729 



measures about six feet in diameter by sixty-one feet in length ; 

 another, four feet in diameter by seventy feet in length ; and the 

 others, of various thickness, but all bulky enough to equal the masts 

 of large vessels, range in length from thirty-six to forty-seven feet. 

 It seems strange to one who derives his supply of domestic fuel from 

 the Dalkeith and Falkirk coal-fields, that the carboniferous flora 

 could ever have been described as devoid of trees. I can scarce take 

 up a piece of coal from beside my study fire, without detecting in it 

 fragments of carbonized wood, which almost always exhibit the cha- 

 racteristic longitudinal fibres, and not unfrequently the medullary 

 rays. Even the trap rocks of the district inclose, in some instances, 

 their masses of lignite, which present in their transverse sections, 

 when cut by the lapidary, the net-like reticulations of the Coniferae. 

 The fossil botanist who devoted himself chiefly to the study of micro- 

 scopic structure would have to decide, from the facts of the case, not 

 that trees were absent during the carboniferous period, but that, in 

 consequence of their having been present in amazing numbers, their 

 remains had entered more palpably and extensively into the composi- 

 tion of coal than those of any other vegetable. So far as is yet known, 

 they all belonged to the two great divisions of the coniferous family, 

 araucarians and pines. The huge trees of Craigleith and Granton 

 were of the former tribe, and approximate more nearly to Altingia 

 excelsa, the Norfolk-Island pine, — a noble araucarian, that rears its 

 proud head from a hundred and sixty to two hundred feet over the 

 soil, and exhibits a green and luxuriant breadth of foliage rare among 

 the Coniferae, — than any other living tree. 



" Beyond the coal measures terrestrial plants become extremely 

 rare. The fossil botanist, on taking leave of the lower carboniferous 

 beds, quits the land, and sets out to sea ; and it seems in no way sur- 

 prising, that the specimens which he there adds to his herbarium 

 should consist mainly of Fucaceae and Conferveae. The development 

 hypothesis can borrow no support from the simple fact, that while a 

 high terrestrial vegetation grows upon dry land, only Algae grow in 

 the sea ; and even did the Old Red Sandstone and Silurian systems 

 furnish, as their vegetable organisms, fucoids exclusively, the evidence 

 would amount to no more than simply this, that the land of the Pa- 

 laeozoic periods produced plants of the land, and the sea of the Palaeo- 

 zoic periods produced plants of the sea." — p. 185. 



The three formations of the Old Red Sandstone — the Upper, the 

 Middle, and the Lower — seem to have had each its own peculiar 

 flora. In the Upper, the only vegetable remains met with appear to 

 Vol. in. 5 b 



