308 ASSINNIBOINE AND SASKATCHEWAN EXPEDITION. 



bask in the pale rays of the Arctic sun ; and therefore I 

 claim a temperature for those seas, at least similar to that 

 which now prevails in the British Islands ; and I may add 

 that the Ammonite, from its habits, was essentially depen- 

 dent on the temperature of the air as well as on that of 

 the water." 



" There is at present a difference of 49° 5' between the 

 mean annual temperature of Point Wilkie and Dublin ; 

 and if this change of temperature be supposed to be 

 caused by a change of the relative positions of land and 

 water, the temperature of Dublin, or of some place on 

 the same parallel of latitude, must be supposed to be 

 raised to 99° 5', while the temperature of the thermal 

 equator will exceed 124°, — a temperature only a few de- 

 grees below that requisite to boil an egg. I reject, 

 without scruple, a theory that requires such a result, 

 which must be considered as a minimum, as it is probable 

 that the Ammonite required a finer climate than that of 

 Britain for the full enjoyment of its existence. 



" The theory of central heat, also, appears to me to be 

 open to the same objection, as a mode of explaining this 

 remarkable geological fact ; for it will simply add a 

 constant to our present climates, leaving the difference to 

 remain, as at present, to be accounted for by latitude and 

 distribution of land and water. 



" The astronomical theory of Herschel, also, which 

 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 possi- 



