FROM NORTHWESTERN EUROPE 95 
The dental lamellae are strong and divergent. The median septum also appears 
to be well developed and a possible septalium is indicated by one specimen. 
DisTRIBUTION. The species is only known from the type locality. 
OccURRENCE. The species is found in the Alt na Cuile Sandstone which Arkell 
(1933) described as consisting of “‘ thick beds of white sandstone separated by black 
carbonaceous layers’’. The associated fauna consists of lamellibranchs and 
ammonites ; the rhynchonellids are the most abundant element of the fauna. 
Remarks. According to Arkell, the Alt na Cuile Sandstone has not yet yielded 
ammonites capable of defining precisely the zones present, although it is undoubtedly 
either topmost Oxfordian or basal Kimmeridgian. As the main fossil band is 
towards the top of the unit, it seems probable that the rhynchonellids are basal 
Kimmeridgian in age. 
Arkell suggested that, as the rhynchonellids were the best preserved element of 
the fauna, it might be possible to use them to give a more accurate date to the strata. 
Unfortunately, there do not seem to be comparable forms of this age on the con- 
tinent, probably as that area was largely occupied by coral and sponge reef facies, 
with their specialized faunas, while the Alt na Cuile Sandstone almost certainly 
represents a limited near-shore facies with a fauna presumably adapted to those 
conditions. 
Although the poor preservation makes generic identification rather hazardous, the 
species is tentatively referred to Septaliphoria Leidhold. This determination is 
based on the relatively coarse, simple ribs and the fact that the anterior commissure 
may show either a symmetrical uniplication or be slightly asymmetrical ; the 
internal characters visible are consistent with this designation ; however, without 
more detailed information of the internal structures, which is unlikely to be forth- 
coming, it is not considered that a definite generic diagnosis is possible. Davidson 
(1878) suggested that the casts from Alt-na-cuile, ‘“‘ may also probably be referable 
to Schlotheim’s species (Rhynchonella lacunosa)’’. It can be safely stated that S. 
(2?) septentrionallis does not belong to the genus Lacunosella. 
Genus TORQUIRHYNCHIA nov. 
1886 Inconstans-Sippe (pars) Rothpletz, p. 91. 
1918 Rhactorhynchia (pars) Buckman, pp. 50-52. 
1932 Septaliphoria (pars) WiSniewska, pp. 18-20. 
NaME. Latin se torquere—to twist : all members of the genus are markedly 
asymmetrical. 
Type species. Terebratula inconstans Sowerby. 
DiaGnosis. Large, asymmetrical rhynchonellids with coarse, simple ribbing ; 
septalial plates reduced or absent ; median septum present but usually very weakly 
developed ; crura radulifer. 
STRATIGRAPHICAL RANGE. In Europe the species appears to be restricted to the 
_ Kimmeridgian and lower Volgian ; however, Makridin (1964) has figured specimens 
from the Russian Platform which appear to belong to Torquirhynchia and which 
include material from the upper Oxfordian and the middle and upper Volgian. 
