148 Association of American Geologists and Naturalists. 



" III. A section from Blue Mounds to Wiskonsin River, exhibiting 

 the following descending series of rocks : 



1. Beds of siliceous chert, containing the fossils of the cliff 



and forming the peaks of the mounds, - - 410 feet. 



2. The cliff limestone, containing in its lower portion lead 



ore, - 169 " 



3. The blue fossiliferous limestone, very thin, and in some 



places wanting, - - - - - - ■ 00 " 



4. Saccharoid sandstone, ------ 40 " 



5. Alternations of saccharoid sandstone and lower magne- 



sian limestone, ------- 188 " 



6. Sandstone, --.----- 3" 



7. Lower magnesian, ...... 190 " 



Total, - - 1000 feet. 



By lower magnesian limestone is not meant the magnesian limestone 

 of Europe. The name was given by Dr. Owen in contradistinction to 

 the cliff limestone, (which is the upper magnesian,) both containing 

 magnesia. What has been denominated by me the cliff limestone, — a 

 name adopted by Dr. Owen, — is properly divided into three portions, 

 which other geologists may consider three distinct formations. 



The following is Dr. Owen's subdivision of the cliff series : p. 24, 

 Document 239, 26th Congress. 



" Upper ieds. — More regularly stratified, and less frequently verti- 

 cally fissured than the middle and lower. Also, more rich in siliceous 

 fossils, containing layers of chert, and indeed passing wholly into masses 

 of flinty rocks, containing also good iron ore, and much crystallized 

 carbonate of lime ; but lead rarely, and in unprofitable quantities. 



" Middle beds.— Aspect more arenaceous, though it contains but a 

 small per centage of sand. Cherty masses are rare. Stratification 

 imperfect, with numerous vertical fissures. Rich in ores of lead and 

 zinc, associated with iron in small quantities. 



" Lower beds. — Also of arenaceous appearance ; rather more dis- 

 tinctly stratified than the middle beds, and imbedding more frequently 

 than these siliceous cherty masses. They contain the same ores as the 

 middle beds, with the addition of copper ore and sulphuret of zinc." 



These several beds are distinguished by their fossils. The several 

 fossils enumerated by Dr. Owen are : 



" Upper ieds. — TerehratulcB, seYeral species of Catenajwra, Calami- 

 pora, Columnaria tuiipora, Aulopora, Sarcissula, Astrea, CyatJwphylla, 

 Caryojjhylla and Orthocerites. 



^'■Middle and loioer beds. — Coscinipora {sulcata? Gr.), the only 

 coralline, a Cirrus resembling perspectious ; Ampularia, in perfect im- 

 pressions of a long, spiral univalve, resembling the genus Vivipara. It 

 seems by the above, that there was no absolute zoological distinction 

 between the middle and lower beds." 



