j06 [Assembly 



the lenses of the eyes very perfectly. The Dalmania calliteles is 

 another small species (Fig. 30, No. 7) : its tail is fringed with 

 small pointed projections. Other species are exceedingly rare. 

 Among the chambered shells is one very large coiled species, the 

 Phragmoceras maximus, found near Madison in Lewis's quarry 

 and elsewhere in Central New-York, fifteen inches in diameter. 

 Smaller species are also found ; and there are many Orthocerata, 

 one small species of which, common in Central New- York, is sur- 

 rounded with rings or swellings which have caused it to be com- 

 pared to the tail of the rattlesnake, to which, in the eyes of some 

 beginners in geological observation, its jointed structure, sepa- 

 rating at the partitions, seems a striking feature of resemblance. 



A few AsTERi^, or starfishes, have been found in this rock, but 

 they are as yet very rare ; and there is in the Collection a slab 

 of stone containing several badly preserved specimens pf some- 

 thing very like an Echinus, or modern " Sea-egg." These are 

 animals bearing some relationship to the starfish, but generally 

 of a circular or flattened-oval form, and covered with projecting 

 spines, which are articulated to the body, and by the movement 

 of which they walk or crawl on the sea-bottom. A specimen of 

 a recent Echinus is laid in the case, to explain the nature of the 

 fossil. Many more specimens of such forms will probably be 

 discovered, when observers are so numerous as to examine all 

 parts of the State above the limestones. 



The appearance of Terrestrial Plants is a very interesting fea- 

 ture of the Hamilton group. Specimens may be seen in the 

 cases : they are of several kinds ; one is a large flattened stem ; 

 another a long stalk, marked with scale-like protuberances (Fig. 

 34 a) ; others are branched, like that in the figure, No. 34 b. 

 Their appearance seems to mark a step in the great progress of 

 creation, when the earth, previously bare of trees or land-plants, 

 began to produce its first vegetable growths. The attention of 

 observers is urged to this class of fossil remains, which may be 

 expected to be found in considerable abundance in the Hamilton 

 and higher groups, especially east of Seneca and Tompkins coun- 

 ties, west of which they seem to be less common. 



The fish-bones of the Hamilton group seem generally to belong 

 to species of Asterolepis, allied to those of the limestone of the 

 Marcellus slate. They are as yet rare. 



The Crinoids are not common in a perfect state, but scattered 

 joints and short stems are common. (There is in Western New- 



