184?6.] BROWN ON ERECT FOSSIL TREES. 393 



run in a stiff clay, went in a horizontal direction without striking so 

 deeply into the mud *. 



As before stated, no distinct fibrils can be traced for any distance 

 in the matrix of fire-clay at Dukinfield owing to the dark colour of 

 the deposit, but at St. Helens the whole of the strata teemed with 

 them, and they could be traced five or six feet from the roots, ra- 

 diating in all directfons ; some were found within fifteen inches of 

 the commencement of the stem and before the depressed areolae 

 could be distinguished, but at four feet distance the roots became 

 true Stigmaria and then no further dichotomization took place. 



It seems evident that Sigillaria was a plant of an aquatic nature 

 from the position of the St. Helens' trees, which were found on the 

 identical spots where they grew, imbedded in a fine silty clay six- 

 teen yards above and sixteen yards below, or midway between two 

 seams of coal; but more observations on the internal structure of 

 its wood are required before we can pronounce with certainty as to 

 the true nature of this extraordinary fossil plant. 



3. On a Group of Erect Fossil Trees in the Sydney Coal- Field 

 of Cafe Breton. By Richard Brown, Esq. 



In a hasty sketch of the geological structure of the island of Cape 

 Breton, which appeared in the second number of the ' Quarterly 

 Journal of the Geological Society f,' I stated that excellent sections 

 of the Sydney coal-measures were exhibited in the sea-cliffs ex- 

 tending from Miray Bay to Cape Dauphin. I have recently exa- 

 mined one of the most interesting sections within those limits, viz. 

 that afforded by the cliffs on the N.W. shore of Sydney Harbour, 

 which runs directly at right angles to the strike of the strata, ex- 

 posing almost every individual bed from the old red sandstone, 

 through the overlying carboniferous limestone, millstone grit and 

 coal-measures. 



The total thickness of the coal-measures, calculated from the 

 highest bed of the millstone grit to their abrupt termination on the 

 sea-coast, is 1843 feet, their dip being N.E. at an angle of 8°. 



In this section erect fossil trees are found at various levels, but 

 they are more particularly abundant in a stratum of arenaceous 

 shale lying almost immediately under the main coal, where witliin 

 a space of eighty feet, measured along the base of the cliff, eight 

 erect trunks are seen with roots and rootlets attached to them. 



Fig. 1 is a section of the strata under the main coal, showing the 



* The roots D and E must indeed liavc gone upwards at such an angle as to 

 have been soon lost in the bed of coal, 

 t Vide vol. i. p. 207. 



