118 ROYAL SOCIETY OF CANADA 



rather than to the Laurentian proper, and neither of these series has 

 yielded any fossil evidence whatever of determinative value. 



The age of much of the granite and other igneous rocks which, 

 in the classification of 1870-1, were assigned to the lower Laurentian, 

 is also largely problematical; and the same remarks will apply to large 

 portions of the original Huronian, which in the published map of 

 southern New Brunswick were described under the head of Pre- 

 Cambrian. These views were latter modified as a result of recent 

 examinations in Charlotte country. For while without doubt there 

 are areas of these rocks which are fairly entitled to be classed as Pre- 

 Cambrian, other large portions, both of the igneous and stratified rocks 

 about St. John and westward, once regarded as Laurentian or Huron- 

 ian, have been found to be newer intrusives which alter sediments 

 containing Silurian fossils, or to be still new^er sediments, in part of 

 Devonian age, which have been changed into schists and crystalline 

 limestone, in which the remains of organisms can be readily ob- 

 served. As for the supposed Laurentian rocks about St. Stephen 

 in Charlotte county, on which much of the geological classifi- 

 cation of this part of the province was based, it must be said that 

 they present but small evidence, either in their physical character 

 or their stratigraphical relations, to entitle them to such a position. 



On the other hand, the general aspect of the crystalline lime- 

 stone, associated slate and quartzite of the series resembles closely 

 the recognized Cambrian rocks of the district but in a higher state 

 of metamorphism. Such alteration has been largely local in character, 

 and the causes can be readily seen in the presence of large masses of 

 igneous intrusive rocks, the metamorphism being more marked as 

 these igneous rocks are approached. Much of the alteration is 

 also doubtless due to the large amount of fokling which has affected 

 great portions of the several formations. In the case of the limestone 

 such alteration is evident in the fact that otherwise bluish slaty beds 

 are changed to the white crystalline character, while the granite and 

 diorite often cut across the limestone and slate and sometimes carry 

 pieces of the adjacent rock in the igneous mass. 



The limestone developments are often quite local, occurring fre- 

 quently as small narrow lenses surrounded by slate or quartzite, while 

 in other places they spread out into areas of considerable extent, 

 though in such cases the limestone is broken up and largely reduced 

 by the granite. In the occurrence of these limestone bands they 

 closely resemble portions of the lower Sillery formation of eastern 

 Quebec. 



The presence of sponge spicules in these rocks is also interesting. 

 Similar forms are very abundant in the lower and middle Sillery 



