123 



Dr. S. as S.fuscus. A mere difference in a shade of color, such as 

 is here noticed, is of no importance as a specific character. 



Page 341. Lacf.ophrys camel inus. This genus appears to be 

 altogether unnecessary. 



Dr. C. T. Jackson reported on a paper committed to him 

 and others for examination, entitled "ati Hypothesis to ex- 

 plain, &c. the changes of the surface of the earth/' By 

 Charles Stoddard. 



Dr. J. considers the theory of paroxysmal elevations of the 

 earth's crust as satisfactorily proved, in opposition to the theory of 

 gradual change proposed by Mr. Lyell, and that it only remains to 

 examine into the causes of the paroxysms. Here we have three 

 sets of causes to examine : 1st. the expansion of the internal mat- 

 ter of the globe ; 2d. its secular refrigeration ; 3d. a change of in- 

 clination of the earth's axis. The last is the power appealed to by 

 the author of the paper before us. This hypothesis is eminently 

 popular, for it seems to be illustrated by what we know of the 

 forces acting on a revolving sphere composed of soft and yielding 

 materials. Dr. J. remarks, " he does not know where it origina- 

 ted, but finds it is a common opinion among the people of New 

 Hampshire and Maine, insomuch that he has often heard it ad- 

 vanced as a new theory by many different men." 



Viewing the earth as a globe of molten matter, having a com- 

 paratively thin crust of solid materials, it is easy to conceive that 

 with each change of axis of the revolving globe the surface would 

 be elevated or depressed, and a force exerted adequate to the rup- 

 ture of the earth's crust, and sufficient for the elevation of chains 

 of mountains and whole continents at a single operation. The hy- 

 pothesis, therefore, suggests an adequate cause of the phenomena 

 to be explained. 



The thesis under examination, Dr. J. remarks, is an ingenious 

 and well written expose of this hypothesis. The principal objec- 

 tion to it is, that the author has not shown any cause adequate to 

 produce a change of axis of rotation of the earth. Dr. J. con- 

 cluded by expressing his wish that the author would continue his 

 researches upon the subject, and by recommending that an abstract 

 of the paper be inserted in the Proceedings of the Society. 



Dr. C. T. Jackson made a verbal communication on re- 

 searches made by himself and Mr. A. A. Hayes, of Rox- 



