IOWA ACADEMY OP SCIENCES. 
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succinct description that is of interest geologically. Catlin was 
especially desirous of visiting the famous red pipestone quarry 
from which the various tribes of Indians had from time imme- 
morial obtained material for their calumets. His account, 
therefore, centers around the layers yielding pipestone rather 
than the formations enclosing it. Incidentally, however, the 
characters of the red quartzite are well described. The stone 
from which the pipes are made is shown to be a sedimentary 
deposit. The specimens of this rock carried away were exam- 
ined both mineralogically and chemically by Dr. C. T. Jackson, 
of Boston, who called it catlinite, after the explorer. 
Half a decade later, NicolleH' published an account of his 
geographic explorations in the upper Mississippi region, and 
among the numerous descriptions of the geology of the region 
he calls special attention to the red pipestone locality. The 
appearance and relation of the rock in the vicinity and the lith- 
ological characters are minutely described. The names or ini- 
tials of the members of the expedition cut in the quartzite, and 
still visible, show that the party visited the place in July, 1838. 
In 1865, James Hallf visited southwestern Minnesota, making 
numerous geological observations throughout the region. 
Although visiting only a part of the quartzite outcrops, he came 
to the conclusion that the rocks were Huronian in age. This 
appears to be the first attempt to associate a definite geological 
age with the formation under consideration. 
The following year HaydenJ passed through southeastern 
Dakota, stopping at a number of quartzite outcrops, which were 
carefully examined. At Fort James, on the James river, it was 
noted that marls containing well preserved Cretaceous fossils 
directly overlie the quartzite beds. Exposures of the red quartz- 
ite were also found on the Vermillion river and on the Big Sioux 
at Sioux Falls and elsewhere. At the latter place Hayden 
believed that he found distinct outlines of bivalve shells in the 
quartzite. This writer also visited the pipestone quarry, which 
he describes with considerable detail. His remarks bearing 
especially upon the age of the rocks in question are as follows: 
“Now the question arises as to the age of the rocks we have attempted 
to describe and which include the pipestone layer. Owing to the absence 
of well defined organic remains the problem becomes a difficult one. Their 
exceedingly close-grained, compact, apparently metamorphic character 
* Report Intended to Illustrate a Map of the Hydrographic Basin of the Upper 
Mississippi River, Sen. Doc. No. 237, 26th Cong., 2d Sess., Vol. V, part 2. Washington, 
+ Trans. Am. Philosophical Soc., Vol. II, p. 15. Philadelphia, 1867. 
t Am.your. Sci., (2), VoL XXXXIII, pp. 15-23. 1867. 
