CONCH 
'ftdte, arc very many's the chief of them are the gryphytse 
of the fofliiogifts, of which there are feveral fpecies: and 
a very large flat kind with equal valves, found in Shot- 
over and Heddirigton quarries, in Oxfordlhire. But the 
largeli bed that is known of foflil oyfters, is-that near 
Reading, in Berk (hire. They are entirely fhaped, and 
have the fame fnbflance with the recent oylter-ftiells $ and 
yet, fince the oldeft hiftories that mention the place, give 
an account of them, we mult fuppofe they have lain there 
in the fame, (late for a long time. They extend over no 
lefs than fix acres of ground; and juft above them is a 
large ftratum of a greenifti loam, which fome writers call 
a green earth, and others'a green farid. It is compofed 
of a crumbly marie, and a large portion of land. Under 
them is a thick ftratum of chalk. They all lie in a level 
bed; and the ftrata above the (Hells are.natural, and ap¬ 
pear never to have been dug through till the time of find¬ 
ing the fliells. The oyfter fliells and green earth united 
make a ftratum of about two feet thick ; and over this 
there is a much thicker ftratum of abluilh and very brittle 
clay ; but neither has this ever been dug through, except 
where the fhells are found. This is vulgarly denominated 
piercy-clay, and is efteemed ufelefs. This clay-bed is about 
a yard deep, and above it is a ftratum of fuller’s earth, 
about two feet and a half deep; it is extremely good, 
and is ufed by the clothiers. Over this there lies a ftra¬ 
tum of a fine white land, unmixed'eitlier with the clay or 
fuller’s earth: this is near leven feet deep, and above it 
is a ftratum of a liiff red clay, of which tiles are ma'de. 
This is again covered with a little vegetable mould; the 
depth, however, of this ftratum of tile-clay cannot be af- 
certairied, on account of the unevennefs of the hill. Thefe 
oyfters are occafionally found whole, but moft frequently 
in Angle (hells. When they are in pairs, there is gene¬ 
rally fome of the green fand found within them : they 
feldom ftick very fall together ; fo that, unlefs very care¬ 
fully taken up, it is not eafy to prelerve them in pairs. 
ANOMIA.—The fourth and lalt family in the divifion 
of fliells with unequal valves, and that (hut ciofe, is the 
anomiae. This family lias long been known foflil, and 
contains a great number of fpecies, all of which, except 
three or four,' remain yet imdifcovered in a living ftate ; 
and even the few kqown are dilcoveries made within the 
lalt forty years. Columna firft mentioned fome foflil fpe¬ 
cies, and he being convinced that all foflil fliells were real 
exuviae or fpoils of animals, and not finding thefe de- 
fcribed or noticed by concholog'ifts as fliells, called them 
conchse rariores anomise; which word anomia has (nice 
been fo generally ufed for them, that it is now become 
the imiverlal and eftablilhed name of the family. 
Columna defcribed and figured fome foflil kinds. Lifter 
lias alfo figured feveral in his Appendix de Conchitis to 
his Hilloria Conchyliorum ; but no recent kind being 
difcovered fo early, is the reafon that neither he, Boo- 
nnnni, Rumphius, nor other early authors, have taken 
aqy notice of them. Dr. Woodward was the frill who ar¬ 
ranged the anomise from the foflil fliells. He kept the 
eftabliflied name, and ranked them with fhells.'of unequal 
valves, and not eared; and further defined them to have 
both valves convex, and one of them beaked. He then 
arranged them into fmooth, ftriated, and fulcated, each of 
which articles has feveral necellary fubdivifions. Wood¬ 
ward had only foil'll fliells to inl'peft, confequently lie 
could not accurately define their peculiar interior (frac¬ 
ture; or their hinge : his definition, however, is very juft, 
except that he makes both fliells convex, which is not fo 
in feveral fpecies. 
