PLATE VI. 
Fig. 1. 
Melbourn Rock, Dover (“ The Grit Bed ”). 
This is an extremely well-marked form of nodular rock, occurring not 
only in the “ Grit Bed ” but in many exposures at this horizon, as well 
as in the Richmond well-boring. 
a.a. small nodules of chalk; b. matrix consisting chiefly of 
Inoceramus-prisms ; c.c. coarse fragments of Inoceramus-shell showing 
prismatic structure ; c. the prisms are here cut diagonally. 
Fig. 2 
Melbourn Rock, Hitchin, Herts. 
A nodular rock in which the nodules are not so clearly defined as 
in Fig. 1. 
a. portion of a nodule ; b. the matrix containing a large proportion 
of coarse shell fragments, chiefly prisms of Inoceramus mytiloides; 
c. a small tubular boring in the nodule, now filled with granular 
crystalline calcite. 
