15 to 24

1 Clear, with a few A little.. None.... A little, mac- Lithostylidium

with red spots;

rounded

and

sharp both; a

little Chalce

dony in smooth

cubic grains;

not over .25mm

in diameter.

erated.

denticu

latum, Ehr.

35 to 50

1 Clear, with a few A little.. None.... A little, mac- Lithostylidium

yellow and

brown grains;

not over .25mm
in diameter.

erated.

denticu

latum, Ehr.

ed, and sharp;

not over .25mm

2 Clear and red, A little.. None.... A little, mac- Lithostylidium
spotted, round-

erated.

50 to 59

59 to 64

red and blue

None.

Report of the chief of engineers U.S. army

United States. Army. Corps of Engineers, United States. Mississippi River Commission