Fig. 
cl 
EXPLANATIONS OF PLATE XII. 
GRAPTOLITHUS RICHARDSONI, page 107. 
. A fragment of slate, preserving a stipe, with six branches in its apparent con- 
tinuation, and impressions of two others in the intermediate space ; two of 
these again bifurcating. 
. A fragment preserving several branchlets, which are compressed in different 
directions, showing the sides and apertures of the cellules. 
. An impression of a bifurcating fragment, the cellules of which were filled with 
mineral matter and vertically compressed. 
4, A fragment of a branch laterally compressed. 
. The impression of a bifurcating branch where the cellules are somewhat 
obliquely compressed, and partially filled with mineral matter. 
6. A fragment enlarged, giving a lateral view of the cellules. 
7. An enlargement from an impression of a branchlet, from fig. 5, which is 
obliquely compressed, having the cellules filled with mineral matter. 
. Enlargement of a fragment, from fig. 1, where the cellules are filled with min- 
eral matter and vertically compressed. 
GRAPTOLITHUS RAMULUS, page 108. 
9. A small bifurcating branch. 
10. An enlargement of fig. 9, showing the form and extent of the cellules. 
