S. L. Penfield—Apatites containing Manganese. 867 
the section will, I feel sure, he admitted by any impartial geol- 
ogist in whose hands the map is ed. 
I venture to put forward these views with diffidence, and 
because it appears to me to be a matter of great importance 
not merely in regard to the geological structure of the West, 
but to questions in dynamical and physiographical geology, 
that the true structure of the Archzan nucleus of the Wahsatch 
Mountains should be correctly interpreted. Mr, King, in his 
great memoir, has treated that area as a kind of type, and has 
based upon it much of his speculation regarding the form of 
the Archean land, and the nature and effects of subsequent 
fractures of the rocky crust. I confess that it was with con- 
siderable incredulity that I read in his interesting chapters 
reiterated assertions that the Archzan land was so stupend- 
ously mountainous, that some of its peaks rose more than 
5$ miles into the air, and remained above water during the 
whole of Paleozoic and Mesozoic time. I asked myself how 
much loftier and broader these mountains must really have 
denudation. For the dimensions assigne r. King must 
on his own showing be a minimum, reckoned after all these 
ages of ceaseless waste. But if I am correct in regarding the 
am inclined to adopt regarding the structure of this range 
differs from that proposed by Mr. King; and perhaps I may 
be permitted to communicate it on another occasion in the 
pages of this Journal. 
— 
ART. XLV.—Analyses of some Apatites containing Manganese ; 
by Samurn L. Penrrenp. (Contributions from the Sheffield 
Laboratory of Yale College, No. LIX.) 
In their description of the mineral locality at Branchville, 
Conn, (this Journal, July, 1878), Messrs. Brush and Dai 
mention the occurrence of a green manganiferous apatite 
accompanying the other manganese minerals. Apatite occurs 
there of many shades of color, from those which are white and 
“ar gan to those which are dark green, and still others of a 
bluish shade. The green varieties occur in flat crystalline 
