1869. } DAWSON—SIGILLARIA. 165 
course of formation by means of confervoid alge. He therefore 
regarded the whole of these beds as in a certain sense sedimentary, 
and though due to organic agency, yet still deriving their original 
mineral matter indirectly from the basalt. The basalt contained a 
considerable amount both of phosphorus and sulphur; and if the 
ores had been derived directly from the basalt, both these substances 
would have been present in them. This was an argument against 
any direct metamorphism. The presence of vanadium afforded addi- 
tional reason for regarding these ores as formed in the same manner 
as bog-iron and similar ores. 
Sir Cartes Lyerzi had observed in the basalts of Madeira red 
ochreous bands which represented old land-surfaces, in one of which 
Mr. Hartung and he had discovered a leaf-bed containing vegetation 
of much the same character as that of the island at the present day. 
Near Catania, in a recent lava-stream, he had seen the junction of 
the lava with the soil of the ancient gardens ; and in character the 
soil now under the lava resembled the red beds of Madeira. 
Mr. W. W. Suyru was on the whole inclined to admit the power 
of metamorphism to produce such changes as had been here effected. 
He commented on the advantages of employing this Irish ore for 
admixture with hematitic ore, on account of the abundance of alu- 
mina present. Possibly there had been some difference in the che- 
mical character of the different flows of basalt. 
Mr. Evans suggested that the Ballypalidy beds might be the litto- 
ral deposits of a lake in which the pisolitic ores of the other parts 
of Antrim were deposited further from the shore, and subsequently 
buried under a basaltic flow. 
Mr. ErurripeGE inquired whether the pisolitic ore had been sub- 
jected to microscopic examination, with a view of finding traces of 
organic forms, such as G'aillonella. 
Mr. Tarr, in reply, defended his views as to metamorphic action. 
He thought the uniformity in thickness and character of the pisolitic 
ore band over so large an area showed that it could not be a lacustrine 
deposit. He had not as yet discovered any diatoms in the spheroids. 
2. Notes on the Srrucrure of SicInLaRta. 
By Principal Dawson, F.R.S., F.G.S., Montreal. 
|The publication of this paper is deferred. | 
(Abstract. ) 
In this paper the author criticised the statements of Mr. Carruthers 
on the structure of Srgillaria (see Q. J. G. S. xxv. p. 248). He 
remarked that Sigillaria, as evidenced by his specimens, is not 
coniferous, that the coniferous trunks found in the coal-formation 
of Nova Scotia do not present discigerous tissue of the same type as 
that of Srgillaria, that no conifer has a slender woody axis sur- 
rounded by an enormously thick bark, that Calamodendron was 
probably a Gymnosperm and allied to Sigillaria, that, although 
Stigmaria may not always show medullary rays, the distinct sepa- 