Gualtieri, who figures three recent kinds, has made a 
particular genus for them, and calls it terebratula. He 
defines them, very erroneoufiy, as (hells with equal valves, 
and diffimilar lides, of a peculiar If rupture, for inltead of 
a beak it has a perforation, and alfo has a very Angular 
articulation or connedlion within-fide. Linnaeus, to efta- 
blilh his ufual precifion, pofl'efl'ed fome of the living fhells, 
and iuade them his genus 314. anemias. He has mixed the 
OLOGY, 31 
recent with the foflil kinds, and defines them to be fhells 
with unequal vaLves, one valve being flattifh, the other 
convex, the beak perforated, and the hinge inarticulate 
or toothlefs. However, he miftook fome fpecies ; for he 
propofed the gryphites, which, by all its charadlers, is a 
time oyfter, and the pellucid or glafs Cliinefe oyfter, im¬ 
properly fo called, as fpecies of anomiae. Davila treats 
this clal's fyftepiatically, and as a genus of his firft family 
of oyfters. He defines them as fliells whofe beak or top 
. of the under valve is perforated, and riles curved up on 
the upper valve. He does not, however, particularize 
any charadfers of the hinge, though lie gives an excellent 
figure of the inner ftrufture, or appendices. He defcribe's 
them in the following manner: the hinge of the under 
valve is compofed of two final! hooks, which are taken in 
or hinged into the finufes or cavities of the upper valve'; 
and it has two interior appendages fixed towards the top 
of the upper valve : this ftrudture lie obferved in two fpe¬ 
cies. In another fpecies, the hinge was nearly the fame, 
but had two long and narrow fide appendages proceed¬ 
ing from the top of the upper valve, which extend them- 
felves to the middle of it, where they are bound or flopped 
by two (mail ligaments, and then return again towards 
the top, in a very remarkable and curious manner. And 
a third fort, (which is that of Gualtieri,) has an interior 
appendage, fome what like a perpendicular gutter or pipe, 
fixed at the.top, and running down to the middle of the 
upper valve. 
Da Cofta defines the anomiae as follows, bivalves with 
unequal valves and never eared, the beak of the largeli 
or under valve is greatly produced, and rifes or curves 
over the-beak of the lmaller or upper valve, and is perfo¬ 
rated or pierced through like a tube, from which particu¬ 
lar they have alfo obtained the name of terebratula. The 
hinge is inarticulate or toothleft, and they have always a 
remarkable interior llruflure. Yet, by what obfervations 
can be made, fome of the foflil kinds have an evident 
multarticulate or many-toothed hinge. It feems there¬ 
fore, that the valves of the anomiae are connected together 
in two ways, inflead of being only inarticulate, viz. 1. 
By an inarticulate hinge ; and, 2. By a multarticulate 
hinge. The firft fet have no teeth or joints on the hinge ; 
but the finaller or upper valve is always indented into a 
wide Anus, or opening of the larger or under Valve, in 
which it plays like a joint, when the exigencies of the 
animal reqftire opening or fhutting. The fecond fet 
have a vifible and regular multarticulate hinge ; exaffly 
like that of the Noah’s arks, or the multarticulate cockles. 
On a due conlideration of the deep grooves, the in¬ 
dentings,.the undulated margins, and other diftortions, of 
thefe fliells, more than in any other genera, and by the 
beak, which is perforated or tubular quite within, it 
would appear that thefe animals feldom open their fliells, 
as molt others do, to take their food ; but nourifti theirj- 
(elves through the tube'or perforated beak only. By ob¬ 
fervations made on the few living fpecies lately dilcover- 
ed, this opinion (lands in fome meafure confirmed; as 
the living anomiae have all been found lurking in the 
nooks between the branchings of corals, or cavities of 
rocks. They lie-therein • lifted upon their flat furfaces 
horizontally, without any prop or folid body to reft on, 
but are upheld or fuftained only by a llrong adlielion of 
their tubes or. perforated beaks to the lides of the' cavi¬ 
ties,, as if,in the aflion of fucking; and this pofuion is 
the general one of the recent kinds. If appears likewife 
that the hole in the beak of the conchse anomiae is for the 
purpofe of tranfmitting a llrong ligament or griftly fub- 
llance, by which they adhere firmly to the rocks, corals, 
&c. in the fame manner as that chefs of Ihelis commonly 
called bears paws; at ieaft fome fpecies of them have :in 
opening between the two valves on one fide the hinge, 
through which paffes, from the infide of the fliells, a 
llrong ligament, whereby the fifli adheres firmly fo any 
contiguous body. The interior Itruclure of one of the 
living kinds feems allb riot at ail particularly .adapted 
t« 
