84 The American Geologist. August, 1902. 
The account states that the shock was felt for 200 miles around. 
There seemed to be a blowing out of the earth, bringing up coal, wood, 
sand, etc., accompanied with a roaring and whistling produced by the 
impetuosity of the air escaping from its confinement, seemed to increase 
the horrid disorder of trees being blown up, cracked and split and fall- 
ing by thousands at a time. The surface settled and a black liquid 
rose to the belly of the horses who stood motionless, struck with panic. 
Afterwards the whole surface remained covered with holes which re 
sembled so many craters of volcanoes surrounded with a ring of car- 
bonized wood, and sand which rose for about seven feet. A few 
months after, these were sounded and found to exceed 20 feet in depth. 
The country here was level and covered with occasional small prairies. 
Now it is covered with ponds and sand hills or monticules which 
are found where the earth was formerly lowest. There seemed to be 
a tendency to carbonization in all vegetation soaking in the ponds, 
produced by these eruptions. A lake was produced 27 miles west of 
the Mississippi with trees standing in the water 30 feet deep. 
Dr. Drake in his "Pictttres of Citicinnati," classified the 
shocks. The first shock of the i6th of December, 181 1, that 
of 23rd of January, 1812, and the first on the 7th of Febrtiary, 
constitute the first class. The second class includes those of 
yh. 20m. A. ^[., December i6th, that of 27th January and the 
10 hour, P. ]M., of February 7th. Of the others — one-half 
to a fourth class, and others a third class of intermediate viol- 
ence. Numerous tremors, detected by pendulums and lesser 
tremors may constitute a fifth class. 
Dr. Drake makes the following general remarks : — 
1. The original focus of these concussions was the valley of the 
Mississippi, between New Madrid and Little Prair*^, N. Lat. 36° — W. 
Long, from Washington 12° 30'. But after the second j^ear of their 
duration they seem to have ascended the Mississippi to the Ohio, then 
up that river 100 miles to the U. S. Saline, at which place shocks were 
felt nearly every day for nearly two \-ears. 
2. They were more numerous during the same period on the Mis- 
sissippi than on the Ohio. 
3. The shocks at Cincinnati, which have been referred to the first 
and second classes, were generally the most violent on the Missis- 
sippi. 
4. The convulsions on the Mississippi were different from those 
felt at Cincinnati. Those at Cincinnati were undulatory. Those on 
the Mississippi seem to have been vertical. 
5. The convulsion was greater along the Mississippi, as well as 
along the Ohio, than on the uplands. 
6. All the principal shocks on the IMississippi were attended or 
preceded by an explosive sound, denominated bj' the people of that 
region subterranean thunder. This noise was generally heard to the 
southwest, which some ascribe to the low countrv in that direction. 
