PAPERS OX GEOLOGY AXD GEOGRAPHY 421 



NOTE OX THE OCCUEEEXCE OF FUSULES'AS IN 

 THE PEXXSYLVAXIAX ROCKS OF H^LIXOIS. 



Haeold E. Culyek^ State Geological Sueyey. Uebas"a 



1. Brief resume of literature: 



Probably the earliest reference to Fusuliuas in the 

 PemisylYanian of Illinois is found in the reports pre- 

 pared under the direction of A. H. Worthen. These re- 

 cord a large form, now known as Fnsnlina secalica, Say, 

 in the rocks outcropping along Embarrass EiYer in Cum- 

 berland County. There are references also to another 

 and smaller fusulina called Fusulina venfricosa, ci/Iin- 

 drica, Yar. but now knoYm as Girtyina Yentricosa, which 

 was found in the limestone cap rock OYer Xo. 6 coal in 

 Fulton County, in St. Clair County, and other districts 

 farther south. 



Udden reported Fusulinas from two zones in the rocks 

 of the Peoria quadrangle. The lower of these was the 

 limestone capping Xo. 6 coal and the other was the marl 

 at the base of the Lonsdale limestone about 100 feet 

 higher. The fossil in the lower zone was called Fusulina 

 secalica, Say, and its abundance was noted. The Fusul- 

 ina of the upper stratum was also listed as Fusulina 

 secalica, Say, but with a parenthetical note suggesting 

 an easily recognized distinction between the fonns. 



Two foiTQs in similar relations were reported from the 

 BelleYille-Breese area. Here the zones were but half as 

 far apart (50 feet), and the distinction between the Fusul- 

 inas was apparent. The upper was doubtfully referred 

 to Fusulina secalica, Say, with a statement that it was a 

 long, slender type, "quite different from the form of 

 Fusulina found in the roof limestone oYer the Heriin 

 coal''. 



The later references to Fusulinas in Illinois are in 

 large part records of new occurrences of the Fusulina of 

 the Xo. 6 horizon which were refeiTed without particular 

 iuYestigation to the Girtyina ventricosa type. 



