THE MINERAL CONCHOLOGY OF GREAT BRITAIN V03, SOWERBY 1812 to 1834

THE MINERAL CONCHOLOGY OF GREAT BRITAIN; OR COLOURED FIGURES AND DESCRIPTIONS OF THOSE REMAINS OF TESTACEOUS ANIMALS OR WHICH HAYE BEEN PEESERVEB AT VARIOUS TIMES AND DEPTHS IN THE EARTH By JAMES SOWERBY, F.L.S G.S W.S HONORARY MEMBER OF THE PHYSICAL SOCIETY OF GOTTINGEN, OF THE SOCIETY OF JENA, &C AUTHOR OF BRITISH MINERALOGY, EXOTIC MINERALOGY, TISH MISCELLANY, ENGLISH FUNGI, A BOTANICAL DRAWING BOOK, AND A NEW ELUCIDATION OF COLOURS BRI- ; DESIGNER OF ENGUSH BOTANY, ^e Many, O Lord my God, are thy wonderful works which thou hast done; they cannot be reckoned up in order to thee: if I would declare and speak of them, they are more than can be numbered Psalm VOL xl III LONDON: Printed by And W ARDING, 21, Old Boswell Court, Carey Street by the Author, J Sowerby, No 2, Mead Place, Lambeth; Longman and Co and Sherwood and Co Paternoster Row, &c sold MDCCCXXL PECTEN cornea TAB CCIY Spec Char Orbicular, much nearly equal ears small, depressed, smooth • * two obtuse teeth near the ears within each valve -A THIN fragile shell whose Talves are very nearly being both of them very acute ; flat and shining the ears prominent and well defined of each within the valves is : ; alike^ the beak is at the base an obloug blunt tooth slight difference observable in the relative position these teeth points out the two valves most readily : a of Well preserved individuals retain some traces of the original markings like such are of a deep brown colour with a horn- ; transparency on the sides, and of an opaque pale brown from the front to the beak, near which the colours are very distinct : other specimens are altogether of a pale brown colour, these are the most tender Found Blue 3Iarle stratum below high water in Hampshire It has much affinity with Pecten Pleurouectes, but is more slender, and in the mark, at Stubbington, otherways distinct difficult to preserve Mr Holloways such as Perfect specimens are very rare, and ; I am therefore much oblisred to for the pains he has taken to procure exliibit clearly all the characters me s PECTEN obscura TAB CCV.— F/g- Spec Sub-orbicular, depressed, with oblongitudinal rugse upon the Char arched scure surface Somewhat ; ears large longer than wide : the surface is dull, almost furrows has some indications of diverging smooth but it The edge is thick of Stonesfield, Occurs upon the sandy Limestone slate to me long forwarded near Oxford My specimen was ; since by Dr Williams PECTEN Tx\B lens CCV.— Figs and Orbicular, convex; surface marked diverging arched striae; strise deeply Spec Char wilh punctured Nearly shell near the beaks; t!ie remains are much broken lenticular, but thickest seems to be tender, as its my specimens the ears are not perfect in either of produce of t'ue forest marble near Oxford A PECTEN laminata TAB CCY.-^Fig, Char Spec arched, diverging striee equal A HE Suborbicular^ striae ; depressed^ striated; ears triangular^ un- : the largest plaited are slij^htly undulated; to the naked eye they appear smooth, but when carefully examined with a lense, plaits minute lines may be traced across them The upon the ear form a strong character, whence the name In shelly Limestone (Cornbrash) Chatley Lodge, at in Somersetshire PECTEN TAB Spec Char arcuata CCV— Figs Orbicular, : ears large ; with arched upon the stride sur- the side beneath the largest arched is A SMALL shell, prettily marked with arched, sometimes forked farrows largest and depressed, punctured and diverging face is quadrangular ; The ; the they are both punctured I have a single valve of this along with Ostrea gregarea (tab (fig 7.) 111 Devizes, and another upon Coral rag perfect and dotted, ears are dissimilar f in sandstone, (fig 5.) & 3.) from but not so PECTEN similis TAB CCV.— Fig Char Spec Suborbicular^ depressed^ striated ; archedj diverging; ears unequal; sides striaB straight HIS differs from the last in having a straight side be- neath the larger ear, in being long^er, and having no dots first sight it much resembles it Limestone, probably belonging to the Forest Marble, from Shotover Hill, Oxford in the striae Upon ; but at shelly PECTEN rigida TAB CCV.