286 Account of a Remarkable Fossil Tree. 
limestone based upon floetz sandstone. This formation. 
which constitutes the north-eastern angle of the state of Ili- 
nois, where the waters of Michigan lake and the Hlinois 
river often approach within a few miles of each other, and 
actually communicate at Chicago, continues east, and north- 
east, spreading in its course through Indiana into Ohio, and 
embracing the entire peninsula of Michigan. It is covered 
with a deposit of alluvial soil of a productive character, and 
presents to the eye a series of level prairies, intersperse 
with occasional forests, and irrigated by numerous small 
lakes and streams. These features may be considered as 
peculiarly ie of the distriet of country drained b 
the rivers Kankakee and Des Plaines, which uniting their 
channels at the distauve rn forty miles south of Chicago, pro- 
duce the Hlinois. The junction is effected on the southern 
slope of table land which confines lake Michigan to the 
north, at.a point where the waters descend with considerable 
velocity, over a horizontal layer of shelving rock, which pro- 
duces a series of rapids, and is continually yielding to the 
action of the water; but there is nothing in the mineral 
physiognomy of the : spot so remarkable as the petrified tree. 
which is found in the bed of the river Des Plaines about 
forty rods above its junction with the Kankakee. 
is extraordinary species of phytolites occurs ittibed- 
ded in a horizontal position in a stratum of newer floetz sand 
stone, of a grey colour, and close grain. There is now fit 
ty-one feet, six inches of the trunk visible. It is 
inches in diameter at the smallest end, which appears to 
have been violently broken off, prior to the era of its mine- 
ralization. The root-end is still overlayed by the rock and 
earth in the western bank of the river, and is two feet six 
inches in diameter at the point of disappearance ; but cit- 
es will justify the conclusion that its diameter at the 
concealed end, cannot be less than three feet. The 1s 
straight, simple, scabrous, wil branches, and has the 
taper rved in the living , 
of 
