THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 PRESENTED BY 
 
 PROF. CHARLES A. KOFOID AND 
 MRS. PRUDENCE W. KOFOID 
 
 EARTH 
 SCIENCES 
 LIBRARY 
 
THE FOSSILS 
 
 YORKSHIRE LIAS 
 
 DESCRIBED FROM NATURE, 
 
 WITH A CAEEFULLY MEASUEED SECTION OF THE STEATA, 
 AND THE FOSSILS PECULIAE TO EACH. 
 
 MARTIN ^IMPSON, 
 
 LECTURER ON NATURAL SCIENCE, AND CURATOR OF 
 
 THE WHITBY MUSEUM ; AUTHOR OF A GUIDE 
 
 TO THE GEOLOGY OF YORKSHIRE. 
 
 SECOND EDITION. 
 
 WHITBY : 
 
 PRINTED BY FOETH & SON, FLOWEEGATE. 
 SOLD AT .THE MUSEUM. 
 
 LONDON : 
 
 JOHN WHELDON, NATURAL HISTOEY BOOKSELLEE, 
 58, GEEAT QUEEN STEEET-* LINCOLN'S INN FIELDS. 
 
 1881. 
 
QE733 
 
 PREFACE. EARTH 
 
 SCIENCES 
 LIBRARY 
 
 THE Fossils of the Yorkshire Lias, and especially 
 the Ammonites, had been objects of superstition, 
 and poetick fiction, from mediaeval times, but re- 
 specting their true nature, no one ventured to 
 express an opinion. 
 
 Whilst it was generally believed that the hills 
 and valleys, and the whole face of nature, were 
 the same as they had ever been, from the creation 
 of the world, except some modification which it had 
 suffered by a transient deluge, the forms of orga- 
 nized beings found deeply buried in the earth 
 remained inexplicable. It was only about the 
 middle of last century that correct views respecting 
 the changes which had taken place on the earth's 
 surface were promulgated, and the origin of the 
 noble, sublime, and popular science of Geology, 
 now established upon indubitable evidence, can 
 scarcely be placed earlier than the beginning of the 
 present; whilst the systematick study of Fossil 
 Remains, or Palaeontology, as it has been named, is 
 still more recent. 
 
 The honour of first introducing the study of the 
 rocks and organick remains of eastern Yorkshire 
 into Whitby and the region round about, is due to 
 the Rev. George Young, M.A., of Edinburgh. In 
 
IV. 
 
 1818, he published his History of Whitby, a work 
 of high literary character and antiquarian research, 
 in which he gave a very luminous and correct ex- 
 position of the rocks and organick remains of the 
 district. 
 
 The publication of this work immediately produced 
 a general revolution in publick opinion respecting 
 the fossil remains of the district, and excited great 
 zeal for further discovery. There was, indeed, at 
 this time, in Whitby, a strong desire after intellec- 
 tual pursuits, not only amongst the learned, but 
 amongst many whose circumstances in life were 
 unfavourable to such pursuits. The cessation of a 
 long and exhausting war, the energies aroused by 
 that war, and the want of employment before the 
 return of commercial prosperity, all had a tendency 
 to intellectual pursuits, and, no doubt, contributed 
 greatly to the establishment of Philosophical Insti- 
 tutions and Museums, which the great wealth and 
 the national prosperity of the present era scarcely 
 sustain. 
 
 Immediately after the publication of the History 
 of Whitby, Young, with his companion, Mr. John 
 Bird, an artist, and a man of a philosophical turn of 
 mind, undertook a thorough investigation of all the 
 strata of the Yorkshire coast, from the Hurnber to 
 the Tees, and of their western outcrop towards the 
 Vale of York and the Cleveland hills. This survey, 
 in every way worthy of a pupil of the celebrated 
 
V. 
 
 Playfair, was performed with great accuracy, minute 
 investigation, and care, during four years of assidu- 
 ous labour, and the result was published in 1822, 
 under the title of a Geological Survey of the York- 
 shire Coast. In this work a fair and accurate 
 description of the series of strata along the coast 
 was given, which formed an important guide in 
 further researches. The publication of this work, 
 and the visits of the authors to various localities, 
 and their intercourse with men of scientifick tastes, 
 gave a great impulse to geological pursuits through- 
 out the district. At Scarborough, Mr. Bean and 
 Mr. Williamson, by their enthusiastick and inde- 
 pendent labours, rendered a great and lasting benefit 
 to Palaeontology. In January of 1823, the Whitby 
 Museum was established, and became the receptacle 
 of the fine fossil, Teleosaurus Chapmanni, and 
 other remains, which have rendered Whitby famous 
 amongst all men of science. The Scarborough 
 Museum was formed in 1831, where was soon 
 displayed a fine and instructive collection of fossils 
 from all the coast strata, arranged in systematick 
 order. 
 
 Thus, by the enthusiastick and perseveriug labours 
 of not a few persons, such collections were made as 
 enabled Mr. John Phillips, when, in 1829, he pub- 
 lished his Illustrations of the Geology of Yorkshire, 
 to give an extensive systematick catalogue of the 
 fossils from all the strata, especially those of the 
 
VI. 
 
 Oolite, which has proved of great utility in the 
 promotion of the science. 
 
 In 1837, I was appointed Lecturer on Natural 
 Science to the Whitby Literary and Philosophical 
 Society, and Curator of their Museum. Here I found 
 a large accumulation of fossils from the Yorkshire 
 strata, chiefly from the Lias, which, through want 
 of means for displaying them, had remained un- 
 touched for many years. As many of them had 
 not been named, and others, though named, had 
 been only imperfectly described, or described in 
 books inaccessible, I resolved to make my own 
 book, and wrote descriptions of every fossil which 
 came under my notice. In the beginning of 1843, 
 I published descriptions of more than one hundred 
 Ammonites of the Yorkshire Lias, in a short Mono- 
 graph. These being favourably received, in 1855, 
 I published descriptions of all the then known fossils 
 of the Yorkshire Lias, together with an outline of 
 the Geology of the Yorkshire Coast, intended as a 
 guide to strangers. In this I followed the divisions 
 of the strata laid down by my predecessors ; and 
 considered the Lias under three main divisions, the 
 Upper, Middle, and Lower Lias. But being con- 
 vinced by observation that few species of the Lias 
 fossils had existed during the deposition of any 
 great thickness of strata, but, on the contrary, were 
 often confined to thin seams, I measured carefully, 
 with a two feet rule, all the beds and seams of Lias, 
 
Vll. 
 
 both to the south and north of Whitby, and at the 
 same time collected the fossils from each stratum. 
 This section I published in 1868, in the fourth 
 edition of my Guide to the Geology of the York- 
 shire Coast. This section I now reprint, with slight 
 alterations, and to which the fossils in the catalogue 
 are referred. 
 
 Notwithstanding all this labour and research into 
 the Lias formation in Yorkshire during more than 
 half-a-century, two gentlemen of high scientifick 
 attainments, and of indefatigable labour and zeal, 
 Mr. Ralph Tate, now Professor of Natural Science 
 in the University of Adelaide; and the Rev. J. F. 
 Blake, M.A., now Professor of Natural Science in 
 Nottingham College, had the courage to enter upon 
 a thorough and exhaustive survey of the Yorkshire 
 Lias, both as regards its Stratigraphical Phenomena, 
 and its Palaeontology. As they expressed their 
 intention to recognize and do justice to my previous 
 researches and publications, I willingly laid open to 
 them what I had been accumulating towards the 
 further illustration of our Lias. Their work was 
 published in 1876, and is the most exhaustive of 
 any work which has appeared on that subject ; and 
 the scrupulous fidelity and honour with which they 
 have treated my labours gives me the highest grati- 
 fication. After the publication of a work on our 
 Lias so exhaustive, anything further from me on the 
 subject might appear uncalled for ; but their work 
 
Vlll. 
 
 is written for the learned, and, for the descriptions 
 of many of the fossils, works by foreign authors in 
 foreign languages are necessary. On the other 
 hand, on whatever subject I write, I have constantly 
 before me persons of ordinary education, and for 
 their benefit I sink, as much as possible, anything 
 which might appear technical or learned ; and on 
 the issue of the former edition of this work, it gave 
 me the greatest pleasure and satisfaction to find 
 that illiterate persons could distinguish species by 
 my descriptions. 
 
 The publication of my catalogue of our Lias 
 Fossils having been long delayed from causes over 
 which I had little control, some foreign naturalists 
 published descriptions of our fossils in their own 
 language. The consequence is, that I have had to 
 alter many of my names, as their names have the 
 priority of publication. The names I gave to the 
 ammonites, having priority, remain nearly the same 
 as in the Monograph. 
 
 To all friends who have assisted me, in any way, 
 in my scientifick pursuits, I tender my grateful 
 acknowledgments ; and for the honour done me by 
 the Council of the London Geological Society in 
 awarding to me a portion of the Murchison Donation 
 Fund, u in recognition of my life-long researches 
 into the Palaeontology of the Jurassic rocks of 
 Yorkshire," I entertain sentiments of the deepest 
 obligation and thankfulness. 
 
 Whitby, June 3, 1884. 
 
A SECTION OF THE YORKSHIRE LIAS. 
 
 As each bed of the Yorkshire Lias is strongly charac- 
 terized by its peculiar fossils, some years ago I measured 
 with much care all the accessible beds of Lias between 
 Whitby and Peak, and also those to the north of Whitby, 
 and, as far as I was able, assigned to each bed its 
 peculiar fossils. 
 
 In order to promote greater exactness in collecting 
 specimens, I distinguished each bed by a numeral, or a 
 letter of the alphabet, which, in collecting, might be 
 applied to each example. After a lapse of ten years, 
 with the hope of engaging other collectors in this sort of 
 labour, and to give a more definite idea of our Lias 
 than was then generally entertained, in 1868, I pub- 
 lished this Section in the fourth edition of my 
 Guide to the Geology of the Yorkshire Coast. Since 
 that time, I have carefully collected the fossils of each 
 bed, and paid particular attention to the Belemnites, 
 which I found to be as strictly confined to certain strata 
 as the Ammonites, or any other fossils. In these labours 
 I have been greatly assisted by Professor Ealph Tate, 
 F.G.S., who made important discoveries in our Lias 
 fossils, and who very generously sent me examples of 
 many new species ; and I have also availed myself of the 
 permission to describe those he deposited in the Museum 
 of Economick Geology in London ; so that I am now 
 better able to assign each species to its particular bed. 
 
 In the main divisions of our Lias I adopted those of 
 previous British geologists, and considered it as divided 
 into Upper, Middle, and Lower Lias. I subdivided the 
 Middle into the Ironstone and Arenaceous beds ; and the 
 Lower into the Ironstone series and the Indurated bands. 
 
 The Yorkshire Lias is in general overlaid by strata of 
 ferruginous sandstone, containing marine remains, and 
 often by a band of ironstone nodules, the whole called 
 by miners the top bed of ironstone; but these have 
 
X. 
 
 been identified with the Inferior Oolite of the southern 
 counties. Above these are often displayed in the cliffs, 
 above thick beds of shale, clay and sandstone, sometimes 
 mistaken for Lias ; but which are generally of a lighter 
 colour. These are chiefly of fresh water origin, and contain 
 numerous remains of plants, but in some localities they are 
 entirely marine . The whole have been denominated E stua- 
 rine or Deltick, from a supposition that they have formed 
 the Delta of some large river, and are a local deposit, 
 little of it reaching further southward than the Humber. 
 
 UPPER LIAS. 
 
 Alum. 
 
 The Upper Lias in Yorkshire is very homogeneous in 
 its lithological character, being a dark smooth slaty 
 shale; but as different beds are strongly distinguished 
 by different species of fossils, I find it advantageous to 
 consider it under eight subdivisions. 
 
 Div. Ft. In. 
 
 1. From the ferruginous sandstone bed of Inferior 
 Oolilte, which caps the Lias, down to a 
 nodular bed of Lias limestone, there is, near 
 Whitby, 34 feet of blue shale, increasing 
 gradually to 40 feet at Normanby Stye Batts, 
 on the Hawsker shore. 
 
 The top of this division in some localities is 
 rather sandy, as at Peak. The upper half 
 contains an abundance of nodules of Lias lime- 
 stone, which is manufactured into a valuable 
 hydraulick cement - - - - - -340 
 
 The fossils most characteristick of this division are 
 Belemnites vulgaris, Ammonites communis and bifrons, 
 Leda ovum, and Myacites donacif ormia ; all which are 
 abundant. Here also have been found many remains of 
 Saurians; Belemnites limatulus, glaber, inclusus, levi- 
 densis,; Nautilus astacoides; Ammonites Jurensis, 
 heterophyllus, subcarinatus, crassus, vortex, fibulatus, 
 subarinatus, Lythensis, Roulbyensis, Beanii, striatulus ; 
 Trigonia literata; Venus tenuis; Pholadomya gallina; 
 Astacus rostratus. 
 
XI. 
 
 Div. Ft. In. 
 
 2. We commence the second division with a band 
 of hard Lias limestone, generally about three 
 inches thick, but often interrupted, and in 
 places swelling out into flattened nodules more 
 than a foot in thickness. This may be called 
 the first indurated band, and it appears to be 
 very constant over extensive areas. Beneath 
 this is 18 feet of dark blue shale, less produc- 
 tive of alum, and with fewer fossils. It was 
 in this bed that the first specimen of Teleo- 
 saurus Chapmanni was found (1758) - - 18 
 
 3. We then come to a band of indurated shale, 
 thin, uninterrupted, ferruginous, generally 
 two inches thick, but thicker in places, 
 passing gradually into ordinary shale be- 
 neath, where we find Lingula venusta, and 
 where Mr. Kershaw discovered Astacus (Ergon) 
 Hartmanni. 
 
 It is seen a little to the north of Whitby 
 harbour, both in the cliff and on the beach, 
 where it dips beneath the sea, and emerges 
 not far from the north Nab at Saltwick, and 
 forms a very distinct, red line in the cliff. 
 Between this and the next indurated band, 
 there are 18 feet of shale, in which the fossils 
 of the upper divisions are very sparingly 
 scattered, with Myacites rotundata - - 18 
 
 1. The third indurated band, which overlays the 
 fourth division, is ferruginous and interrupted, 
 forming large thin patches on the beach, with 
 nodules of Lias limestone, both above and 
 below, which contain Ammonites ovatus, and 
 is known to collectors as the Ovatus band. 
 
 It may be seen on the beach on the north 
 side of the north Nab at Saltwick, and rises 
 nearly to the top of it where the road crosses, 
 and is a good line of demarcation over wide 
 areas. 
 
Xll. 
 
 Div. Ft. In. 
 
 Between this band and the next, there are 
 18 feet of shale, and this may be considered 
 the end of the Alum shale, as the shale be- 
 neath is hard and unproductive of Alum - 18 
 
 The most characteristick fossils of this 
 division are Belemnites curtus, dorsalis, and 
 subtenuis in large masses, with A. ovatus. 
 5. The fourth indurated band, with which we 
 a. commence the fifth division, consists, like the 
 second, of hardened ferruginous shale, about 
 four inches thick, hard at the top, and passing 
 into ordinary shale beneath. It is first ob- 
 served rising from the beach at the base of 
 the Nab at Saltwick, towards the end of 
 which it attains a considerable height, and 
 afterwards dipping, it may be seen sweeping 
 across the bay. It then rises into the cliff, 
 where it forms a very distinct line, and is 
 about twenty feet above high water under the 
 Light-houses. 
 
 Between this band and a line of large, flat, 
 widely separated nodules of Lias limestone, 
 there are ten feet of shale. The most charac- 
 teristick fossil is a Belemnite which I name 
 B. urbanus. 
 
 b. Here we first come in sight of Ammonites 
 Mulgravius, in large crushed examples, and 
 descending twelve feet more, we come to a 
 nodular bed where good examples of this fossil 
 
 may be obtained 22 
 
 This lower part of our fifth division is 
 comparatively rich in fossils. Belemnites 
 tubularis, compressus, acuminatus, insequis-- 
 triatus, politus, levis, subtenuis, dorsalis, 
 pollex; Ammonites Mulgravius; abundance 
 of crushed Inoceramus dubius ; Pachyphyllum 
 peregrynurn. 
 
Xlll. 
 
 Div. Ft. In. 
 
 6. From this line, not very well displayed, to the 
 next indurated band, which caps the Jet 
 Rock, there are twenty-four feet of hard, 
 compact, bituminous shale, which forms flat 
 scars on the beach - - - - - -240 
 
 It has yielded some good jet and many 
 interesting fossils : The large Ichthyosaurus 
 crassinianus, now in the Whitby Museum ; 
 many Fishes, Gyrosteus mirabilis, Dapedius, 
 Lepidotus, Ptycholepis, Pachycormus, Lepto- 
 lepis ; Sepia with the ink-bag ; Belemnites 
 trisulculosus, validus, robustus, obtusus ; Am- 
 monites Mulgravius, crassulus, gracilis. 
 Jet Rock. 
 
 7. Our seventh division is capped by a strong 
 band, about four inches thick, very regular 
 and continuous on the north of Whitby, 
 forming a well denned line in the lower part 
 of the cliffs ; but to the south it is much in- 
 terrupted, and when washed by the sea, often 
 takes the form of large millstones, very con- 
 spicuous on the beach, sometimes incrusted 
 with cone in cone coraloid. In general it 
 consists of hard Lias limestone with a con- 
 choidal fracture, offering considerable resist- 
 ance to the sea, but in places it differs little 
 from indurated shale. 
 
 Beneath this band there is about twenty 
 feet of very hard bituminous shale, called, by 
 way of eminence, the Jet Rock. The whole is 
 strongly impregnated with bitumen, which 
 gives out a peculiar odour. It is full of nodules 
 of fine Lias limestone, which generally contain 
 fossils, and also mineral oil, at first a green 
 liquid, which hardens into a kind of pitch by 
 exposure to the atmosphere - - - - 20 
 
 It contains many of the fossils of the stratum 
 above. Those most peculiar are Lepidotus 
 
XIV. 
 
 Div. Ft. In. 
 
 semiserratus, Ptycholepis Bollensis, Ammo- 
 nites exaratus, often in large masses ; Am. 
 elegans, Hildensis, nitidus ; Trigonolites Whit- 
 byensis, Nerita buccinoides, neglecta. 
 8. This division is not separated from that above 
 by any well denned line, but, unlike the Jet 
 E-ock, it is soft and readily denuded by the 
 sea, and in colour a dark grey. It is also dis- 
 tinguished by an absence of nodules in its 
 upper part, and the lower part is very soft 
 and rotten. In the middle there is a seam 
 about two feet thick with nodules containing 
 Ammonites annulatus, constantly accompanied 
 with Belemnites cylindricus. With these ex- 
 ceptions, this division is exceedingly destitute 
 of fossils. 
 
 Below this seam we have the following section : 
 
 Ft. In. 
 
 Soft shale 10 
 
 Nodular band 3 
 
 Soft shale 4 
 
 Nodular band .. 03 
 
 Soft shale 4 
 
 Nodular band 03 
 
 Soft shale 1 6 
 
 Nodular band ... ... ... 04 
 
 Sulphurous rotten shale, with nu- 
 merous broken Belemnites and 
 other comminuted shells ... 36 
 
 24 1 40 
 
 Upper Lias at Whitby 194 
 
 Increasing to 220 feet in thickness at Nor- 
 inanby Stye Batts, on the Hawsker shore. 
 At Boulby, about twelve miles north of 
 Whitby, it is 200 feet, and in some places it 
 reaches 240 feet in thickness. In all places 
 the increase or diminution is gradual. 
 
XV. 
 
 MIDDLE LIAS. 
 
 Ironstone Series. Syn. Kettlen-ess Beds, T. A B. 
 
 The uppermost part of this series is well known as the 
 Cleveland Ironstone, which is of great economical value 
 in the north-east, but which becomes deteriorated to the 
 south and west. It has its debased representatives at 
 Normanby Stye Batts, and at another reef known as 
 Peak Steel, on the south cheek of Robin Hood's Bay. 
 
 The thickness of the Ironstone beds wrought at the 
 Eston mines, is about 17 feet ; at Staithes six feet ; at 
 Kettleness, at present, it is not worth working. 
 
 The Ironstone beds wrought at the Grosmont mines 
 are lower in the series. From the top of the Middle 
 Lias to the Pecten bed it is 30 feet ; from thence to the 
 Aviciila cygnipes bed it is 32 feet more. On the 
 Hawsker shore the Avicula band is only nine inches in 
 thickness, and instead of 62 feet, it is only 30 feet from 
 the top, and at about the same distance to the north of 
 Whitby, where it is exposed on the beach a little to the 
 north of Old Nab, near Staithes. The Pecten band is 
 probably d or e of the following section. 
 
 The following is the Hawsker Bottoms section, com- 
 mencing at a point called Nornianby Stye Batts, O. Sur. 
 The same strata rise above the sea at a similar project- 
 ing point, called Old Nab, near Staithes. A few feet of 
 the same strata may be seen at the intervening Kettle- 
 ness point. 
 
 Div. Ft. In. 
 
 a. Ironstone nodular band, 4 in.; dark blue shale, 
 2 ft. ; ironstone band, 3 in. ; indurated grey 
 band, 1 ft. 3 in. ; sandy and micaceous shale, 
 
 5 ft. 6 in. 91 
 
 Belemnites insequalis, cylindricus; Ammo- 
 nites spinatus, laboratus, subnodosus, Birdi j 
 Turbo cyclostoma ; Cerithium liassicum, acri- 
 culum ; Pecten sublsevis ; Modiola scalprum ; 
 Corbula cardiodes ; Myacites costata ; Terebra- 
 tula tetrahedra. 
 
XVI. 
 
 Div. Ft. In. 
 
 6. Ironstone nodular band, 10 in. ; sandy and 
 micaceous shale, with ironstone nodules, 
 
 5 ft. 6 in. 61 
 
 c. Ironstone nodular band, 6 in. ; blue shale, 1 ft. 1 6 
 
 Pecten sublsevis, major, much Dicotyledo- 
 nous wood. This and the next are probably 
 the Pecten seam of the Grosmont mines. 
 d. Ironstone nodular band, 6 in. ; blue shale, 2 ft. 2 6 
 
 Myacites intermedia. 
 e. Ironstone nodular band, -1 in.; blue shale, 
 
 2 ft. 6 in. - -. 2 10 
 
 Belemnites excavatus; Ammonites Haws- 
 kerensis; Pecten planus ; Mytilus ensis. 
 /. Ironstone nodular band, 6 in. j blue shale, 2 ft. 2 6 
 
 Among these thin bands we find various 
 interesting fossils. Ammonites lenticular is, 
 reticularis, vittatus, margaritatus ; Leda lon- 
 gicaudata, complanata. 
 
 g. Ironstone nodular band, 3 in. ; blue shale, 2 ft. 2 3 
 h. Ironstone nodular band, 6 in. ; blue shale, 2 ft., 
 
 with patches of fossils - - - - - 2 6 
 i. Ironstone nodular band, 3 in. ; blue shale, 
 
 2 ft. 9 in. 30 
 
 fc. Ironstone nodular band, 9 in. A thin rotten 
 seam of fossils, Pecten cygnipes, &c. The 
 Avicula band of miners; seen also on the 
 beach a little to the north of Old Nab near 
 Staithes. Blue shale, 1 ft. 6 in. - - - 2 3 
 I. Ironstone nodular band, 3 in. ; blue shale, 
 
 1 ft. 6 in. Ammonites margaritatus - - 1 9 
 m. Ironstone nodular band, 6 in. ; blue shale, 15 ft'. 15 6 
 n. Ironstone band, 10 in. A thin, interrupted, 
 fossiliferous band, Cardium truncatum. Blue 
 
 shale, 10 ft. 10 10 
 
 o. Ferruginous band, 2 in., at the base of Clock- 
 case Nab ; blue shale, 5 ft. - - - - 5 2 
 
 Belemnites cuspidatus; Ammonites cornu- 
 copia, a large size. 
 
/>' Ft. In. 
 
 p. Sandy, micaceous, indurated shale; Cardium 
 truncatum abundant ; a thin ferruginous band 
 of comminuted fossils ; Belemnites laevigatus, 
 retusus, atheticus; Pecten; micaceous sandy 
 shale, with ironstone nodules interspersed, 
 worn into, hillocks by the sea scouring the 
 joints, 5 ft. - - - - - -50 
 
 Mytilus scalprum ; Corbula cardiodes ; Mya- 
 cites levis ; Pholadomya gallina. 
 
 q. Ironstone nodular band, 8 in. ; Dentalium band, 
 1 ft. 6 in., hard, micaceous, upper part full 
 of Dentalium giganteum; beneath, small 
 oysters ; Pecten planus ; Cardium truncatum ; 
 Terebratula tetrahedra ; sandy shale, 3 ft . 10 in. 6 
 
 79 3 
 
 The strata of this series are very regular 
 throughout the district, and may be taken at 
 80 feet, or a little more, in thickness. Staithes 
 85 feet. Hob Hill 80 feet. 
 
