148 Association of American Geologists and Naturalists. 
- “TIL A section from Blue Mounds to Wiskonsin River, exhibiting 
the following descending series of rocks : 
. Beds of siliceous chert, containing the fossils of the cliff 
and forming the peaks of the mounds, 410 feet. 
_— 
2. ie “eA eageny ih containing in its lower portion lead ‘ 
1 [4 
3. The. thay Peieitbifenti limestone, very thin, and i in some 
places wanting, - Y 
4, Saccharoid sandstone, 40 “ 
5. Alternations of ieehantaa éaailstéte at fiver riihtiee 
sian limestone, - - - - - - ao eS 
6. Sandstone, - - - . - - - . a * 
7. Lower magnesian, - - . : . no. JOD es 
. 
Total, - - - 1000 fect. 
By lower magnesian Gehcetahh | is not meant the magnesian limestone 
of Europe. The name was given by Dr. Owen in contradistinction to 
he cliff limestone, (which is the upper magnesian,) both containing 
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 beds.—More regularly stratified, aad less frequently: -yerti- 
cally, fissured than the middle and lower. Also, more rich in siliceous 
containing layers of chert, and indeed passing wholly i 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. = Aepect 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 an 
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 
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 beds.— Terebratule, several species of Pitenciaar Calami- 
pora, Colimnaria tubipora, Aulopora, Sarcissula, Astrea, Cyathophylla, 
yophylla and Orthocerites. 
= « Middle and lower beds.—Coscinipora, (sulcata ? Gr.), “ase ay 
It 
ia, in 
pitenions of a long, spiral 41 univalve, resembling the genus wae 
seéms by the above, that there was no absolute zoological distinction 
between the midale and lower beds.” 
*y. 