—Fig Char Spec striated; Orbicular, stride depressed ; strongly arched, diverging; ears large, unequal, decussated A LARGER shorter, From the Rev shell than the last, which it resembles, but and has fewer and deeper striae is Castle Combe, in Forest Marble, by favour of H Steiuhauer CUCULL^A oblonga TAB CCYL—Figs Syn CucullEea oblonga Spec Char Miller, and MSS Transversely oblongs gibbose^ lon- gitudinally shaped HE width i striated lines ; anterior ; wedge- side beneath the cartilage numerous of this Cucullaeais above twice its length the front inclines slightly to the posterior side, which : is upon the surface are numerous, irreguThe beaks are the edge is entire lar, and elevated the flat rhomboidal space between elegantly incurved small the : striae : ; them marked with from is The specimen of finest pair figured it : much labour and perseverance by Mr J S Miller, of Bristol me parallel lozenges belongs to a valuable collection that has been made with also sent 12 to this shell as yet obtained is the G W Braikenridge, Esq has a good example at Dundry in the The single ore They were both found inferior Oolite, holding grains of iron valve represented was sent me by the it is in the Rev Mr Steinhauer, from Cross Hands same kind of stone I regret that a single valve exhibiting the teeth more perfectly, which I have just received from Mr Miller, did not arrive time enough for me to : alter the figure It shews the lateral plates bent at right angles near their bases where they approach the middle Mr Steinhauer has of the hinge from little also sent me fragments Sodbury The name is that Mr Miller has given and in a catalogue of lent me some valuable for publication it in his letters, shells he has kindly CUCULL^A decussata, TAB, CCVL Figs Cucullaea decussata Syn Char Spec Transversely ovate longitudinal ridges gular lines wA-BOUT one-fiftli Parkinson III 171 flattish ; and ; g-ibbose^ with anterior side an- ; beneath the cartilage wider than long : few^ the ridges are but and are decussated by fine and close lines the interior margin in old shells is crenu- elevated, little of growth lated : : the teeth of the hinge, when they are not worn, are striated or crenulated upon their Sides, as I have ob- served when speaking of C glabra, (Vol I p T received this from the same gentleman 152, t.67.) who sent Mr Parkinson the specimens he describes, Mr Francis Crow, who collected them all near Faversham, in Kent : they are silicious casts, with a small portion of the shell re- maining ISO remarkable for size Fig- is inserted to 8' ffive an id©^ of the crenulations between the strite CONUS coiieimius.— TAB CCClh~Fig.2.- Spec Char Fusiform^ angular in the middle^ spPre ornamented with knobs and granulated strise ; base produced^ sulcated HIS elegant Cone is nearly three times as long as broad, the spire occupying little more than one third of the length both ends are pointed ; the sulci upon the base are deepest towards the point From Ilighgate Hill, and Barton ; not very common^ ^ ; — TAB CCCU.—Fig, J\s it is not likely we shall again have so good an opportunity of searching the clay of Highgate Hill, as Avas afforded by cutting the road through it in 1811, I have tijought it adviseable to figure a very much corroded and imperfect Cone found there, without being able to give a satisfactory character or name to it It is not impossible that it may be a very large specimen of C concinnus, but the canal around the spire, and its shorter form, render it doubtful there are obscure indications of tubercles or large crenulations upon the spire I cannot reft it to any species described by Lamarck or Brocchi : • : CONUS scabHcolIT.