 Sandy and Micaceous Beds. Syn. Staithes Beds, Y. A B. 
 
 Marlstone, Phil. 
 
 r. Massive sandstone, 6 ft., containing layers of 
 oysters, forming a precipice on the beach. 
 Coarse shale, 5 ft. It forms the base of Penny 
 Nab, Staithes - - 11 
 
 Belemnites planulatus ; Ostrea tuuiidulosus ; 
 Ophiura Milleri. 
 
 s. Ironstone seam, 1 in. Oysters in thin layers, 
 and sandy shale with Cardium truncatum 
 abundant. Three indurations - - - 5 
 t. Sandstone, 3 ft. ; sandy and micaceous shale, 
 
 10ft. - - 13 
 
 Ammonites Clevelandicus, Bechii,bispicatus, 
 nitescens. 
 
 u. Ironstone nodules, 6 in. ; oyster band, 6 in.; 
 sandy shale, 1 ft. ; oyster band, 1 in. ; sandy 
 sandy shale, 1 ft. ' - - -'31 
 
 b 
 
XV111. 
 
 Div. Ft. In. 
 
 v. Oyster band, 4 in. ; coarse, light-coloured shale, 
 
 4 ft. 2 in. 46 
 
 w. Ironstone band, 4 in. ; sandy and micaceous 
 
 shale, 11 ft. - - - - - - - 11 4 
 
 x. Ironstone nodules, 3 in., very f ossilif erous ; 
 
 shaly sandstone, 4 ft., worn into channels on 
 
 the beach by the sea scouring the joints - 4 3 
 Ammonites capricornus, Henleyi; Turbo 
 
 undulatus, large ; Pecten ; Avicula Rosebury- 
 
 ensis; Mytilus hippocampus; Cardium trun- 
 
 catum. 
 y. Ironstone band, 3 in. ; indurated band of large 
 
 oysters, 3 in.; sandy shale, 6 ft., worn into 
 
 irregularities on the beach by the sea - - 6 6 
 North point of Robin Hood's Bay, and base 
 
 of Colburn Nab, Staithes. 
 
 Thickness of the Arenaceous beds on the 
 
 Hawsker shore - - - - - -58 8 
 
 Thickness of the Ironstone series - - - 79 3 
 
 Thickness of the Middle Lias south of Whitby 137 11 
 
 The average thickness of the Middle Lias in Yorkshire 
 may be taken at about 150 feet or 160 feet. 
 
 The Arenaceous beds vary much in thickness. Within 
 a very short space, the beds r, s, i, are reduced to about 
 14 feet at Castle Chamber, and then swell out towards 
 Bay Town, r forms the roof of the chamber, and u the 
 floor. They increase in thickness northwards and are 72 
 feet thick at Staithes. 
 
 LOWER LIAS. 
 
 Ironstone Series. 
 
 North Cheek of Eobin Hood's Bay. 
 
 A great lithological change here takes place. We lose 
 sight of the great Oyster and Sandy beds of the Arena- 
 ceous series, and are introduced to a repetition of the thin 
 dark-coloured muddy shales, and Ironstone bands of the 
 Middle Lias, which must have been deposited in a tran- 
 
XIX. 
 
 quil sea, allowing ferruginous precipitates or concretions . 
 The bed of large Oysters., seen at the north point of 
 Robin Hood's Bay and at the base of Colborn Nab, 
 Staithes, forms a good line of demarcation. 
 Die. Ft. In. 
 
 a. Lias limestone nodules, 3 in. ; blue shale, 6 ft. 6 3 
 b. Lias limestone nodules, 3 in., containing Am- 
 monites maculatus ; blue shale, 6 ft. - - 6 3 
 c. Indurated ferruginous band, 2 in.; ironstone 
 
 nodules, 3 in. ; blue shale, 2 ft. 6 in. - - 2 11 
 
 Ammonites maculatus ; Gryphaea depressa. It 
 also occurs at the base of Colborn Nab, Staithes. 
 d. Ironstone nodules, 6 in. ; blue shale 14 it. - 14 6 
 e. Ironstone nodules, 3 in. ; blue shale, 8 ft. - 8 3 
 f . Ironstone nodules, 6 in. ; blue shale, 4 ft. 6 in. 5 
 g. Ironstone nodules, 6 in. ; blue shale, 4 ft. 6 in. 5 
 h. Interrupted ironstone band, 4 in. ; blue shale, 
 
 4 ft. 8 in. 50 
 
 i. Ironstone nodular band, 4 in.; blue shale, 
 
 3 ft. 8 in. 40 
 
 This and the next division are well charac- 
 terized by a thin line of comminuted fossils 
 which appears to be very constant, and may 
 be seen on the beach where the strata rise at 
 Skinningrove. 
 
 These and the following down to t, are the 
 chief repositories of fusiform and other inter- 
 esting Belemnites. B. dens, elegans. 
 k. Ironstone nodular band, 2 in. ; blue shale, 4 ft. 4 2 
 1. Ironstone nodular band, 3 in.; blue shale, 
 
 11 ft. 6 in. - 11 9 
 
 m. Ironstone nodular band, 2 in. ; blue shale, 3 ft. 3 2 
 n. Ironstone nodular band, 3 in. ; blue shale, 10 ft. 10 3 
 o. Ironstone nodular band, 2 in. j blue shale, 6 ft. 6 2 
 p. Ironstone nodular band, 2 in. ; blue shale, 3 ft. 3 2 
 q. Ironstone nodular band, 2 in. ; blue shale, 3 ft. 3 2 
 r. Ironstone nodular band, 4 in. ; blue shale, 8 ft. 8 4 
 s. Ironstone nodular band, 8 in* ; blue shale, 16 ft. 16 8 
 Belemnites microstylus ; Pecten defossus. 
 
Div. Ft. In. 
 
 t. Ironstone nodules, 4 in. ; blue shale, 3 ft. - 3 4 
 
 Ammonites Loscombei, armatus, brevispina, 
 and other armed varieties occur in these 
 divisions. 
 
 u. Ironstone nodules, 3 in. ; blue shale, 4 ft. - 4 3 
 v. Ironstone nodules, 6 in. ; blue shale, 4 ft. 2 in. 4 8 
 w. Indurated fossiliferous band, 4 in. ; blue shale, 
 
 4 ft. 6 in. 4 10 
 
 Pinna folium abundant ; Pholadornya trun- 
 cata. Base of Huntcliff. One of the most 
 persistent strata in the Lias, Scotland, &c. 
 x. Ironstone nodular band, 6 in. ; blue shale, 8 ft. 8 6 
 y. Pyritous band, 3 in. ; very thin and interrupted, 
 but full of interesting fossils. It rises above 
 the beach a little to the north of Bay Town, 
 and is high in the cliff at Peak. Blue shale, 
 about 25 ft. - - 25 3 
 
 Ammonites Taylori, Jamesoni, subtriangu- 
 laris, aculeatus, Huntoni, tubellus, rutilans, 
 trivialis abundant. Turbo Youngi, concinnus ; 
 Pecten punctatus, aheneus; Lima novem cos- 
 tata ; Perna gerosa ; Myacites punctata, concava ; 
 Terebratula hispidula, &c. 
 
 z. Ironstone nodules, 3 in. ; blue shale, 6 ft. - 6 3 
 Ammonites tardecrescens. 
 
 180 10 
 
 INDURATED BANDS. 
 
 Between Bay Town and Peak. 
 
 These bands sweep round the bay in grand curves, 
 dipping at an angle of about eight degrees to the north, 
 then to the west, and on the south side of the bay, to 
 the south. The beds near Bay Town contain many 
 interesting small lenticular Ammonites, and have been 
 distinguished by Tate and Blake as the Ammonites 
 oxynotus group ; but I have never heard of this southern 
 Ammonite being discovered in our strata, 
 
XXI. 
 
 Dir. 
 
 Ft. 
 
 In. 
 
 1. Indurated band, 12 in.; blue shale, 4 ft. 
 
 5 
 
 
 
 Ammonites tubellus, Huntoni, trivialis. 
 
 
 
 2. Indurated band, 1 ft. 6 in. ; blue shale, 8 ft. 6 in. 
 
 10 
 
 
 
 Ammonites gagateus, raricostatus. 
 
 
 
 3. Indurated band, 4 in. 
 
 blue shale, 6 ft.^ 
 
 6 
 
 4 
 
 4. Indurated band, 4 in. 
 
 blue shale, 4 ft. 
 
 4 
 
 4 
 
 5. Indurated band, 2 in. 
 
 blue shale, 2 ft. 
 
 2 
 
 2 
 
 6. Indurated band, 6 in. 
 
 blue shale, 3 ft. 
 
 3 
 
 G 
 
 Ammonites Eobinsoi 
 
 li, Dennyi. 
 
 
 
 7. Indurated band, 5 in. 
 
 blue shale, 3 ft. 
 
 3 
 
 5 
 
 8. Indurated band, 3 in. 
 
 blue shale, 1 ft. 6 in. 
 
 1 
 
 9 
 
 9. Indurated band, 3 in. 
 
 blue shale, 10 in. 
 
 1 
 
 1 
 
 10. -Indurated band, 2 in. 
 
 blue shale, 1 ft. 5 in. 
 
 1 
 
 7 
 
 11. Indurated band, 3 in. 
 
 blue shale, 2 ft. 2 in. 
 
 2 
 
 5 
 
 12. Indurated band, 1 ft. ; 
 
 blue shale, 1 ft. 3 in. 
 
 2 
 
 3 
 
 13. Indurated band, 3 in. 
 
 blue shale, 3 ft. 
 
 3 
 
 3 
 
 The following fossils occur in this locality, 
 which is too often covered with sand : Belem- 
 nites acutus; Ammonites Dennyi, aureus, 
 gagateus, raricostatus,- integricostatus, arcig- 
 erens, lens, E-obinsoni, flavus ; Gryphsea, Mac- 
 cullochi. 
 
 14. A double indurated band, 1 ft. 3 in. ; blue 
 
 shale, 1 ft. 6 in. * - - 2 9 
 
 This is a very good line of demarcation, 
 which comes close up to the base of the cliff 
 at Mill Beck, full of ramose bodies resembling 
 marine plants, which appear to send their 
 roots down into the shale beneath. This band 
 is about 35 feet high in the cliff, at about half 
 way between Stow Beck and Peak Road, where 
 the strata attain their greatest elevation; it 
 then descends to the beach at Peak Road, and 
 continues to sink until it arrives at the great 
 dislocation. 
 
 Belemnites acutus ; Ammonites Buckii, 
 Simpsoni. 
 
xxn. 
 
 Die. Ft. In. 
 
 15. Indurated band, 4 in. ; blue shale 15 ft. - 15 4 
 
 16. Partially indurated band, 2 in. ; blue shale, 1 ft. 1 2 
 
 Ammonites obtusus, saggitarius, stellaris, 
 
 planicostatus ; Cardinia; Hippopodium pon- 
 
 derosum. 
 
 17. Partially indurated band, 2 in. j blue shale, 1 ft. 1 2 
 18. Partially indurated band, 2 in.; blue shale, 
 
 2 ft. 6 in. - 2 8 
 
 19. Partially indurated band, 2 in. ; blue shale, 4 ft. 4 2 
 20. Partially indurated band, 2 in. ; blue shale, 3 ft. 3 2 
 
 Base of the cliff covered with debris. 
 21. Partially indurated band, 2 in.; blue shale, 
 
 10 ft. or more - - 10 2 
 
 These partially indurated and interrupted 
 
 bands do not form very satisfactory divisions ; 
 
 so that at Stow Beck and Peak they can 
 
 scarcely be distinguished, and flattish scars 
 
 are formed on the beach; and the thickness 
 
 of the intervening shales cannot be very 
 
 accurately estimated. 
 22. Indurated band, 6 in., very hard ; blue shale, 
 
 6ft. - 6 6 
 
 23. Indurated band, 2 ft., in places separated into 
 
 two 12 in. bands; blue shale, 3 ft. - - 5 
 
 Belemnites acutus; Ammonites stellaris, 
 
 planicostatus ; Gryphsea incurva very abundant. 
 24. Two indurated bands, with a parting of shale, 
 
 6 in. ; blue shale, 1 ft. - - 1 G 
 
 Belemnites acutus ; Ammonites semicostatus, 
 
 acuticarinatus, Conybeari, Turneri, nodulosus, 
 
 geometricus, angulatus, erugatus, Belcheri, 
 
 Johnstoni. 
 
 25, Indurated band, 2 in. ; blue shale, 1 ft. - 1 2 
 
 26. Indurated band, 2 in. ; blue shale, 10 ft. - 10 2 
 
 Upper part very fossiliferous. 
 27. Indurated band, 12 in. Lumpy dark shale, 
 
 reaching out 20 or 30 yards, broken up into 
 
 deep holes, difficult to be traversed, and covered 
 
XX111. 
 
 Ft. In. 
 
 with Laminaria. No appearance of any more 
 
 bands. Considering the dip, eight degrees ? 
 
 the thickness must be considerable - - 10 ? 
 
 Examined August 21st, 1868, during a very 
 
 low ebb tide and a smooth sea. 
 
 Aggregate of Indurated bands and Shale - - 121 10 
 Aggregate of Ironstone series - 180 10 
 
 Lower Lias exposed at Robin Hood's Bay - 302 8 
 
 According to this section there are about 660 feet of 
 Lias exposed on the coast to the south of Whitby, and 
 according to Tate and Blake's section of the Eedcar 
 rocks, there are about 20 feet more of Lower Lias 
 exposed in that locality, which are characterized by 
 Ammonites Bucklandi, bisulcatus, angulatus, planorbis ; 
 Ostrea liassica ; Cardinia Listeri ; Myacites crowcombei. 
 
 Below these, they give sections from various localities 
 and borings of Lower Lias strata about 30 feet still 
 lower down, which consist of alternate beds of clay and 
 limestone, known as the Pleuromya Limestone, charac- 
 terized by compressed Ammonites planorbis, and Myacites 
 crowcombei. This they consider the base of the Lias 
 formation. Thus we have on an average : Upper Lias, 
 220 feet; Middle Lias, 160; and Lower Lias, 360 feet; 
 making the thickness of the Lias in Yorkshire about 740 
 feet, and which may in some localities amount to 800 feet. 
 Tate and Blake give 1281 feet as the whole thickness, 
 which seems excessive. 
 
 Below the Lias there are the Rhsetick beds, 15 feet in 
 thickness ; succeeded by the Keupers of the New Red 
 Sandstone series. This, with its associate Gypsum, may 
 be seen near Wilton, at no great distance from Eston 
 Nab ; where the Lias rises 630 feet above the sea. It may 
 also be seen in the bed of the Leven, at the base of the 
 lofty hills south of Stokesley. 
 
 The whole thickness of the strata of East Yorkshire 
 above the New Red Sandstone, may be taken at about 
 2,500 feet ; having a general rise towards the north-west 
 of about 40 feet per mile. 
 
NOTES AND EXPLANATIONS. 
 
 Sow. Sowerby's ff Mineral Conchology." Plates and 
 
 Descriptions. 
 Y. fy B. Young and Bird's "Geological Survey of the 
 
 Yorkshire Coast." Plates and Descriptions. 
 
 1822-1828. 
 Ph. Phillips 's "Illustrations of the Geology of York- 
 
 shire/' Plates. 1835. 
 Simp. The Author's Monograph. Descriptions, 1843. 
 
 " Fossils of the Yorkshire Lias/' 1855. 
 
 " Guide and Section of the Yorkshire Lias/' 1868. 
 T. # B. Tate and Blake. "The Yorkshire Lias." Plates 
 
 and Descriptions. 1876. 
 Pal. Palaeontographical Society's Publications, Plates 
 
 and Descriptions. 
 E.H.B. Robin Hood's Bay. 
 
 TVTT Tvn^rMo (rioo The numerals and small letters 
 iyj_.j_j. 
 
 iyj_.j_j. jjj.ivj.u.ifc; r -LJitio. _ . . . , , 3 ty* IT j 
 
 T T _ Lower ; distinguish the different beds. 
 
 Some errors in the names are corrected in the Index, and 
 marked with an asterisk *. 
 
 The greatest part of the Fossils described are in the 
 Whitby Museum,, the rest are in the Museum of 
 Economic Geology, in London. 
 
THE FOSSILS 
 
 OF THE 
 
 YORKSHIRE LIAS. 
 
 IN considering the Fossils of the Yorkshire Lias, 
 it would be very erroneous to suppose them to be 
 scattered indiscriminately through the whole for- 
 mation ; for few species range through any great 
 thickness of strata. On the contrary, most of the 
 species are confined to particular beds, and are 
 scarcely to be found in those above or below them. 
 
 The word fossil originally signified any substance 
 dug out of the earth ; but in recent times, and 
 especially in scientifick literature, it is restricted to 
 substances which have been in a living state, and, 
 having become buried in the earth, have undergone 
 a mineralizing process, by which they have been 
 greatly changed. Whilst this process of mineral- 
 ization was going on, their general form, anatomical 
 structure, and even their finest characteristick 
 marks, are often wonderfully preserved, 
 
 Fossils are never so perfect as recent species ; 
 and their investigation is attended with greater 
 B 
 
2 
 
 difficulty; but they possess a higher interest, on 
 account of their vast antiquitj^, and the wonderful 
 changes which they prove to have taken place on the 
 earth's surface during countless ages. 
 
 The discovery of the remains of animals and 
 plants buried deep in the earth, possessing all the 
 essential characters of living 1 beings, has given a 
 great impulse to the study of natural history in 
 our times; and it is chiefly on the evidence disclosed 
 by fossil remains, that there has been constructed 
 the new, popular, and sublime science of Geology. 
 
 For the classification of the vast variety of or- 
 ganized beings which have inhabited the earth in 
 every period of its history, many systems have been 
 invented, which possess more or less merit ; but in 
 drawing up a Descriptive Catalogue of the Fossils of 
 the Yorkshire Lias, which are almost entirely the 
 remains of animals, I have no hesitation in adopting 
 the views of the late Baron Cuvier, which appear to 
 me to be by far the most comprehensive, the simplest, 
 and the most instructive of any which have been 
 promulgated on the classification of animals. Whilst 
 Cuvier's system, founded upon the strictest and 
 most perfect anatomical investigations, embraces 
 and unites both the systems of Aristotle and Lin- 
 naeus, his principles of nomenclature seem to me 
 the best calculated to rescue natural history from 
 that confusion into which it has unhappily fallen. 
 By adopting the comprehensive generick groups of 
 
Linnaeus as Genera, under which Species are to be 
 united and named, thousands of names which now 
 becloud and perplex natural history, might be ren- 
 dered either very subordinate, or entirely swept 
 away. And by adopting such Genera as those of 
 Lamarck as Sub-genera or divisions of Genera, the 
 Species can be more easily described and understood. 
 Also, by this method, naturalists having different 
 views of nomenclature might still understand each 
 other. For whilst the followers of Cuvier and Lin- 
 naeus would adopt the names of the more com- 
 prehensive groups as the names of their Genera, 
 others might prefer the names of the smaller 
 groups for their generick names, as those of 
 Lamarck ; yet both parties would understand each 
 other; the Sub-genus being merely a division of the 
 Genus. If, however, naturalists will go on, as they 
 do, multiplying generick names of but little impor- 
 tance in the great system of nature, and often 
 worse than synonymous, the prediction of Cuvier 
 will be verified, u That the advantages of the 
 binominal nomenclature, so happily imagined by 
 Linnaeus, will be lost," and men of general learning 
 will in a great measure be excluded from pursuing 
 the details of Natural History, the number of 
 Genera being already far beyond any ordinary 
 man's comprehension. 
 
 Cuvier, following the views of the great ancient 
 naturalist, Aristotle, considered all animals to be 
 
formed upon four distinct types, and therefore 
 capable of being classed in four divisions, which he 
 named Vertebrata, Mollmca, Articulata, and Radiata. 
 The Vertebrate animals are such as have a back- 
 bone, and framework of a skeleton, by which the 
 softer parts are supported. The Mollusca are the 
 soft animals, which have no such framework. The 
 common snail is a familiar example of such an 
 animal. Some of them are naked, others form shells 
 for their protection and habitation. Such are the 
 oyster, the mussel, and all other shell-fish. The 
 Articulated animals are formed in a manner different 
 from either of the foregoing divisions. The softer 
 parts of many are protected by an outer crust, which 
 is composed of various parts fitted and joined 
 together. Such are all crabs and lobsters, which 
 have a sort of external skeleton. Others are formed 
 of numerous rings, united together; of these the 
 common earthworm affords a familiar example. 
 Besides all these, there is a vast number of animals 
 which cannot be properly arranged under any 
 of the foregoing divisions. As many of these are 
 in the form of a star, spreading out arms in different 
 directions, like rays, they have been united under 
 the division Kadiata. Such, for example, is the 
 star-fish. This division also comprehends an in- 
 numerable multitude of creatures, many of which 
 can scarcely be discerned with the naked eye, and 
 others, though larger, differ but little from vegetables. 
 
VERTEBRATA. 
 
 The vertebrate animals are arranged in three 
 classes: the Mammalia, or such as suckle their 
 young; Birds, Reptiles, and Fishes. The remains of 
 vertebrate animals, hitherto discovered in the York- 
 shire Lias, are entirely those of Reptiles and Fishes. 
 
 EEPTILES.. 
 
 Reptiles differ from the Mammalia in being all 
 cold-blooded, and from Fishes in that they breathe 
 the atmospherick air. The remains of seventeen 
 species of Saurian Reptiles have been recorded as 
 existing in the Yorkshire Lias, chiefly in the upper 
 beds. Of these, only a few have been obtained in 
 anything like a perfect state of preservation. They 
 vary in length up to 30 feet, equal to the crocodiles 
 of the present day. 
 
 No remains of a decided land animal have been 
 discovered in the Yorkshire Lias; but the remains 
 of a species of crocodile, an animal generally am- 
 phibious, and breathing the atmospherick air, along 
 with other lizard-like animals, are by no means 
 uncommon. Of the crocodile, or Teleosaurus, remains 
 of two or three species have been discovered in 
 our Lias, but the skeleton of only one has been ob- 
 tained in anything like a state of good preservation. 
 
 TELEOSAURUS. 
 
 Their distinctive characters are legs for walking, 
 ending in separated claws. 
 
1. TELEOSAURUS CHAPMANNI, Konig 
 
 Head with an excessively long, slender beak, 
 gradually tapering to a narrow snout, where 
 there is a sudden depression. 
 
 The largest, and upon the whole, the most perfect 
 specimen which has yet been obtained is now in the 
 Whitby Museum, and was discovered in the Alum Shale 
 of the Upper Lias at Saltwick, in 1824. A considerable 
 portion of the beak* had been broken off previous to the 
 discovery ; but the length of the remaining parts still 
 measures 15 feet 6 inches ; so that we may suppose the 
 whole length of the animal, when alive, to have been 
 about 17 feet or 18 feet. The hind legs are very perfect, 
 some of the claws still remaining. It is also covered in 
 some places, both on the back and belly, with scales, 
 similar to those of recent species, so there can be no doubt 
 of its analogy with recent crocodiles ; especially with one 
 which inhabits the Ganges, L. Gangetica, Linn. As this 
 animal was fully and accurately described by the Rev. 
 Dr. Young at the time of its discovery, and more recently 
 by Professor Owen, along with other Saurian remains, in 
 his valuable work on British Fossil Eeptiles, my remarks 
 on this, and the other species of this order, will be very 
 brief. The first specimen, of which we have any account, 
 was discovered January, 1758, by Messrs. Chapman and 
 Wooller, at the mouth of Whitby harbour. It was 12 feet 
 long, and is described and figured in the Philosophical 
 Transactions, and also in the Gentleman's Magazine of 
 that period. Judging by the rude figures and the descrip- 
 tions there given, there can be no doubt that it was the 
 same species as that in the Museum, or one closely allied 
 to it; but not a bone of it can be found. Another 
 specimen, 15 feet long, was discovered seven or eight 
 miles to the north of Whitby, in 1791. Another very 
 perfect animal, but much smaller, was discovered near 
 Whitby a few years ago, and is now in the British 
 Museum. Many other remains, especially heads, have in 
 
late years been discovered, showing that crocodiles were 
 by no means solitary in these regions, at some very 
 remote period. Besides this there is another species. 
 
