48 [Assembly 



gives them a general resemblance to a lily, whence they were 

 often called stone-lilies ; but it is very rare that a specimen is 

 found in a complete state. Short pieces and separate joints of 

 the stems and arms are very common : the body is not often pre- 

 served in a perfect condition. The most perfect specimens in 

 the collection are from the Lower Helderberg limestones, and are 

 in the cases belonging to those rocks. A figure of a beautiful 

 and characteristic species is given hereafter in describing the 

 Portage group (Fig. 39.) A fragment of a single starfish has 

 been found and figured ; its name PalcBaster matutina^ being given 

 in reference to its being the earliest of its race yet known. 



Corals are numerous, generally of small size. One species 

 {ChcBtetes ly coper don) is very abundant (Fig. 6, No. 2). It is a 

 low rounded form with a flat base, and would not be suspected 

 as a coral by a casual observer ; but when broken, the columns 

 of which it is composed are plainly seen radiating from the centre 

 of the base to the convex side. A few branching corals *are 

 found also, and several species of another form, conical and 

 slightly curved like a horn. In these last, a single animated 

 inhabitant or zoophite lived in the cup-shaped cavity of the 

 larger end ; while in the other forms, each coral was inhabited 

 and formed by a large community of tenants, (Corals of the 

 single-celled forms, not unlike those here referred to, are illus- 

 trated in figure 31.*) 



Next in upward succession lies the 



HUDSON-RIVER GROUP, 



an enormous mass of sandstone, slate and shale, f in the eastern 

 part of the State 1500 feet thick or more. It is well seen in the 

 north of Oswego, south of Lewis, and middle of Oneida; also 

 through the Mohawk valley, and on the Hudson river, from 

 which it takes its name. West of Schenectady it is generally 

 level and undisturbed ; but near the Hudson its strata are 

 upheaved, broken, and crushed in every conceivable manner, as 



♦These *' Corals," as they are commonly called, include forms of very various nature; 

 most of them being like the " Eeef- coral " of the present day, built by *^ radiated" 

 animals which live in the separate cells ; but the animals which inhabit many of the smaller 

 forms are more nearly allied to Mollusea, and are termed Bryozoa. 



t A Shale is a soft slaty rock, but of less fissile and thin-bedded character than a pure 

 Slate ; generally breaking with a rough fracture, and often approaching iu character to a 

 hardened clay. 



