No. 200. 1 307 
In the rocks of the upper part of this series, and also in the bitumi- 
nous limestone below, we find an arrangement of parts, presenting, ex- 
ternally, a ligniform appearance. In breaking a mass of the rock, we 
often observe portions to separate, presenting the appearance of black- 
ened wood; these are coated with bituminous matter, often bright and 
shining. These ligniform masses are often four or five inches long, and 
not more than one-fourth, or half an inch thick: again, we find them very 
short, and several inches thick. Sometimes the fibrous portions are so 
short, as to present only an undulating seam in the rock. These curious 
formations have been called Lignilites, but they possess no organized 
structure, and the ligniform appearance is doubtless owing to the bitu- 
minous matter. 
Carboniferous or ^Mountain Limestone. 
This rock succeeds the gypseous formation, but as it occupies very 
little of the counties which have been minutely examined, its descrip- 
tion will be deferred for a future report. 
SECTION VII. 
Diluvium and Diluvial Action. 
The indications of diluvial action are every where perceived in the 
accumulations of gravel, sand and pebbles, with boulders of all dimen- 
sions strewed over the surface. Diluvial hills of considerable elevation 
are found in Wayne, and the eastern part of Monroe counties; but from 
the Genesee to the Niagara river, the country is comparatively level 
throughout the northern counties, with the exception of the mountain 
ridge. The soil, however, is of diluvial origin, and the surface is 
strew^ed with boulders, many are of rocks foreign to the district. — 
These boulders consist of the various granites and gneiss, together with 
those of the sandstone from below, and of the limestone from above. 
Besides this unequivocal evidence we have other, and if possible, more 
positive proof, in the furrowed and polished surface of the limestone, 
which is seen wherever the rock is exposed, from the Genesee to the 
Niagara river. The surface of this rock bears palpable evidence of the 
wearing action produced by running water, carrying with it heavy ma- 
terials of sufficient hardness to wear away, and in some instances, actu- 
ally to polish the surface of the rock over which it passed. Where the 
rock is exposed we find the surface has been worn, in some instances^ 
till it is perfectly smooth, and in others the original inequalities are but 
partially obliterated. We often observe that the abrupt offsets from one 
thin stratum to another, have been worn down to a gradual slope. In 
some places slight scratches only are perceived, while in others they are 