 2. T. BREVIOR, Owen. 
 
 Several heads of this species have been discovered at 
 various times, but were confounded with the last, from 
 which it materially differs. The head is shorter in pro- 
 portion, and instead of a depression at the end of the 
 snout, there is an enlarged protuberance of an obovate 
 form, whilst it also possesses more powerful teeth. The 
 largest head I have seen is three feet long and fourteen 
 inches wide across the skull, tapering to a little more 
 than two inches near the muzzle. It was dug out of the 
 alum pit at Kettleness, and is now in the British Museum. 
 
 Many Crocodilian remains have been discovered from 
 time to time, but nothing which has thrown much light 
 on the subject. 
 
 A phalangeal bone of the Streptospondylus, a closely 
 allied genus, is in the Whitby Museum, and it may be 
 expected that other remains of that animal may be dis- 
 covered ; but the closing of the alum works is very much 
 against the discovery of Saurian remains. 
 
 All the fossil remains, both of animals and vege- 
 tables, can be arranged under the same general 
 heads as those of living species, indicating that 
 there were the same laws and operations of nature 
 in the most remote ages of our planet, as at the 
 present day; but in their more subordinate parts 
 and combinations they often differ from any crea- 
 ture now in existence. Of all the strange forms 
 of animal nature brought to light by geological 
 research, our greatest naturalist, the Baron Cuvier, 
 considered the 
 
8 
 
 PLESIOSAURUS 
 
 * c to have been the most singular, and in its 
 characters, the most anomolous which had been 
 discovered amid the ruins of a former world. To 
 the head of a lizard it united the teeth of a croco- 
 dile, a neck of enormous length, resembling the 
 body of a serpent, a trunk and tail having the pro- 
 portions of an ordinary quadruped, the ribs of a 
 chameleon, and the paddles of a whale." 
 
 The Plesiosaurus is readily distinguished from the 
 rest of the Saurians by the excessive length of the 
 neck ; and, upon a more particular examination, we 
 find the vertebrae more like those of a land animal 
 than those of a fish, being more closely fitted to 
 each other with flat, or nearly flat, surfaces. By 
 this structure of the back-bone, the body had 
 greater strength, but less flexibility. Judging from 
 the shortness of the tail, we may presume that the 
 animal did not possess great power for rapid motion 
 through the water. This defect was, however, 
 in some measure, compensated by its large and 
 powerful paddles, which, unlike those of the whale, 
 were four in number. The paddles of all these Sau- 
 rians are modifications of the arms and legs of 
 other creatures, ending in five fingers and toes, and 
 thus form an intermediate link between the mam- 
 malia and fishes. 
 
 The remains of eight or ten different species of 
 Plesiosaurus have been extracted from the Lias in 
 
the neighbourhood of Whitby. The localities which 
 have proved the most prolifick in such remains are 
 Saltwick and Kettleness, where animals of this 
 kind seem to have congregated, and probably, like 
 the recent crocodile, basked on the mud banks, now 
 hardened into shaly Lias. We notice 
 
 1. PLESIOSATJRUS HOMOLOSPONDYLUS, Owen. 
 
 It is so named on account of the flat or close-fitting 
 ends of the vertebrae ; but the complete skeleton is dis- 
 tinguished by its small head and long neck. It has been 
 well illustrated from specimens in the British and York 
 Museums. There are 15 caudal vertebrae in the Whitby 
 Museum, which were rescued from the rubbish of the 
 alum pit at Saltwick. 
 
 2. P. GRANDIPENNIS, Owen. 
 
 This has also a small head, with very large paddles ; 
 and is now in the Cambridge Museum. A figure of this 
 species, drawn at the time of its discovery (1840), was 
 published in Reed's Guide to Whitby, and afterwards in 
 Simpson's Lias Fossils. It has since been named P. 
 niacropterus, apparently without any good reason ; and 
 Mr. Blake also proposes to call it P. dubius. 
 
 3. P. CJELOSPONDYLUS, Owen. 
 
 The only remains of this species I am acquainted with 
 are 16 vertebrae in the Whitby Museum, from the rubbish 
 of the alum pit at Saltwick. The distinctive character 
 of these vertebrae is, that their uniting surfaces are more 
 concave than is usual in this genus. 
 
 4. P. CRAMPTONI, Carte fy Bailey. 
 
 This is a noble fossil, 22 feet 5 inches in length, with a 
 powerful head, 3 feet 4 inches long. It has the 
 peculiarity of having only four fingers in each paddle. 
 It was extracted from Lord Normanby's alum pit, at 
 
10 
 
 Kettleness, and presented by him to Sir Philip Crampton, 
 and is now in the Dublin Museum. It is very like the 
 next. 
 
 5. P. PROPINQUUS, Blake. 
 
 The length of this animal is 15 feet, and the head is 
 rather less in proportion than the last, being not quite 
 one-sixth of -the whole length, and is about half the 
 length of the neck. Only one of the paddles is perfect ; 
 and it has the full complement of five fingers. It was 
 named by Mr. Charlesworth P. macrocephalus, from which 
 however it differs in several particulars. It has also been 
 named by Professor Owen P. brachyspondylus. It was 
 extracted from the Kettleness alum pit, and purchased 
 for the Whitby Museum, where it is still preserved. 
 
 6. P. ZETLANDI, Phillips. 
 
 This has been described as having a "head the most 
 bulky, and the neck probably the shortest of all known 
 species/' The length of the animal is about 19 feet ; the 
 head 3 feet 6 inches, and the neck 4 feet 4 inches in 
 length, and it possesses very large teeth. It is in the 
 York Museum. 
 
 7. P. ROSTRATUS, Owen. P. LONGiROSTRis, BlaJce. 
 
 The length is 15 feet 10 inches. The head, which is 
 imperfect, measures 2 feet in length ; and the greatest 
 breadth 8 inches, tapering to the snout, which is only 
 If inches broad. The paddles are large. 
 
 8. P. BRACHYCEPHALUS, Owen. 
 
 The short headed, of which little is known. Some 
 vertebrae are in the York Museum. 
 
 9. P. RUGOSUS, Owen. 
 
 Some vertebras from Whitby have received that name, 
 from their rugosity. 
 
 Professor Blake notices other remains in the ironstone 
 mines at Eston. T. & B., p. 253. 
 
11 
 
 ICHTHYOSAURUS. 
 
 The Ichthyosaurus differs very materially from 
 the Plesiosaurus, and, in the structure of its body, 
 comes nearer to the class of Pishes. The neck -is 
 short, and the tail long. The uniting surfaces of 
 the vertebrae are deeply cupped, like those of Fishes, 
 giving to the body great flexibility. Like the Plesi- 
 osaurus, it had four paddles ; whilst the head, in its 
 general outline, resembled that of the Dolphin. Its 
 great peculiarity is the enormous magnitude of the 
 orbit of the eye, measuring, in one example, four- 
 teen inches across. The largest portion of the eye 
 was protected by bony plates, which encompassed 
 it all round, leaving an opening, or pupil, in the 
 centre for the admission of light, which could be 
 expanded or contracted at the pleasure of the 
 animal. Also, by means of these sclerotic plates, 
 the eye could be made more or less convex, so as 
 to become either telescopic or microscopic, and thus 
 enabled the animal to see objects at a great distance 
 or near at hand; a structure of the eye, and a 
 power of vision possessed by the Golden Eagle and 
 some other birds of prey. The skin was smooth 
 and destitute of scales. 
 
 The remains of five or six species of Ichthyosaurus 
 have been discovered in the Yorkshire Lias, but the 
 skeletons of only three species are in any manner 
 perfect. 
 
12 
 
 1. ICHTHYOSAURUS ACUTIROSTRIS, Owen. 
 
 Length of the head about four times its width across 
 the eye ; snout long, slender, sharp pointed, and curving 
 slightly downwards ; teeth moderately slender pointed, 
 slightly bent inwards. 
 
 This is by far the most common in our Lias. It may 
 be known by the sharpness of the beak, and by the tri- 
 angular form of the transverse section of the humerus 
 and femur. 
 
 2. I. PLATYODON, 06. 
 
 Length four times that of the head; length of the 
 head about three times the breadth across the eye ; beak 
 deeply concave before the eye, then tapering to an obtuse 
 point, armed with numerous strong conical striated teeth 
 flattened at the point ; lower jaw very strong, convex 
 beneath ; the fore and hind paddles equal. Cervical 
 and lembar vertebrae 45, tail 75 ; in all, about 120. Owen, 
 Pal. pi. xxi., f. 1. 
 
 A specimen in the Whitby Museum, extracted by Mr. 
 Louis Hunton, from the Lofthouse alum, excavations, is 
 16 feet 8 inches in length. The cervical and lembar 
 vertebrae are so displaced and concealed under the ribS as 
 not to be counted. Length of head, 4 feet ; breadth 
 across the eye, 14 inches ; length of body, 4 feet ; of tail, 
 8 feet 8 inches, with 86 vertebrae ; diameter of the largest 
 2f inches, and If inches in thickness; length of hind 
 paddle, 20 inches, width 6 inches ; length of femur, 6 
 inches, width, 5 inches ; fore paddle, similar but imper- 
 fect. 
 
 3. I. CRASSIMANUS, Owen. 
 
 This noble fossil was extracted from the alum pit at 
 Kettleness, and is now in the York Museum. It is nearly 
 30 feet long, and some of the vertebrae are 8 inches in 
 diameter. It differs from P. platyodon in having the 
 fore paddles larger than the hind paddles. Another, now 
 in the Whitby Museum, is 25 feet long, and was extracted 
 from the bed above the Jet Eock, at Hawsker. 
 
13 
 
 4. I. TENUIROSTRIS, Cb. 
 
 Some remains of this species are in the British Museum. 
 
 5. I. INTERMEDIUS, Cb. 
 
 Some imperfect remains have been noticed. 
 
 6. I. LONGIROSTRIS or LATIFRONS, Blake. 
 
 Some remains in the British Museum from Whitby. 
 They have long, narrow snouts. 
 
 Most of the saurian remains are from the Upper Lias. 
 Some also occur in the main ironstone beds of the Middle 
 Lias, and some in the Lower Lias, but very rare. 
 
 FISHES. 
 
 The fishes in our Lias are highly interesting, but 
 they are comparatively rare and very imperfect. 
 For a scientifick arrangement of fossil fishes we are 
 principally indebted to Agassiz, the celebrated Swiss 
 naturalist. His arrangement is founded on the 
 scales, or external covering, and is well adapted for 
 the investigation of fossils, because these parts are 
 the best preserved. They may be arranged in two 
 Orders : The Placoideans and the Ganoideans. 
 
 OEDEE PLACOIDEI. 
 
 The Placoideans are those which have hard 
 enamelled plates on their skin, often of considerable 
 dimensions ; whilst they are sometimes reduced to 
 small points, such as we find on the skins of many 
 Sharks, and the prickly, tooth-like tubercles on the 
 skin of Rays. 
 
 Messrs. Tate and Blake, in their very exhaustive 
 work on the Yorkshire Lias, record the small 
 
14 
 
 remains of only five species, which belong to three 
 Genera : A crodus, Hybodus, and Notidamus. 
 
 1. Acrodus nobilis, Ag. 
 
 " Several fine teeth in juxtaposition/' L.L., E.edcar. 
 
 2. A minimus., Ag. L.L. and Rhaetic. 
 
 1. Hybodus reticulatus, Ag. L.L.,, E/edcar. 
 
 2. H. minor, Ag. L.L., Redcar. 
 
 1. Notidamus amalthei, Op. M.L., Hawsker. 
 Tooth in the Whitby Museum. 
 
 OKDEK GANOIDEI. 
 
 The Ganoideans are distinguished by their bright 
 shining scales, which are of an angular form, and 
 composed of horny or bony plates, covered with a 
 thick plate of enamel. Eighteen species of this 
 Order have been discovered in the Yorkshire Lias. 
 They have been arranged in two Groups or Families : 
 Lepidoides and Sauroides. 
 
 FAMILY LEPIDOIDES. 
 
 These are well distinguished by their large, im- 
 bricated, rhomboidal scales, very thick, and coated 
 with beautiful enamel. Tail either regularly forked 
 or rounded. The most common in our Lias is: 
 
 1. LEPIDOTUS SEMISERRATUS, Ag. 
 
 Head short, thick, mouth broad ; teeth slender, inflated 
 near the points; body fusiform and lengthened; scales 
 half serrated. ILL., 7, Whitby. 
 
 2. L. PECTINATTTS, Egerton. 
 
 Of a small or moderate size, depth about one-third the 
 length; scales with delicate radiating striations which 
 serrate their posterior margins. U.L., 6, Whitby. 
 
15 
 
 3. L. RUGOSUS, Ag. 
 
 Head conical, tapering to a narrow mouth ; teeth 
 short, strong, sharp, conical; bones and scales rugose. 
 U.L., 7, Whitby Museum. 
 
 1. TETRAGONOLEPIS OVALIS, Ag. ^SCHMODUS, Eg. 
 1. SAURICTHYS APICALIS, Ag. Bhaetic. 
 1. DAPEDIUS MICANS, Ag. 
 
 Body ovate, tail forked, fins large. 
 
 There is in the Whitby Museum the impression of a 
 fish which corresponds with Agassiz's figure, and many 
 scattered scales which may belong to this species. U.L., 
 6, Whitby. 
 
 1. EUGNATHUS FASCICULATUS, Ag. 
 
 I. GYROLEPIS ALBERTI, Ag. E-hsetic. 
 
 FAMILY SAUKOIDES. 
 
 The Sauroid, or Lizard-like fishes, which were so 
 abundant in the earlier periods of our Earth's 
 existence, have become nearly extinct. Only two 
 genera remain, which inhabit fresh waters : the 
 Lepidosteus or bony Pike, of the large American 
 rivers, and the Polypterus in the Nile and Senegal. 
 The Sauroid fishes of our Lias are small compared 
 with those of an earlier period. 
 
 Teeth conical, pointed, alternating with little 
 teeth in a brush. Scales flat, rhomboidal, parallel 
 on the body, which is entirely covered by them. 
 
 1. PTYCHOLEPIS BOLLENSIS, Ag. 
 
 Length four times the depth ; tail forked ; one dorsal 
 fin, one abdominal, one caulal ; scales longer than deep, 
 longitudinally and irregularly striated or crinkled. 
 Not uncommon. U.L., 6, Whitby. 
 
16 
 
 1. PACHYCORMUS ACUTIROSTRIS, Ag. 
 
 " Snout pointed ; teeth fine, very sharp/' Ag. 
 
 2. P. CURTUS, Ag. 
 
 Length more than twice the depth, fusiform, head 
 conical, mouth small. Not uncommon. U.L., 6, Whitby. 
 
 3. P. GRACILIS, Ag. 
 
 " Near P. curtus, but more delicate ; tail with very fine 
 rays, and broadly forked." York Museum. ILL. 6, Whitby. 
 
 4. P. LATIROSTRIS, Ag. 
 
 "Very large, with short head and pointed snout." 
 U.L., 6, Whitby. 
 
 5. P. LATUS, Ag. 
 
 " Very large and oblong ; head short and small/" U.L. 6, 
 Whitby. 
 
 6. P. MACROPTERUS, Ag . 
 
 Head elongated, pectoral fin large. York Museum. 
 Blake. ILL., 6, Whitby. 
 
 1. ASPIDORHYNCHUS ANGLICUS, Ag. 
 
 Body very long, cylindrical ; tail regular ; upper jaw 
 prolonged into a long beak. ILL., 6, Whitby. 
 
 1. BELONOSTOMUS ACUTUS, Ag. 
 
 Many long, slender, sharp-toothed jaws frequently 
 occur in U.L. 6, which may belong to this species or to 
 the preceding. 
 
 1. LEPTOLEPIS SALTVICIENSIS, Simp. 
 
 This little fish occurs in considerable numbers in the 
 large lenticular nodules, a little above the Jet Eock, in 
 the Upper Lias. Contrary to what occurs in most of our 
 fishes, the external covering has perished, and the in- 
 ternal skeleton only has been preserved. Professor Blake 
 has given the following description : ff The pectoral, 
 ventral, and anal fins are about the same size, and are at 
 equal distances apart. The dorsal is rather large, and 
 is situated opposite the interval between the anal and 
 ventral. The vertebral column is ossified, and the tail 
 
17 
 
 homocercal. The head is small,, and the teeth are com- 
 paratively large, and lie apparently in clumps. Length 
 4 inches by f inch." U.L., 5a, Whitby. 
 
 In connection with these, we may notice the 
 occurrence of large spines belonging to the fins of 
 some fish of this family, of which there are at least 
 two species. 
 
 The most remarkable of our Lias fishes, on account 
 of its immense size, is the 
 GYROSTEUS MIRABILIS, Ag. 
 
 Large bones of this fish occur in the Upper Lias, 
 chiefly in the bed above the Jet Rock. They were con- 
 sidered by Agassiz to belong to some large Sauroid fish ; 
 but not a single tooth, or scale, or vertebra has been 
 discovered which could be referred to this animal ; and 
 the remains, more recently, have been judged, with 
 greater probability, to have been those of a fish closely 
 allied to the Sturgeon, which has no teeth, and feeds by 
 suction. U.L., 56. 
 
 MOLLUSCA. 
 
 The Molluscous animals have been divided into 
 six classes : Cephalopoda, Pteropoda, Gasteropoda, 
 Acephala, Brachiopoda, and Cirrhopoda. 
 
 CEPHALOPODA. 
 
 These are so named because they have the feet 
 placed round the head. With these they crawl at 
 the bottom of the sea, seize their prey and swim. 
 A familiar example of a Cephalopodous animal is 
 the Sepia or Cuttle-fish. They have been divided 
 into several genera ; the principal which occur in 
 C 
 
18 
 
 our strata are Sepia, Belemnite, Nautilus, and 
 Ammonite. 
 
 Those which are destitute of an external shell 
 form the genus Sepia, of Linnaeus, and to this 
 modern research has added the Belemnite. 
 
 SEPIA, Linn. 
 
 This animal has a kind of shell or bone, which is 
 often found in a fossil state ; and also a bag-, con- 
 taining a black fluid, or ink, which it emits in time 
 of danger. It is exceedingly interesting that ink- 
 bags, in a fossil state, are occasionally found in our 
 Lias, accompanied with a horny body, very much 
 resembling, in structure, that of the recent Loligo. 
 These bodies, and their accompanying ink-bags, we 
 can have no doubt, belonged to that division of the 
 Cephalopoda which have no external shell. The 
 recent Sepia are also provided with horny beaks, 
 like those of a Parrot, for crushing their prey ; but 
 none of these have been discovered in our Lias, 
 although they are not uncommon in the Lias at 
 Lyme Regis. Of this genus we have several species. 
 
 1. SEPIA OBTUSALIS, Simp. 
 
 Length of the bone about three times the width, 
 a little wider at one end than at the other ; apex 
 very obtuse; a keel between two furrows along the 
 middle ; colour brown ; often covered with a thin, 
 variously striated, black epidermis, which readily 
 comes off. 
 
19 
 
 They are found from two to seven inches long, and 
 appear to have been comparatively stout. One of these, 
 two inches long, has the ink-bag well preserved. Just 
 above the bone, is a brown substance, probably copro- 
 litick, and then the ink-bag, three inches long and one 
 inch wide at the round end, where it is suddenly contracted 
 into what looks like a neck a quarter of an inch wide. The 
 bag, however, has been compressed, and the ink has been 
 squeezed to one side. The bag has been thick, and 
 probably horny, and is of a light brown colour. The 
 whole is imbedded in compact Lias shale, and apparently 
 water-worn by exposure on the beach. The upper part 
 of the neck is gone, but a portion of the ink having been 
 removed from the extremity of the remainder, the con- 
 cave surface of a part of the interior of the bag may be 
 seen, and the edge may be traced along one side of the 
 ink, and around the base on the other side. Fragments 
 of the bag may also be seen at a little distance from the 
 main body of the ink, crushed together, and containing 
 a film of ink between them. It is from the hard shale 
 of the Upper Lias at Whitby, and is preserved in the 
 Whitby Museum. 
 
 The figure Mr. Blake has given of his Belemnoteuthis 
 Leckenbii is so like the bone of this species, that it surely 
 must be the same, T. & B. Yorks. Lias, pi. iv., f. 2. 
 
 2. S. CUSPIDATA, Simp. 
 
 Triangular, five inches long and two inches broad 
 at one end, tapering to a sharp point at the other ; 
 an elevated triangular ridge or mid-rib the whole 
 length ; epidermis striated logitudinally. 
 
 The body appears to have been thin and flat; and they 
 vary much in their proportional length to the width, 
 some being much elongated. ILL., 6, Whitby, 
 
 S. HATJSTRTJM, Simp. 
 
 Triangular, with an obtusely rounded apex ; 
 longitudinal, diverging striae, strong, unequal ; at a 
 
20 
 
 little distance from the middle, a strong groove on 
 either side ; many oblique striae. 
 
 It appears to have been very thin and fragile,, and is 
 seldom found perfect. The smaller end appears to have 
 been hollow like a scoop. Length of example described, 
 six inches, greatest width 2^ inches. ILL., 6, Whitby. 
 
 I suppose this is the species figured by Mr. Blake 
 under the name Geotenthis coreaceus. Quin. T. & B. 
 Yorks. Lias, pi. iv., f. 1. 
 
 S. INCOMPOSITA, Simp. 
 
 Mr. Blake considers this to be a neural arch of a ver- 
 tebra of the Gyrosteus mirabilis. Plate ii., f. 3. I may 
 merely repeat what I said before on the subject ; Lias 
 Fossils, page 21 : 
 
 " Under this name I may notice a fossil, respecting the 
 true nature of which I perhaps have no definite idea. It 
 is about nine inches in length, and of a triangular form ; 
 apex conical j base flatted, irregular, and unfinished." 
 U.L., Whitby. 
 
 I am disposed to place under the Genus Sepia 
 
 TBIGONELLITES WHITBYENSIS, Simp. 
 
 Some have imagined it to have been the operculum of 
 an Ammonite ; but of this there does not appear to be 
 any good evidence, and in all its characters it appears 
 strongly to ally itself with the bone or pen of the Cuttle- 
 fish. In what appears to be its natural state, its length 
 is about the same as the width, with a triangular mid-rib ; 
 the upper end square, with the angles rounded, the lower 
 end obtusely rounded and diminished ; the striae are 
 very numerous, fine, distinct, parallel with one side and 
 lower end. It is generally found in two separate pieces, 
 or with the pieces joined only at the broader end. 
 Thinking that one of these pieces might be a valve of 
 some shell, I gave the following description : 
 
 " Excessively depressed, subtriangular, transverse ; two 
 sides straight, forming a right angle ; base rounded at 
 
21 
 
 both ends ; posterior end diminished ; disc with a groove 
 near the longer straight side, increasing to the posterior 
 end; very finely striated; one inch long, If inch wide. 
 They are not uncommon in the Jet Rock, ILL., 7, where 
 alone I have found them." 
 
 BELEMNITES. 
 
 The Belemnite is an exceedingly curious and 
 interesting- fossil. On account of its pointed and 
 dart-like form, it has been named Thunderbolt; and 
 this idea has been strengthened by the abundance 
 of pyrites often found at the thick end, which when 
 struck with a hammer gives out a sulphurous odour. 
 Kecent discoveries have now proved beyond all 
 doubt, that the Belemnite has been enclosed in the 
 body of a Cephalopodous animal, resembling the 
 Sepia, or Cuttle-fish ; and it has also been proved, 
 that, like this creature, some of the species, at least, 
 possessed an ink-bag. 
 
 Belemnites are exceedingly abundant in our Lias, 
 and so variable that it is difficult to determine their 
 species with anything like certainty. 
 
 The fossil which we call the Belemnite, indepen- 
 dent of the animal which formed it, consists of three 
 principal parts: the Guard, the Case, and the 
 Phragmocone. 
 
 1. The Guard, rostrum, or sheath, is generally of 
 a conical form, terminating at the wider end in a 
 hollow cone or Alveolus, which is the receptacle of 
 the Phragmocone. 
 
22 
 
 The substance of the Guard has the same struc- 
 ture, and the same specifick gravity, as the shell of 
 the recent Pinna. It is composed of an infinite 
 number of fibres, radiating from a centre, and formed 
 by concentrick lamellae, or depositions of calcareous 
 matter, from the mantel of the animal, which had 
 invested it on every side. These lamellae, or stages 
 of growth, are well exhibited in polished sections 
 of the Guard, whilst the exterior surface is often 
 corrugated by the impressions of the mantel, and 
 sometimes has a pearly or silky lustre. The sub- 
 stance of the Guard becomes very much diminished 
 where it invests the Phragmocone, but the external 
 layer, or peristome, is continued far beyond it. 
 
