1878.] Saurians of the Dakota Beds of Colorado. 83 - 
inferior portion of the shaft. They are also separated anteriorly 
by a shallow open groove. The external condyle is rather more 
robust than the internal. 
The length of the femur is six feet four inches; the elevation 
a 4 
Fig. 16—A caudal vertebra of A mphicælias 
latus; a from before, b from the left side. 
of the dorsal vertebra three feet 
three inches. The animal, if pro- 
portioned anteriorly like the Cam- 
arasaurus supremus, must have 
been able to elevate itself to a 
height of thirty feet. Its length 
cannot yet be conjectured. 
If inthis fauna, the Camarasaurus 
Supremus was preeminent in gen- 
eral proportions, and the Amphi- 
celias altus was the tallest, the 
Amphicelias latus was the most ` 
robust. It is represented in Mr. 
Lucas’ collection by a right femur 
and four caudal vertebree which 
are in good preservation. They 
reveal the existence of another 
saurian of huge dimensions, and . 
Fig. 17—Left femur of Amphicelias Of great mass in proportion to 
 Žatus, from behind. its height. 
The caudal vertebrae are apparently from the anterior part of 
the series. They are all strongly biconcave; the anterior face 
- more so than the posterior. They are much more deeply bicon- 