— TAB CCCIII Spec Char strias Fusiform, rather short, striated; elevated, toothed var /3, elongated, striae numerous, minutely toothed, (fig 2.) Syn Conus scabriculus Brander, 21 HE greatest width a is rather less than half the' the stride vary only one-third from to 24 ; when few, each consists of a series of large, sharp, compressed teeth, in proportion as they are fewer they are more elevated, and the teeth are smaller ; the last whorl is rather swelled out of the regular conical form ; the aperture is longer than the spire ; the right lip is sometimes plaited at the edge^ ojjposite the teeth in the striae, and the left lip is not J- length : in var /3 it in is : visible A common shell at Barton I Salisbury for several specimens am indebted to Miss ISl MUREX infeiToptus TAB CCCIV Spec Char Subturrited transverse sulci with two body covered by broad, the remaining whorls smooth along their upper edges sulci Murex Syn ; ; interruptus, Linn Soc VII p 117 Pilkington, in Trans t 11, / about twice as long as wide Shell a broad ; runs along- the smaller whorls, above furrows ; the last wnorl in full are it grown flat space two sharp individuals is quite covered with furrows, which are broader than in the other whorls, it is also convex, the right lip is plaited within, the left so thin that sion of the sulci beneath beak is One it it receives the impres- and so becomes striated ; the elongated and slightly curved of the varieties of this shell Mr Pilkington, who discovered Hampshire fossil shells made by others have since been noticed at was it first in published by a collection of T Swainson, Esq.; Barton by Lady Bar- I goyne, from whose choice cabinet the specimens fig are taken; I have since received it from Miss Beminster, and an unknown Friend ; in the specimens from these latter persons the band does not extend so far down the spire as in those collected by Lady Burgoyne, (see fig 2.) 182 I have no hesitation in pronouncing them to be the same as Mr Pilkington's shell although Miss Beaminster's nearly three times as long specimen is fig 2, is intermediate, the specimen at and the smallest of Lady Bu? goyne's corresponds exactly 183 INOCERAMUS concentricus TAB CCCV Spec Char Unequalvalved, ovate, one of the beaks much produced, incurv:ed Inoceramus concentricus Syn Parkinson in Trans Geol Soc vol V p 58 Birostrina One other, Jean Andre lasvis of the valves of this shell is t 1./ De Luc, M S, rather deeper than the and has an acute, produced, incurved beak beak of the other striated is very short and undulated the ; ; ; the both are transversely stride distant imbricated plates ; the width straight, : the hinge is are the edges of the length is nearly double containing about a dozen grooves for the reception of the ligament the composed of two coats, the outer brownish and : shell is of a fibrous structure, the inner pearly There rently no sinus for the passage of a Byssus is appa- Found abundantly in the dark coloured blue Marl at Folkstone, and also in blue Marl of a lighter colour near Lewes in Sussex Figures 1, 2, and 3, shew portions of the hinge Miss Curtis was so kind as to favor me in 1813 with first specimen in which I saw the hinge I have not since seen better, and should have figured it long ago, but did not wish to be too precipitate It was found the ; at Folkstone I defer giving the characters of the Genus Inoceramus, until I figure the species found in Chalk, which I have named Cuvieri, in a paper read before the Linnean Society in 1814 I must observe however, that it differs from Perna Byssus in not having a sinus for the passage of a 184 INOCERAMUS sulcatus TAB cccyi Spec Char Unequalvalved, oblong with promi- nent beaks, and about large, longitudinal, beak of one valve incurved, acute Inoceramns sulcatus Parkinson in Trans plaits Syn ; Geol Soc vol r p ,59 t.l.f 5, De Birostrina costata Luc, MS J.N general form this resembles the last, but shorter and more spatulate tions in the hinge : it it is rather has also fewer crenula- the angular folds resembling those of Ostrea Crista Galli are a sufficiently remarkable disr : tinetion Equally abundant with the last, at Folkstone it has been found near Lewes in Sussex Mr Jean Andre De Luc, of Geneva, has good specimens of both, : also collected at Folkstone by himself in 1797 but as he ; had not seen the hinge, he was induced to name the genus under which he placed them, from the beaks; and in 1820 was so kind as to send me sketches of them named as above quoted : should the inequality of the valves prove a generic character, to