61 



the Lucina of the permian, and the Opis of the trias, that the 

 Lamellibranchiate Mollusks existed in the same rich variety of 

 development at these periods as during the tertiary and present 

 times; and no prepossession can close the eyes to the fact that the 

 Lamellibranchiate have superseded the Palliobranchiate bivalves. 



On negative evidence Orthisina, Theca, Product^ or Spirifer are 

 believed not to exist in the present seas : neither are the existing 

 genera of siphonated bivalves and univalves deemed to have 

 abounded in permian, triassic or oolitic times. To suspect that 

 they may have then existed, but have hitherto escaped observation, 

 because certain Lamellibranchs with an open mantle, and some 

 holostomatous and asiphonate Gastropods, have left their remains 

 in secondary strata, is not more reasonable, as it seems to me, than 

 to conclude that the proportion of mammalian life may have been 

 as great in secondary as in tertiary strata, because a few small 

 forms of the lowest orders have made their appearance in triassic 

 and oolitic beds. 



Turning from a retrospect into past time for the prospect of 

 time to come, and I have received more than one inquiry into 

 the amount of prophetic insight imparted by Palaeontology I may 

 crave indulgence for a few words, of more sound, perhaps, than 

 significance. But the reflective mind cannot evade or resist the 

 tendency to speculate on the future course and ultimate fate of 

 vital phenomena in this planet. 



There seems to have been a time when life was not; there may, 

 therefore, be a period when it will cease to be. 



Our most soaring speculations still shew a kinship to our 

 nature : we see the element of finality in so much that we have 

 cognizance of, that it must needs mingle with our thoughts, and 

 bias our conclusions on many things. 



The end of the world has been presented to man's mind under 

 divers aspects : as a general conflagration ; as the same, preceded 

 by a millennial exaltation of the world to a Paradisiacal state, 

 the abode of a higher and blessed race of intelligences. 



If the guide-post of Palaeontology may seem to point to a 

 course ascending to the condition of the latter speculation, it 

 points but a very short way, and in leaving it we find ourselves 

 in a wilderness of conjecture, where to try to advance is to find 

 ourselves 'in wandering mazes lost.' 



With much more satisfaction do I return to the legitimate 

 deductions from the phenomena we have had under review. 



