38 



PETRIFACTIONS AHD THEIR TEACHING. 



CHAP. I. 



laid bare a magnificent trunk of a Sigillaria, with Stigmaria- 

 roots extending upwards of twenty feet in the clay. 



In the Pictou coal-field of Cape Breton, in Nova Scotia, 

 many similar instances have been brought to light ; the re- 

 markable phenomenon existing in that locality, of successive 



