Fig. 
Fig. 
Fig. 
Fig. 
16. 
17. 
18. 
20. 
Zi 
22. 
23. 
24, 
25. 
26. 
27. 
EXPLANATIONS OF PLATE I. 
GRAPTOLITHUS NITIDUS, page 69. 
A young individual with the radicle and the two stipes. 
. The extremity of a stipe enlarged, showing the partially-developed cellules. 
. A larger specimen similar in character to fig. 1, showing the pustules at the 
base of the cellules. The extremities are not quite entire. 
. A part of the left side of fig. 3 enlarged, showing the pustuliform elevations. 
. An enlargement from fig. 8, with the cellules obliquely compressed and the 
pustules obscure. 
. Two smaller individuals, which, from juxtaposition and similarity, seem as if 
they may have originated from a common base. 
. An impression of a more extended form, proportionally narrower than fig. 3. 
. A still narrower stipe, diverging almost rectangularly from the direction of 
the radicle. 
. A well-preserved small individual, enlarged three diameters. 
GRAPTOLITHUS PATULUS, page 71. 
. A specimen preserving the radicle, and a stipe on one side two and a half 
inches in length. 
. The distal extremity of a larger stipe. Some of the cells are filled with pyrites. 
. A short stipe broken off near the radicle, showing the narrow form near the 
base, and a width beyond greater than in ordinary forms. 
. A part of fig. 12 enlarged. 
. A part still further enlarged to show the strie parallel to the cell-apertures. 
. An enlargement from fig. 11, where some of the cells are filled with iron 
pyrites showing their extension almost to the back of the stipe. 
GRAPTOLITHUS BIFIDUS, page 73. 
A small specimen from the same fragment of slate with fig. 17. 
An individual of ordinary size. 
An enlargement of the upper part of one stipe of fig. 17. 
GRAPTOLITHUS INDENTUS, page 74, 
An individual of the natural size, the continuation of the stipes having been 
broken off on ode side. 
GRAPTOLITHUS EXTENUATUS, page 75. 
A fragment of the stipe, natural size. 
A portion of the lower extremity enlarged ; a part of the specimen retaining 
the substance of the fossil, and a part being an impression in the slate. 
GRAPTOLITHUS CONSTRICTUS, page 76. 
A young individual, natural size. 
An older specimen, the stipe broken off on one side. 
A part of a much more extended stipe, but which is not wider than fig. 23. 
A part of a stipe from Gros Maule. 
An enlargement of the last, showing the form of cells, the cell-denticles or 
apertures, and the characteristic apparent constriction. 
