TRANSACTION* OP^HE SECTIONS. 661 



not until last year that he was enabled satisfactorilj'^ to remove 

 the doubts that some still entertained, by showing that the ^rau- 

 caria Cunninghami, and a species of Caliitris from Moreton 

 Bay in New Holland, were equally destitute of annual layers. 



Since the author first began to direct his attention to the 

 structure of fossil woods, he has examined some hundreds Of 

 specimens from various countries widely separated from each 

 other. From the tertiary formations he has obtained monoco- 

 tyledons and dicotyledons, but, with one exception, no ConifercB. 

 The exception is in the island of Sheppy, from whence, in the. 

 Edinburgh College museum, there are two specimens the coni- 

 ferous origin of which cannot be doubted. The tertiary forma- 

 tion of the island of Antigua is well kno^vn to furnish many spe- 

 cimens of fossil wood ; and out of a hundred and fifty specimens 

 from that quarter there was not a single coniferous plant, the 

 greater part being dicotyledons, the rest monocotyledons. From 

 a tertiary formation in the island of Java, the author has lately 

 examined several specimens, but found no Coniferce among them. 

 Yet although coniferous fossils would seem to occur sparingly, 

 at least in some tertiary formations, they are evidently widely 

 distributed among the different rocks of the carboniferous depo- 

 sits. The author has examined many specimens of fossil wood 

 not only from the coal districts of this country, but also from 

 those of New Holland, and Nova Scotia in America, and found 

 them all to be ConifercB. Most of them are siliceous, but some 

 are calcareous, and others partly siliceous and partly converted 

 into the bituminous state of jet. Of the last, Mr. Nicol has in 

 his possession a very illustrative specimen which he found in 

 the lias formation in the vicinity of Whitby. The siliceous 

 portions of this specimen, which have been twisted round in 

 different directions, display distinctly the coniferous reticulated 

 structure, and the larger portions of the jet have the same 

 blackish zic-zac lines which occur in every transverse section 

 of that bitumen, but show no trace of the original structure. In 

 another specimen, however, consisting partly of an earthy mat- 

 ter and portions of jet, which he also found in the same locality, 

 some of the portions of jet retain, though much obscured, the 

 true coniferous structure, and this is the only example of the 

 kind he has ever observed. 



Jet, as generally found in the vicinity of Whitby, consists of 

 detached masses resembling the trunks or branches of trees very 

 much compressed. When cut into thin slices it is perfectly 

 transparent, and of a deep red or pale yellow colour, according 

 to the thickness ; but although the three principal sections pre- 

 sent a peculiar and constant structure, the author has never 



