IOWA ACADEMY OF SCIENCES. 105 



2. The Coggon beds, as described by Professor W. H. 

 Norton in the reports of the Iowa Geologial Survey, 

 overlie the Gower stage of the Silurian, and are immedi- 

 ately beneath the Otis beds of the Wapsipinnicon stage, 

 the lowest Devonian terrane recognized in Iowa. The 

 lithological affinities of the Coggon are with the Niagara, 

 but the very meagre fauna inclines rather toward the 

 Onondaga limestone of the Devonian. The specimen from 

 Bieler's quarry in Cedar county, was analyzed by Miss 

 Herri n ton. 



CaCOi 58.2 per cent. 



MgCUs 39.5 



Fe203 and AhOs 0.9 



SiU. 1.3 



Total 99.8 per cent. 



This is not a true dolomite, but more nearly approaches 

 it than the rock described in 1. 



3. The Gower stage as defined by Professor Norton 

 includes two distinct lithological types: A hard crystal- 

 line rock used exten.sively for lime, and hitherto known 

 as the LeClaire limestone; and a granular, evenly-bedded 

 rock which furnishes the best building stone in the state. 

 This was until recently designated as the Anamosa beds, 

 which have usually been assigned rank as a distinct geo- 

 logical formation; but the Iowa Geological Survey in it& 

 recent reports, has taken them to be but' a lithogical phase 

 of one formation. The name Goiver has been assigned 

 them from the township in Cedar county in which the 

 important Bieler quarries are situated. Both types of 

 rock are found in the Bieler quarries. The specimen of 

 the granular laminated building stone was analyzed by 

 Miss Herrinton. It varies only slightly from a true dolo- 

 mite. 



CaCUs 56.4 per cent. 



MgCUs 42.6 



Fe203 and AI2U3 7 



Si02 0.4 



Total lOU.l per cent. 



