410 
ELEMENTS OF GEOLOGY. 
ynrds from the base of the clitf. The thickness of the beds 
alluded to, between d and is about 2500 feet, the erect trees 
Fig. 439. 
Section of the cliffs of the South Joggins, near Minuclie, Nova Scotia. 
c. Grindstone, d, g. Alternations of sandstone, shale, and coal containing uprio-ht 
trees. e,f. Portion of cliff, given on a larger scale in Fig. 440. /. Four-foot coal 
main seam. A, i. Shale with fresh-water mussels, see p. 418. 
consisting chiefly of large Sigillarim, occurring at ten distinct 
levels, one above the other. The usual height of the buried 
trees seen by me was from six to eight feet; but one trunk 
was about 25 feet high and four feet in diameter, with a con¬ 
siderable bulge at tile base. In no instance could I detect 
any trunk intersecting a layer of coal, however thin; and 
most of the trees terminated downward in seams of coal. 
Some few only were based on clay and shale; none of them, 
except Catamites^ on sandstone. The erect trees, therefore, 
appeared in general to have grown on beds of vegetable mat¬ 
ter. In the underclays Stigmaria abounds. 
These root-bearing beds have been found under all the coal- 
seams, and such old soils are at present the most destructible 
masses in the whole clifl* the sandstones and laminated shales 
being harder and more capable of resisting the action of the 
waves and the weather. Originally the reverse was doubt¬ 
less true, for in the existing delta of the Mississippi those 
clays in which the innumerable roots of the deciduous cypress 
and other swamp trees ramify in all directions are seen to 
withstand far more effectually the undermining power of the 
river, or of the sea at the base of the delta, than do beds of 
loose sand or layers of mud not supporting trees. It is obvi¬ 
ous that if this sand or mud be afterwards consolidated and 
turned to sandstone and hard shale, it would be the least de¬ 
structible. 
In regard to the plants, they belonged to the same genera, 
and most of them to the same species, as those met with in 
the distant coal-fields of Europe. Dr. Dawson has enumer¬ 
ated more than 150 species, two-thirds of which are European, 
a greater agreement than can be said to exist between the 
same Nova Scotia flora and that of the coal-fields of the Uni¬ 
ted States. By referring to the section, Fig. 439, the position 
of the four-foot coal will be perceived, and in Fig. 440 (a sec¬ 
tion made by me in 1842 of a small portion) that from etof 
