No. 425.] THE TREMATASPIDE. 381 
The mysterious treasures of this classic spot have drawn to 
its sides many famous scientific men from all quarters of the 
globe. From time to time during the last forty years or more 
many beautifully preserved eurypterids and an occasional Trema- 
taspis have been taken from this insignificant pit in a pasture. 
During the past twelve or thirteen years the spot has been 

kp 
The d ] surf. f the head of Tremataspis. 

FIG. 2. 
worked more systematically by Mr. A. Simonson, who has col- 
lected, with very few exceptions, all the material of Tremataspis 
and Thyestes that has ever been found ; and yet, with the most 
careful and painstaking work, and with considerable assistance 
from common laborers, two or three, very rarely four, frag- 
mentary heads of Tremataspis are all that reward the labors of 
a wholé summer. I considered myself fortunate, therefore, in 
being able to purchase nearly all of the fossils collected by Herr 
Simonson during that season. The collection contained many 
specimens of Thyestes, Cephalaspis, and Bunodes, together with 
four heads of Tremataspis, some of which were in exceptionally 
