via 
PREFACE. 
together with a general statement of the prin- 
ciples, on which I conceive the study of 
extraneous fossils ought to be conducted : but 
I found, that the materials collected for this 
design, if joined to the following sheets, 
would extend the work far beyond its proposed 
limits. Hence these intended definitions of 
terms. See., have been published in a distinct 
treatise, under the title of “ Outlines of an 
“ Attempt to establish a knowledge of extraneous 
“ fossils on scientific principles!' T o that pub- 
lication I beg leave to refer the reader for such 
information as may be necessary for the better 
understanding of the system and language now 
adopted 
It remains to be observed, that the syno- 
nyms which ought to have followed the specific 
* The reader’s attention is, in particular, called to the sense in which we have 
employed the terms Reliquia, Petrijicata Conservata; Helmintholithus, 
Erismatolithus ; Stirps, Stipes, &c.-. Species, permanent and temporary, 
marked by S. p. and S. t. at the end of the specific characters ; Families, penna- 
neiit and temporary; Soil, Seat, Tract, 'most ancient, ancient, less ancient, 
modern; Matrix, Nucleus, &c. &c. 