distinguish them from Inoceramus,* or should Mr De Luc's name have been given prior to 1814, it will be right to retain it, and also his specific names, if they have been pub- lished Figures mens : Esq : fig fig 4, and 7, are from Folkstone specifrom Lewes, collected by G A Mantell, is from a clay cast foimd at Clophill in 1, 2, 3, Bedfordshire the is : similar ones are said also to be found in Campton and in the Southill MarLpits, and near Beadlow same county, above the Woburn Sand * The Inoceramns equalvalved Cuvieri, the type of the genus, shell, as I have lately examined have been led to suspect is probably an by some good specimens INDEX TO VOL Tab Ammonites annuliitus 222 Bechei 280 biplex Birchi 293/ 267 1, Page 41 143 108 121 2C3/.'1&:5 114 Browni decipiens 294 254/ Goodhalli 255 Heuslowi 262 heterophyllus 266 Koenigi 263/1,2 l(i9 falcifer 99 JUl) Ill 119 ^3 212/.1,2&3 73 242/ 73 242/ 74 293/, 169 Sowerbii 213 23 Strangewaysi 254/ 1&2 99 triplicatus 292 & 293/ 167 Ampullaria acuta 284 151 patula 284 152 sigaretina 284 152 Area appendiculata 276/ 135 Branded Astarte excavata planata Avicula costata echinata Tab Helicina expansa j Inoceramiis con- | rostra ta Lima sulcata tener antiquata proljoscidea 183 lirata ovalis Melanea constricta costata fasciata 184 lineata 57 103 77 295/ 295/ 295/ 214/ 172 172 171 264 115 75 218/ 241 241 / / 209/.5,6 &7 Iffivigata 209/3 ' 209/ 1&2 pisum 209/ 13 212/ 210/.3&4 cuneata gibbosa Hillana 211/ 211/ subcarinata ? coronatus cristatus interuptus tuberosus angulifera 14 15 17 19 19 212/ 21 212/ 1&3 210/ 5to7 21 19 248/ 2!l/ 248/ 87 20 87 210/1 17 230/ 52 230/ 1&2 52 304 229/ 51 229/ 51 224/ 6&7 46 minax 181 Jiterata 14 18 93 22 aspera Scalprum Myai 72 72 bipartita minima 179 ISO 71 33 251 plicata reniformis 260/.1&2 108 302/ 180 25 48 47 47 33 71 210/2 imbricata &6/'"^ Mures 25 227 225 226 tequalis aliformis Modiola 171 I 241/ dormitor 301 scabriculus 303 V-scripta Mytilus aliformis 224/ 45 224/ 2to5 46 275/ 133 Antiquorum 209/8tol3 16 fibrosa 207/ 206/3&4 pectinatus Nautilus bilobatus 207/ complanatus 249/ 261 pentagonus tuberculatus 249/ 249/ oblonga 206/ 1&2 Fusus acuminatus 274/1,2 > & 3| asper 131 274/4to7 131 228 49 291/ lto6 165 bifaciatus bulbiformis ficulneus 291/ 166* rugosus 274/ 8&9 132 plicatilis 91 305 truncata / 3, 4,5, Hamites armatus nodosus 250 214/ rudis Lutraria ambigua 175 56 149 edule 283/ 150 eduHnum 283/ 149 Cirrus Leachi 219/ 36 nodosus 219/.1,2&4 35 Conularia quadrisulcata 260"),„_ revoluta Cucullea carinata decussata ^ minima 232/ globosa 153 129 233 257 244/ 243 similis 273/4 centricus ^ sulcatus 306 Isocardia minima 295/ Cardium angustatum 283/ Corbula gigantea , Hippopodium pouderosum 276/ 1&2135 297 h2g 285 218/ 241 / margaritacea Conus concinnus & inequivalvis 244/ &3 78 Cardita lunulata 232/ 1&, 55 teres Page 273/ 1,2 polita solaiioides 113 Lamberti Leachi omphaloides rotundus III 234/ 216/ 234/ spiniger 216/ spinulosus 216/ tuberculatus 216/ &5 turgidus 216/ 59 30 59 29 29 30 80 Nerita laevigata sinuosa Oiiva Branderi Salisburiana 282 147 2&3 89 217/ 217/, 288 288 109 89 90 31 32 159 160 Orthocera cordifor- „ _ -*' ^^ mis I gigantea 246 81 Ostrea expansa 238/, 65 flabellula 253 97 Meadei 252/ 1&4 95 pulchra 279 141 tener 252/ 2&3 95 undulata 238/ 65 INDEX TO VOL Page Tab, 205/ 5&7 Pecten arcuatus 53 231 bavbatus 204 Cornells 67 lamellosus 239 laminatus 205/ 205/ 2&3 Lens 205/ obscuius 205 f rigidiis 205/ similis 145 Pinna lanceolate 281 79 Plicatula spinosa 245 Rostellaiia macrop- P 298, 299 > ,," tera^SOO | 286 Seraphs convolutus Terebellum fusiforme 287 diinicliata277/'' Terebratula inconstans 277/.3&4 Mantice 277/ I 277 / obliqua 269 Spirife.r glnber obtiisiis 26S 269 pinguis 271 oblatiis strialus trigonalis Trigonia affitiis aliformis *,,, duplirata excentrica 270 265 208 / 215 ' lo5 157 138 137 137 137 123 123 124 125 125 117 11 237/ 4&5 208/ &2 gibbosa pennata striata Tab Paj 235, 236 237 / 237/1,21 & 3/ 221 / Trocbus bicarinatu concavus extensus 272/ 278/ 2&3 140 Gibbsi ornatus * 'reticulatus sulcatus Turbo carinatus muricatus ornatus ,, Veuericardia carinata deltoidea globosa oblonga 289 289 258 256 296 290/1,2) Magorum Unio concinnus 259/ 259/1 varicosa Voluta costata 220 240/ 1&2 69 senilis Venus turgida 220/ 278/ 37 139 37 f 272/.3&4 127 39 221/ 272/ 128 220 / 38 69 240/ 240/ i> 1-27 fasciatiis granuiatiis irnbricatus 27 63 11 III 290/ 223 106 106 161 162 105 101 173 164 43 ERRATA Page 1, 3, 4, 5, 1, IS, 27, 46, 75, 78, 81, 87, cornea" read " cornens." line I, " obscura" read " obscurus." line 1, " laminata" read " laminatus." 