 2. The Case. This is a very thin horny substance 
 in the form of a cup, which lines the Alveolus, and 
 and invests the Phragmocone, and being greatly 
 extended beyond it, forms a larg*e anterior cham- 
 ber, which contains the ink-bag and other viscera, 
 and has been named the pro-ostracum. The Case 
 is also continued in the opposite direction in a 
 filamentary tract to the posterior apex of the Guard. 
 This tract greatly resembles the pith of a tree, and 
 around it have been deposited the numerous con- 
 centrick layers of which the Guard is composed, 
 and from which the fibres radiate as a centre. 
 When the Phragmocone has been detached from 
 the Guard, the Case may be seen covered with very 
 delicate striae in systematick geometrical forms. 
 
23 
 
 3. The Phragmocone, or conical part, which occupies 
 the Alveolus, is transversely divided by thin horny 
 plates, which are convex towards the apex, and 
 separate it into narrow air-chambers. Attached to 
 these, on the ventral side, there is a fine, strait tube, 
 along* the whole length of the cone, called the 
 Siphuncle. In many examples, it is filled with white 
 calcarious spar, when it becomes beautifully con- 
 spicuous. 
 
 The apex of the Alveolus is generally turned more 
 or less out of the centre of the Guard, the deposi- 
 tion of the belemnitick matter from the Mantel 
 having been more copious on one side than on the 
 other. 
 
 We may observe that the Mantel is the fleshy 
 part which envelopes the whole. 
 
 From what we know of the animal, it appears 
 to have been long in proportion to the width, the 
 Guard being little more than one-third the whole 
 length. Whilst some of them have been very small, 
 others have been very large, several feet in length, 
 and must have been formidable enemies to fishes. 
 The fleshy parts of all animals have perished ; but 
 a very perfect specimen of a Belemnite has been dis- 
 covered in the Lower Lias at Charnrnouth, where 
 the whole outline of the animal could be traced. It 
 has been fully and clearly described by Professor 
 Huxley, and has thrown a great light on the struc- 
 ture and nature of the Belemnite. The entire length 
 
24 
 
 of this example, from the summit of the beak to 
 the apex of the guard, is 12^ inches, whilst its 
 greatest breadth does not exceed If inch. Around 
 the beak there had sprung a number of arms 1-^ inch 
 long, provided with numerous hooks for securing 
 its prey. It is remarkable that the hooks are per- 
 forated like the fangs of venomous serpents. The 
 beak is horny, like that of other animals of this 
 order, and is situated in the centre of the arms. 
 The ink-bag is pear or flask-shaped, contracted into 
 a narrow neck. The ink-bag and all the viscera 
 are enclosed within the pro-ostracum, above the 
 phragmocone, in the middle portion of the animal. 
 Other examples, though less perfect as a whole, 
 present the same characters. 
 
 The Belemnite, so far as we know at present, first 
 made its appearance during the formation of the 
 lowest beds of Lias, and soon became exceedingly 
 abundant in numbers, and of great variety. During . 
 the Oolitic period there are examples of immense 
 size, but it had greatly diminished, both in numbers 
 and variety, and no true Belemnite has been dis- 
 covered in European strata more recent than the 
 Chalk ; but we hear that our friend, Professor Tate, 
 has discovered a true Belemnite in Tertiary strata, 
 in Australia. Fossils of a Beleinnitic character, 
 however, occur in Tertiary strata in this country ; 
 and the Orthoceras, a fossil very like the Belemnite, 
 was abundant in very early geological times. 
 
25 
 
 In arranging a Catalogue of Yorkshire Lias Bel- 
 emnites, I have found it convenient to divide them 
 into Upper, Middle, and Lower Lias Belemnites ; 
 and I imagine this arrangement will assist in col- 
 lecting them. I also 
 think difference in time 
 ought to be taken 
 largely into account 
 in determining species. 
 
 As many have a great 
 difficulty in understand- 
 ing the nature of a 
 Belemnite, I give the ac- 
 companying figure, drawn 
 in accordance with the 
 above example, one-third 
 the size. 
 
 At the top are the arms 
 with their little hooks; 
 in the middle is the ink- 
 bag ; and the lowest part 
 represents the horny 
 Belemnite with its phrag- 
 niocone ; the whole 
 invested by the mantle or OU 
 fleshy part. The figure a 
 a magnified view of a 
 perforated hook. We may 
 presume that the form of 
 the animal would vary in 
 accordance with the form 
 of the guard. 
 
26 
 
 UPPEK LIAS BELEMNITES. 
 
 Slender and elongated. 
 
 1. BELEMNITES TUBULARIS; F. <$ B. Pal., pi. xiv., f. 36. 
 
 Guard very long and slender, generally with a 
 large portion towards the apex crushed flat, slightly 
 increasing towards the alveolar region ; alveolus 
 short, little expanded. 
 
 The largest I have seen is about a foot in length and a 
 quarter of an inch wide, gradually tapering to the trun- 
 cated apex, which is about half the width of the other end. 
 The flatted part exhibits nothing of the ordinary radiated 
 structure, and varies very much in length. In some 
 examples, three-quarters the length is flat ; in others, 
 a very small portion only is flat, and in some I have 
 observed an irregular thickening and flattening. It is 
 supposed to have been tubular, or the inner part soft, the 
 outer part hard, which has cracked by the superincum- 
 bent pressure. 
 
 In some examples the upper part of the guard is 
 strongly striated, corrugated, and granulated. One 
 variety, having these characters, but stouter, without any 
 flattening, and ending in an obtuse apex, I named 
 B. productus. Geo. Rep., p. 216 
 
 This species may be most conveniently obtained near 
 the two Nabs at Saltwick, where it is by no means scarce, 
 but it is found wherever the stratum 5& is exposed, from 
 Peak to Eunswick. U.L., 5&. 
 
 2. B. COMPRESSUS, Y. 4* B. 
 
 Stout, length of guard five times or more the 
 width, one-third flatted, coarsely striated, or cor- 
 rugated to the rounded apex ; transverse section 
 irregularly ovate ; length five to seven inches. 
 
27 
 
 This resembles the last in having the apical half 
 crushed and flattened,, but is very much stouter. One 
 example I got at Sandsend is three-quarters of an inch 
 wide at the alveolar end, and after having tapered for 
 more than half the length, is flattened, and spreads out 
 like the head of a lance ; and this is more or less the 
 character of the species. It is by no means uncommon 
 in stratum 6, U.L. 
 
 Young's name has the priority, and it represents a 
 large, distinct species. 
 
 3. B. INJEQUISTRIATTJS, Simp. Pal., pi. xix., f. 48. 
 Length of guard generally about six inches, six 
 
 or seven times 'the width, regularly tapering, and 
 sometimes curving towards the rounded apex, which 
 is sometimes flatted, and with numerous strong strife 
 and grooves about 1^ inch long, and smaller ones 
 much longer ; alveolar part moderately expanding ; 
 transverse section ovate. 
 
 Not uncommon at Saltwick. The Sandsend specimens 
 are stouter and straighter ; and one example is without 
 grooves or striae. ILL., 6. 
 
 4. B. INCLUSUS, Simp. 
 
 Length six times its greatest width, half that 
 width near the apex, which is slightly compressed ; 
 apex obtuse, eroded ; alveolus much expanding, 
 extends far down the guard. U.L., 1, Whitby. 
 
 5. B. EROSUS, Simp. 
 
 Long and rather slender, sides straight ; apex 
 rough and unfinished, from whence proceed many 
 slender grooves ; the surface, for half the length, is 
 covered with long, irregular, distinct striae, or cor- 
 rugations ; length eight inches, six times the width. 
 U.L., 1, Peak. 
 
28 
 
 This is closely allied to the last, but much stouter, 
 especially in the apical half. It is also from a different 
 bed. The mistake in assigning this and several others 
 to the Lower Lias has arisen from the abutting of the 
 Lower Lias against the uppermost beds of the Upper at 
 the great Peak dislocation. 
 
 6. B. GLABER, Simp. 
 
 The whole length 9 inches ; guard 5-| inches, 
 width an inch and two-tenths, much flatted, tapering 
 to a very obtuse apex, which is eroded and has a 
 shallow groove ; transverse section very elliptical ; 
 phragmocone protruding beyond the guard Scinches, 
 and expanding to a width of two and two -tenths 
 inches. U.L., 1, Peak. 
 
 It is of a brown colour, and very smooth in its texture. 
 The outer layers of the guard not reaching quite to the 
 apex, gives that part an eroded appearance. It is well 
 distinguished by its broad, flat appearance, and, judging 
 from the matrix, I have no doubt that it is from the 
 very uppermost bed of Lias. 
 
 7. B. LIMATUI/US, Simp. 
 
 Conical, elongated, much compressed ; apex obtuse, 
 with about five principal, deep, triangular furrows, 
 and others smaller, and many distinct striae ; texture 
 close and smooth ; length six inches, width of the 
 base one inch. 
 
 It was amongst the Yorkshire Lias Fossils, in the 
 Scarborough Museum, and described by me in the G-eo. 
 Eep., p. 216. 
 
 I have now got a good specimen from the uppermost 
 or cement stone nodular bed of the Upper Lias, at 
 Whitby. The guard is eight inches long, and the greatest 
 diameter of the cross section one inch. The guard, for 
 
29 
 
 half the length,, maintains its stoutness, and then rather 
 suddenly contracts,, and the portion towards the obtuse 
 apex becomes attenuated and compressed. The trans- 
 verse section, with the grooves and striae, are the same as 
 in the Scarborough example. The part of the phragmo- 
 cone protruding was unfortunately mislaid and lost. 
 
 Another example in the Whitby Museum, which I 
 suppose to be of the same species, has a rather crushed 
 phragmocone expanding four inches beyond the guard to 
 the width of full two inches, whilst the whole example 
 is only nine inches in length. This has the sudden con- 
 traction of the guard about the middle still more distinct. 
 Blake refers them to B. insequistriatus, but they are 
 much stouter, and the contraction at the middle of the 
 guard is a strong character. U.L., 1, Whitby. 
 
 I think it probable that the B. concavus of the first 
 edition may be the apical half of the above species, but 
 I repeat its characters : 
 
 Length of guard about six times its greatest width, 
 slightly depressed ; sides for about half its length from 
 the apex, concave ; apex unfinished, with one wide 
 groove and many narrow ones. 
 
 8. B. OPTATUS. 
 
 There is in the Whitby Museum the apical half of some 
 large Belemnite. It is nearly seven inches in length, 
 and an inch in diameter at the thick end, slightly com- 
 pressed into a regular ellipse. One side is quite straight,, 
 the other rather convex, gradually tapering to a blunt,, 
 eroded apex. It is very regular in the outline, and has 
 the smoothness and density of structure so characteristick 
 of the other long Belemnites of the uppermost bed of the 
 Upper Lias. It is broken off nearly at the end of the 
 alveolus, which is rather eccentrick. A perfect specimen 
 is much desired. 
 
 We may here place some elongated Belemnites which 
 are highly characteristick of the Jet Eock and the 
 stratum immediately above it ; and which some consider 
 to be the B. tripartitus of Schlotheim, on account of the 
 
30 
 
 apex being divided by three grooves. But as that name 
 has been applied to very different species, I am at present 
 disposed to retain the names I formerly gave them. 
 
 9. B. TRISULCULOSUS, Simp. Pal., pi. xi., f . 28. 
 Length of guard seven inches, nine times its 
 
 greatest width, subcylindrical for more than half its 
 length, then, in tapering, one side being more convex 
 than the other, the apex is thrown to one side; apex 
 sharp, with three long, broad, shallow furrows ; 
 transverse section irregularly ovate. 
 
 Some have an additional fine triangular groove at the 
 apex, others have the apex striated. The phragxnocone 
 appears to be small. They occur both in the Jet Rock 
 and in the stratum above. Saltwick and Sandsend, 
 U.L., 6, 7. 
 
 10. B. DISTORTTJS, Simp. Pal., pi. xi., f. 29. 
 
 Guard subcylindrical, length eight inches, nine 
 or ten times its diameter; apex slender, bent to 
 one side, with a strong groove on the concave side, 
 which becomes double at the extremity ; two other 
 principal grooves, and many small ones or striae ; 
 phragmocone protruding beyond the guard, small. 
 
 It is closely allied to the last, but more slender. Some 
 are rather fusiform, the guard being diminished in 
 thickness about the alveolar region ; others have the apex 
 less bent, and the grooves shallower. It is more slender 
 in proportion than B. subaduncatus, Voltz. U.L., 6, 
 Whitby. 
 
 11. B. INCISUS, Simp. 
 
 This is more slender, straight, and conical than the 
 above, finely tapering to a finely pointed apex, from 
 whence proceeds a deep, narrow, triangular groove, for 
 
31 
 
 about one-fifth the length of the guard; deepest at a 
 short distance from the apex; also two broad, shallow 
 grooves of equal length at the apex. ILL., Whitby. 
 
 12. B. MULGRAVIUS. 
 
 Length five inches, seven or eight times the 
 width, two opposite sides much compressed, nearly 
 parallel for two-thirds the length ; apex finely pro- 
 duced, pointed, and with a long deep groove on the 
 protuberant ventral side, and many long distinct 
 striae on the opposite side, and a groove on the 
 compressed sides; transverse section obovate. U.L., 
 6, Sandsend. Pal , pi. vi,, f. 16/., gives the general 
 outline. 
 
 There is also another with the guard rather depressed 
 and the transverse section an ellipse. The apex is rather 
 obtuse. It is smooth and regular, with little else to dis- 
 tinguish it. Let us call it B. modestus. Length 5 inches. 
 
 Another I cannot distinguish from B. pyramiformis of 
 the Lower Lias. They are both from the Jet Bock, ILL., 7. 
 
 13. B. BITUMINOSUS. 
 
 Conical, length five inches, five times its width, 
 alveolus widely expanding, guard finely tapering 
 to an acute and finely pointed apex ; apex grooved 
 and numerously striated. ILL., 7, Saltwick and 
 Sandsend. 
 
 This is well distinguished from the other Jet B-ock 
 Belenmites by its shorter and more conical form, and 
 especially by the enlargement of the alveolus and phrag- 
 mocone. Examples vary in respect of their grooves and 
 striae. In one example the fine striae, with some inter- 
 ruptions, are continued far up the guard. 
 
32 
 
 14. B. DENSUS, Simp. 
 
 Length of guard four inches, width six-tenths of 
 an inch, subcylindrical, slightly compressed, of a fine 
 dense texture ; apex obtuse, eroded. The whole 
 length which remains is six inches ; the portion of 
 the phragmocone protruding beyond the guard 
 being two inches in length, and its greatest dia- 
 meter 11 inch. U.L., 7. 
 
 There is in the Whitby Museum the upper portion of a 
 phragmocone seven inches long,, the diameter of the top 
 three inches, at the bottom 1 inch. If we could imagine 
 this fragment placed upon the above, the figure would 
 closely agree with those given of Miller's B. elongatus. 
 It is in a nodule from the Jet Rock. In the extensive 
 workings of the Jet E-ock, portions of the phragmocone 
 of some large Belemnite frequently occur, but no perfect 
 example of such a Belemnite has been preserved. Large 
 phragmocones, detached from the guards, sometimes 
 occur, when the striations of the case are beautifully 
 displayed. Mineral oil is not unfrequently found in the 
 cells. 
 
 15. B. SUBSTRIATUS, Simp. 
 
 Length 5^ inches, width seven-tenths of an inch, 
 sub-conical, rather cylindrical, both sides of the 
 guard equally convex, most towards the apex, 
 smooth and regular; apex blunt, central, striated; 
 transverse section circular. U.L., 6, Salt wick. 
 
 It is of a brown colour, but less conical than B. teluni 
 or spicatus, and too large to be B.le vis. Blake assimilates 
 it to B. striolatus, but the strise are confined to the apex. 
 
 16. B. TELUM, Simp. 
 
 Conical, rather depressed, length four inches, four 
 times the width, sides nearly straight, gradually 
 
33 
 
 tapering- to a somewhat attenuated but obtuse apex; 
 apex central ; transverse section elliptical. U.L., 1, 
 Whitby. 
 
 Another example is more robust, with one side rather 
 convex, and the apical portion strongly corrugated ; no 
 striae or groove. Syn. B. Voltzii, Ph. Pal. pi. xvii., f . 45c?. 
 
 17. B. CINERETJS. 
 
 Length five inches, five times the width, sides 
 convex ; apex obtuse, without grooves or striae. 
 U.L., 1, Whitby. 
 
 It is of a grey colour and rough to the touch. A smaller 
 example has two obsolete grooves at the apex. 
 
 18. B. SPICATUS, Simp. 
 
 Conical, length five inches, five or six times the 
 width ; transverse section circular ; apex central, 
 very acute, finely pointed, a few striae, with two 
 shallow grooves, and one long, narrow, concave, 
 deep, widening upwards. U.L., 5, Whitby. 
 
 Very slender. 
 
 19. B. SUBTENUIS, Simp. Pal. pi. x., f. 27. 
 
 Length four inches, eight or nine times the width, 
 slender, regularly tapering to a fine pointed apex ; 
 apex with three long, shallow grooves, and finely 
 striated. U.L., 4, 5, Whitby. 
 
 This is a very abundant species in the middle of the 
 Upper Lias, and varies much in the slenderness of the 
 guard, and in respect to the grooves and striae at the 
 apex ; the grooves and striae becoming obsolete. 
 
 Var. (a.) Grooves obsolete ; apex not striated. 
 (b.) Thicker in proportion ; apex not striated. 
 
 D 
 
34 
 
 20. B. DORSALIS, Ph. Pal. pi. x., f . 24. 
 
 Like the last, but with a groove or slit in the alveolar 
 region, concave on the grooved side ; apex finely pointed, 
 seldom striated, grooves obsolete. Length 21 inches; 
 generally less. 
 
 It is most plentiful near the fourth indurated band of 
 the Upper Lias, at Saltwick ; rare in the beds above. 
 
 21. B. TRIVIALIS, Simp. Pal. pi. x. 
 
 Subconical, moderately stout, alveolus expand- 
 ing ; apex rather obtuse, with numerous fine striae ; 
 length two or three inches. U.L., 5. 
 
 Intermediate between B. subtenuis and levis. 
 
 22. B. LENTUS, Simp. 
 
 Very slender, sub-fusiform, length 3^ inches, nine 
 times the width, finely tapering to the apex; apex 
 with three long, deep, triangular grooves. ILL., 
 Whitby. 
 
 23. B. TENTJIS, Simp. 
 
 Slender, elongated, tapering towards both ends ; 
 transverse section circular. U.L., 8, Hawsker. 
 
 B. longiformis (Bl.) is its nearest ally, but it is the 
 thickest in the middle. 
 
 24. B. EXIGUUS. 
 
 Very slender, smooth and regular, gradually 
 thickening from the alveolar part to near the apex, 
 which is acute, and very sharply pointed U.L., 8, 
 Hawsker. 
 
 It is not to be confounded with B. microstylus, Ph. 
 
 The two last are from a very rotten bed immediately 
 above the Middle Lias, full of fragmentary fossils along 
 with B. clavatus, longiformis, and others, too fragmentary 
 for description. Further discoveries may be made in 
 that bed at Hawsker and Kettleness. 
 
35 
 
 Shorter and thicker in proportion. 
 
 25. B. EXPANSES, Simp. 
 
 Cylindrical, or subfusiform, being contracted in 
 the alveolar region, and then moderately expand- 
 ing ; general length from two to four inches, seven 
 times its diameter ; apex central, with two shall6w 
 grooves on opposite sides, and another principal 
 groove expanding into a wide convex area ; on the 
 opposite side a few strise ; cross section circular. 
 U.L., 1, Whitby. 
 
 We may notice two principal varieties : 
 
 Var. (a.) Apex elongated, and finely pointed. 
 (b.) Apex very obtuse, groove large, deep, coarse. 
 
 This last might be considered a very distinct species, 
 but it has the characteristic!? groove only exaggerated. 
 The formation of this groove I imagine has arisen from 
 a peculiarity of the mantel not having deposited the 
 belemnitick matter in that part. One would have thought 
 that the groove would have been ventral, but judging 
 from the crushing of the alveolus, it is on the right side. 
 
 Something of this structure may be observed in 
 B. rudis, Ph. Variety (a.) is very plentiful in the upper- 
 most division of the Upper Lias, and I do not recollect 
 finding it much below. 
 
 26. B. EEPANDUS, Simp. 
 
 Subfusiform, much bent, convex on the grooved 
 side ; apex pointed. U.L., 3. 
 
 It has the characteristic^ groove of the last, and may 
 be a variety of it. It is a good deal like Blake's fig. 9, 
 pi. iv., but more curved. 
 
 27. B. LEVIS, Simp. Pal. x., f. 23. 
 
 Length of guard three or. four inches, about five 
 times it width, rather depressed, smooth and regular; 
 
36 
 
 apex generally compressed, often striated, more or 
 less obtusely pointed, sometimes with a flatted pro- 
 cess. ILL., 56, Saltwick, Whitby. 
 
 This species is plentiful about forty feet above the Jet 
 Rock. Some are rather cylindrical, others more conical. 
 The surface in places towards the smaller end is often 
 finely and distinctly corrugated like leather. May not 
 this be B. striolatus, Ph. ? Nearly all have one side of 
 the guard more depressed than the other, which renders 
 the transverse section irregularly ovate. 
 
 28. B. APTUS. 
 
 This has the same general form as the last, but with a 
 long, deep groove on one side proceeding from the apex. 
 It differs from B. incisus in being more cylindrical, and 
 in the apex being rather obtuse. Length four inches. 
 The lower portion is rather bent to one side. U.L., 56. 
 It is not badly represented by Pal. pi. x., f. 27. 
 
 29. B. PINQUIS. 
 
 Tumid, length four inches, four times the width, 
 sides regularly convex ; apex obtuse with a rather 
 large foramen, and on both sides a very flat, long, 
 broad groove; transverse section circular or slightly 
 
 ovate. 
 
 One example five inches long, five times the width, has 
 many fine striae diverging from the apex on the ventral 
 side. A smaller example has a strong, shallow groove 
 at the apex on the ventral side, and a triangular groove 
 on two opposite sides. 
 
 They are all of a dark blue colour, and very smooth 
 and soft to the touch. ILL., 2, Whitby. 
 
 30. B. ROSTRATUS. 
 
 Length three inches, six times the width, sub- 
 cylindrical, apical portion elongated, like the bill of 
 
37 
 
 a bird, obtusely pointed, three long, deep furrows, 
 and many striae. U.L., 4, Whitby. 
 
 31. B. WOOLLERI. 
 
 Length five inches, five times the width, much 
 depressed, two opposite sides being much flatted, 
 gradually tapering ; apex elongated, acute, from 
 whence proceed along the two more rounded sides 
 a keel between two long, triangular furrows, with 
 many shorter striae. ILL., 5, High Whitby. 
 
 Some examples are less flatted, and the apical part less 
 drawn out, and thus graduate into the more robust 
 varieties of B. levis. 
 
 I name this in memory of Mr. Wooller, who, when 
 engineer of Whitby Piers and Harbour, along with Mr. 
 Chapman, in 1758, discovered the first known example of 
 Teleosaurus Chapmanni, and described and figured the 
 same, though roughly, in the Philosophical Transactions, 
 vol. 50. The observations there made show that Wooller 
 was far ahead of the age in which he lived. 
 
 32. B. ACUMINATUS, Simp. Pal. pi. ix., f. 22. 
 Length 2^ inches, five times its diameter, cylin- 
 drical for nearly its whole length, then suddenly 
 ends in a sharp point, more or less produced ; trans- 
 verse section circular or slightly ovate ; grooves, if 
 any, at the apex very obscure. ILL., 5, Whitby. 
 
 33. B. CYLINDBICUS, Simp. Pal. pi. xx., f . 52. 
 Cylindrical for the greatest part of the length, 
 
 transverse section circular ; length five inches, from 
 five to seven times the diameter; apex rather 
 obtusely pointed. U.L., 8. 
 
