Association of American G'eologists and Naturalists. 147 
Provided only, that in all cases where the paper is to be with- 
drawn, as above, there shall be no discussion on the su’ 
The Association then adjourned until 33 o’clock, P. M. 
Monday, April 25th, 34 o’clock, P.M.—Prof. Locke in the chair. 
Prof. Locke exhibited sections of the rocks of the lead regions 
of the Upper Mississippi, with remarks on the geology of the west. 
Prof. L. proceeded to state as follows :—I present to-day some geo- 
logical sections of the lead region of the Upper Mississippi. These 
were made by myself during the survey of the Mineral Lands ordered 
by Congress, and by Dr. Owen and myself with numerous assist- 
ants in 1839. A detailed report of that survey was made to the 
Department of the Land Office early in 1840, but owing to some mis- 
management at Washington, it was published without the illustrations, 
which were numerous, and so connected with the text that the doct- 
ment became nearly unintelligible without them. As this paper, imper- 
fect as it is, has been seen by few of our geologists, and as the sections 
before us are chiefly in connection with what I have denominated the 
cliff limestone of the west, I will ask leave to read from my printed 
report some remarks upon that rock. ‘This I do more especially as it 
appears not to be known or recollected that I have a claim to the dis- 
covery that the metalliferous rock of the Mississippi is identical with 
the cliff limestone of Ohio, and that the same rock wherever it has 
been found is more or less metalliferous. [Here was read part of the 
report of Prof. L. to Dr. Owen, referred to as published in Document 
239, 26th Congress, United States. —The following sections were also 
xh explained.] it ekeahae 
. Asection from the Reights of Little Mahoquetn through Jubuq 
aisacipeetiotiatia Mound, fifteen miles. This section exhibited, 
1. The cliff limestone, containing in its middle and lower portions the 
Jead veins Ste 
2. The blue limestone (Trenton enaianithe 
3. Presumptively, the lower magnesian aden the blue. 
“I. A section at Prairie du Chien exhibiting the following rocks, 
descending series : 
1. Soil and cliff limestone, wife - . " 60 feet 
2. Blue fossiliferous limestone, .+ - - - decree BBE eee 
3. Buff colored limestone, ss - - ‘ 20 « 
4. Soft saccharoid sandstone, - - - - “ 4 : 
5. A portion covered by soil, 
6. seta magnesian limestone resombiil the elif litho. 
pda oe is mets destitute of — 190 « 
os Saechar - " ined “ 
| te is pa at low ‘ali. : 
x Tapacnees ampere eo 
