24 
481 of the "Elements." "The total length was 60 feet. Its diameter at 
the top was 7 inches and at the base 5 feet in one direction and 2 feet in 
the other. The bark was converted into a thin coating of the finest coal, 
forming a striking contrast to the white quartzose sandstone in which it 
lay. The beds were unaltered and undisturbed at the" point of junction, 
showing that they had been tranquilly deposited round the tree. They 
were composed chiefly of siliceous sandstones in laminae so thin that from 
6 to 14 might be counted in an inch. Some of these contained coaly 
matter and the lowest were calcareous. The interior of the tree still 
preserved the woody texture in a perfect state, the petrifying matter being 
for the most part calcareous." 
It has since been quarried away, and at the time of my visit not a fragment 
of it could be found. 
At some distance above 'lies a bed forming a well-known dividing 
line in the lower carboniferous shales, and called, from the locality 
where it was first examined by Dr. Hibbert, the Burdie House lime- 
stone. It is not more than 25 feet thick and lies about 3000 feet above 
the top of the Old Eed Sandstone and about 800 feet below the base of 
the Mountain Limestone. It is worked at the crop near Loanhead and 
followed for some distance under ground along the dip of about 20 Q . 
The blocks of this fine grained limestone are full of Sphenopteris affinis, 
Lepidodendron with its fruit Lepidostrobus, Calamite stems, and the remains 
of fish of different species, such as the Ganoids, Eurynotus and Palaso- 
niscus, Rhizodus, and Megalichthys. 
At the distance of 3800 feet from the base of the system we reach the 
bottom of the Mountain Limestone. At this epoch the action of the igneous 
forces on the east of the Pentland axis ceased altogether while in Linlith- 
gowshire it continued with equal or greater intensity. Taking the 
Edinburgh or eastern side first, instead of the thick marine deposits and 
fossil remains of our own middle limestone we find about an equal 
thickness, 2000 feet, of alternating layers of shale and sandstone, bands of 
ironstone and seams of coal, with 6 thin bands, not exceeding in all about 
40 feet, to represent the typical Mountain Limestone, containing, however, 
many of the organisms with which in this neighbourhood we are so 
familiar, such as — 
Productus longispinus. Goniatites. 
Encrinites. 
Three of these limestone bands are within 500 feet of the base of the 
scmireticulatus. 
Chonetes Hardrensis. 
Orthoceras.] 
Bellerophon. 