The general rounded form is constant, and for the most 
 part very cylindrical, but some incline to the conical, 
 whilst others, being slightly contracted in the alveolar 
 region, become somewhat fusiform. The apex is some^ 
 times rather finely pointed, and with two or three slight 
 grooves. In one example it is also finely striated. It has 
 a considerable range of strata. It occurs sparingly in 
 the uppermost beds of the Lower Lias, more common in 
 the Middle Lias, and is very plentiful, and the most 
 perfect, in the lowest bed of the Upper Lias, where it 
 accompanies Am. annulatus over wide areas, which, with 
 the exception of an imperfect Nautilus, and the frag- 
 mentary remains in the rotten bed immediately above 
 the Middle Lias, are the only fossils I have been able to 
 detect in that stratum. 
 
 34. B. ATHLETICUS, Simp. 
 
 Conical, with the outline gently and regularly 
 curved; length 4 inches, about four times the 
 greatest diameter ; transverse section circular ; apex 
 obtuse. U.L., 1, Peak, R.H. Bay. 
 
 This is a strong, coarse species, with little to charac- 
 terize it, except its general form. It is more conical 
 than the last, and of a grey colour and coarse texture. 
 It was brought to us as from the Lower Lias, but I have 
 no doubt it is from the uppermost bed of the Upper Lias, 
 where Blake places it. 
 
 35. B. VULGABIS, F. B. Pal. pi. xvi., f. 40, 41. 
 Robust, subcylindrical ; length four or five times 
 
 its width, outline most convex near the obtusely 
 pointed apex, irregularly and slightly compressed 
 on two opposite sides; apex inclined to one side, 
 with two and sometimes three grooves; general 
 length from six to eight inches. U.L., 1, 2. 
 
39 
 
 It is very plentiful in the uppermost strata of the 
 Upper Lias, and is rather variable, the smaller examples 
 being rather conical, approaching to B. spicatue. The 
 phragniocone is often well preserved, extending consider- 
 ably beyond the guard, and not unfrequently exhibiting; 
 the siphuncle like a white line. 
 
 36. B. CURTUS, Simp. 
 
 Very thick, short, and conical. 
 
 It occurs in the shale below the third indurated band. 
 It is generally regarded as a mere variety of the last, 
 but it is sufficiently distinguished by its very short 
 conical form, and by the phragniocone being always 
 rotten. In this it also differs from the next. Both the 
 above are of a brown colour. U.L., 4. 
 
 37. B. UBBANUS. 
 
 Conical, general length three or four inches, 
 about four times the width, expanding much at 
 the alveolar part ; transverse section ovate ; apex 
 central, acute, with three shallow grooves. ILL., 5. 
 
 This is more finely and regularly formed than B. vul- 
 garis. Some are rather inclined to be subcylindrical in 
 the upper part, but in all the apical portion is finely 
 taper and pointed. In one very taper example, the apex, 
 besides the grooves, is finely striated. It approaches 
 B. regularis (Ph.). Pal. pi. xv., f. 38Z. It is very cha- 
 racteristick of the upper part of the fifth division of the 
 Upper Lias at Saltwick, and almost confined to it. It 
 may be well to observe that B. validus and robustus 
 occur in the lower part of this division, and their young 
 may be mistaken for this species, but they have the apex 
 somewhat out of the centre. 
 
 38. B. POLITUS, Simp. 
 
 Robust, subcylindrical, rather fusiform, being 
 slightly contracted in the alveolar region, and tumid 
 towards the apex ; length 3^ inches, five times the 
 
40 
 
 width; transverse section circular; apex short, 
 obtuse, ending in a small blunt point, with two 
 shallow grooves on one side. U.L., 5, High Whitby. 
 Pound also in the same bed in Cleveland by Mr. R. 
 Tate. Geo. Rep., p. 216. 
 
 It is of a dark colour, smooth and regular, as if turned 
 in a lathe. The phragmocone appears to have been small. 
 It is much too long to be mistaken for the young of B. 
 pollex, and the little blunt point at the apex bears no 
 resemblance to the apex of B. acuininatus. 
 
 39. B. POLLEX, Simp. Pal. pi. ix, f. 20. 
 Subcylindrical, length 3^ inches, width 1 inch, 
 
 one side rather flatted ; apex very obtuse, with a 
 short irregular groove. U.L., 5. 
 
 40. B. BOBUSTUS, Simp. Pal. pi. v., f. 14. 
 
 Conical, length of guard 5| inches, three times 
 its width, with a strong wide groove on two oppo- 
 site sides the whole length ; apex obtuse, turned to 
 one side. U.L., 5, Whitby, Hawsker. 
 
 This species is well figured by Phillips, but I think he 
 has done very wrong to change the name, especially as 
 he had both the published description and the labelled 
 specimen, which is in the Whitby Museum, to go by. The 
 phragmocone, in a very crushed state, spreads out far 
 beyond the guard. In. the smaller examples which I 
 have found, the upper part was so rotten as not to be 
 preserved. 
 
 41. B. OBTUSTJS, Simp. 
 
 Subcylindrical, rather flatted on two opposite 
 sides, length of guard five inches, four times the 
 width, with a shallow groove or depression on one 
 
41 
 
 side towards the alveolar end; apex obtuse, central, 
 with four short, broad, shallow grooves. U.L., 5, 
 Whitby. 
 
 On one side of the apex the groove is sharper and 
 deeper than on the other. Phragmocone small. The 
 central position of the apex distinguishes it most from 
 the kindred forms. It is also shorter in proportion than 
 the next, and the apex more obtuse. 
 
 42. B. VALIDUS, Simp. T. & B., pi. iii., f. 4. 
 Cylindrical, with a shallow groove on one side 
 
 the whole length, deepest in the alveolar region ; 
 transverse section circular; apex eccentrick, obtusely 
 pointed ; length six inches, six times the diameter. 
 ILL., 5. 
 
 43. B. LEVIDENSIS, Simp. T. & B., pi. iii., f. 3. 
 Depressed, regularly tapering to about half the 
 
 width, wide at the base ; apex obtuse ; texture 
 coarse; length three inches, three times its greatest 
 width ; an obsolete groove or flattening at the apex 
 on one side. U.L., 1, Whitby. 
 
 Var. (a.) Less taper, rather cylindrical, with two long 
 
 deep grooves from the apex. 
 (6.) More robust, with two short wide grooves at 
 
 the very obtuse apex. 
 
 (c.) Length 3 inches, three times the width, much 
 depressed; apex broadish, obtuse, with a 
 short broad groove on the dorsal side. The 
 outline resembles that of B. pollex. The 
 apex of all is very blunt, and has a large 
 foramen. Colour grey, and texture coarse. 
 I very much doubt whether Mr. Blake's 
 example is identical with any of these 
 varieties. 
 
42 
 
 44. B. DACTYLUS. 
 
 Subquadrate, of nearly the same thickness the 
 whole length; length 3J inches, four times the 
 width, sides nearly parallel, one side occupied by a 
 wide shallow groove, or flatted space, the opposite 
 side rounded ; apex very obtuse, with a large fora- 
 men; transverse section subquadrate. U.L., 1, 
 Whitby. 
 
 It is of a soft light grey colour, and has the appear- 
 ance of a very thick clumsy finger. It is much more 
 robust than the continental B. digitalis, and the trans- 
 verse section more quadrate. 
 
 The next is still of the finger form, but widely sepa- 
 rated in time from the above, and seems to have a family 
 relation with B. levis. 
 
 45. B. DIGITTJ8. 
 
 Subcylindrical, much depressed on one side; apex 
 obtuse, with a very sharp ridge between two narrow 
 furrows in the end ; length 3^ inches, four times 
 the breadth ; of a brown colour. U.L., 56, Whitby. 
 I may notice here the apical portions of two Belemnites 
 of kindred form, which I found in the Am. Mulgravius 
 seam at Saltwick. 
 
 (a.) Cylindrical, depressed ; apex obtuse, with a deep 
 triangular groove, and some strong striae on one 
 of the more convex sides ; transverse section 
 ovate ; length two inches, containing the end of 
 the phragmocone. 
 
 (&.) Less depressed ; apex with a broad groove on one 
 side. ILL., 56. 
 
 46. B. CABIN ATUS, Sirup. 
 
 Conical, slightly depressed, a strong irregularly 
 striated rib, or keel between two furrows the whole 
 
43 
 
 length of the guard, with many other slight furrows 
 towards the apex, which is obtusely rounded, and 
 less than half the width of the other end ; length 
 2-| inches, five times the width. ILL., 5, Salt wick. 
 It was discovered' by Mr. Beckles, and is probably in 
 his possession. 
 
 MIDDLE LIAS BELEMNITES. 
 
 47. B. IN.&QUALIS, Simp. 
 
 Length 3^ inches, about four times the width > 
 subconical, alveolar region moderately expanding; 
 apex central, pointed, with two or three depressions- 
 or broad furrows; apex of phragmocone much 
 inclined to the more convex side. Geo. Rep., 
 p. 216. 1865. 
 
 It is very minierous in the uppermost beds of the 
 
 ironstone series of the Middle Lias,, at Hawsker and 
 
 Kettleness ; and it also occurs in the beds below. It is 
 
 subject to much variety. We may notice the following: 
 
 Var. (a.) Longer in proportion, and tapers more finely 
 
 to the apex. 
 
 (b.) Subcylindrical, apex obtuse. 
 (c.) B. ferreus. Simp. Short, thick; apex obtuse, 
 with a little point drawn out like a nipple, 
 difficult to extract without fracture. Kettle- 
 ness. 
 
 All this must remind one of what has been said of B. 
 breviformis. Pal. pi. iv. 
 
 48. B. RUDIS, Ph. Pal. pi. xvi., f . 42. 
 
 Length three inches, four times the width ; apex 
 obtuse, bent to one side, without grooves or striae; 
 apex of alveolus much inclined to one side. M.L.,. 
 Ironstone, Kettleness. 
 
44 
 
 If I am right respecting B. rudis (Ph.), the belemnitick 
 matter is much wanting on one side of the apex. In this 
 it resembles B. expansus. 
 
 49. B. TERES.. 
 
 Length four inches, six times the width, tapering 
 to a slender apex; transverse section elliptical ; apex 
 central, with two narrow grooves. M.L.,p, Hawsker. 
 
 This and the next are closely allied to B. elegans. 
 
 50. B. LEPTOS. 
 
 Conical, transverse section circular, length 2^ 
 inches, six times the diameter; apex elongated, 
 finely pointed, faintly grooved. M.L., o, Hawsker. 
 
 Intermediate between the last and B. araris. 
 51. B. LJEVIGATUS, Simp 
 
 Length four inches, six or seven times its greatest 
 width, depressed, sides nearly straight, tapering- 
 little ; transverse section elliptical ; apex broad, 
 truncated, two obsolete grooves, foramen large. 
 M.L., />, Hawsker. Geo. Rep. 
 
 If the above name be inadmissible, it may be called 
 B. complanatus. 
 
 From the same bed, and with nearly the same characters, 
 I have a robust example, coarse in texture and of a grey 
 colour, which may be an overgrown B.lsevigatus, but I am 
 disposed to name it 
 
 52. B. GRANDvEVUS. 
 
 Length four inches, five times the width, trans- 
 verse section rather quadrate. 
 
 -53. B. PLANULATUS. 
 
 Conical, length five inches, five times its width, 
 much depressed towards the apex, sides rather 
 
45 
 
 convex, alveolar part moderately expanding ; apex 
 blunt, flatted, wide obsolete grooves ; in some the 
 apex is narrower; transverse section elliptical. 
 M.L., r, Hawsker. 
 
 54. B. ARENACEUS. 
 
 Conical, stout, length 4^ inches, nearly five times- 
 the diameter ; transverse section circular ; apex 
 obtuse. M.L., ^?, Hawsker. 
 
 It greatly resembles B. athleticus, but it is too widely 
 separated in time to be that species. 
 
 55. B. LONGICONUS. 
 
 Conical, length of guard four inches, about four 
 or five times its width, depressed ; alveolar region 
 wide ; apex obtusely pointed ; transverse section 
 ovate ; alveolus central, reaching far down the 
 guard. M.L., e, Hawsker. 
 
 The chief character of this Belemnite is the great 
 length of the alveolus and included phragmocone^ 
 reaching within one-third of the N apex. 
 
 56. B. RETUSUS. 
 
 Under this head I propose to consider some Belem- 
 nitick forms which occur in a thin ferruginous seam in, 
 the division p of the Middle Lias, on the Hawsker shore, 
 full of fragmentary fossils. 
 
 Subconical, with the sides regularly convex, 
 transverse section circular ; apex hemispherical. 
 
 The specimen described is four inches in length, four 
 times its greatest diameter,, very smooth and regular as 
 if turned in a lathe, without furrows or striae. I observe 
 in this example, and also in another, that the alveolar 
 part, at least, one-half of it, terminates abruptly, and is 
 rounded over inwardly. 
 
46 
 
 There is much difference in the sleiiderness of the 
 guard. The length of some is six times the diameter. I 
 have a fragment three inches in length, and only four- 
 tenths of an inch in diameter, and this does not reach 
 the alveolus, which is wanting. It reminds one of 
 Xiphoteuthis elongata. M.L., p, Hawsker. 
 
 I have another example more cylindrical and robust, 
 with the apex very obtuse, foramen considerable. M.L., /,-, 
 Hawsker. 
 
 Pal. pi. xv., f . 37^, may be taken as the general form. 
 
 57. B. PESSULUS. 
 
 A cylinder through its whole length, with a very 
 obtuse rounded apex, length 2^- inches, eight times 
 its diameter ; greatest part of the alveolus wanting. 
 M.L., p, Hawsker. 
 
 58. B. LONQIFOBMIS, Blake. PL iv., f. 8. 
 
 Fusiform, lance shaped, much depressed ; length 
 four inches, eight or nine times its width ; apex 
 obtuse. M.L., z,^, Hawsker. 
 
 I have four specimens varying from three to four 
 inches in length, which I found in the Middle Lias on 
 the Hawsker shore. They are all stout with obsolete 
 grooves or depressions at the apex, and the alveolar part 
 expanding moderately. 
 
 59. B. DEMISSUS. 
 
 Length two inches, very smooth and taper, rather 
 depressed ; apex blunt. 
 
 It occurs in the rotten bed immediately above the 
 Middle Lias, and in some beds below. Through want of 
 character, I am unable to associate it with any other 
 Belemnite. It is more elongated and slender than 
 B. acutus. M.L., Hawsker. 
 
47 
 
 LOWER LIAS BELEMNITES. 
 
 60. B. ELEGUNS, Simp. Pal. pi. xx., f. 50. 
 Subfusiform, length of guard from three to five 
 
 inches, seven or eight times the width, expanding 
 but little at the base, gently swelling in the middle, 
 and elegantly tapering to the apex, which is central ; 
 at the apex, on one side, there are two deepish 
 grooves of moderate length, and on the other side 
 several coarse striae ; alveolus central, small ; trans- 
 verse section circular. L.L. Ironstone -Series, north 
 cheek of R.H. Bay. 
 
 Since publishing the above description, I have collected 
 a great many, ranging through nearly all the upper beds 
 of the Lower Lias, from the bed 6, of my section, down 
 to x, but they are the most plentiful about the bed Jc. 
 They are subject to some variety. In some the apex is 
 sharp, in others rather blunt. They also vary much in 
 their proportional thickness. One fine example which I 
 possess, five inches long, is eight-tenths of an inch 
 diameter in the middle, contracted by one-eighth of an 
 inch in the alveolar region, and slightly concave in the 
 apical region. L.L., k. The most constant characters 
 are the circular section and the more or less lengthening 
 of the apical region. 
 
 61. B. ATTENUATUS. 
 
 Length five inches, eight or nine times the width, 
 regularly tapering to a fine, obtusely pointed apex; 
 transverse section circular. L.L., >, R.H. Bay. 
 
 This is far more slender and elongated than any variety 
 of B. elegans. The sides of the guard are but slightly 
 convex, smooth and regular. I have two from a lower 
 part of the series r and $e, which are rather stouter, main- 
 taining their thickness more towards the apex. In all 
 the alveolus expands moderately. 
 
48 
 
 62. B. ACUS. 
 
 Length of guard five inches, eight times the width, 
 regularly tapering to a fine rounded apex, cut by a 
 long, deep triangular groove; transverse section 
 circular. L.L., z, R.H. Bay. 
 
 It differs chiefly from the last by the long groove in 
 the apical region. It is also stouter in the upper part. I 
 have two examples from the same beds which I might 
 associate with either of the above, but they are shorter 
 in proportion, rather cylindrical, and the alveolar portion 
 expands more. One of them has a long, obsolete groove 
 from the apex. 
 
 63. B. SCOLOPS. 
 
 Cylindrical, very smooth and regular, length five 
 inches, about eight times the width, tapering but 
 little to a rather blunt apex ; apex central ; trans- 
 verse section circular ; alveolar part little expanded. 
 L.L., wz, R.H. Bay. 
 
 This is so like the bill of a woodcock that it needs little 
 more description. They differ slightly in thickness, and 
 on the lower portion of one there is a long, faint groove 
 or depression. 
 
 64. B. OBLONGUS. 
 
 Cylindrical, length three inches, five times the 
 width ; transverse section circular ; apex obtusely 
 pointed. L.L., v, R.H. Bay. 
 
 It closely resembles some varieties of B. elegans, but 
 the apical portion is short, and consequently less acute. 
 Two examples are rather flatted on one side, and so 
 approach the next. One of them strongly resembles 
 B. levis. Some are rather conical. 
 
49 
 
 65. B. PYRAMIFOBMIS. 
 
 Length four inches, seven times the width, taper- 
 ing with a gentle curve to a rather obtnse, central 
 apex; a broad shallow groove or depression along 
 the whole length of the guard ; transverse section 
 irregularly ovate. L.L., wz, R.H. Bay. 
 
 The groove or depression is the chief character, and is 
 constant. One example is rather fusiform,, with the 
 groove stronger. 
 
 66. B. PERFORATUS, Simp. SYN., B. ASPERGILLUM, Blake. 
 Length four inches, five or six times the greatest 
 
 width, sides concave, width over the alveolus twice 
 that at the apex ; apex truncate, hollow ; transverse 
 section ovate. L.L., s, R.H. Bay. Geo. Rep. p. 216. 
 
 67. B. TURRIS, Simp. 
 
 Length four inches, five times the width, rather 
 flatted on one side, sides nearly parallel for two- 
 thirds the length, apical region drawn out to a 
 point, and with three broadish grooves. The alve- 
 olus expands but little; transverse section ovate. 
 L.L., R.H. Bay. Geo. Rep., p. 216. 
 
 They occur in all the beds from L.L., y, up to the 
 arenaceous beds M.L. The length of the apical portion 
 of the guard is its principal character, in which it 
 resembles B. Woolleri. In some it is shorter, and 
 graduates in the next. In most the groves are obsolete 
 or wanting. It is a rather robust species. 
 
 68. B. TRUNCULUS. 
 
 Subcylindrical, short, thick, length two inches, 
 four times the width ; transverse section circular, 
 or with one side rather flatted; apical portion 
 E 
 
50 
 
 obtuse, but finely pointed. L.L., Ironstone Series, 
 R.H. Bay. 
 
 They occur in all the beds of the upper division of the 
 Lower Lias on the north cheek of R.H. Bay, but the 
 apical part is often eroded. I have one example from 
 the seventh indurated band which may be a variety of 
 B. penicillatus, Sow. Pal. pi. i. 
 
 69. B. CTTSPIDALUS. 
 
 Very cylindrical for the greater part of the length, 
 length three inches, five times the diameter; trans- 
 verse section circular; apical region elongated, of 
 double curviture, finely drawn out and acutely 
 pointed. No grooves or striae. L.L., Ironstone 
 Series, R.H. Bay. 
 
 They differ in the length of the apical region, in which 
 however it is always longer than in B. acuminatus. 
 
 70. B. DELICATTJ8. 
 
 Very slender and conical, the apical half of the 
 guard very finely striated; length two inches, five 
 times the diameter. L.L., &, R.H. Bay. 
 
 If it had been in the Upper Lias, I should have placed 
 it under B. subtenuis. It differs chiefly from the next in 
 its striated apex. 
 
 71. B. ARARIS, Blake. 
 
 Conical, slightly fusiform, finely taper to an acute 
 apex, an obsolete groove or depression on one side 
 of the guard; transverse section circular; length 
 two inches, six times the width. L.L., &, R.H. Bay. 
 
 Of these fine smooth-pointed Belemnites some are 
 much thicker in proportion. A fine specimen Mr. Blake 
 kindly sent me is much more conical and finer pointed 
 than his figure pi. iv.,-f. 1, Yorks. Lias. 
 
51 
 
 The following is Mr. Blake's description : 
 " Guard short, delicate, very slightly fusiform, with no 
 apical, and only faint lateral lines ; section rather angular, 
 not depressed ; length two inches, which is six times its 
 breadth/' 
 
 Shorter and thicker. 
 
 72. B. ACUTTJS, Miller. Pal. pi. i., f. 3. 
 
 Very acutely conical, length 2^ inches, four or 
 five times the width, apex central, sharply pointed, 
 without grooves or striae; alveolar region much 
 expanding. 
 
 They are subject to great variety, if, indeed, they are 
 all the same species. In many examples the guard is 
 much depressed. Some have also an obsolete, broad 
 groove along the whole length, with the transverse sec- 
 tion very elliptical ; in others the section is circular. 
 The alveolus extends half down the guard, with the apex 
 and filament central. The sides of the phragmocone are 
 concave, corresponding with the alveolar part of the 
 guard. 
 
 They are common to all the indurated bands of the 
 Lower Lias, at R.H. Bay. 
 
 73. B. DEPRESSUS, Simp. SYN., B. INTUNDIBULUS, Ph. 
 Pal. pi. i., f. 3. 
 
 Much depressed, length of guard about four or 
 five times its width, widened at the base, the sides 
 somewhat parallel, apex moderately pointed ; trans- 
 verse section an elongated ellipse. L.L., R.H. Bay. 
 
 74. B. INFUNDIBULUS. 
 
 The name B. infundibulus might be appropriated to a 
 large triangular Belemnite which is almost entirely 
 occupied by the alveolus. It occurs in the lowest beds 
 of Lias in R.H. Bay, but so rotten as not to be preserved. 
 
52 
 
 It is probably the same as noticed by Mr. Blake in the 
 Lowest Lias at Redcar. Yorks. Lias, page 327. I have a 
 part of one from L.L., 23, R.H. Bay. 
 
 75. B. CONICUS, Simp. 
 
 A cone, length 2 inches, three times the diame- 
 ter, transverse section circular ; alveolus large ; apex 
 eroded. L.L., R.H. Bay. 
 
 A portion of the guard of a very much larger example, 
 having the same proportions, is in the Whitby Museum, 
 and was from the Lower Lias at Redcar. 
 
 76. B. DENS, Simp. Pal. pi. ii., f. 6. 
 
 Length of guard 1 inch, not twice the width, 
 much depressed, sides straight, finely striated lon- 
 gitudinally, or corrugated, and roughened with small 
 tubercles most towards the blunt apex. 
 
 I found it in the upper part of the Lower Lias about 
 the middle of the north cheek of Robin Hood's Bay. 
 
 Another, discovered by the Rev. Dr. Cookson in the 
 same locality, did not show the same ornamentation, but 
 was equally compressed. 
 
 77. B. PALLIATUS, Dum. Blake, pi. iv., f. 4. 
 
 Under this name Mr. Blake has given the following 
 description of two examples from the L.L., R.H. Bay. 
 
 " A very remarkable form in which the alveolus is very 
 large, and the guard very thin. The end of the guard 
 has a triangular section and slightly recurved apex; 
 there are two dorso-lateral depressions, and an irregu- 
 larity on the ventral side. The whole is conical, with the 
 sides concave, the angle of the cone being about thirty 
 degrees. Length 1 inch, which is twice its greatest 
 breadth. 
 
 "The phragmocone occupies four-fifths of the whole 
 length, the septa are numerous, and it is eccentrick, lying 
 
53 
 
 nearer one side of the triangle, opposite to the direction 
 in which the apex is curved. 
 
 "It differs from B. calcar by the concave sides and 
 triangular section, and is not so robust ; and from B. dens, 
 by the want also of the peculiar ornamentation." 
 
 78. B. CALCAR, Ph. Pal. pi. ii., f. 5. 
 
 I supposed the little article Phillips calls B. calcar 
 might be an immature B. dens, where the alveolus 
 occupies nearly the whole of the interior of the guard. 
 
 Fusiform. 
 
 79. B. SCABROSUS, Simp. Pal. pi. xx., f. 51. 
 Fusiform, length seven inches, fourteen times its 
 
 greatest width, very much roughened and granulated 
 about the alveolar region ; alveolus moderately ex- 
 panded, transverse section circular ; apical region 
 elongated, obtusely pointed with three long grooves. 
 I obtained this fine specimen at the middle of the north 
 cheek of Eobin Hood's Bay, L.L., i. It has been beau- 
 tifully figured by Phillips. 
 
