20 F.V. Hayden on the Geology of Northeastern Dakota. 
The first detailed account of the Pipestone ce. that I have 
been able to find, is that of Catlin, in this Jou 1 (2h XXxViii. 
that paper he regards them as of = same age with the Huro- 
nian rocks of Canada and Lake Supe 
At the time Mr. Catlin made his et to the quarry he sent 
a portion of the peer to Prof. C. T. Jackson, of Boston, for 
analysis. Prof. J. a e it the name of Catlinite, with the fol- 
lowing composition 
Water, - - ; : Sida 
Silica, . . = é 48-2 
Alumina, - - < - ~ 282 
Magnesia, . = i 6-0 
Peroxyd of iron, - : = 20 
Oxyd of manganese, - * a 0-6 
Carbonate of lime, . ain Bell 
Loss (probably magnesia), - - 1-0 
100 
The Pipestone layer, as seen at this point, is about 11 inches 
in thickness, only about 24 inches of which are used for manu- 
facturing pipes and other ornaments. The remainder is too im- 
pure, slaty, fragile, &c. This rock possesses almost every cola 
and texture, from a light cream to a deep red, depending upon 
annual visit to secure a portion of the precious aueet They 
laced a higher value on the rock, because, while being so firm 
in texture it is so easily wrought, ‘and because they could make 
far more beautiful and showy pipes than from any other mate- 
rial known to them. ides, this was and is now, the only — 
locality from whence the true pipestone can be obtained, and 
the labor is so great in throwing off the five feet of solid quartz 
Fe eee 
