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Supplement to Dana’s Mineralogy. _ 353 
dentition in other animals. These two pachyderms having im- 
mense teeth develop them, as we have elsewhere said, succes- 
sively from behind forwards, to prevent the jaws from being over- 
charged with the weight at any one time. On the whole, we are 
disposed to consider this as the result of that law, which, in con- 
sequence of the hardness of the substances used for food, gives 
these animals an unusual power of dental development, which 
may be displayed from circumstances not known to us. 
Se ee ae 
Arr, XXX VI.—Supplement to the Mineralogy of J. D. Dana, 
by the Author.—Number I. 
Iy continuing in this Journal the semi-annual reviews of min- 
eralogical researches, I propose to give them the form of Supple- 
ments to the last edition of my Mineralogy, believing that they 
will thus prove more convenient to many mineralogical readers 
of the Journal. The following abstracts cover the first six 
months since the publication of the work: they are given as 
briefly as is consistent with their object; and if deemed too 
Concise, they may be taken as an index to the papers where the 
subjects are discussed at length. My own observations or criti- 
cisms are enclosed in brackets. 
he new facts which have been brought to light, suggest no 
essential modification of the general arrangement of the work. 
ome minor changes in the grouping of the species are proposed, 
such as the following :—Boltonite according to Dr. J. Lawrence 
Smith, should be united to Chrysolite: also, as the author shows 
yond, from the observations of Haidinger, Partschin should 
probably be placed near Allanite and Epidote, if not united 
to one or the other; Mosandrite also should follow Epidote ; 
Keilhauite, should follow Sphene, the probability of this relation, 
announced by the author, having now become a certainty on 
crystallographic as well as chemical grounds. 
Important contributions to American mineralogy have been 
recently made by Dr. J. Lawrence Smith, Dr. F. A. Genth, and 
G. J. Brush. Observations on some American, minerals have also 
been published by Dr. Kenngott of Vienna (including analyses by 
M.C. von Hauer, ) whose “ Mine 
Corrections, serve only to multiply doubts, at least in Europe if 
Not in this country. 
~ Thave adopted an alphabetical arrangement, and distinguished 
Species pats ee as new, by putting the name in large 
Szconp Szates, Vol. XIX, No. 67—May, 1855. 45 
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