 80. B. SPADIX ARI, Simp. 
 
 Fusiform; length of guard four inches, greatest 
 diameter a quarter of an inch, least diameter one- 
 eighth of an inch ; transverse section of club circular, 
 of alveolar region irregularly angular, arising from 
 long irregular ridges and depressions in that region; 
 apex obtuse; alveolus small. L.L., R.H. Bay. 
 
 This is well distinguished from the rest of the fusiform 
 group by the great length and slenderness of the shank 
 which connects the alveolar region with the club. I have 
 seen only two examples, the one now described in the 
 Whitby Museum, the other in the British. They were 
 both from the Lower Lias on the north cheek of E-.H. Bay. 
 
54 
 
 81. B. MICBOSLYLUS, Ph. Pal. pi., f. 31. 
 
 Very slender and delicate, length If inch, greatest 
 diameter one-eighth of an inch, least one- tenth, 
 gradually thickening towards the rather blunt apex, 
 transverse section at the apical part circular, at the 
 alveolar octagonal. L.L., s, R.H. Bay. 
 
 82. B. FUSTEOLUS, Simp. Pal. pi. iii., f. 7. 
 
 Guard much contracted in the alveolar region, 
 then gradually and moderately swelling out into a 
 lengthened club with an acute apex; length 2-| 
 inches, eight or nine times the greatest diameter; 
 transverse section of the club circular, of the alveo- 
 lus octagonal ; alveolus small, moderately expanding. 
 L.L., y, R.H. Bay. 
 
 The depressions or grooves in the alveolar region are 
 rather irregular. In the more typical examples there is 
 a distinct groove running down into the club. I have 
 collected them from all the beds on the north cheek of 
 R.H. Bay from bed b to No. 2 indurated band. The 
 alveolar part is generally wanting. 
 
 83. B. CLAVATUS, Simp. 
 
 Guard contracted in diameter at the alveolar 
 region, then gradually swelling into a club, with 
 an obtuse apex. L.L., R.H. Bay. 
 
 I am much at a loss to determine what is really in- 
 tended by the above name of authors. What I take to 
 be our B. clavatus is a rather short, thick kind, about 
 two inches long plentiful in the Lower Lias, and 
 occasional in the Middle, but the alveolar part generally 
 wanting. It resembles the next. 
 
55 
 
 84. B. CHARMOUTHENSIS, Blake. PI. iv., f. 5. 
 
 Length If inch, four times the diameter of the 
 club, contracted in the alveolar region, which is 
 multangular with elevations and depressions ; apex 
 obtusely pointed with a very distinct foramen. L.L., 
 K.H. Bay. 
 
 Mr. Blake, who kindly sent me a specimen he collected 
 from the Lower Lias at K.H. Bay,, says : "The part near 
 the alveolus is quadrangular, and the apex of the guard 
 is obtuse." Yorks. Lias, p. 317. 
 
 Beds between the Lias and the Oolite. Blea-Wyke, Peak. 
 
 B. ALVEOLATUS, Simp. Syn. ? B. INORNATUS, Ph. Pal. 
 
 pi. xviii., f . 46. 
 
 Short, thick, conical ; length 3| inches, width across 
 the alveolus an inch, tapering with a gentle curve to 
 a rather obtuse apex ; transverse section elliptical. 
 Phillips's figure is more elongated, and the apex is 
 grooved. 
 
 B. PROCUSTJS, Simp. 
 
 General form of the last, but the apical region much 
 flatted ; apex broad, wedge-shaped, with two short,, 
 strong grooves. Mackie's Geo. and Nat. Rep., 
 p. 215. 1865. 
 
 B. MILLERI, Ph. Pal. pi. xviii., f. 19. 
 
 Cylindrical for the greater part of the length, then 
 tapering to an obtuse apex ; length three inches, width 
 four-tenths of an inch. I obtained them in a bed about 
 fourteen feet above the Lias at Blea-Wyke. 
 
56 
 
 NAUTILUS. 
 
 The fossil Nautilus, which has laid buried in our 
 rocks for countless ages, is similar in every respect 
 to the shell of the common Nautilus, which now 
 inhabits the great Indian Ocean and the adjoining 
 seas ; so we can have no doubt, that the creature, 
 which formed it for its habitation, was like those 
 now living. The shell of the living Nautilus is 
 comparatively light, and is divided into air-cham- 
 bers by shelly plates or partitions called septa. 
 Through the centre of these, a tube passes, called 
 the siphuncle, and to which it is firmly attached. 
 The animal resides in the outer cell, which is very 
 spacious. In general form the animal resembles 
 the Cuttle-fish. It is provided with thirty-six 
 arms, or tentacles, which it can throw out at plea- 
 sure, or retract into its cell. With these arms it 
 walks on the bottom of the sea, and seizes its 
 prey, the shell being lighter than the water, rising 
 above it. By expanding its arms, and drawing 
 its body partly out of its cell, it can ascend to the 
 surface, and by withdrawing them, descend to the 
 bottom. The siphuncle is also of use in regulating 
 the animal's motions. For the tube being pliant, 
 when the animal forces into it a certain fluid, it 
 swells out on all sides into the chambers, thus 
 rendering the shell so much heavier. But when 
 the creature wishes to lighten the shell, it with- 
 daws the fluid, and the tube collapses by the 
 
57 
 
 expansion of the air in the chambers. Like the 
 Sepia, it is provided with a horny beak resembling 
 that of a parrot, with which it crushes crabs and 
 molluscous animals, on which it lives. 
 
 The fossil Nautilus, being- a heavy stony mass, 
 may appear to be a very different thing" from the 
 light hollow shell of the recent Nautilus ; but on 
 an attentive examination it will be found that the 
 only difference is, that the interior of the fossil 
 has been filled with stony matter, and the shell 
 has undergone a mineralizing process. 
 
 When cut through the middle, and polished, 
 besides shewing the septa, the siphuncle is often 
 beautifully displayed. It will be seen that this 
 interesting apparatus, like that of the recent Nau- 
 tilus, is situated near the middle of the septa, 
 where it is contracted into a narrow neck, and 
 then swells out between each septum, giving the 
 idea of a row of connected beads, gradually dimi- 
 nishing in size towards the interior. When the 
 animal was perishing 1 , the mud and earthy sub- 
 stances in which the shell became imbedded, en- 
 tered the siphuncle, and filled it up ; but there 
 being no intermediate communication between the 
 exterior and the air-chambers, which form the 
 principal part of the cavity of the shell, they are 
 found either hollow, or as is generally the case, 
 filled with carbonate of lime, and such other sub- 
 stances as have passed through the pores of the 
 
58 
 
 shell, or the membranous siphuncle. These sub- 
 stances, for the most part, are crystallized. In 
 not a few cases, however, the siphuncular mem- 
 brane has given way, and then the black muddy 
 matter of the Lias has entered the hollow spaces, 
 or chambers, which intervene between the septa. 
 
 We may presume, that the remains of the 
 Nautilus, preserved in the strata, bear only a small 
 proportion to the numbers which then existed. 
 For on the death of the animal of the recent 
 Nautilus, it remains for some time at the bottom. 
 But when the fleshy matter has decayed, the shell 
 by its great buoyancy rises, and floats on the 
 surface of the sea ; and is ultimately washed 
 ashore, and destroyed by the waves. It is only 
 when the outer cell, and the siphuncle get filled 
 with earthy matter that the shell can become 
 imbedded. So it has been with the fossil Nautilus. 
 The same remarks may be applied to the Am- 
 monites. 
 
 Generic Characters. Shell univalve, involute, 
 chambered ; septa plain, concave towards the mouth ; 
 siphuncle passing nearly through the centre of the 
 septa. 
 1. NAUTILUS ASTACOIDES, Y. fy B. 
 
 Outer whorl ventricose; inner volutions rapidly 
 diminishing, concealed ; umbilicus small ; striae lon- 
 gitudinal, coarse, often obsolete. 
 
59 
 
 The common Nautilus of the Upper Lias is undoubtedly 
 the one Young named N. astacoides. It often attains to 
 a considerable size. There is a fine specimen in the 
 Whitby Museum, eleven inches in diameter, and eight 
 inches thick. The shell is thin, and of a dark brown 
 colour, but it is seldom preserved. The cast is smooth 
 and shining, displaying the curved edges of the septa, 
 which give it the appearance of the joints of the lobster's 
 tail. It is well known amongst collectors as the Lobster- 
 tail Nautilus. As the various chambers are often held 
 together merely by the stony matter, which has filled the 
 siphuncle, they are often readily dislocated, so as to shew 
 in a very instructive manner the structure of the whole. 
 In some specimens a slight elevated line may be seen, 
 passing along the back of the whorls, as in Sowerby^s 
 N. lineatus, but this is by no means a constant character. 
 
 I may here give a description of one which may be a 
 variety of this. 
 
 2. Umbilicus wider than common, longitudinal striae 
 numerous, strong, zigzag, and waving, equal to the in- 
 tervening flattish spaces, crossed by numerous fine, faint, 
 transverse striae, and many more distinct lines of growth, 
 which bend strongly from the aperture in passing over 
 the back ; cast smooth ; diameter four inches. It might 
 be named N. reticulatus. Mr. Blake suggests this may 
 be a variety of N. striatus, Sow., but the striae are very 
 different. 
 
 3. N. YOUNGI. N. ASTACOIDES, Simp. 
 
 Back flatted ; strise transverse, obsolete, bend 
 from the aperture in passing over the back. 
 
 Mr. Blake suggests that this may be N. intermedius, 
 Sow., but the transverse striae forbid it. 
 
 4. N. ANNTJLARIS, Ph. N. UNDULATUS, Y. $ -# 
 
 Rather depressed, umbilicus rather wide; radii 
 broad, obtuse, prominent, slightly waving, obsolete 
 on the back; shell thick; longitudinal striae strong, 
 
60 
 
 distinct; sides and back regularly convex, inner 
 margin of the whorl quickly rounded; diameter 2 
 inches, width across the aperture 1-| inch. 
 
 This may be called thick, but by no means ventricose, 
 as is usual in this genus; and the whorls appear to 
 diminish little towards the interior ; but the inner volu- 
 tions are wanting. The umbilicus is rather wide, and 
 the sides slope but little. It is well distinguished by the 
 short, obtuse radii, or undulations on the side of the 
 whorl, and by its thick shell. It was first described and 
 named by Young, who says it was from the alum shale, 
 but does not say from what particular bed. Young named 
 it N. undulatus, but as Sowerby had previously given that 
 name to another, I adopt that given by Phillips. Whitby 
 Museum. 
 
 5. N. HETEROGENUS, Simp. 
 
 Outer whorl rather ventricose, sides and back 
 regularly convex, inner margin quickly rounded, 
 aperture transverse ; inner volution half exposed ; 
 umbilicus wide; shell thick, decussated with coarse, 
 obsolete, longitudinal and transverse striae, which 
 vanish towards the aperture, where there are some 
 irregular tubercles ; diameter two inches. 
 
 In this example there is a strong peculiarity. For 
 besides the usual central siphuncle, there is what appears 
 to be another, along the inner margin of the whorl ; but 
 this, no doubt, is only a hollow spur passing from one 
 septum to another. It is in the Whitby Museum, and 
 was previously in Mr. Belcher's collection. The matrix 
 indicates the L. Lias. 
 
 6. N. ARARIS, Dum., BlaJce. 
 
 This has been noticed as occurring in the upper half of 
 the Lower Lias at Robin Hood's Bay. "It is distin- 
 guished by the aperture becoming narrower towards the 
 front before making the convexity, and by the obliquity 
 of the septa." No good example has been obtained. 
 
61 
 
 AMMONITES. 
 
 The Ammonite, the Cornu Ammonis of the an* 
 cients, and the Snakestone of more modern times,, 
 is now well known to be an extinct genus of shells, 
 found buried in the strata over a large portion of 
 the temperate regions of the northern hemisphere. 
 After a careful examination of the structure of the 
 shell, and of all the circumstances connected with 
 it, which have come under our observation, there 
 can be no doubt, that the animal which formed 
 it was, in its general nature, like that of the 
 recent Nautilus. In this opinion all naturalists 
 of the present day concur ; but it is a matter of 
 doubt, whether the animal was enclosed in the 
 shell, as in the recent Nautilus pompifcux, or whether 
 the shell was enclosed in the fleshy part of the 
 animal, as in the Nautilus spirula. The thinness 
 and delicacy of the shell, and the small space 
 allowed for the animal within the shell, and other 
 circumstances lead to the belief, that the mantel 
 of the animal enclosed the whole of the shell. 
 
 In respect to the shell, they differ; for whilst 
 the Nautilus has the siphuncle passing through 
 the middle of the septa, the siphuncle of the Am- 
 monite passes along the back. In the Nautilus,, 
 the septa are plane, and concave to the mouth ; 
 whilst in the Ammonite the septa are convex to 
 the mouth, and their edges ramify in numerous, 
 foliations and meanderings, which are beautifully 
 
62 
 
 displayed where the shell happens to be removed. 
 Ammonites have existed from very remote geo- 
 logical periods, but it was during the formation 
 of the Lias and Oolite, that they appeared in the 
 greatest numbers and variety. They then began 
 to decline, and became extinct with the chalk. 
 
 Generic Characters. Shell univalve, involute, 
 chambered ; septa angulated or waving ; siphuncle 
 passing along the back. 
 
 The Ammonite constitutes so noble, and well- 
 defined a genus, that it cannot be divided into 
 sub-genera with any degree of usefulness or pro- 
 priety. 
 
 For the better recognition and classification of 
 the species, we will, as before, consider them as 
 forming certain artificial groups, with some degree 
 of laxity. 
 
 I. Those without a dorsal keel or furrow. 
 II. With a dorsal keel. 
 
 III. A keel between two furrows on the back. 
 
 IV. A dorsal furrow only. 
 
 I. Without a dorsal keel or furrow. 
 (a.) yo spines. 
 
 1. A. HETEROPHYLLUS, Sow., pi. 
 
 Inner volutions concealed, outer whorl rather 
 more than half the diameter of the shell ; umbilicus 
 small ; striae numerous, annular, diverging, rather 
 
63 
 
 flatted, separated by concave spaces ; aperture 
 ovate ; diameter from an inch to sixteen inches. 
 
 This Ammonite is found in every bed of the Upper Lias ; 
 but those specimens which are obtained from the upper 
 part of this division are the largest. The striated shell 
 is thin, and when removed, the varied angular and 
 rounded forms of the septa are displayed, which give to 
 the cast a beautiful foliated appearance. On the outer 
 whorl. of some large specimens maybe observed straight, 
 obtuse radii, which spread out like a fan, and become 
 obsolete before reaching the .back ; but in the smaller 
 specimens, these are scarcely discernible. 
 
 Var. With the striae distant. 
 
 2. A. EASINGTONENSIS. 
 
 Inner volutions concealed, outer whorl tumid, 
 rather more than half the diameter, with a line 
 along the middle of the side, and a slightly concave 
 band within it ; umbilicus deep ; striae numerous, 
 annular, diverging, distinct, fine, rounded, sepa- 
 rated by sharp grooves ; aperture ovate ; diameter 
 
 4^ inches. 
 
 This greatly resembles A. heterophyllus ; the whorls 
 are more tumid, and the striae are closely united, and 
 finely rounded ; and on the inner half of the whorls 
 there is a slightly concave space, and a line as if formed 
 by the bending of the shell, in the same way as a line is 
 often formed by the bending of writing paper. In the 
 same block, there is a young shell, which has this char- 
 acteristick line and depression. It is from the Jet Rock 
 at Boulby ; upon a slab containing a great number of 
 A. exaratus. I am not able to see the septa. 
 
 3. A. LABRATUS, $imp. , 
 
 Inner volutions concealed, outer whorl nearly 
 
64 
 
 two thirds the diameter ; umbilicus small with an 
 elevated rim ; striae numerous, fine, slightly fim- 
 briated or roughened ; aperture ovate ; diameter 
 2^ inches. 
 
 This also greatly resembles A. heterophyllus, but it has 
 a rim round the umbilicus, and the septa are more simple 
 and of a different form. Specimen imperfect. 
 
 4. A. PEREGRINUS, Simp 
 
 A fragment with a finely rounded back equal to a semi- 
 circle, then a sudden depression on the side, a flat space, 
 and a shallow umbilicus ; siphuncle well displayed where 
 the shell is wanting ; transverse striae numerous, flat, in 
 places nearly obsolete ; diameter three inches. 
 
 5. A. ANTIQUATUS, Simp. 
 
 A fragment, deeply indented by the succeeding whorl, 
 with numerous, irregular, obsolete ribs, or undulations ; 
 and in many places may be observed numerous fine, 
 transverse striae, crossed by faint, distant, longitudinal 
 striss ; but little of the shell remains : aperture ovate, 
 resembling that of A. heterophyllus, but the outer whorl 
 has been much narrower ; diameter eight or nine inches. 
 I have seen a larger fragment from the Lower Lias at 
 Eedcar. 
 
 6. A. LOSCOMBEI, Sow. PL clxxxiii. A. AMBIGUTJS, Simp. 
 Much depressed ; volutions four, inner ones 
 
 eight-tenths concealed, outer whorl more than half 
 the diameter ; radii twice bent, numerous, faint 
 aperture ovate ; diameter 2^ inches. 
 
 The markings on the shell, which is very thin, differ 
 very little from those on the cast. L.L., w, E.H. Bay, 
 Huntcliff. 
 
65 
 
 7. A. ERRATUS, Simp. 
 
 Much depressed ; volutions four, inner ones eight- 
 tenths concealed, outer whorl half the diameter, 
 sides flatted ; radii twice bent, unequal, pass over 
 the back ; aperture ovate ; diameter an inch and 
 four-tenths. 
 
 This ammonite reminds one of A. elegans or A. 
 exaratus ; but it is entirely destitute of a keel. The shell 
 is thin and of a greyish colour, and where it is absent 
 the cast is black and shining. Jet Rock, U.L., Whitby. 
 
 8. A. SUBCARINATUS, Y. Sf B. 
 
 Inner volutions concealed, outer whorl half the 
 diameter, flatted on the back ; radii straight, obtuse, 
 irregular, nearly obsolete ; striae very numerous, 
 fine, irregular, annular, diverging ; aperture ovate ; 
 diameter four inches. ILL., 1, Whitby. 
 
 This species is well charaterised by an elevated line 
 along the middle of the back. The striae resemble fine 
 hairs, which unite in places and then separate, and 
 occasionally split in two. 
 
 9. A. FABRICATES. 
 
 Rather tumid ; inner volutions concealed, outer 
 whorl more than half the diameter ; umbilicus 
 large ; radii on the inner part of the whorl broad, 
 flattish, obsolete on the rounded back ; striae nu- 
 merous, annular, fine, fimbriated ; aperture ovate ; 
 diameter half an inch. 
 
 Probably from the Jet Rock. 
 
 10. A. PBRSONATUS, Bean's MSS. Simp. 
 
 Volutions four or five, exposed, outer whorl 
 one-third the diameter ; sides gently rounded, back 
 F 
 
66 
 
 rather angular with a slightly elevated line or 
 obsolete keel ; radii obtuse, irregular, inclining 
 backwards, nearly obsolete towards the aperture, 
 obsolete on the back ; transverse strige obsolete, 
 cast smooth ; aperture ovate ; diameter 1 inch. 
 Not the young of A. subcarinatus. L.L., ind. band,, 
 26, E.H. Bay. 
 
 11. A. DENNYI, Simp. 
 
 Volutions three, inner ones half concealed, outer 
 whorl about half the diameter, sides flatted, back 
 obscurely triangular or round ; radii few, nearly 
 obsolete ; sulci or constrictions regular, small, 
 distant, straight, diverging, distinct on the inner 
 margin of the whorl, obsolete on the back ; aper- 
 ture sub-quadrate or ovate ; diameter half an inch. 
 
 Considering its small size, it is rather a thick species. 
 The constrictions are generally obsolete on the back, but 
 in some places they are visible : they are then observed 
 to make a sudden bend towards the aperture. It is 
 smooth and shining, and of a bronze colour. L.L., ind. 
 band, 13, E.H. Bay. 
 
 Var. Without constrictions. 
 
 12. A. ARCTUS, Simp. 
 
 This greatly resembles the last, but the outer whorl is 
 narrower; the back is rounded; it has a few obscure 
 annular radii, but no constrictions ; it occurs along with 
 the last. 
 
 13. A. NANUS, Simp. 
 
 Volutions several, inner ones three-quarters con- 
 cealed, outer whorl less than half the diameter, 
 with deep constrictions on its inner part passing 
 
67 
 
 over the rounded back ; aperture ovate ; diameter 
 quarter of an inch. 
 
 This is a cast and greatly resembles A. Benny i, but 
 the outer whorl is narrower, and the ramifications of the 
 septa are much more deeply lobed. Probably from the 
 Lower Lias. 
 
 14. A. ILLATUS, Simp. 
 
 Volutions four or five, much exposed ; radii 
 strong, straight, not equal to the intervening con- 
 cave spaces; aperture ovate; diameter 1J inch. 
 
 The outer whorl is considerably more than one-fifth 
 the diameter 3 there is something like an imperfect keel, 
 but the back is rather water-worn ; the radii on the 
 inner whorls have a triangular appearance, ending in a 
 sharp point; shell roughish, with obsolete transverse 
 strise. L.L., R.H. Bay. 
 
 15. A. SOCTALIS, Simp. T. & B., pi. vii., f, 6. 
 Volutions several, exposed, outer whorl . two- 
 fifths the diameter ; radii irregular, diverging, pass 
 unaltered over the back ; striae fine, longitudinal ; 
 aperture rather ovate ; diameter four inches, L.L. , 
 R.H. Bay. 
 
 16. A. INVOLTJTUS, Simp. 
 
 Volutions seven, inner ones quarter concealed, 
 outer whorl two-fifths the diameter, sides rather 
 depressed, inner margin full and rounded; radii 
 obtuse, bend towards the aperture in passing over 
 the back ; aperture ovate ; diameter 3| inches. 
 
 The radii of the cast are nearly obsolete ; the shell, 
 where it exists, is smooth, and without strise ; the radii 
 in general pass over the back undivided; but in the 
 intervening furrows, may be seen, in many places, strise 
 
68 
 
 or the rudiments of other radii. The ramifications of 
 the septa are exceedingly numerous, intricate, and 
 pointed on the outer whorls, crowding the entire surface. 
 L.L. 
 
 17. A. JUBENSIS, Zeit. Pal. Ixxiv., f . 3. A. GUBEBNATOB, 
 
 Simp. 
 
 Volutions four or five, inner ones quarter con- 
 cealed ; outer whorl not quite half the diameter, 
 inner margin prominent, suddenly rounded ; aper- 
 ture ovate ; diameter 3 inches. U.L., 1, Peak. 
 
 This is a smooth bright shell, without radii or striae. 
 In the rapid diminution of the whorls it resembles A. 
 fimbriatus, but the prominence of the inner margin of 
 the whorls, and the partial concealment of the inner 
 ones, at once distinguish it. 
 
 18. A. FIMBBIATUS, Sow: PL 164. 
 
 Volutions four or five, rapidly diminishing, ex- 
 posed, covered with numerous undulating, annular 
 fimbriated striae; outer whorl not half the diameter; 
 aperture ovate ; diameter 4 inches. ILL., 6, 7. 
 
 This is one of the most handsome shells found on our 
 coast. It is by no means rare, and often reaches a large 
 size. On the inner whorls may sometimes be observed 
 obsolete radii, and also a few constrictions, but its most 
 distinguishing character is its fringed striae, caused by 
 numerous concentrick striae crossing the other. It is not 
 uncommon to find Orbecula reflera attached to the shell. 
 
 It is Young's A. cornucopia, but as Sowerby's name 
 has priority I have given Young's name to another. 
 I have a part of the outer whorl of a similar form ; but 
 the striae are nearly obsolete. It was in stratum s of 
 the Lower Lias at R.H. Bay. It is noticed by Mr. Blake, 
 as occurring in the same bed at Huntcliff. It is so far 
 
69 
 
 separated from Sowerby's shell that it can scarcely be 
 the same species and may be named A. senex. 
 
 A fragment of an outer whorl of an Ammonite which 
 I found in bed s of the Lower Lias at the north cheek 
 of Eobin Hood's Bay,, which may have been four or five 
 inches in diameter, belongs to this group. It is tumid, 
 the inner margin of the whorl full and quickly rounded, 
 the outer part ovate. It has the same slender annular 
 striee, but little of the shell remains, and the cast is 
 smooth. It may belong to this species, but there is A. 
 lineatus. Sch. 
 
