TRANSACTIONS OF THE SECTIONS. 59 
pteris Hibernica show that this fossil fern belongs to the family of Hymenophylle, 
forming a peculiar genus, to which he gives the name of Hopteris. 
The species of Sagenaria he names S. Batlyana. In the fruit of this species, 
which differs trom S. Veltheimzana, the scales are extremely long, and nearly subu- 
lated. On some specimens very large and distinct sporules were arranged at the 
bases of the scales; this he considered very remarkable, as no other species, of 
which the fruit is known, have such large sporules, a proof, as he remarks, of 
inferiority of the plant, probably the oldest of the genus. 
Tn the last collection of fossils made at this place by myself and the fossil-col- 
lectors of the Geological Survey, parts of a crustacean, including the chelz or 
pincers, were obtained, presenting clear evidence of the existence of Pterygotus 
amongst this assemblage. This species I pee to name P. Hibernicus. The 
discovery of these characteristic portions of a genus, which appears to have pre- 
ceded Eurypterus, is of considerable importance, both stratigraphically and as serv- 
ing to explain the more exact relationship of specimens formerly obtained from 
this place, and doubtfully referred to the latter genus, but which will, I believe, 
be found to be identical with P. Hibernicus. 
The fish-remains hitherto discovered are, for the most part, in the condition of 
detached bones and plates or scales, and are therefore necessarily difficult of deter- 
mination. Glyptolepis and Coccosteus are the prevailing forms; there are others, 
however, which require study and additional specimens for their elucidation. 
It is hoped therefore that further explorations at this important fossil locality will 
throw considerable light upon the fossils of the Old Red Sandstone. 
On the Molluscan Fauna of the Red Crag. By Atrrep BEtt. 
The results of a critical comparison of the shells of the different crags are con- 
sidered by the author to justify him in the following conclusions :— 
That the series of deposits constituting the Red Crag proper commences at 
Walton-on-the-Naze, and does not extend further north than Chillesford, where it 
appears as the base-bed of the pit under the church. 
hat the molluscan fauna contained in this area dived in the Red Crag seas, and 
are not derived from the débris of an older formation (except in a very few cases). 
That the beds containing these shells were deposited in quiet waters, and 
That the proportion of recent forms is about 65 per cent. (exclusive of land and 
freshwater shells). 
In support of these propositions it is shown that the lowest Red Crag deposits, 
t. e. those at Waldringtield and Walton-on-the-Naze, while the nearest in their 
relations to the preceding formation, containing such characteristic Coralline Crag 
shells as Gastroma laminosa, Artemis lincta, Cardium decorticatum, Voluta Lamberti, 
Fusus consocialis and alveolatus, Terebra inversa, Eulima polita, Cerithium inver- 
sum, Pyramidella leviuscula, and others, are marked by the introduction of at least 
new forms. 
f the 400 species found in the Coralline,not more than about half range upwards to 
the Red Crag, and the greatest diversity in their respective faunz obtains where, as 
at Ramsholt and Sutton, the two formations are seen in juxtaposition. The small 
solid Pyramidella may serve for an example. Abundant in the White Crag at 
Sutton, it is altogether absent in the Red Crag at the same place. 
The following short list will suffice to show the difference in the characteristic 
shells in the older and newer Red Crags, most of the abundant forms of the lower 
beds (Coralline Crag and earlier Red) being altogether absent, or but sparely 
represented in the upper horizon, and also the reverse. 
Older Red Crag of Walton and Waldringjield. 
Coralline Crag shells as already quoted: Artemis exoleta, Mactra glauca, Tellina 
Benedenii, Cardium Parkinsonii, Nucula levigata, Cyprea anglie, Nassa elegans 
and veticosa, Purpura tetragona, Buccinum Dalei, Cancellaria coronata, Acteon 
(var.) noe, Xe. 
Newer Red Crag of Builey and Ramsholt. 
Pecten gracilis, Mytilus edulis, Nucula Cobboldie, Yoldia myalis, Cardium gren- 
