No. IV. APPENDIX. 395 



this remarkable geological fact ; for it will simply add 

 a constant to our present climates, leaving tlie dijBPer- 

 ences to remain, as at present, to be accounted for by- 

 latitude and distribution of land and water. The astro- 

 nomical theory of Herscbel, also, wliich would account 

 for former changes of climate by changes in the 

 radiating power of the sun, would only increase the 

 temperature at each latitude, leaving the differences as 

 at present. 



The only speculation with which I am acquainted, 

 which is capable of solving this opprobrium geologicorum, 

 is the hypothesis of a change in the axis of rotation 

 of the earth, the admission of which, as a geological 

 possibility, is matliematically demonstrable, and which 

 has recently had some singular evidence in its favour 

 advanced by geologists. In 1851 I brought forward, 

 at the Greological Society of Dublin, a case of angular 

 fragments of granite occurring in the carboniferous 

 limestone of the County Dublin ; and explained the 

 phenomena by the supposition of the transporting 

 power of ice. In 1855 Professor Ramsay laid before 

 the Geological Society of London a full and detailed 

 theory of glaciers and ice as agents concerned in the 

 formation of a remarkable breccia, of Permian age, 

 occurring in the central counties of England ; and still 

 more recently the same agent has been employed by 

 the geological surveyors of India to account for the 

 transport of materials at geological periods long ante- 

 cedent to those in which ice transport is commonly 

 supposed to have commenced. The motion of the 

 earth's axis would reconcile all the facts known, and 

 it must be regarded as a geological desideratum to 

 determine its amount and direction, and to assign the 

 cause of such a movement. The solution of this pro- 

 blem I regard as quite possible. 



It is well worthy of remark, that the arguments from 

 the occurrence of coal-plants and ammonites strengthen 



