The Fauna of the Burlington Limestone. — Rowley. 247 
Next to Melo, Schizoblastus sayi is the most common Bur- 
lington blastoid and is found plentifully in its zone. It ranges 
from the very base of the Upper Burlington to near the middle 
of that formation, being most abundant below. Most of the 
variation in this species is in the ornamentation. The shape 
is more or less round even in the young, although elongate 
specimens are not rare, neither are they confined to the young. 
A large variety occurs near Curryville, ornamented bv 
festoons of node-like granules almost large enough to be 
called warts. The cherts at the base of the Upper Burlington 
are rich in natural casts of the inside of this blastoid. The 
writer has found a single undersize specimen of S. savi at 
the top of the Lower Burlington. 
Fully half of the specimens of S. sayi have the central 
opening above arched over by a covering of minute pieces, 
continuing for a little way over the ambulacra. One speci- 
men has the anal opening at the top of a short proboscis, 
composed of small pieces. This can hardly be an abnornial 
feature and a suspicion, long present in the writer's mind, 
that two other Burlington blastoids possessed in life short anal 
probosces, is here strengthened. 
In order of importance, Granatocrinus or Orbitremites 
norwoodi comes next. 
In the cherts near Curryville this fossil is far more abund- 
ant than Schizoblastus sayi, but the reverse is the condition 
at Louisiana. The chief character of this species is its 
deep basal concavity. It varies both in size and ornamenta- 
tion, but less so in the latter respect than Melo. A single 
rotund specimen was taken from the top of the Lower Bur- 
lington limestone at White Ledge, Mo., probably G. norwoodi 
var. fimbriatus. 
At Louisiana it occurs near the top of the Upper Burling- 
ton above the S. sayi horizon. 
The beautiful internal casts of this blastoid are a perfect de- 
light to the chert breaker. 
From a Spencer Creek flint, hardly two feet square and 
nine inches thick, the writer obtained twelve perfect casts 
and destroyed half as many more. 
Pentremites elongatus ranges throughout the Upper Bur- 
lington but is always rare. It occurs in southwest Missouri 
