nuclei in testaceous re- 

 mains. 

 Marlite. 



Argillaceous. Kirw. p. 99. F. An. 

 Bituminous. Kirw. p. 103. Bituminous 

 Marl Slate. Jam. p. 529. F. An. and Veg. 

 The animal, generally of fish. 

 Calcareous Sandstone. Kirw. p. 361. F. An. 

 We have seen an aggregate stone of this kind 

 in the form of shells. 

 Ferricaldte. Kirw. p. 110. F. An. 



* * Fluates. 

 Fluor'. 



Sparry. Kirw. p. 127. F. An. Fluor spar 

 sometimes occurs in Derbyshire in the form 

 of Entrocliittf ; we have also found it, but 

 not often, constituting festal reliquia. 



