-56 Stone Lilies of the Trenton Limestone. 



twecu each two of the projecting rings. "When the number is thus large- 

 one of them in the centre increases in thickness, and forms a new aunulation, 

 The edges of the rings are bent very slight downwards, and each alternate 

 one (in all the specimens examined,) in the lower part of the column is notched 

 on the underside, as seen in fig 5. The columns are much larger at the top 

 than at the bottom. One specimen tapers from one fourth of an inch at the 

 base of the cup to one eighth, at the distance of fifteen inches below. Others 

 become more rapidly small, while some of them are more gradual in their 

 decrease. The length for individuals of the size above figured would be from 

 twenty-four to thirty inches. 



The form of the alimentary canal varies a great deal in difierent parts 

 of the same column, being in general more or less star shaped with five rays, 

 but sometimes circular. The separate thicker joints are usually seen in the 

 shape of a flattened ring with the outside margin thick and rounded, but 

 thinned down to a sharp edge around the perforation in the centre. 



We think this species grew to a great size, there are columns in the 

 Trenton Limestone on the Ottawa river more than half an inch in diameter 

 at the larger or upper extremity, and which when perfect appear to have 

 been six feet in length. Their form is the same as in this species, except 

 that the annulations are not notched at the edges. The plates of the cup 

 are smooth — the rays are keeled — there are four plates in each of the secon- 

 <laries — the arms are branched and composed of very numerous thin and fiat 

 joints. We think these are large full grown specimens of G. ramulosiis. 



The exceedingly prolific genus Glyptocriuus was established by 

 Professor Hall, in 1847, m the first volume of the Pateontology of New 

 Vork, and he there describes a very beautiful species G. decadactylits from 

 the Hudson Eiver Group. Afterwai^ds, another species, G. Basalis, was 

 found in North Wales, at Alt, yr Anker, Meii"od, Montgomeryshire, in 

 Lower Silurian Slates of an age nearly the same as that of the Trenton 

 Limestone. It is described in Sedgewick and McCoy's British Palaeozoic 

 Pocks, page 87. A figure of the same species is given in Sir Poderick 

 Murchison's new work, Siluria, page 180, where it is stated that " fine 

 specimens are to be seen in the Cabinets of the Museum of Geology in Jer- 

 myn Street, and in the Woodwardian collection of Cambridge." The sur- 

 faa3s of both of these species are ornamented with radiating bars or ridges 

 which cover them with a net w^ork of triangular spaces. The name of the 

 genus, Glyptos, " sculptured" and Krinos, " lily," was suggested by the 

 beauty of this peculiar ornament. Our species differs from both, not only 

 iti its smooth plates but in many other respect, and it is therefore to be con- 

 sidered new. It is proposed to designate it by the specific name ramulosus, 

 in allusion to its branching arms. 



There is another si^ecies of Glyptocrinus also of great size, but with 

 the plates of the cup bordered by an elevated margin. Only one head of 

 this species has been found. 



Professor Hall has figured and described an encrinite under the name 

 of Schizocrinus nodosus, the columns of which have the same structure and 



