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BULLETIN OF THE NATURAL HISTORY SOCIETY. 



the whole of these rocks Ijelonged to the Graywacke group, tlie- 

 upper only bore a close resemblance to the Silurian rocks of Europe. 

 For the purpose of making plainer Dr. Gesner's brief state- 

 ments of the age of the two series of the Graywacke system, and 

 to show its relation to the intrusive and the secondary rocks, 

 the author has constructed the followinf;- section. 



Explanation OF Section.— 3, Intrusive Syenite, etc., (of Pre- Cambrian age.) 

 3o. Older Graywacke System. 3b, Newer Graywacke. 7, Red Conglomerate ami 

 Sandstone, a. Fossil " terebratula." b, "Cactus." o, Anthracite coal seam. 

 c. Fossil couiferous trees. 



This section will convey Dr. Gesner's conception of the 

 structure of the peninsula between the Kennebecasis river 

 and the Bay of Fundy. On the south-east, at the base of his 

 " older Graywacke group" is a mass of hard contorted slates, 

 and schists with beds of volcanic ash rock ; the middle of the 

 group consists of Graywacke with some clay slate, and the upper 

 part is a mass of coarse conglomerate. 



Resting on these unconformably is his " newer Graywacke 

 group;" having at the base limestones with beds of Graywacke 

 and intrusive trap ; then the series of slates and Graywacke on 

 which the city of Saint John is Iniilt ; and finally compact 

 Graywacke with fine grained clay slates. Dr. (lesner compared 

 the newer Graywacke group to the Silurian of Murchison, but 

 he does not appear to have given any name to the lower group,, 

 or to have compared it with any European system.* 



♦ They are called Metamorphic rocks in his " New Brunswick," 1847. 