13, " arcuata" read "arcuatus." line 11," rigida" read " rigid us." line from the bottom, " TRIGONA" read " TRIGONIA" line 13, and last but one " Parkham" read " Parhani." line 1, " ala^formis" read " aliformis." from the bottom, " Parkham" read " Parham." line 1, " V sciipta" read V-scripta." line 22, " 5" read " 4." line 3, from the bottom " T O Marsh, Esq." read " the Rev T O Marsh." line 14, " radi" read " radii." line 1, " gygantea" read " gigantea." line 1, " cuneata" read " Scalprum" Unfortunately the name cuneata had been previously applied to another Modiola, see line 1, for " tab 211 89, line 24, " I not know they" read " I not 93, line 1, " alseforniis" read " aliformis." 125, line 2, know that they." " CCLXXI" read " CCLXX." " pinquis" read " pinguis." from the bottom " Beaminster" read " Bemiuster." 18, 132, line 6, 133, line 20, " alsBformis" read " aliformis." " Beaminster" read " Beminster." " Gibsi" read " Gibbsi" and line 3, from the bottom " Gibs" read " Gibbs 141, line 6, from the bottom " genius" read " genus." 143, line 18, " different" read " differently." 145, line 3, and „ j^,^^^„ ^^^^ » 13.5, line 17, 139, line 1, | j.-eland." ) 147, last hne 149, line from the bottom, and 150 last line " edulina" read " edulinum." Ttie description of Fttsiw jiculneus, tab 291, f was accidentally omitted, it will be found upon a separate leaf in Number 33 The Binder is requested to place it next to page 1G6 187 A >SUPPLEMEN lAKY INDEX TO VOL III Arranging' the Shells described therein, according to tkz several Strata in which they icere found imhtddtd, from the neivest towards the oldest in the British Series THE following Letter, received from my kind nleiid Mr Farey, which inclosed his manuscript of the Supplementary ludex to my Third Voitane which he had kindly prepared, I beg to insert here, by way of prefact; to that Index SIR, IF on the completion of my Stkatigrapiiical Index to your Second Volume, I had occasion to apologise to you and your "Readers for delay in completing the same, I feel that I have now much greater indulgence to claim, for the very protracted appearance of the enclosed Index to your Third Volume: and which indulgence I trust that yourself and they will grant, on being assured, that ciicumstances untoreseen and not within my controul, have prevented, at any earlier period since yoii finished printing tiie Volume, my giving that very careful, and I maysay laborious attention, to the compiling of this Index, which I had deterndned to bestow upon it, and which iiovv^ the same has had It is to me a subject of the deepest regret, that since the period when compiled the Index to your Second Vohxme, only one jnore Number fthe 4t';0 of " Strata Identified by Organised Fossils," has appeared, from the pen of my greatly respected and very ill-used friend My WiLLiAM Smith; and, that besides the three remaining Numbers of this work, the second part of his " Stratigraphical System of Organised Fos-^ sils," is also yet unpublished Foil warn of my being able to consult the latter part of Mr Smith's Catalogue and Arrangement of Organised Fossils, and for want of knowing the localities, whence his specimens in the British Museum were obtained, with regard to all those parts of the British Series of Strata which lav below the Marlstone, I have experienced considerable difficulties, and liave been in much doubt in several instances, whilst compiling the present Index suffice it to say, that I have spared no pains to mv best towards presenting a correct and useful arrangement of the Shells'of this volume Althol'GH I was by no means first in discovering the important truth, that particular and definable species or varieties of