DAWSON ON THE GEOLOGY OF NOVA SCOTIA. 329 



Synopsis of the Carboniferous Rocks of Pictou. 



1. Newer Coal Formation. — The prevailing rocks are alternations of 



reddish and grey sandstones and shales, with some coarse conglomerates, 

 especially in the lower part. Subordinate to these, are dark grey con- 

 cretionary limestone, thin beds of coarse sandy limestone, two thin beds of 

 coal and one of g-ypsum. Thickness, 5000 feet or more. 



Fossils. — Coniferous wood, Calamites. ferns, fyc. Ganoid fish, tracks of land 

 animals. 



2. Older Coal Formation. — The prevailing rocks are dark shales and clays, 



grey and brown sandstones ; and subordinate to these are coal, ironstone, 

 dark limestone. Thickness, 5000 feet. 



Fossils. — Ferns, Stigmaria, Calamites, Lepidodendra, fyc, Cypris. 



3. Mountain Limestone, or Gypsiferous Formation. — The prevailing 



rocks are reddish sandstones, shales, and clays, with some grey beds ; con- 

 glomerates, especially in lower part ; and subordinate to these, thick beds 

 of limestone, thick beds of gypsum with anhydrite. Thickness, 6000 feet 

 or more. 



Fossils. — Calamites, fragments of carbonized plants. Producta, Terebratula, 

 Encrinites, Madrepores, 8fc. 



Small quantities of copper ores are found in the sandstones of 

 the gypsiferous and newer coal formations, especially in the latter. 

 Salt springs rise from the older coal and gypsiferous formations 

 in a few places. Veins of hematitic iron ore occur in the gyp- 

 siferous rocks of the East River. The strata of the two older 

 members of the carboniferous system are more disturbed and 

 hardened than the newer series, and contain inter stratified and 

 intrusive traps, which appear in no part of the newer coal form- 

 ation, except the conglomerate at its base. 



Appendix. — On the Junction of the Carboniferous and Silurian 

 System at 31accara's Brook. 



Silurian and Lower Carboniferous Rocks as seen in the Coast Section 



at Maccara's Brook. 



8. Sandstone and shale of a red and grey colour. 

 2. Conglomerate. 



I. Hard shales and impure limestone (Silurian) of a dark grey colour. 

 Fossil shells. 



In my notes on the lower carboniferous rocks, I described this 

 place ; but from want of time, and owing to the state of the tide, 

 when I examined it last summer, I was unable to ascertain the 

 exact nature of the junction of the two formations. Having re- 

 examined the section under more favourable circumstances, I have 

 been enabled to observe distinctly the unconformable superposition 

 of the carboniferous system on the Silurian rocks. As I formerly 

 noticed, the gypsiferous system at this place, in consequence of 

 the absence of gypsum, and the presence of great beds of horn- 

 blendic trap, presents a very unusual appearance, and could 



