52 [Assembly 



Thus far I have seen few species of other fossils which are 

 associated in the same beds with these crinoids. The most con- 

 spicuous forms are of a peculiar character, of which we have no 

 analogues except in the middle or lower part of the Chemung 

 group of New- York. There are, however, other species in the same 

 strata, which bear a close resemblance, if not positive identity, 

 with species found in the argillaceous sandstones below the 

 Burlington limestone of Iowa. 



Farther exploration of the locality, which I hope to make, will 

 probably afford the means for a more positive opinion regarding 

 the geological relations of these beds. In the mean time, the 

 publication of this notice may attract attention, and induce ex- 

 amination, at other points in the same horizon. 



GENUS ACTINOCRINUS. 



; ,^ftL- r- ACTINOCmNUS DAPHNE ( n.s.). 



Body broadly turbinate, of medium size ; base slightly projecting 

 over and beyond the column. Basal plates of moderate height, 

 and barely indented at the suture-lines. First radial plates 

 larger than any other plates in the body : second radials hex- 

 agonal ; third radials pentagonal, hexagonal and heptagonal 

 ( sometimes the upper lateral angles being simply truncated ), 

 smaller than the second, supporting on their upper oblique 

 edges a simple supraradial plate on each side. These supraradial 

 plates from the outer sloping side give origin to a simple arm, 

 and on the inner superior side they support a bifurcated plate, 

 which in turn gives origin to two arms, making six arms to the 

 ray. One of the ray (the anterior one probably) exhibits some 

 appearance of having but five arms ; which would give a 

 formula of 



¥~F =z 29 arms. 



In the interradial series the lower plate is hexagonal, supporting 

 two in the second range; above which they are not known. 



Arms long and slender, not bifurcating, composed of a double 

 series of short plates. The arms in ihe middle become flattened 

 on the back, and in their upper part grooved along the junction 

 of the plates. 



Tentacula long and slender, composed of several joints, each of/ T^ct^ 

 which supports an ascending spine. " j ^ 



Surface of plates marked by radiating ridges, extending from 

 the centre to the margins of the plates. Approaching the di- 

 visions of the ray, and in the supraradial series, the plates 

 become angulated from the centre to the margins. 



Column large, round, composed of alternating larger and smaller 

 joints. 



