OF NORTH AMERICA. 
119 
strata of America were disentangled; and also because in many geological works, published in 
America and in Europe, this classification is attributed mostly or wholly to James Hall. This is not 
only (alse in itself, but a great injustice to the true discoverers of this series. Vanuxem was the 
first to recognize the Transition character of the New York strata; Vanuxem and Conrad classified 
the greater part of them; then come Emmons aud Mather; and of the whole five, James Hall is the 
one who contrihuted the least to this important work. 
The Geological Surrey of the Upper Mississippi required more time than that of the State of New 
York, on account of the vast extent of country it emhraced, being more than four times as large 
as New York State. The Federal Government entrusted it to David Dale Owen, a very competent 
and gifted geologist for such an arduous task. Owen the pupil of Maclure, Say, Lesueur, and 
Troost, has nobly continued the work of those first geological pioneers of the Ohio valley, and has 
extended to the borders of the Mississippi and .Missouri the researches that Maclure and Vanuxem 
had made with such success in the States hordering the Atlantic. Owen was assisted in his gigantic work 
by Dr. J. G. Norwood of Madison, one of the best American geologists ; J. Evans, the first ex- 
plorer of the Mauraises Terrc« of Nebraska, and geologist of Steven’s e.xpedition; Dr. B. F. Shiimard, 
one of the best paleontologists; Richard Owen, now Professor at Nashville; J. B. Meek, a geo- 
logist and paleontologist of great talent; C. Whittlesey and A. Litton. The following is his classi- 
fication of the Paleozoic rocks of the States of Wisconsin, Iowa, and Minnesota, published in 1851. 
(Extract from the Table of Colors o! the Geological Map of Wisconsin , Iowa, amt Minnesota : exhibiting, also, the extension 
of the loica Coal-field into Missouri, and Us relation to the Illinois Coal-field; by David Dale Owen. Washington , 1851.) 
Formation of South Western Iowa. 
F. 6. 
Formation of the vicinity of the j 
«des Moinesi) , Rapids of the ) 
F. 5. 
Mississippi. I 
Formation of Cedar valleys . . 
F. 4. 
Upper Magnesian Limestone of 
F. 3. 
Iowa and Wisconsin. ) 
) Upper series, 
j Lower series. 
j c. Upper Coralloid limestone, 
j b. Middle shell bods. 
( a. Lower Coralline beds. 
1 c. Coralline and Pentamcrus beds. 
/ b. Lead bearing bods, 
j a. Shell beds. 
Coal Measures. 
Carboniferous Limestone. 
Devonian Period. 
Upper Silurian Period. 
Lower Silurian Period. 
Upper Sandstone of Minnesota 
and Wisconsin. 
Lower Magnesian Limestone of 
Iowa and Wisconsin. 
Lower Sandstone of Wiscon- 
sin and Minnesota. 
F. 2. 
c. White sandstone. 
b. Magnesian limestone with veins 
of quartz. 
a. .Magnesian limestone with oolitic 
layers. 
f. With intercalations of .Magnesian 
limestone. 
e. Soft fine sandstones. 
d. Upper Trilobile beds. 
c. Coarse Lingula grits. 
b. Lower Trilobile beds. 
a. Red sandstone of Lake Superior. 
Lower Silurian L’eriod. 
Lower Silurian Period. 
