136 STUART WELLER 



by Shepard, the Sac limestone is really fossiliferous in most 

 localities where it is exposed, and frequently affords beautifully 

 preserved specimens. One of the best fossil localities in the 

 formation known to the writer, is at an old quarry about eight 

 miles northeast of Springfield, east of the Fair Grove road where 

 it crosses the north branch of the Little Sac. The species col- 

 lected at this locality will be enumerated, with notes on their 

 occurrence elsewhere. 



1. Platycrinus ollicula S. A. M. 



2. Platycrinus annosus S. A. M. 



3. Platycrinus absentivus S. A. M. 



All three of these species of Platycrinus were originally 

 described from the Chouteau limestone of Pettis county, Missouri. 



4. Dichocrinus sp. undet. A single specimen of this crinoid has been 

 observed. It is too imperfect for specific identification, but it 

 resembles D. inornatus from the upper Kinderhook beds at Le 

 Grand, Iowa. 



5. Schizoblastus roemeri Shum. This species originally described from 

 the Chouteau limestone at Providence, Missouri, is one of the com- 

 monest species in the Sac limestone at the locality under discussion. 



6. Leptaena rhomboidalis Wilck. This species is entirely absent from 

 the lower Kinderhook beds at Burlington, Iowa, making its first 

 appearance in the upper " Yellow Sandstone," bed No. 5. 1 The 

 species is also absent from the Louisiana limestone fauna of the 

 lower Kinderhook, but is universally present in the upper Kinder- 

 hook. 



7. Chonetes logani N. & P. This little species is particularly charac- 

 teristic of the oolite bed No. 6 2 of the Burlington section. It is also 

 possible that C. omatus Shum., from the typical Chouteau lime- 

 stone, is not specifically distinct. 



8. Productus blairi S. A. M. This species was originally described 

 from the Chouteau limestone of Pettis county, Missouri. 



9. Productella concentrica H. This species occurs abundantly in the 

 Chouteau limestone of central Missouri, and is also a member of the 

 oolitic limestone (bed No. 6) fauna at Burlington, Iowa. 



10. Schisophoria swallovi H. The specimens referred to this species 

 are smaller than the normal form of the species in the Burlington 

 limestone. Specimens agreeing in all respects with those from the 

 Sac limestone, are also present in the typical Chouteau limestone. 



1 Iowa Geol. Survey, Vol. X, p. 76. 2 Loc. cit., p. 77. 



