EXPLANATION 01 JOGCUNI SECTION. 183 



Btone spreading out at the ba.se, and among these sire numerous 

 Calamites, also represented by sandstone casts, and, like the trees, 

 standing at right angles to the beds, which arc now inclined at an 

 angle of 19 degrees, but which must have been horizontal when these 

 plants grew and were entombed. The manner in which the plants 

 were preserved in their present state and position can easily be under- 

 stood. Imagine a forest of trees and a tall brake of reed-like plants 

 growing together on a swampy flat. The Hat is inundated and over- 

 spread with sand to the depth of several feet. The plants are thus 

 killed and their dead tops project for some time above the sand. At 

 length they decay and are broken off, and eventually the wood decays, 

 leaving only a hollow cylinder of bark. Sancf is next washed into 

 the perpendicular pipes produced by the decay of the trunks and 

 stems, forming casts of them. The whole is now buried up by suc- 

 ceeding deposits and becomes hardened into stone, and so remains 

 until tilted up, elevated above the water level, and exposed by the 

 action of the tides and waves. 



One stump observed in the particular bed now under consideration 

 is named in the section a Lepidodendron, with a note of interrogation 

 to show that its surface was not so well preserved as to make it certain 

 that it belonged to that genus. The Lepidodendra were tall and 

 graceful trees, but allied botanically to the humble club-mosses 

 (Lycopodia) of our modern Avoods. Their trunks were marked with 

 diamond-shaped leaf-scars, and their branches and twigs were thickly 

 clothed with long lance-shaped or linear leaves, and bore cones at 

 their extremities. These trees did not send up straight trunks with 

 numerous small branches, like the pines, but branched out by the 

 continuous division of the trunk and limbs into pairs of branches, in 

 the manner in which standard pear-trees are often trained by con- 

 stantly cutting out the main ascending twig and allowing two lateral 

 branches to grow in its place. The Lepidodendra must have been 

 among the most beautiful trees of the coal period, and their roots 

 would appear to have been constructed on the same regular type with 

 those of the Sigillaria. Mr Brown of Sydney has described some 

 trees believed to be Lepidodendra, and having such roots, in the coal- 

 field of Cape Breton. Mr Carruthers, of the British Museum, has 

 recently made a similar statement in regard to Lepidodendra in the 

 British coal-fields. I have not, however, met with any instance of 

 this in Nova Scotia. 



Subdivision II. is a barren scries of sandstones and shales, repre- 

 senting beds of sand and mud conveyed by water over the last terres- 

 trial surface of the first group. For aught that the section shows to 



