GRAPTOLITES OF THE QUEBEC GROUP. 
CHAPTER I. 
INTRODUCTION. 
§ I.—NATURE AND FORM OF GRAPTOLITES. 
Until recently the graptolites were, with two or three exceptions, known 
only as simple, straight, or slightly curving linear stipes or stems, usually 
lying in the same plane upon the slaty lammee in which they were imbedded. 
Nearly all these were evidently fragmentary, and, though varying some- 
what in their proportions, rarely exhibited anything that could be regarded 
as the commencement or termination of their growth or development. 
These bodies, in their flattened condition, present a range of serratures 
either on one or on both sides of the stipe; and seldom preserve more 
of their substance than a carbonaceous or corneous film or test of extreme 
tenuity. Under more favorable circumstances, these serratures are dis- 
covered to indicate the apertures of cellules, symmetrically arranged in 
reference to each other, and to the axis of the linear stipe. Others show 
parallel entire margins, with transverse indentations across the central 
portion of the stipe. This appearance we now know to be due to the 
direction of the pressure upon the body exerted at right angles to the 
cellules, and which will be explained in the sequel. 
The earliest opinion regarding these fossils was that they were of vege- 
table origin; and they have been thus considered by some authors even 
at a very late period. Subsequently, they were referred by Wahlenberg, 
and after him by Schlotheim, to the Cephalopoda, being regarded as 
extremely slender orthoceratites.. This opinion may have received sup- 
port from specimens in such condition as G. sealaris, where the indentations 
are limited on each side by a continuous margin; but in such as present 
a single or double series of marginal serratures, the analogy seems very 
remote. Professors Geinitz and Quenstedt advocated the same view at 
a much later date; though it has since been abandoned by these authors, 
from more extended investigations. | 
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