 I have observed in the ironstone bands at Hawsker 
 Bottoms, a small Ammonite, which has a strong resem- 
 blance to the one now described. The whorls are natter, 
 and I am not able to see the fimbriated striae. I am 
 therefore unable to say whether it be a distinct species, 
 or the young of A. fimbriatus. 
 
 19. A. CORNUCOPIA, Simp. Pal. pi. Ixxiii. 
 
 Very similar to the last, but a much coarser 
 shell ; the striae are scarcely fimbriated ; and the 
 aperture is round, or transverse. M.L.^ 0, 
 Hawsker. 
 
 It is generally of a large size, and is obtained from a 
 bed lower in the series than the last. Both naturalists 
 and fossilists consider it a distinct species. 
 
 There are in the Whitby Museum two good examples 
 of this fossil twelve inches in diameter, and I discovered 
 one of equal size, but imperfect at the base of clock case. 
 Nab, Hawsker Shore. 
 
 20. A TENTJICOSTATTTS, T fy S. 
 
 Volutions six, exposed, rapidly diminishing ; 
 outer whorl two-fifths the diameter ; radii very 
 numerous, slender, annular; aperture ovate ; diame- 
 ter 2^ inches. M.L., o, Haweker. 
 
70 
 
 The form of the whorls of this Ammonite strongly re- 
 sembles the last. It is distinguished by its very slender 
 hair-like radii, which are entirely destitute of fimbrise. 
 
 21 A. rAsciATUS, Simp. 
 
 Depressed ; volutions exposed ; outer whorl 
 more than one-third the diameter; radii annular, 
 nearly obsolete ; striae annular, separated by flat 
 or slightly concave spaces ; aperture ovate ; dia- 
 meter 1 inch. U.L., v, 7. 
 
 The cast of the inside is smooth, with very obsolete 
 radii, or annular swellings, towards the aperture ; the 
 striae resemble narrow thin strips of paper, laid on so as 
 to show one edge ; the aperture is nearly a very regular 
 ellipse of but little eccentricity. The inner whorls of 
 the only specimen I have seen are defective. I found it 
 ia the Jet Rock at Hawsker Bottoms. 
 
 22. A. NITIDUS, T. $ B. A. BALHEALUS, Ph. 
 Volutions three or four, rapidly diminishing, ex- 
 posed ; on the outer whorl are numerous, irregular, 
 slender, annular lines, or rings, which are nearly 
 obsolete on the inner margin; aperture circular; 
 diameter 1 inch. ILL., 7. 
 
 This beautiful shining little Ammonite is from the 
 Jet Rock on the Hawsker shore, where it is not very un- 
 common. The rings, or radii, are very irregular, even 
 on the same specimen ; sometimes prominent, at other 
 times nearly obsolete. 
 
 23. A. ANGUIFOBMIS, Simp. 
 
 Volutions five or six, exposed ; radii straight, 
 very obtuse, nearly obsolete on the back and inner 
 whorls ; transverse striae irregular, faint ; aperture 
 
71 
 
 circular ; diameter one inch and seven-tenths. 
 L.L., ironstone bands, R.H. Bay. 
 
 The inner whorls of this species are very slender and 
 delicate, but the outer whorl is rather coarse. Many 
 specimens have a row of small tubercles on the outer 
 margin of the whorls, but this is not a constant cha- 
 racter. With a strong magnifier may be seen faint 
 longitudinal striae, in places merely fimbriating or 
 dotting the transverse striae. 
 
 24. A. TUBELLTJS, Simp. 
 
 Volutions five, exposed ; rapidly diminishing', 
 smooth, gradually rounded ; radii few, obsolete ; 
 aperture ovate, enlarged ; diameter three-eighths 
 of an inch. L.L., z. 
 
 This is the most beautiful thing which I have seen of 
 the kind, with its golden, shining, attenuated whorls 
 just touching one another, and its trumpet-shaped 
 mouth. The edges of the septa are very simple, con- 
 sisting of three slightly indented lobes, which bend 
 towards the aperture on each side of the whorl. The 
 enlargement of the mouth shows them to be full-grown 
 specimens. I have seen several with tubercles, and 
 stronger radii, near the aperture. They are found on 
 the beach close to Bay-town. 
 
 25. A. ERUGATUS, F. fy B. 
 
 Depressed ; volutions six, exposed, back rounded ; 
 radii straight, obtuse, nearly obsolete on the outer 
 whorls ; striae diverging, aperture ovate ; diameter 
 1-J- inch. 
 
 Although the radii are distinct on the inner whorls^ 
 and the striae still remain on the outer whorls, this is, 
 nevertheless, nearly a smooth species. It is from the 
 Lower Lias at Robin Hood's Bay. It not unfrequently 
 
72 
 
 occurs in a semi-transparent state, when the waving 
 septa are beautifully displayed. 
 
 26. A. RUTILANS, Bean's MSS. Simp. 
 
 Depressed ; volutions six, inner ones but little 
 concealed ; outer whorl rather more than one-third 
 the diameter ; sides regularly rounded ; radii obtuse 
 on the inner whorls ; more numerous and nearly 
 obsolete on the outer whorl ; aperture ovate ; 
 diameter If inch. L.L., y. 
 
 Var. With small sharp tubercles on the inner whorls. 
 
 On the inner whorls the back is triangular, but on the 
 outer whorls it is rounded ; where the shell remains it is 
 quite smooth and destitute of striae, but in general it is 
 wanting, when the edges of the septa are beautifully 
 displayed ; on the inner whorls the lobes are very plane, 
 but on the outer whorls they become more serrated, 
 shooting out lengthened fingers, until they occupy the 
 whole surface. This shell is of a fine yellow colour, and 
 is by no means uncommon in a thin brassy bed or layer 
 in the Lower Lias at Eobin Hood's Bay, which is also 
 rich in other fossils. 
 
 27. A. BELCHEBI, Simp. Pal. pi. xv., f. 7. 
 Volutions six or seven, exposed, rather flat on 
 
 the sides, back rounded ; radii straight, prominent, 
 obtuse, obsolete on the back, separated by concave 
 spaces ; aperture squarish ; diameter 1^ inch. A 
 cast, L.L., R.H. Bay. 
 
 28. A. JOHNSTONI, Sow. PI. ccccxlix. 
 
 This greatly resembles the last. The ribs are less 
 prominent and the back rather angular. It is from the 
 very lowest beds of Lias at Eedcar. Dr. Wright has 
 figured several kindred forms. Pal. pis. xv., xvi. L.L., 23. 
 
73 
 
 29. A. CONVOLUTUS, Simp. 
 
 Volutions five, exposed ; radii strong, waving, 
 rather obliquely inclined towards the aperture, ob- 
 solete on the back and the inner whorls ; aperture 
 round ; diameter- sixth-tenths of an inch. L.L., 
 E.H. Bay. 
 
 30. A. RESUPINATUS, Simp. 
 
 Volutions five, exposed ; radii on the outer whorls 
 sharp, prominent, bend from the aperture, separated 
 by wide concave spaces, form sharp points on the 
 outer margin of the whorl, nearly obsolete on the 
 back, absent on the inner whorls ; striae numerous, 
 distinct, rather bent ; shell thick ; aperture quad- 
 rate ; ' diameter one inch. 
 
 This species is smooth and shining, both on the cast 
 and where the shell remains. The block from whence it 
 was extracted is in the Whitby Museum, and was pro- 
 cured from the Lower Lias at Eobin Hood's Bay. Ind. 23. 
 
 31. A. EXORTTJS, Simp 
 
 Volutions five, exposed, outer whorl more than 
 a quarter the diameter ; radii prominent, strong, 
 annular, separated by concave spaces ; aperture 
 sub-quadrate ; diameter one inch and three-tenths. 
 
 The aperture is nearly square, and on the outer angles 
 of the whorls the radii in places have slight tubercles. 
 Mr. Clarkson's Col. L.L. j R.H. Bay. 
 
 32. A. TRIVIALIS, Bean's MSB. Simp. 
 
 Volutions five, exposed, outer whorl one-third the 
 diameter; radii numerous, sharp, slender, diverging, 
 
74 
 
 form obtuse angles on the back ; diameter three- 
 quarters of an inch. 
 
 This beautiful little ammonite is from the Lower Lias, 
 and, like several others from those beds, it is of a fine 
 bronze colour. This, together with the elegance of the 
 whorls and radii, render it one of the most beautiful of 
 our ammonites. On the inner whorls the radii are very 
 close, and on the outer whorls they are gradually more 
 and more separated by flattish spaces ; the aperture 
 becomes more and more quadrate, and the radii, before 
 passing over the back, form small tubercles. On some 
 the radii are strong and prominent, others have the outer 
 whorl nearly smooth ; indeed the varieties are so numerous 
 that they can scarcely be defined. L.L., x, R.H. Bay, 
 Saltburn. 
 
 33. A. EIPLEYI, Simp. 
 
 Volutions five or six, exposed ; radii straight, 
 diverging, obtuse, bent towards the aperture in 
 passing over the back, where they are obsolete ; 
 a row of minute tubercles on the outer margin of 
 the whorls ; aperture quadrate ; diameter six-tenths 
 of an inch. L.L., R.H. Bay. 
 
 34. A. AUBEUS, - 
 
 Volutions five, exposed, outer whorl a quarter 
 the diameter ; radii numerous, straight, sharp, 
 equal to the intervening concave spaces, orna- 
 mented with two rows of flattened tubercles ; back 
 ronnded, nearly plane ; aperture sub -quadrate ; 
 diameter one inch. L.L., R.H. Bay. 
 
 This resembles A. Eipleyi, but the outer whorl is 
 narrower, and the radii are much sharper, and more 
 
75 
 
 prominent, and have two rows of tubercles j the 
 ramifications of the septa are very delicate, rounded, 
 and numerous. 
 
 35. A. PLANICOSTATUS, Sow. PL Ixxiii. 
 
 Volutions five, exposed; radii slender, prominent, 
 on the back bend towards the aperture, separated 
 by flattish spaces, aperture nearly circular. The 
 older specimens have knobs near the aperture. 
 L.L., 22, R.H. Bay. 
 
 They are rather plentiful in the shale beneath the 
 A. stellaris bed, but the middle whorls are often want- 
 ing. They are more slender than the southern examples, 
 if indeed they are the same species. 
 
 36. A. DIVEBSTJS, Simp. 
 
 This species is closely allied to the next, and at pre- 
 sent is very rare. I have seen only a portion of the two 
 outer whorls. The radii on the outer whorl are more 
 distant and much sharper than in A. gagateus. They 
 have, also, two rows of small tubercles towards the mid- 
 dle of the whorl, and are separated by flattish concave 
 spaces. The radii on the inner whorl are still more 
 distant, and are blunter, aperture circular; diameter 
 2 inches. 
 
 37. A. GAGATEUS, F. # B. 
 
 Volutions six, exposed, inner margin of the 
 whorls rather prominent ; radii prominent, annular, 
 separated by concave spaces; aperture roundish, 
 rather transverse ; diameter If inch. 
 
 The radii pass over the back with very little altera- 
 tion, or very slightly flatted. The shell, which is gene- 
 rally wanting, is roughish, and the cast is often black 
 and shining. L.L., 13, R.H. Bay. 
 
76 
 
 38. A. NEGLECTUS, Simp. 
 
 Volutions seven or eight, exposed ; radii prominent, 
 separated by widish concave spaces, slightly bend 
 towards the aperture on the back near an elevated 
 line or imperfect keel; aperture circular; diameter 
 If inch. 
 
 The shell is rough, wth a few annular striae. It is 
 more depressed than A. gagateus, which it much re- 
 sembles. L.L., E.H. Bay. 
 
 39. A. LURIDTTS, Simp. 
 
 Thickish ; volutions five, exposed, outer whorl 
 more than a quarter the diameter ; radii sharpish, 
 strong, annular, rather depressed on the back, 
 where they bend towards the aperture, separated 
 by widish spaces ; a few annular striae ; aperture 
 little more than a semicircle ; diameter If inch. 
 
 The whorls of this Ammonite diminish very little in 
 width, forming a shallow umbilicus. The shell is 
 thick, and formed of several layers, of a brown colour. 
 Mr. Leckenby's Col. 
 
 40. A. INTEGRICOSTATTJS, Simp. 
 
 This resembles A. gagateus, but it is more de- 
 pressed, and the whorls are more slender, very 
 prominent on the back, and separated by wide con- 
 cave spaces ; the aperture is about a semicircle. 
 
 The outer whorls of this Ammonite are rather abun- 
 dant in a bed a little to the south of Bay-town ; but the 
 inner whorls are so decomposed as not to admit of 
 description. 
 
 41. A. VITREUS, Simp. 
 
 Volutions seven, exposed, central ones quite 
 
77 
 
 smooth ; radii on the remainder numerous, pro- 
 minent, sharp, slightly bend towards the aperture, 
 where there is a flattish space, separated by con- 
 cave spaces,; shell smooth, glassy, and cracked; 
 aperture round ; diameter three-quarters of an 
 inch. L.L. 
 
 Inner whorl very delicate ; outer ones stronger than 
 in A. arcigerens. 
 
 42. A. CEREUS, Simp. 
 
 Volutions six, exposed, outer whorl nearly a 
 quarter the diameter ; radii very prominent on the 
 sides, nearly obsolete on the back, separated by 
 rather wide concave spaces ; aperture ovate, trans- 
 verse ; diameter nine-tenths of an inch. 
 
 Shell smooth and bright, with a few striae, colour 
 light-brown. L.L., R. H. Bay. 
 
 43. A. ARCIGERENS, PH. 
 
 Volutions six, exposed, slender ; radii prominent, 
 meet in very obtuse angles on the back, separated 
 by concave spaces ; aperture circular ; diameter 
 three-quarters of an inch. 
 
 This may be easily distinguished from any of the fol- 
 lowing by the slenderness of the whorls. 
 
 Var. Radii nearly obsolete on the back. L.L., E.H. 
 Bay. 
 
 44. A. OMISSUS, Simp. 
 
 Volutions five, exposed, outer whorl more than 
 one-third the diameter ; radii numerous, prominent, 
 sharp, separated by concave spaces, suddenly bend 
 towards the aperture in passing over the back ;. 
 
78 
 
 aperture roundish ; diameter one and two -tenths 
 of an inch. 
 
 This may be distinguished from A. defossus by the 
 inner whorls being more slender and numerous, and by 
 their having more numerous and finer radii. It is from 
 the same beds as the last. 
 
 45.. A. FiGULiNUS, Simp. 
 
 This also has sharp radii, strongly bent towards the 
 aperture on the back ; but the whorls are much stronger, 
 and the radii separated by wider and deeper concave 
 spaces ; the aperture between the radii would be cir- 
 cular, but if taken in a line through the radii, it would 
 be many-sided, for the outline from the inner edge of 
 the whorl is first convex, then, for a short space, it be- 
 comes concave, so as to form two angles on the side of 
 the whorl ; it then undulates across the back, where 
 the radii seem as if rubbed up with the finger in a 
 plastic state. 
 
 46. A. DEFOSSUS, Bean's MSB. Simp. 
 
 Volutions five or six, exposed ; radii prominent, 
 sharp, straight, suddenly bend towards the aper- 
 ture in passing over the back, where they are much 
 flatted ; intervening spaces flattish ; striated ; aper- 
 ture quadrate ; diameter If inch. 
 
 This has long been confounded with the next, which 
 it much resembles. As it occurs so frequently in this 
 form, there can be little doubt that it is a distinct species. 
 It may readily be distinguished from the last by the 
 flatted back, which in some places is even concave. The 
 whorls are less numerous than in A. arcigerens. L.L., d, 
 K.H. Bay. 
 
 47. A. CAPBICOBNUS, Schlotheim. 
 
 As this name has been applied in a loose way to a 
 number of species which have strong, prominent, annu- 
 lar ribs, I retain Young's name for the next, and confine 
 
79 
 
 this to a variety with sharper ribs, and deeper concave 
 spaces, which is rather plentiful in the ironstone band, 
 x, M.L., Hawsker. 
 
 48. A. MACULATUS, F. 4" -B. Pal. pi. xxxiv., xxxv. 
 Volutions six, exposed ; radii prominent, annular, 
 
 obtuse, separated by wide concave furrows, rather 
 flatted on the back ; striated ; aperture circular ; 
 diameter 3^ inch. 
 
 This shell is obtained from the uppermost beds of the 
 Lower Lias, and is often spotted with whitish, a character 
 which it receives from the rock in which it is imbedded. 
 
 In some specimens I have observed the outer whorl to 
 be greatly enlarged, but I still consider them as the same 
 species. 
 
 49. A. JAMESONI, Sow. PI. dlv. 
 
 Volutions five or six, much exposed ; outer whorl 
 one-third the diameter; radii annular, rather sharp, 
 slightly flatted on the back, where they turn towards 
 the aperture, not equal to the intervening concave 
 spaces ; shell irregularly and transversely striated ; 
 cast smooth; aperture ovate; diameter 2^ inches. 
 L.L., g, R.H. Bay. 
 
 This comes the nearest to A. Jamesoni of any I have 
 seen. Where the shell remains, the radii are more obtuse, 
 and in the older specimens there is an elevated line on 
 the back, amounting almost to a keel. 
 
 50. A. SAGITTARIUS, Blake. PI. vii., f. 2. 
 
 Volutions four or five, inner whorls but little con- 
 cealed, outer whorl one-third the diameter; radii 
 sharp, prominent, not equal to the concave spaces; 
 striae in the direction of the radii ; aperture ovate ; 
 diameter 2^ inches. 
 
80 
 
 This has been reckoned a variety of A. Jamesoni, but 
 I agree with Mr. Blake in making it a different species. 
 Very seldom more than the outer whorls remain, which 
 are strong. The radii are but slightly bent towards the 
 ovate aperture., and meet on a rounded elevation, or im- 
 perfect keel on the back, where they become obsolete. 
 In some examples the radii, before reaching the back, 
 form small tubercles. The outer whorls are very plenti- 
 ful at the indurated band, No. 16, L. Lias, E.H. Bay. 
 
 51. A. CBENULARIS, Ph. G. Y., pi. xii, f. 22. 
 
 Whorls rapidly diminishing, inner ones slightly 
 concealed, outer whorl nearly half the diameter ; 
 radii straight, rather slender, prominent, unequal, 
 pass over the back, where they are rather flatted ; 
 aperture elliptical ; diameter 3J inches. L.L. 
 
 I possess only a fragment of this ammonite, which is, 
 however, highly characteristick. The curvature of the 
 sides is rather greater near the inner margin of the whorl, 
 from whence proceed more than one-half the radii ; the 
 rest commence about the middle of the whorl, and they 
 all have a strong resemblance to pieces of cord laid on. 
 The sides of the whorl become less convex near the 
 aperture, which is a somewhat eccentrick ellipse. 
 
 52. A. CHARMASSEI, D'Orb. 
 
 A fragment sent me by Mr. Tate as a variety of this 
 species from the Lower Lias at E-edcar. 
 
 Much depressed, whorl broad, flat; radii numerous, 
 round, broader than the intervening concave spaces, 
 gently bend to the aperture. 
 
 Specimen very imperfect. It may be a variety of the 
 last. 
 
 53. A. JEQUALIS, Simp. 
 
 Outer whorl nearly one -third the diameter, inner 
 margin prominent ; radii equal, bend towards the 
 
81 
 
 aperture on the outer part of the whorl, nearly 
 obsolete on the middle of the back, not equal to the 
 intervening spaces ; aperture ovate ; diameter 1 
 inch. 
 
 A cast with the centre broken; probably from the 
 Lower Lias. 
 
 The following species,, to the end of the section, have all 
 
 a family resemblance to A. communis : 
 Whorls narrow, exposed, with numerous slender, an- 
 nular ribs, which generally split in two on the back. 
 
 54. A. ANNULATUS, Sow. PL ccxxii. 
 
 Volutions seven or eight, exposed ; radii numerous, 
 slender, annular ; aperture circular ; diameter 3^ 
 inches. ILL., 8. 
 
 This differs chiefly from A. communis in having a 
 greater number of whorls, and in the radii being more 
 slender, and in often passing over the rounded back un- 
 divided, like rings. As the round nodules in which these 
 are contained readily split when struck with a hammer 
 so as to display the fossil, and can be closed up without 
 much shewing the fracture, they are known amongst 
 collectors by the name of Jack in the Box. 
 
 55. A. ANNULIFERUS, Simp. 
 
 Radii obtuse, on the outer whorl separated by narrow 
 grooves, split in two, then pass straight over the back, 
 where they are nearly obsolete ; aperture an ellipse, in- 
 dented by the succeeding whorl. 
 
 56. A. SEMICELATUS, Simp. 
 
 Depressed ; volutions seven or eight, inner ones 
 nearly half concealed, outer whorl more than one- 
 fourth the diameter, inner margin depressed, de- 
 pressed near the back ; radii annular, pass nearly 
 G 
 
82 
 
 straight over the back, rounded, fine, numerous, 
 equal to the intervening concave furrows, double in 
 number on the back ; aperture ovate ; diameter 3^ 
 inches. ILL. 
 
 The form of the radii and the smoothness of the cast 
 render this species very like a compressed variety of A. 
 anmilatus ; but it may be distinguished by the greater 
 width of the outer whorl, partly concealing the inner 
 ones, as well as by its more depressed form. 
 
 On the inner whorls the inner margin is prominent ; 
 radii regular, distinct, split in two near the back, flatted, 
 separated by concave spaces ; radii of the cast round the 
 aperture ovate. 
 
 57. A. ATHLETICUS, Simp. 
 
 This resembles A. communis, but is more robust ; the 
 ribs are sharper, and more elevated, some split in two on 
 the outer margin of the whorl, others pass over the back 
 undivided ; inner margin of the whorls prominent ; aper- 
 ture ovate ; diameter four inches. M.L., Hawsker. 
 
 58. A. VEKMIS, Simp. 
 
 Volutions slender j radii nearly obsolete on the outer 
 whorl; aperture nearly round. Jet rock. 
 
 59. A. COMMUNIS, Sow. PL cvii. 
 
 Volutions seven, much exposed, outer whorl less 
 than one-fourth the diameter; radii numerous, an- 
 nular, split in two near the back, distinct, not quite 
 equal to the intervening concave spaces; aperture 
 ovate; diameter three inches. U.L., 1. 
 
 The foliations of the septa are not crowded nor intri- 
 cate ; besides the dorsal lobe, which points from the 
 aperture with two fingers, on the sides of the whorls 
 there are two principal lobes pointing towards the aper- 
 ture, with serratures by no means deep, and which are 
 
83 
 
 rather rounded ; again, there are three principal lobes,, 
 which point in the opposite direction ; the middle lobe 
 has three long points or fingers, of which the middle one 
 is the longest; they are all accompanied with smaller 
 serratures, but subject to much modification. 
 
 As far as I have been able to observe, this is the gen- 
 eral form of the septa also of A. fibulatus, and all the 
 kindred ammonites. 
 
 This is one of the most abundant fossils of the coast, 
 and it appears to be confined to the Upper Lias. They 
 are extracted from round nodules, which, at one time, 
 literally paved some parts of the beach near Whitby ; 
 and a cart-load might have been obtained in a short 
 time. The great demand for these nodules, for the 
 manufacture of Roman cement, has of late rendered 
 them less abundant. As this is the most common 
 species, and the most easily obtained, its value in the 
 market is greatly depreciated. On this account many 
 are rubbed down on one side, and polished, and wrought 
 up into ornaments. By this means their internal struc- 
 ture is beautifully displayed, and in this respect, they 
 are equal to the rarest species. The siphuncle, as in 
 all ammonites, passes along the back, but is very seldom 
 discernible. And as it does not appear that there has 
 been any communication with the exterior and the 
 internal chambers, by means of this apparatus, the cham- 
 bers have been filled by infiltration of carbonate of lime, 
 and other substances, through the pores of the shell.* 
 These substances may be seen deposited in layers around 
 the inner surface of each chamber, until the whole has 
 
 * In some species of ammonites, especially the larger, the process of 
 infiltration has been arrested, so that when cut open they are found 
 empty, affording a beautiful illustration of the structure of the shell. 
 The interior surface of these hollow chambers are often coated with 
 beautiful crystals, shooting in various directions. 
 
 Some from the Jet Kock have the cavities filled with a green kind of 
 oil, which, by exposure to the atmostphere, hardens into a black pitch, 
 that burns with a crackling noise. 
 