Shells or other organic Remains, are peculiar to, and not elsewhere found (fossil or living), but in certain beds or definable portions (as to thickness) of the Strata of the Earth, yet I believe myself to have been the first to publish, and the most steady and consistent of any one else in maintaining this doctrine su replete with interest, and so fertile in consequences deduciblefrom it botii of a theoretic and a practical kind and my chief endeavours herein have been directed, not to the bringing forwards individual cases, wherein the doctrine appears to be supported ; that task I leave to yourself and others, wliom many of my cotemporaries will be disposed to think more impartial evidences, and who are performing this task as effectually as I could wish but to the pointing out, as I have done at some length in Vol.53, p 112, 120, &c ofDr Tilloch's " Philosophical MagaziuV as many as possible of those instances, in which at present Shells passinounder the same name, appear from their localities, as probably referable to more than one Stratum each with my earnest request, which I be.) Ammonites ; ? Cardita ? Conularia qnadrisuicata, (3 teres ? 297, 260, 2G0, Inver Brora Inver Brora Tronlie Bank p 176 f f f land Tronlie Bank DERBYSHIRE PEAK, Limei^tone Under-coal, Metaliferous, Basaltic, or Mountain Limestone Kendal, AJdstone (purple blue, No 31.) : Ammonites Henslowi Conularia quadrisuleata, a Hippopodium ponderosum, Melanea constricta Modiola bipartita, (3 Nautilus bilobatns complanatfis pentagonus tuberculatus Orthocera cordiformis gigantea Spirifer glaber oblatus 262, 260, Scarlet f Head 3to5 Kot-V/ells&Westmoreland, Colebrook Dale j3 2')0, & 218, f Buxton Tideswell (3d L.) 210, f Llantrisent 249, f.2and3 Closebiirn Scarlet Head 261, 249, f Bathgate-hills&Closeburn 249, f Closeburn Closeburn &Thornlie-bank 247, Bajarg and Closeburn 240, Chelmerton, Ireland, and 269, up Tideswell, 3d L Axton-Quarry, Derbyshire, 268, and Westmoreland obtusus pinguis striatus 269, 271, 270, trigonalis 265, Terebratula Mantiae — 277, lo Scaliber, Black Rock Bake well.^Castleton, 1st L and(Cork) Black Rock Cave Dale, N Monyash, and Overton (l&t L.) f Ireland have been unable to place in the above List, either T fusiformis 3, p 158, or Venus.? p 174, for want of more local information Note I ERRATA which have unfortunately escaped correction in the printing of the 3d Volume, in addition lo the List, p 186 3, last line, for " near Oxford" read " Oxfordshire." 41, after line insert " Syn Lister's An Aug t 5, var a, Phil Mag Vol 54, p 136." 47, line 11, for " Norton" read " Wooton." 67, after line insert " Syn Pecten - - - Smith's Strut Syst p 40, and Page Strata Identified, p 16, and Portland Stone, plate f 6 from the bottom, for " fifth" read " third." from the bottom, for " the- other figure" read " fig 3." 17, for " Sanguar" read " Sanquar." from the bottom, for " ports" read " posts." from ihe bottom, for " Sandgate" read " Sandown." 15, " Keewick" read " Kendal." from the bottom, for " 28" riad " 48." first line, for " triplicatus" read " trifidus," in consequence of triplicatns having been used before: the same erratum occurs in the Index 180, line 17, for " and 2" read " and 3." And in the Index, for " Murex interuptiis" read " M interruptus"; for " Trigonia excenti ica" read " T ecctntrica" and also insert " Araraouite* 67, 78, 82, 82, 93, 108, 123, 167, line line line line line line line ; biarmatus," page 122 Several Errors in spelling the Nameji of Places ure eorreeted in the Siipplemert,tiiry Index, ... leaves the beaked end of this Modiola so small as to give it much of the contour of a Mytillus gether is The depth of the two valves to- greater than the width, and the length the depth The roughness... of keel from the centre of which the shell tapers towards the beaks ; these are not very prominent; and together with the small 22 convexity of the posterior lobe, give that end a narrow contour... by the Nearly 1.8 from the remainder of the shell by a kind of step parti- cularly prominent near the beak also ; the length is greater the carinated form of the beak not so evident ; and the