OUTLINES. 
147 
sandstones and shales are usually blackened on either side of these trap 
dikes to a distance of several feet or yards, proportioned to the size of the 
dike, and not unfrequently they have undergone complete inetamorphisuj. 
It is due to Prof. Dana that we are able to describe these dikes as 
dolerytic instead of diorytic , his investigations among the traps of the 
Connecticut valley having determined this point for them, and the ex- 
amination of a typical specimen of the North Carolina traps, sent for 
comparison at his request from the very full collection in the Museum, 
having extended the conclusion to those of this State also. Ot 
valuable minerals, besides the coal, iron ores are the chief, there being 
several beds of limonite, (frequently in the form of a coarse gravel), which 
are persistent for many miles and of 1 to 3 feet thickness. 
Fossils . — In addition to the vertebrate remains of the North Carolina 
Triassic, of which a complete list is found in the Appendix by Prof. 
Cope, the following species of other orders are given by Dr. Emmons: 
MOLLUSCA. CRUSTACEA. 
Posidonia ovalie. Cypris . 
“ Multicostata. 
PLANTS. 
■Chondrites interruptus, 
“ gracilis. 
“ ramosus. 
<3ymnocaulus alternatus. 
Equisetum eolumnaroides. 
Calamites disjunctus. 
“ arenaceus. 
Strangerites oblongus. 
Pdcopteris falcatus. 
“ earolinensis. 
Cyclopteris . 
4crostichites oblongus. 
Sphenoglossum quadrifolium. 
Cheilantliites 
Dyctuoeaulus striatus. 
1 ycadites acutus. 
“ longifolius. 
Zamites framinoides. 
obtusifolius. 
Podozamites lanceolotus. 
“ longifolius. 
Pterozamites decussatus. 
Wal hia diffusus. 
“ longifolius. 
Lepacyclotes circularfs. 
“ ellipticus. 
The coal mines are not wrought, and have not been re-opened, except 
for a few months, since the resumption of the Survey, so that there has 
been little opportunity to add any thing to the pre-existing knowledge 
of our Triassic palaeontology. 
CRETACEOUS. 
This formation is visible in North Carolina only in the river bluffs of 
the southeastern portion of the State, from the Neuse, (and its tributary, 
Cor.tentnea), southward. Dr. Emmons also speaks of it as occuring on 
