208 SIR ROBERT CHRISTISON, BART., ON FOSSIL TREES 
the small end or top, to the thick end or bottom, the angle of inclination was on 
an average 33°. But, as there are two bends in the trunk, in directions opposite 
to one another, the dip varied at different places, as Mr Wiruam ascertained, 
from 20° to 442°, 
The girth of this fossil increases very gradually from the small upper end 
towards the other extremity, and near the bottom it suddenly increases much 
more, like the lower end of most large forest trees of the present day. Along 
its whole length it is considerably flattened, so that a section is everywhere 
rudely elliptical. At the bottom, as it now lies in the Botanic Garden, it 
measures 6 feet across its widest diameter, which is a foot more than Mr 
WITHAM’S measurement; and its narrowest diameter is about 24 feet. At 12 
feet above, the measurement is reduced to 27 inches by 17, and 73 in girth ; 
and at 29 feet, the highest measurable part, it is 24 inches by 16, and in 
girth 52. 
The portion preserved is divided into fourteen blocks by fractures gene- 
rally transverse, but three of them oblique. The lower end is represented in 
the drawing as cut across abruptly without any vestige of root. As preserved 
in the Botanic Garden, too, there is no trace of any root, and the termination is 
rugged and shapeless. Neither is there in the whole of the fossil trunk any 
portion of a branch to be seen. At the upper end of the third block from the 
top there is a superficial cavity presenting very much the appearance of a branch 
having been torn out; and Mr WirHam’s drawing shows a small cylindrical 
fragment of what had been removed from the upper part of the fossil in its bed 
before the drawing was taken, bearing a similar and distinct mark of where a 
branch once had been. Moreover, at five different places, four of them situated 
in the middle of segments, and one at the seat of a fracture, thére are more or 
less continuous transverse ridges, with several bumps on them more or less — 
distinct, presenting altogether very much the appearance of the remains where 
whorls of small branches had been destroyed during the life of the plant. 
WiITHAM mentions and figures a cross section of a small twig which was found 
not far from this fossil. But neither then nor since has there been discovered 
in any part of the quarry any remnant which can be positively called the portion 
of a branch. 
The surface of this fossil is scored in some places with minute longitudinal 
grooves ; in other places small crowded warty excrescences are seen; but no- 
where does it show the fluted structure which abounds in some of the other 
fossils. 
Of the position of Nos. 3 and 4 nothing can now be learned except that 
the former was found in the west end of the quarry not far from the last two, 
and No. 4 at a distance from these near the eastern boundary. Their form is 
known only from the segments preserved at Rockville Villa and Barnton House. 

