130 PALJEONTOLOGY OF NEW-YORK. 
Fig. 2 a. A weathered surface of a mass of this species, showing some irregularities in the ar¬ 
rangement of the series of cells. 
Fig. 2 b. A transverse section of an upper weathered surface, showing the form of the openings, 
and the arrangement in parallel lines with slight interruptions. 
Fig. 2 c. A vertical section, showing the transverse septa within the tubes. 
Fig. 2 d. A vertical section magnified, showing the concave septa and the cellular interspaces 
between the tubes. 
Fig. 2 e. The external surface of several tubes enlarged, showing an obscurely striated surface. 
Fig. 2 /. A fragment showing the lower or convex surface of the septa. 
Fig. 2 g. The openings of several tubes enlarged, contrasting with similar figures from the va¬ 
rieties of the preceding species. 
Position and locality. This species, so far as known, is confined to the upper part of the 
Niagara limestone in Sweden and Ogden, Monroe county. It occurs also at Milwaukie, Wis¬ 
consin, in the same geological position, associated with C. escharoides , Favosites and Heliolites, 
as in the Niagara group of New-York. estate Collection.) 
Genus HELIOLITES (Guettard). 
Millepora subrotundataporis minimis confertis majoribusque crenatis remotis. Fougt : Ltnne, 
Amoen. Acad, i, 203, fig. 24. 
Heliolithe pyriforme. Guettard, Mem. iii, 454, pi. 22, fig. 13, 14. 
Heliopora pyriformis. Blainville, Man. d’Actinol. p. 392. 
Porites pyriformis . Lonsdale : Murchison’s Sil. System, p.686, pi. 16, fig. 2. 
Jlstrea porosa. Goldfuss, Petrefacta, Yol. i, p. 64, pi. 21, fig. 7. 
Mr. Dana (Zoophytes, U. S. Exp. Expedition) proposes to unite under Guettard’s name of 
Heliolitesy certain fossil corals which have been referred to the various genera cited above. It is 
very clear that these corals are neither Porites, Astrea or Heliopora, as the latter genus is 
limited. It is therefore very appropriate to refer them to this genus, which, in its restricted 
signification, includes several interesting silurian corals that have hitherto scarcely attracted 
attention in this country. 
519. 1. HELIOLITES ELEGANS (n. sp.). 
Pl. XXXVI. Fig. 1 a - g. 
Coral massive or hemispheric, increasing by the lateral addition of cells more than by inter¬ 
stitial additions ; cells small, 16 to 18 in an inch ; openings upon the surface marked by twelve 
or more short rays ; transverse septa numerous; interspaces apparently lamelliferous. 
This species has much smaller cells than any described species known to me ; the openings 
upon the surface are much expanded, and the rays are apparently confluent, but on careful 
examination there appear to be intermediate vertical lamelke ; a vertical section shows the 
rays and transverse septa of the tube, but the thick interspaces are often apparently solid. In 
