APPENDIX 331 



beds of limestone and dolomite associated with pre- 

 Cambrian rocks, which Dr. Callaway regards as pro- 

 bably equivalent to the Pebidian of Hicks. In these 

 there are obscure traces of organic fragments ; and in 

 one bed near Bodwrog Church I found a rounded 

 laminated body, which may be an imperfectly pre- 

 served specimen of Cryptozoon, or some allied or- 

 ganism. The specimens collected have not, however, 

 been yet thoroughly examined. These and other 

 pre-Cambnan deposits in Great Britain correspond 

 in their testimony, with the Eozoic rocks of North 

 America, as to the small number and rarity of fossil 

 remains in the formations below the base of the 

 Palaeozoic, and the consequent probability that in 

 these formations we are approaching to the beginning 

 of life on our planet ; though there is still reason to 

 hope that additional oases of life may be found in 

 these deserts of the pre-Palaeozoic. Such rare inter- 

 vals of fertility should be the more valued when the 

 labours of so many skilled observers have proved so 

 meagre in their results in comparison with the great 

 extent and thickness of the beds which have been 

 explored. 



