PEARLS AND PEARL FISHERIES. 
393 
had been won by the whites, the region occupied, and settled communities established, 
do we again begin to find any indications of the search for pearls. For some two 
centuries the Unios lived and multiplied in the rivers and streams, unmolested by 
either the native tribes that had used them for food or the pioneers of the new race 
that had not yet learned of their hidden treasures. 
Fresh-water pearls are found, as before stated, in various species of the Unios, 
frequently, according to Dr. Isaac Lea, in the common TJnio complanatus, but also 
in the following : TJ. blandingianus , IT. buddianus, U. costatus, TJ. elliotti, TJ. fragilis , 
TJ. globulus , TJ. gracilis, TJ. mortoni, TJ. nodosus, TJ. orbiculatus, TJ. ovatus, TJ. torsus , 
TJ. undulatus, and TJ. virginianus, and doubtless to some extent in all the species. Not 
one pearl in a hundred, however, is of good shape, and probably not more than one in 
a hundred of these is really fine. Therefore, as the worth of a pearl depends on both 
luster and form, the greater number obtained are of slight value. Eev. Horace 0. 
Hovey, however, is credited with having found a pearl half an inch across in the shell 
of a TJnio ovatus , near Cincinnati, Ohio. 
Unio pearls have been sought since the settlement of this country, and the narra- 
tives of early voyagers abound with references to them. In an ancient catalogue 1 
of the objects of natural history, made in 1749 by John Winthrop, F. E. S., the follow- 
ing items are mentioned : 
30. Unripe pearls which in time would have become (31). 
31. Bright pearls which are produced in the same shells (30). 
32. Some of the larger sea pearl shells which are often found in deeper waters three times as 
large and hear larger pearls. 
N. B. — Almost all the lakes, ponds, and brooks contain a large fresh-water clam which also bears 
pearls. The Indians say they have no pearls in them at certain seasons, but at the season when they 
grow milky the pearls are digested in them, which causes their milkiness. 
Dr. Samuel P. Hildreth writes : 
Some of the fresh-water shells produce very fine pearls. I have one taken in the waters of the 
Muskingum, from the shell known as the Unio nodosus of Barnes. It is a thick, tuberculated shell, 
with the most rich and pearly nacre of any in the Western rivers. The specimen is perfect in form, 
being plano-convex on one side and a full hemisphere on the opposite. It is nearly one-half inch in 
diameter across the plane face, and three-eighths inch through the transverse diameter, and of a very 
rich pearly luster. Set in a gold watch-key and surrounded by facets of jet it makes a beautiful 
appearance, and is by far the largest and finest pearl I have ever seen. Several others have been 
found, but none to be compared to this. 2 
Within recent years, however, the gathering of Unio pearls has attained to con- 
siderable importance, and economic problems have begun to arise that warrant and 
even demand careful and detailed inquiry. These present aspects will be considered 
in the following pages. 
1 Am. J. Sci., I, vol. 47, p. 284, Jan. 1845. 
2 Am. J. Sci., i, vol. 25, p. 257, April 1834. Ten Days in Ohio, from the Diary of a Naturalist. 
