Association of American Geologists and Naturalists. 97 



Evidence of travellers in high latitudes imperfect, yet in connexion 

 with other circumstances may be allowed to have some weight. 



Conclusion as to the source of the materials that may be deemed ad- 

 missible. 



Part II. — On the causes of elevation of the sedimentary rocks above 

 the level of the sea. 



(A.) Evidences that these rocks have been elevated ahove the sea. 



Cannot have been caused by disappearance of water. 

 Lahd has not the stability usually assigned to it. 

 Examples of elevation and subsidence now progressing. 



(B.) Various causes of relative levels of land and loater considered. 



These causes slightly discussed and shown to be insufficient, or else 

 referable to a more general cause. 



The fourth cause, that of secular refrigeration of the earth, consider- 

 ed more at length. 



The earth a cooling body, but in an asymptotic condition. 



The increased angular velocity resulting from change of temperature 

 considered. 



The day has not varied sensibly for two thousand five hundred 

 years. 



Reasons why this cannot be adduced as evidence that the earth has 

 not diminished in volume, and that no geological effects can have been 

 produced dependent on such a cause. 



Discussion of the various causes that might produce variation in the 

 length of the day. 



A cause adduced that would tend to maintain uniformity in the length 

 of the day if the earth be contracting secularly or paroxysmally. 



Influence that this cause may have had in the elevation of mountains 

 under the tropics. 



Influence of the same cause in the elevation of mountain chains, and 

 the formation of fractures and joints around the earth in an eastward and 

 westward direction between 40° and 50° of latitude. 



Consideration of Prof. Rogers' theory of the physical structure of 

 the Apalachian chain of mountains. 



Views in part adopted. Perhaps all are true. Mode of testing the 

 truth of them. 



Another explanation offered of the folded and reversed strata and 

 eastward dip. 



This effect referred to the influence of inertia, when masses are ele- 

 vated, and thus further removed from the axis of rotation, where their 

 proper linear velocity is greater than their real velocity. 



Vol. xLvii, No. 1.— April-June, 1844. 13 



