APPENDIX. 
Arr: LIL—A New Order of Extinct Reptilia (Stegosauria) — 
the Jurassic of the Rocky Mountains ; by Prof. O. C. Marsa 
THE Museum of Yale College has recently received the 
greater portion of the skeleton of a huge reptile, which proves 
to be one of the most remarkable animals yet discovered. It 
was found on the eastern flank of the Rocky Mountains, in beds 
which I have regarded as corresponding nearly to the Wealden 
of Europe, and which may be classed as upper Jurassic. 
The remains are well preserved, but are embedded in so hard a 
matrix that considerable time and labor will be required to 
prepare them fora full description. The characters already de- 
termined point to affinities with the Dinosaurs, Plesiosaurs, and 
more remotely with the Chelonians, and indicate a new order, 
which may be termed Stegosauria, from the typical genus here 
described. 
Stegosaurus armatus, gen. et sp. nov. 
In this specimen, some of the teeth preserved have com- 
pressed crowns, and are inserted in sockets Others are eylin- 
drical, and were placed in rows, either in thin plates of imper- 
fect bone or in cartilage. The latter are especially numerous, 
and may possibly prove to be dermal — having all the 
pa er characters of teeth, as in some es. e vertebrae 
are biconcave, their neural arches baat. coosified with the 
centra, and the chevrons articulated. The limb bones indicate 
an dae life. The body was long, and protected by large 
bony dermal plates, somewhat like those of Atlantochelys (Pro- 
tostega). These plates appear to have been in part supported by 
the elongated neural spines of the vertebre 
The length of one of the compressed teeth of this ae 
is 112 mm., and the greatest diameter of the crown 2 
One of the. fs areal teeth is 75 mm. in length, and 1 it in 
diameter. Seven of these teeth in position occupy a space of 
63 mm. A trunk vertebra measures 450 mm. from base of 
centrum to top of neural spine, and 170 mm. to the floor of 
the neural canal. The extent of seven posterior caudal verte- 
bre is 660 mm. One of the large dermal plates was over three 
feet (one meter) in length, 
e present species was probably thirty feet long, and 
ge ieee bagerieg by swimming. For its —— science is 
R. Sct.—THIRD tr oro , VoL. XIV, No. 84.—Dec., 
