542 GEOLOGY AND MINERALOGY. 
We must content ourselves therefore, with the present brief statement 
of the general plan and character of the volume. As a work of reference 
it will prove indispensable, for many years to come, to all engaged in 
mineralogical investigations.* Bldy Gs 
SCIENTIFIC AND LITERARY NOTES. 
GEOLOGY AND MINERALOGY. 
ON THE FORMATION OF MOUNTAIN RANGES. BY PROF. JAMES HALL. 
Mountain ranges, as wellas surface inequalities generally, are usually considered 
to have been produced by the direct agency of elevating forces, or by that of 
denudation; or, in certain cases, by the two combined. Professor Hall, whilst 
admitting the action of these forces to some extent, maintains the existence of a 
third cause in the production of the results in question—viz., the unequal 
deposition of sedimentary matter; or, in other words, the special accumulation 
of sediments, by currents, along certain lines or tracts of country. In our notice 
of the first portion of the ‘‘ Geology of Iowa” in the present volume of the Journal, 
we fear that we may not have done entire justice to the author’s particular views 
in this respect—having been under the impression that his arguments were 
couched principally against the supposed influence of elevating or disturbing 
forces in the formation of mountain chains, as opposed to the effect of denudation. 
Nevertheless, if we admit with Professor Hall, that (in certain cases,) mountain 
elavations have arisen from the cause he advocates—denudation, it is evident, 
must be looked upon in connection with this cause, as an accessory power of no 
inconsiderable moment. The occurrence of outliers, for example, (and that of 
synclinals on ridge-summits, as mentioned by Prof. Hall, below) shews clearly the 
influence of this action; and the opponents of the “ special accumulation theory ” 
might argue with some show of fairness, that in many instances, the diminished 
thickness or the absence of particular strata at a given spot, was caused toa 
certain extent, or perhaps wholly, by denudation also. Be this, however, as it 
may, we are happy to lay before our readers the following summary of some 
observations on this subject, made by Professor Hall at a recent meeting of the 
Albany Institute :— 
“Mr. Hall began by stating that the views which he should bring forward were 
the result of many years of personal observation and investigation upon the older 
strata of the North American continent. It was ten years since he had first 
propounded similar views, though with hesitancy, hoping that the questions 
involved would be discussed by others. Farther examination and reflection had 
only tended to strengthen the opinions then entertained, and in his address at 
Montreal in 1857 he had put forth more strongly the same views. 
* The right of translation, we observe, as regards #rance and England, is reserved by the 
publisher under the present international arrangement. 
