134- Silurian and Devonian Rocks 



I. — Lower Silurian. 



The Atlantic coast series, which I regard as probably of this 

 age, has afforded little that is new since my former publication on 

 the subject. It extends continously, with prevailing east and 

 west strike and northerly dip, from Cape Canso to the middle of 

 the peninsula at Halifax Harbour. Thence it continues with pre- 

 vailing north-east and south-west strike to the western extremity 

 of the province. Its most abundant rocks are coarse clay slate 

 and quartzite in thick beds. In some districts the slates are re- 

 presented by mica-schist and gneiss, and interrupted by consider- 

 able masses and transverse bands of intrusive granite. It has 

 afforded no fossils ; but it appears to be the continuation of the 

 older slate series of Mr. Jukes* in Newfoundland, which has 

 afforded trilobites of the genus Paradoxides.-f These fossils 

 would indicate a position in the lower part of the Lower Silurian 

 series, possibly on the horizon of the Potsdam sandstone or Lingu- 

 la Flags. If so, the Lower Silurian limestones are either absent 

 or buried by the unconformable superposition of the next series, 

 or of the carboniferous beds which in some places immediately 

 adjoin these older rocks. 



It is however proper to state that on a comparison of these 

 rocks with the series of altered deposits from Eastern Canada, 

 collected by the Canadian Survey, and elaborately examined by 

 Mr. Sterry Hunt, they appear more nearly to resemble those of the 

 Hudson River group than any other of the series. It seems also, 

 that chiastolite and staurotide, which occur abundantly in some 

 parts of the Nova Scotia coast series, as for example, at Cape 

 Canseau and in Shelburne, are characteristic in Canada and New 

 England of altered Upper Silurian and Devonian rocks. It is 

 possible that this last fact may be accounted for by the local oc- 

 curence of some beds newer than the others ; and the characters 

 of the Silurian and Devonian series, as seen elsewhere in Nova 

 Scotia, seem at least to exclude the mass of these coast rocks from 

 any formation newer than the Middle Silurian. 



II. — Middle akd Upper Silurian. 



The inland group of metamorphic rocks is more variable in its 

 character, presenting many varieties of shales and slates some- 



*Survey of Newfoundland. 



t Salter, Proceedings Geological Society of London, 1859. 



