THE 
GEOLOGICAL MAGAZINE. 
aie 
NEW SERIES. “DECADE Il, VOL. 
No. IX.—SEPTEMBER, 1883. 
(OS EAN YN ey) vad be has HS 
I.—American Jurassic Drnosaurs.—RESTORATION OF 
Bronvrosaurus.! 
By Professor O. C. Marsn, M.A., F.G.S.; 
of Yale College, New Haven, Conn., U.S.A. 
(PLATE IX.) 
N previous articles the writer has given the more important 
characters of the order Sauropoda.? A volume on this group. 
is now in preparation, and the illustrations (90 plates) are nearly 
completed. One of these is a restoration of Brontosaurus, which has 
so many points of interest that a reduced figure is here presented. 
Several new characters of this group are added, some of which will 
_be of interest to comparative anatomists. 
Restoration oF Brontosaurus (Plate IX.). 
Nearly all the bones here represented belonged to a single indi- 
vidual, which when alive was nearly or quite fifty feet in length. The 
‘position here given was mainly determined by a careful adjustment 
of these remains. That the animal at times assumed a more erect 
position than here represented is probable, but locomotion on the 
posterior limbs alone was hardly possible. 
The head was remarkably small. The neck was long, and, con- 
sidering its proportions, flexible, and was the lightest portion of the 
vertebral column. The body was quite short, and the adominal 
cavity of moderate size. The legs and feet were massive, and the 
bones all solid. The feet were plantigrade, and each foot-print must 
have been about a square yard in extent. The tail was large and 
nearly all the bones solid. 
The diminutive head will first attract attention, as it is smaller 
in proportion to the body than in any vertebrate hitherto known. 
The entire skull is less in diameter or actual weight than the fourth 
or fifth cervical vertebra. 
A careful estimate of the size of Brontosaurus, as here restored, 
shows that when living the animal must have weighed more than 
twenty tons. ‘The very small head and brain, and slender neural 
1 From the American Journal of Science, vol. xxvi., August, 1883. 
? See Silliman’s Journal, vol. xvi. p. Ati. Nov. 1878 ; vol. xvii. p- 86, Jan. 1879 ; 
vol, xxi. p. 417, May, 1881 ; and vol. xxiii. p. 81, Jan. 1882. 
DECADE II.—VOL. X.—NO. IX. 25 
