BRECKINRIDGE, OHIO, AND IHIANCOCK COUNTIES. Fi 
poplar all through the country), forms a conspicuous part of 
the forest. Its massive, cylindrical trunk, from two to five feet 
in diameter, is seen everywhere, on lowland and highland 
alike. But after crossing over into the Chester shale, near 
Leitchfield, scarcely a liriodendron is to be seen. So marked 
and conspicuous is its absence that the eye can trace the giv- 
ing out of the Chester shale toward the coal measures by that 
alone. A very few scrubby liriodendrons are found in choice 
locations (heads of branches, streams, etc.) near the juncture 
on the Chester shale side; but these soon give out, and within 
three or four miles of the juncture not one is to be seen. This 
marked disappearance in that region is doubtless due to sur- 
face changes caused by the change of formation, the coal 
measures supplying more of that loose, sandy, moist surface 
so suitable to the liriodendron. This absence of the lirio- 
dendron is confined to the Chester shale, however, and does 
not extend through the whole of the Sub-carboniferous; for 
further on, in the ‘sinking region,” the surface exposure is 
the St. Louis limestone, on which the tulip tree grows in great 
numbers, and to great size. 
Another instance of change in timber, due to a modification 
of the surface soil, is found in a remarkable belt of woods 
crossing the Hartford and Cloverport road about twelve miles 
from Cloverport. The belt is about five miles wide, on a soil 
of thin, shaly sandstone, which forms a nearly level tract of 
land. Although the ground is at least one hundred and fifty 
feet above the drainage of the country, the loose sandy soil 
is always moist. The consequence is a forest of liriodendron, 
chestnut, white oak, and three varieties of hickory, whose 
noble size and height I have not seen surpassed in Kentucky. 
In addition to these, but in less numbers, are also found laurel 
oak, black sugar maple, water beech, white elm, etc. The 
change is very marked on passing from this wood-belt into the 
ordinary timbers that bound it on each side. 
In addition to the methods of choosing plots and numbering 
trees, mentioned before, between these plots I walked along, 
noting down every variety of tree that occurred, so as to 
TIM. I.—5 65 
