Corrcspondefice. 329 
CORRESPONDENCE. 
On the Formation of New Ravines. In the ninth edition 
of his "Principles of Geology" Sir Charles Lyell describes 
a ravine near Milledgeville, Georgia, which was excavated in twenty 
years to a depth of 55 feet. A part of his account follows:* 
"When travelling in Georgia and Alabama, in 1846, I saw in both 
those states the commencement of hundreds of valleys in places where 
the native forest had been recently removed. One of these newly 
formed gulleys or ravines is represented in the annexed wood cut 
from a drawing which I made on the s£)Ot.* * * Twenty years ago, 
before the land was cleared, it had no existence; out when the trees of 
hie forest were cut down, cracks three feet deep were caused by th( 
sun's heat in the clay, and, during the rains, a sudden rush of water 
t.irough the principal crack deepened it at its lower extremity, from 
(vhence the excavating power worked backward, till, in the course of 
twenty years, a chasm measuring no less than 55 feet in depth. 300 
.t'ards in length, and varying in width from 20 to 180 feet, was the re- 
salt." 
The figure which Lyell publishes shows a great gully with precip- 
itous walls. The walls, bottom and surface of the immediately adja- 
cent country are represented as bare of trees. A wooded hight is seen 
in the distance, and a few scattering trees are shown, but all at a con- 
siderable distance from the edge of the ravine. The trees depicted 
are those only which have the outline and habit of broad-leaved kinds, 
none of them are pines and none are near the edge of the ravine. 
Over fifty years have passed since Lyell wrote his description of 
this phenomenon. Finding that Lyell's description is still quoted,t 
.and having some curiosity to know what erosion had been accomplished 
since Lyell wrote, it occurred to me a short time ago to write to 
Milledgeville for information regarding the present condition of the 
ravine. A few days ago I received an excellent description of the 
ravine from Mr. J. Harris Chappell, president of the Georgia Normal 
and Industrial College, who, in company with Prof. Beeson. had paid 
a visit to the gully on the Saturday before, viz., Jan. 22. Following 
is a part of Pres. Chappell's letter: — 
"The 'Big Gully,' by which name it is familiarly known, is situated 
four and one-half miles from Milledgeville on a high ridge of hills over- 
looking the town. The gully is 320 yards long, varies from 80 feet 
to 300 feet in width, and is 65 feet deep in its deepest part. From the 
main stem springs four zig-zag branches, making of the whole quite 
a complex ramification. I should say that the whole wash-out covers 
an area of about ten or twelve acres. * * * In some places the 
gully is covered with a thick forest growth, mainly pine trees, some of 
♦The description stand.s in the lltli and la.st edition exactly as in tlie 9th edition 
p, 204. vol. I, p. 338. 
tVide Merrill's "Rocks, Rock Weathering and Soils," 1897, p. :«)6. 
