1853.] OF THE ROYAL INSTITUTION. 285 
earthquake of that date; Lacustrine and swamp plants have been 
‘growing there in the shallows, and several rivers have annually 
inundated the whole space, and yet have been unable to carry in any 
sediment within the outer bonndaries of the morass. 
In the ancient coal of the South Joggins in Nova Scotia, many 
of the underclays show a network of stigmaria roots, of which some 
penetrate into or quite through older roots which belonged to the 
trees of a preceding generation. Where trunks are seen in an erect 
position buried in sandstone and shale, rooted Sigillariz or Calamites 
are often observed at different heights in the enveloping strata, 
attesting the growth of plants at several successive levels, while 
the process of envelopment was going on. In other cases there are 
proofs of the submergence of a forest under marine or brackish 
water, the base of the trunks of the submerged trees being covered 
with serpule or a species of spirorbis. Not unfrequently seams of 
coal are succeeded by beds of impure bituminous limestone, composed 
chiefly of compressed modiolz with scales and teeth of fish, these 
being evidently deposits of brackish or salt water origin. 
The Lecturer exhibited a joint of the stem of a fresh water reed 
(Arundinaria macrosperma) covered with barnacles, which he 
gathered at the extremity of the delta of the Mississippi or the 
Balize. He saw a cane-brake (as it is called in the country) of 
these tall reeds killed by salt water, and extending over several 
acres, the sea having advanced over a space where the discharge 
of fresh water-had slackened for a season in one of the river’s 
mouths. If such reeds when dead could still remain standing in the 
mud with barnacles attached to them, (these crustacea having been 
in their turn destroyed by a return of the river to the same spot,) 
still more easily may we conceive large and firmly rooted Sigillariz 
to have continued erect for many years in the Carboniferous Period, 
when the sea happened to gain on any tract of submerged land. 
Submergence under salt water may have been caused either by a 
local diminution in the discharge of a river in one of its many 
mouths, or more probably by subsidence, as in the case of the erect 
columns of the Temple of Serapis, near Naples, to which serpulz 
and other marine bodies are still found adhering. 
Sir Charles next entered into some speculations respecting the 
probable volume of solid matter contained in the carboniferous 
formation of Nova Scotia. The data he said for such an estimate 
are as yet imperfect, but some advantage would be gained could we 
but make some slight approximation to the truth. The strata at the 
South Joggins are nearly three miles thick, and they are known 
to be also of enormous thickness in the district of the Albion Mines 
near Pictou, more than one hundred miles to the eastward. There 
appears therefore little danger of erring on the side of excess, if 
we take half that amount or 7500 feet as the average thickness of 
the whole of the coal measures. The area of the coal-field, in- 
cluding part of New Brunswick to the West, and Prince Edward’s 
