A Geological Reconnoissance. 179 



Below the brecciated Gyroceras and Gypidula beds there are 

 indications in a few instances of the Independence shales. 



x\ few quarries opened in the bluff facilitate the work of 

 observing the succession of strata. One of these quarries 

 near the western end of the exposure has been worked down 

 until the upper surface of the brecciated beds is now exposed. 

 For a distance of thirteen feet above the breccia the rocks are 

 made up of soft, light-colored, imperfectly stratified, argil- 

 laceous limestones which are practically destitute of fossils 

 and were therefore in the field notes designated as Xho. Barren 

 beds. These barren beds grade upwards without lithological 

 change of any importance into the Spin'fera -pennata beds as 

 described and limited in the Aiiierican Geologist for Septem- 

 ber, 1 89 1. Xo beds higher than the S. -pennata beds were 

 seen in this locality. 



As intimated above the S. pennata beds, like the Barren 

 beds, are composed of soft, light-colored, argillaceous lime- 

 stones. The layers are a little more compact and more regu- 

 lar than those immediately below them. Some of the layers 

 included in this part of the section are barren; but fossils 

 characteristic of the horizon are found both above and below 

 them. Spirifera pennata 0\\e.n, does not range throughout 

 its whole thickness; but taking the assemblage of layers 

 together, S. pennata Owen, is its most conspicuous fossil. 

 The fauna of these beds contains a number of unsatisfactory 

 casts of two or three species of Paracyclas, one large, orbicu- 

 lar form being probably identical with P. elliptica Hall. There 

 are also a few Polyzoans, but the fauna is conspicuously com- 

 posed of Brachiopoda. The most common forms are 6^. pen- 

 nata Owen; S, binicsialis Hall; Cyrtina haniiltonensis Hall; 

 Atrypa reticularis Liinnxus; A. aspera var., occidentaiis Hall 

 var. ; Orihis impressa or O. iowensis Hall; O. macfarlanei 

 Meek; StropJiodonta demissa Conrad; Productella siibalata 

 Hall. A few straggling specimens of Gypidula occidentalis 

 Hall, occur at this horizon; and, occuring even more rareh% 

 are specimens of Athyris vittata Hall, a Rhynchonella of the 



