PLATE II. 
Fig. 1. 
Fig. la. 
Fig. lb. 
Fig. 2. 
Fig. 2a. 
Fig. 2h. 
Fig. 3. 
Fig. 4. 
Fig. la. 
Fig. lb. 
Page. 
ArclicEocyatJius ? L. G. cle Koiiiuck ... ... ... ... ... 52 
The same specimen, from the opposite side, showing the foldings of the spongy 
tissue and the cavities to which they give rise. The smooth portion repre- 
sents the limestone in which the sponge is in a great measure enclosed ... 52 
A specimen, which by the weathering of the outer wall, exposes the interior 
structure of the tissue ... ... ... ... ... ... ... ... 52 
Amplexus Selwi/iil, L. G. de Koniuck — Specimen of natural size, seen in elevation 5G 
The same, seen from above ... ... ... ... ... ... ... ... 56 
Smaller example, showing the disposition of the tabulae ... ... ... ... 56 
Oosnites expansus, L. G. de Koniuck— Specimen of natural size to a great extent 
surrounded by limestone... ... ... ... ... ... ... ... 57 
BilUngsia alveolaris, L. G. de Koniuck — Branching specimen of natural size, 
in wliich a longitudinal section shows the internal structure of the corallites 
and the disposition of the lateral canals, by whicli they couimuuicato with 
one another ... ... ... ... ... ... ... ... ... 58 
Another specimen, exhibiting the occasional concentric arrangement of the 
corallites ... ... ... ... ... ... ... ... ... ... 58 
A third example, showing numerous plications of the corallum ... ... 58 
