[MATTHEW] GEOLOGICAL A.GE OF THE LITTLE RIVER GROUP 71 



which separates the older metamorphic terranes from those more loosely 

 coherent strata which overlie them. 



The absence of the plant-bearing terrane from the district to the 

 north of the two basins of sediments of the Little Eiver Group 

 shown on our map for a space ten miles or more prevent the 

 actual tracing by connected deposits of these beds to the Silurian 

 strata that surround the intrusive mass of the Nerepis granites. These 

 strata are more or less altered by the granitic intrusion, but in many 

 places they have clearly distinguishable Silurian marine fossils with some 

 poorly preserved remains of plants (as Cordaites). In some of the beds 

 of this terrane, especially the lower ones, the brachiopod shells are 

 dwarfed individuals and there are remains of crustaceans of the family 

 Ehinocaridae. Ostracoderm fishes, Cepalaspis and others, appear to in- 

 dicate that these lower beds of the Silurian were estuarine deposits in 

 brackish water and show proximity to the land at the time they were 

 deposited. 



Comparison with the Silurian Terrane. 



On the south side of the mass of the Nerepis granite the succession 

 of the Silurian beds through which the granite has forced its way is 

 somewhat obscured, and the strata irregularly broken, but on the north 

 side in departing from the granite northward the Silurian rocks are 

 exposed in a more regular succession. They are in ascending order: — 



Gray quartzites or Sandstones. 



Dark gray clay&lates (Cordaites, etc.). 



Paler gray clayslatos. 



Greenish gray calcareous slates (Lepidodendron, cone of). 



The Little Eiver terrane exhibits a similar succession in ascending 

 order : — 



Dadoxylon sandstone (gray). 

 Lower cordaite slates (dark gray). 

 Upper cordaite slates (paler gray). 



There are more or less of sandstone beds in both series in the slaty 

 portion. In both series the plant remains are most abundant in the dark 

 gray clay slates toward the base. Both series have unquestionably a 

 thickness of some thousands of feet, though the folding and faulting of 

 the strata in both makes a satisfactory estimate of the thickness difficult. 



The Little Eiver terrane does not lend itself to a comparison vrith 

 the Devonian of the Baie Chaleur either in the succession of the beds or 

 in the contained plant remains. The known floras are utterly different; 

 the only plants they have in common are such as are of universal distri- 

 bution in the Palaeozoic land terranes. The Gaspé plants are much more 



