66 
as to have induced the late worthy proprietor of this | 
interesting spot, Mr. J. Sherman, to consider them 
as analogous in structure to the basaltic columns of 
Staffa and the Giant’s Causeway; he therefore main- 
tains the extravagant theory that these columns are 
nothing more than gigantic favosites.* We visited 
this famous locality of trilobites not long since, and 
were almost as much delighted with the sublimity 
and grandeur of the cataract, and the picturesque 
and romantic character of the glen, as with the re- 
liques of olden times, which are scattered here in 
such profusion. ae 
The genus Isotelus, derived from 7 ieos, equal, and 
7eAos, eXtremity, is thus characterized by Dr. Dekay. 
Body oval—often contracted, not unfrequendy ex- 
tended. *. ha as 
Head or buckler large and rounded, equalling the 
tail in size, but with two oculiform tubercles! 
Abdomen with eight articulations. , ‘ae 
Frontal process beneath, with two semilunar termi- | 
nations. : ae ‘ 
Post abdomen or tail, broad, expanded with indis- 
tinct divisions, as large as the buckler, Cia |< | 
Longitudinal lobes very distinct. LI Ps Met 
Other distinguishing marks by which this genus 3 
may be known, have ‘ney given in our introduc ion. | 
age ee sthdag 
ie See a Dereryeg of Trenton Falls, by John ‘Sherman, p.17. } 
sap ts “fi ying 