84 
 
 been filled up. In general the chambers become gra- 
 dually larger as they approach the aperture ; but what 
 is very singular, in some specimens, near the aperture, 
 may be observed a long chamber filled with the same 
 substance as the rest. Some have considered this as 
 the last chamber, where the animal has resided at the 
 time of its death ; but in all the specimens which I have 
 examined, I have found it enclosed by a septum, and the 
 last chamber filled with the dark substance of the Lias. 
 
 Under the general name A. communis, no doubt there 
 are comprehended many different species, the distinctive 
 characters of which have been lost in the process of 
 petrifaction. 
 
 Without pretending to say which are species, and 
 which only varieties, to some forms we may give par- 
 ticular names, and others we may leave under the name 
 of A. communis. After examining a great number, I 
 find to be most numerous 
 
 Var. (a.) Sides of the whorls depressed, inner angle 
 
 prominent ; aperture ovate. 
 These may be again thus divided : 
 
 1. Radii and intervening spaces equal. 
 
 2. Intervening spaces wider. 
 
 3. With tubercles on the outer margin of the whorl. 
 The next in point of numbers is 
 
 Var. (6.) Whorl narrower, sides tumid, aperture circular. 
 Under this variety we may reckon 
 
 1. A. ANGULATUS, SOW. 
 
 In general character this differs nothing from A. 
 communis, except that it has the inner angle of 
 the whorls truncated; thus a flattish or concave 
 groove is formed along the inner margin of the 
 whorls. This, however, is by no means a constant 
 character ; for this angular part is frequently to be 
 found only on a small portion of the whorls, and 
 often only on one side. This character may some- 
 times be observed on A. fibulatus. 
 
85 
 
 2. This has the inner margin of the whorls prominent, 
 and, like A. angulatus, the siphuncle is in general 
 clearly displayed ; and as, like A. angulatus, it has 
 the inner margin of the whorls prominent, where 
 they are not truncated by the characteristick groove, 
 I am led to think that these two species or varieties 
 are identical. 
 
 3. This agrees with the last in having the siphuncle 
 clearly displayed, like a white line along the back, 
 and in the inner margin of the whorls being promi- 
 nent ; but the radii on the outer whorl bend from the 
 aperture, and meet undivided at an angle on the 
 back. I have seen only one specimen in this way, 
 and as this singularity exists only on the outer whorl, 
 it may possibly have arisen from some accidental 
 cause. 
 
 4. With the outer whorl suddenly enlarged. 
 
 Var. (c.) Inner margin of the whorl prominent, spaces 
 
 between the radii widish, aperture subquadrate. 
 Var. (d.) Whorls slender, radii often pass over the back 
 
 undivided. 
 Var. (e.) Umbilicus shallow ; aperture ovate ; diameter 
 
 2^ inches. Probably a distinct species. 
 1. Much depressed, radii slender, aperture still more 
 ovate; an elegant variety or species. It may be 
 named A. attenuatus. It is not uncommon in the 
 Upper Lias, at Peak. 
 60. A. GRACILIS, Simp. 
 
 Volutions six, exposed, slender, sides rather 
 flatted ; radii regular, distinct ; aperture sub- 
 quadrate ; diameter three-quarters of an inch. Jet 
 Rock, U.L. 
 
 These are found in masses, and are best distinguished 
 by the slenderness of the whorls. They are generally 
 casts, and where the shell remains, it is of a brown colour. 
 In examining a great many of these, I generally found 
 a chamber near the aperture, of great length, and often 
 hollow. 
 
86 
 
 61. A. DELICATUS, Simp. Bean's MSS. 
 
 Eadii sharper and more ' slender than in the last, and 
 the inner whorls generally wanting. ILL. 
 
 62. A. INCRASSATTJS, Simp. 
 
 Very similar to the next,, but the radii terminate on 
 the outer margin of the whorls in sharp tubercles,, from 
 whence proceed numerous striae, or the back is nearly 
 smooth. ILL. 
 
 63. A. CRASSULUS, Simp. 
 
 This possesses the same precision and elegance of 
 workmanship as A. gracilis, but the whorls are much 
 stronger and thicker, and the inner ones more concealed ; 
 radii distinct on the back ; diameter seldom exceeds one 
 inch. ILL., 6, Hunton, Geo. Tr., 1836. 
 
 Var. (a.) Depressed. 
 
 Yar. (&.) Depressed ; radii flatted. 
 
 64. A. cRASsus, Y. # B. 
 
 This has nearly the same characters as A. comniunis, 
 but it is much thicker, and more robust, with a deep 
 umbilicus. The radii are round, but a part of the shell 
 often comes off, then they appear flat. I am not aware 
 that it is ever found along with A. cominunis, but lower 
 in the series; diameter four inches. II. L., 1. 
 
 65. A. CRASSOIDES, Simp. 
 
 This is still thicker in proportion, the inner whorls 
 are rather concealed, and there is a row of tubercles on 
 the middle of the whorls ; the aperture is transverse, 
 and it is altogether a more elegant shell than the last. 
 Jet Kock, ILL. 
 
 66. A CRASSULOSUS, Simp. 
 
 Thickish ; outer whorl less than one-third the 
 diameter ; radii smooth, strong, prominent, distinct, 
 separated by widish concave spaces, split in two near 
 the back, and bend towards the aperture ; aperture 
 half of a regular ellipse; diameter three inches. 
 
87 
 
 This differs chiefly from the communis or crassus type 
 by the prominence of the radii and their wider inter- 
 vening spaces. The shell is thick, and the whole form, 
 gives the idea of strength. The middle is imperfect. It 
 appears to be from the hard iron bands of fhe Middle 
 Lias. 
 67. A. CKASSESCENS, Simp. 
 
 Thickish ; volutions six, exposed, outer whorl 
 more than a quarter the diameter ; radii obtuse, 
 split in two over the back, on the inner whorls 
 armed with tubercles, or short spines; aperture 
 circular, rather transverse ; diameter 2 inches. 
 
 The radii of this ammonite resembles in general that 
 of A. communis, bending slightly towards the aperture 
 in passing over the back. The outer whorls diminish 
 very little, but the inner ones form a rather deep um- 
 bilicus. Inner margin of the whorl not depressed, as in 
 A. crassus, but very sharply rounded. 
 
 68. A. CE.ASSIBUNDUS, Simp. 
 
 Thickish ; volutions seven or eight, much ex- 
 posed ; outer whorl more than a quarter the diameter ; 
 radii annular, prominent, rounded, scarcely equal to 
 the intervening concave spaces ; aperture semi- 
 circular, or ovate ; diameter 2-J inches. 
 
 This is more depressed than the last, and, like it, the 
 outer whorls diminish but little in thickness, rendering 
 the umbilicus deep in proportion to its width. The sides 
 are slightly flatted near the inner margin, which is 
 sharply rounded ; the radii sometimes pass over the entire- 
 whorl undivided, often cease when having passed over 
 the back, or unite with other radii, so as to become in- 
 terlaced together. Mr. Clarkson's col. 
 
 69. A. CRASSIFACTUS, Simp. 
 
 Thick ; volutions six, inner ones one-half con- 
 
88 
 
 cealed, outer whorl nearly one-third the diameter, 
 sides and back regularly rounded ; radii numerous, 
 fine, regular, annular, distinct, rounded, flat on the 
 cast, split in two in passing over the back, equal to 
 the intervening concave spaces ; aperture more 
 than a semicircle ; diameter 2-^ inches. 
 
 This may be at once distinguished from A. crassus by 
 the fineness of the radii. In this respect it resembles 
 A. Crosbeyi, but differs from this and all other kindred 
 ammonites in having the radii of the cast flat ; these 
 appearing as if formed merely by the excavation of the 
 very distinct and concave grooves. 
 
 They occur, but rarely, in the lower part of the Jet 
 Rock in the Upper Lias. The specimen now described, 
 like many others from the same bed, contains mineral oil. 
 
 70. A. CRASSIUSCTJLUS, Simp. 
 
 Volutions six, exposed, outer whorl one-third 
 the diameter ; radii strong, annular, obtuse, split 
 in two on the back, nearly equal to the intervening 
 concave furrows, on the inner whorls fibulate ; 
 aperture circular ; diameter 1 inch. 
 
 This is a very bright and shining species ; of a brown 
 colour, and whitish in the middle. The radii are 
 stronger and more obtuse than in any of the kindred 
 species ; they very seldom pass entire over the whole 
 whorl, for each alternate one splitting in two near the 
 back, unites with a different one on the other side of the 
 whorl, so that they all become interlaced together. It 
 is moderately thick, and the aperture is nearly a correct 
 segment of a circle. Judging from the matrix, it is from 
 the hard bands of the Middle Lias. 
 
 71. A. CBASSIUSCULOSUS, Simp. 
 
 Thickish; volutions six or seven, outer whorl 
 
89 
 
 one -fourth the diameter, neatly rounded ; radii 
 strong-, prominent, obtuse, split in two on the 
 back; aperture transverse ; diameter If inch. 
 
 This is a very neat and slender species or variety, inter- 
 mediate between A. crassus and A. crassulus. It is from 
 the Jet Rock of the Lias. There is another in the same 
 beds, which resembles it in the slenderness of the whorls, 
 but the aperture is circular. 
 
 72. A. FOVEATUS, Simp. 
 
 Thick; volutions six, well exposed, outer whorl 
 one-third the diameter, sides and back rounded ; 
 umbilicus deep; radii annular, split in two before 
 they pass over the back, strong-, scarce equal to the 
 intervening concave furrows; aperture transverse; 
 diameter 1 inch. U.L. 
 
 In general form this ammonite resembles A. subarmatus, 
 but quite free from spines and tubercles, and the whorls 
 diminish much more rapidly than in A. crassus, forming 
 a deeper and larger umbilicus. The shell, where it 
 remains, is of a light-brown colour, aud very smooth and 
 shining ; the radii are rounded, but on the cast they are 
 flatted, especially on the back. The ramifications of the 
 septa are obtusely pointed, and by no means so crowded 
 as in many species. 
 
 73. A. FONTICULUS, Simp. 
 
 Thick; volutions seven, inner ones nearly half 
 concealed, outer whorl less than one-third the 
 diameter, sides quickly and regularly rounded; 
 umbilicus deep ; radii obtuse, split in two or three 
 near the back, on the inner whorls show a row of 
 flatted bases of tubercles. U.L. 
 
90 
 
 74. A. PUTEOLUS, Simp. 
 
 Thick ; inner volutions three-quarters concealed ; 
 diameter 2\ inches. U.L. 
 
 The whorls are more inflated, the inner angles more 
 rounded, the umbilicus deeper, and the radii less 
 numerous than in the last. Whitl^y Museum. 
 
 75. A. CROSBEYI, Simp. 
 
 Thickish; volutions four, inner ones half con- 
 cealed; radii numerous, slender, annular, generally 
 split in two in passing over the back ; inner margin 
 of the whorls slightly rounded, and overhanging 
 the next; aperture one-half of a regular ellipse: 
 diameter three inches. 
 
 76. A. ANDERSONI, Simp. 
 
 Volutions five or six, inner ones quarter concealed, 
 outer whorl less than one-third the diameter ; radii 
 numerous, slender, annular, rounded, separated by 
 deep concave grooves; aperture one-half of a 
 regular ellipse; diameter 2^ inches. 
 
 In some places the radii pass over the back undivided 
 and unaltered, sometimes with a short one intervening, 
 and in other places they regularly divide into two in 
 the middle of the whorl. The specimen is somewhat 
 distorted. 
 
 (&.) Armed with spines or distinct tubercles. 
 
 77. A. FIBULATUS, Sow. PL ccccvii. 
 
 Volutions six, exposed, rounded on the back; 
 radii numerous, united in pairs by a small knob near 
 the outer margin of the whorl, then split into two 
 or three on the back; aperture rather quadrate; 
 diameter 2^ inches. 
 
91 
 
 The most obvious character of this ammonite is the 
 uniting of the radii by knobs, like a button and loop. 
 In some specimens this style is remarkably uniform ; 
 in most there occur knobs, each united with only one 
 rib; in others three ribs may be seen united in one 
 knob. It is rather plentiful in the alum shale, but by 
 no means so much so as A. communis, which in general 
 form it resembles. It also sometimes has the inner 
 angle of the whorls truncated, as in A. angulatus, Sow. 
 
 Var. Knobs more distant, aperture round. 
 
 78. A. TURRICULATUS, Simp. 
 
 Volutions six or seven, much exposed, outer 
 whorl a quarter the diameter, sides depressed, inner 
 margin prominent, sharply rounded ; radii numerous, 
 fine, annular, pass over the back undivided, with 
 short ones there frequently introduced, on the outer 
 edge of the whorls a row of tubercles or short 
 knobs at intervals of five or six radii ; aperture 
 sub-quadrate ; diameter 2^ inches. U.L. 
 
 This is rather a robust shell. The radii are fibulated 
 at the tubercles, and nearly obsolete at the aperture. 
 Syn. A. Davaei, Y. and B. 
 
 79. A. ANDREW, Simp. 
 
 Volutions six or seven, exposed, outer whorl 
 nearly a quarter the diameter ; radii numerous, 
 prominent, form knobs near the outer margin of 
 the whorls, then split into two or three on the back ; 
 aperture subquadrate ; diameter 2^ inches. 
 
 Towards the aperture, alternate radii are introduced, 
 without knobs, and at length the knobs become entirely 
 obsolete. U.L. 
 
 80. A. OBSOLETUS, Simp. 
 
 Much depressed ; volutions five, exposed, outer 
 
92 
 
 whorl less than a third the diameter, sides flatted, 
 inner margin suddenly rounded ; radii numerous, 
 straight, nearly obsolete, terminate in a row of 
 small tubercles on the outer margin ; diameter 4J 
 inches. L.L. 14, R.H. Bay. 
 
 The radii are very regular, formed merely by a slight 
 groove. I have seen several, probably of this species, 
 quite flatted. They are figured by T. & B., pi. vii., f. 1. 
 
 81. A SUBARMATUS. Sow. PI. CCCCVlL 
 
 Thickish ; volutions six or seven, exposed ; radii 
 rise up in short spines near the outer margin of the 
 whorls, then split into two or three on the rounded 
 back, and bend towards the aperture ; aperture 
 transverse ; diameter 2 inches. 
 
 As the outer whorl of the larger specimens increases 
 but little in thickness, the aperture then is scarcely 
 transverse, and the general form approaches near to that 
 of A. fibulatus, from which it is best distinguished by its 
 coarse radii and larger knobs. It, however, varies much 
 in the prominences of the radii. In some specimens 
 they are grooved, or in the button and loop style. It 
 varies also in the length of the spines, and in the depth 
 of the umbilicus. ILL. 1. 
 
 82. A. SEMIARMATUS, Simp. 
 
 Inner whorls like the last, but the outer whorl wants 
 both the knobs and radii ; aperture half of an ellipse. 
 
 83. A. VORTEX, Simp. 
 
 Volutions six or seven, exposed, outer whorl one- 
 fourth the diameter ; radii numerous, annular, split 
 in two near the back, where there is a row of tuber- 
 cles, and pass directly over without bending towards 
 
93 
 
 the aperture ; aperture subquadrate, transverse ; 
 diameter three inches, and I have seen one much 
 larger inner whorl, imperfect. U.L., 1, Whitby. 
 
 This resembles some varieties of A. subarmatus, having 
 two radii connected with each tubercle, in the button 
 and loop style ; the tubercles, however, are more distant, 
 there being on the outer whorl two radii interposed be- 
 tween those connected with the tubercles. The inner 
 edge of the whorls is also more rounded, forming a deep 
 groove at the suture, and the umbilicus is not so deep, 
 the outer whorl having nearly the same size throughout* 
 The inner side of the whorls is but little indented by the 
 succeeding ones. The radii, which on the inner whorls 
 are strong and rounded, 'and equal to the intervening 
 concave spaces, become depressed and nearly obsolete 
 towards the aperture. Where the shell has been removed 
 there is displayed a very strong siphuncle, without any 
 apparent constrictions. The ramifications of the septa 
 are numerous and pointed, differing very much from 
 those observed in A. subarmatus. 
 
 84. A. VOUTICELLUS, Simp. 
 
 Volutions six or seven, exposed, outer whorl 
 quarter the diameter; radii annular, obtuse, equal 
 to the intervening concave spaces, alternate radii 
 form a tubercle near the outer margin of the whorl,, 
 then split in two, and pass directly across the back ; 
 aperture subquadrate; diameter 1^ inch. 
 
 This is a much more slender and depressed species than 
 the last. 
 
 Another, rather thicker, with the radii on the inner 
 whorls more distant, each having a small tubercle on the 
 outer margin of the whorls, may, for the present, be 
 placed here as Var. (a.) 
 
94 
 
 85. A. IGNOTTTS, Simp. 
 
 Volutions nearly a quarter concealed, outer whorl 
 nearly one-third the diameter, sides flattish; radii 
 numerous, obtuse, equal to the intervening- concave 
 spaces, slightly curved towards the aperture, form 
 a row of tubercles on the outer margin of the 
 whorl, then pass undivided over the rounded back; 
 aperture elliptical ; diameter 2J inches. L.L., y, 
 R.H. Bay. 
 
 86. A. SINUATUS, Simp. 
 
 Volutions exposed, outer whorl one-third the 
 diameter, sides convex ; radii obtuse, separated by 
 rather wide concave spaces, commence on the inner 
 margin, slightly incline towards the aperture, and 
 then in the opposite direction, form a row of tuber- 
 cles on the outer margin, nearly obsolete on the 
 back ; aperture ovate or subquadrate ; diameter 4^ 
 inches. A fragment, L.L., R.H. Bay. 
 
 87. A. MARSHALLANI, Simp. 
 
 Volutions six, exposed, outer whorl more than 
 one-third the diameter ; umbilicus nearly equal to 
 the diameter ; radii prominent, strong, rise up into 
 blunt knobs on the outer margin of the whorls, then 
 split into several on the flatly-rounded back ; aper- 
 ture transverse ; diameter seven-eights of an inch. 
 L.L., y, R.H. Bay. 
 
 88. A. RETUSUS, Simp. 
 
 Rather depressed ; volutions six, exposed ; radii 
 
95 
 
 obtuse, annular, split in two in passing over the 
 rounded back, in the middle of which they have a 
 slight bend towards the aperture, sometimes obso- 
 lete on the inner whorls ; on the outer whorls, 
 towards the outer margin, an irregular row of 
 tubercles ; aperture nearly round, rather transverse ; 
 diameter two inches. L.L., #, E.H. Bay. 
 
 The shell, which is seldom preserved, is thin, and with- 
 out striae ; the tubercles are strong and pointed, and 
 come off with the shell, leaving their flatted bases on the 
 cast. The ramifications of the septa, with their fingered 
 and bushy lobes, are more numerous than in the last. 
 
 89. A. VALIDUS, Simp. 
 
 Volutions six, exposed, outer whorl one-third the 
 diameter ; radii strong, ccarse, annular, wider than 
 the intervening spaces, split in two or three on the 
 back, armed with a row of broad tubercles on the 
 outer margin of the whorls ; aperture circular ; 
 diameter 3 inches. L.L., ?/, R.H. Bay. 
 
 This is a much coarser ammonite than the last, with 
 fewer whorls, and stronger radii, which become almost 
 obsolete towards the aperture ; there are the same large 
 flat scars of the tubercles, and the ramifications of the 
 septa are the same. 
 
 90. A. DECTJSSATTTS, Bean's MSB. Simp. 
 
 Volutions six, inner ones one -fourth concealed ; 
 umbilicus deep ; radii on the inner whorls prominent, 
 each terminating in a distinct knob or tubercle, on 
 the outer whorl, faint, numerous, annular, split in 
 two or three on the back ; tubercles distant, nearly 
 obsolete; decussated by fine, longitudinal, and 
 
96 
 
 transverse striae ; aperture circular ; diameter three 
 inches. L.L., ?/, E.H. Bay. 
 
 . The outer whorl of this ammonite is rather stronger 
 than that of A. crassus, which it much resembles. In the 
 cast, the surface is beautifully adorned by the sharp- 
 pointed ramifications of the septa, which crowd the whole 
 surface. The inner whorls have the characters of A. 
 Marshallani. 
 
 This fine specimen is in the valuable collection of Mr. 
 Bean, of Scarborough. 
 
 91. A. MUTATUS, Simp. 
 
 Volutions six, inner ones one-fourth concealed, 
 outer whorl one-third the diameter ; radii on the 
 inner whorls strong, obtuse, ending in a distinct 
 knob or tubercle, on part of the outer whorl nu- 
 merous, fine, irregular, annular; aperture an ellipse; 
 diameter one inch and eight-tenths. 
 
 This is a smooth, neat ammonite, of a greyish colour. 
 Several of the radii on the inner whorls have a slight 
 groove, running into the knobs ; in some places the 
 grooves go past the knobs, and form additional radii, 
 without knobs ; the radii on the outer part of the outer 
 whorl, in places, are little more than annular striae, and 
 the tubercles become obsolete. It appears to be from the 
 Lower Lias. Mr. Clarkson's collection. 
 
 92. A. OWENENSIS, Simp. 
 
 Volutions five or six, exposed, outer whorl more 
 than one -third the diameter; radii rather distant, 
 straight, distinct,- slender, armed with a row of 
 tubercles near the outer margin, obsolete on the 
 back and on the inner whorls ; aperture round ; 
 diameter one inch. 
 
97 
 
 The whorls diminish rather rapidly; and, in some 
 specimens, the radii are very distant. The cast is very 
 smooth and neat. L.L., R.H. Bay. 
 
 93. A. ARMATUS, Sow. PL xcv. 
 
 Volutions six or seven, exposed, outer whorl 
 more than a third the diameter ; radii strong, ter- 
 minating on the outer margin of the whorls in a 
 row of short, strong spines ; inner whorls striated, 
 four or five striae are gathered into each spine ; 
 these are divided into three on the back, one or 
 two annular strife between the spines, striae obso- 
 lete towards the aperture ; aperture nearly round ; 
 diameter five inches. L.L. , R.H. Bay. 
 
 I have now got a fair specimen of Sowerby's A. 
 armatus, which has caused so much trouble to naturalists. 
 The very central whorls are imperfect, but there is 
 sufficient to show that they are plane, or. nearly so; 
 the succeeding whorls have the characters exhibited in 
 Sowerby's figure. Where the spines have been knocked 
 off, there remain also the oval discs. The siphuncle is 
 also displayed. In places where the striae have 'become 
 obsolete, towards the aperture, the shell has a roughened 
 and granulated appearance. Most of these armed varie- 
 ties occur in the lower part of ironstone series on the 
 north cheek of E.H. Bay, and also at Boulby and 
 Huntcliff. 
 
 It would seem that when Mr. Sfcrangeways visited 
 Whitby, this species was plentiful ; but the specimen I 
 have now described is the only one I have seen ; and the 
 one I formerly took to be A. armatus,, Sow., I believe to 
 be a different species, which we may name A. miles. 
 
 94. A. MILES, Simp. 
 
 Volutions six, exposed, slender ; radii separated 
 
 by rather wide spaces, terminate near the back in 
 H 
 
98 
 
 long pointed spines ; striae numerous, undulating-, 
 annular ; aperture roundish ; diameter 3 J inches. 
 
 This is a smooth and more elegant species than the 
 last ; the spines are more distant, and there cannot be 
 reckoned more than two or three striae on each spine. 
 The sides of the outer whorl are often rather flattened, 
 and the spines being long and slender, are very generally 
 knocked off. 
 
 Inner volutions striated., but without spines or radii. 
 L.L., v., E.H. Bay. 
 
 95. A. HASTATUS, F. # B. 
 
 Volutions six or seven, exposed, sides regularly 
 rounded, tumid, towards the aperture excavated 
 between the spines, back rounded ; a row of long 
 spines on the outer edge of the whorls, nearly 
 perpendicular, spines round on the inner whorls, 
 rather angular on the outer whorl, striated ; aper- 
 ture transverse, ovate ; diameter six inches. 
 
 The shell is rough, with coarse, obsolete strise. Spines 
 sometimes occur two inches in length, but they can 
 never be perfectly extracted from the matrix. L.L., 
 E.H. Bay. 
 
 96. A. SPICATUS, Simp. Pal., pi. xxix. 
 
 Volutions nine, exposed, outer whorl more than 
 one -fifth the diameter, inner edge prominent, back 
 rounded, sides flattish ; radii on the inner whorls 
 numerous, more distant and stronger on the outer, 
 end in strong spines on the outer edge of the 
 whorls, pointing outwards ; spines strong, annular, 
 often with a single groove ; transverse striae on 
 the inner whorls, and on the back, numerous, 
 
99 
 
 obsolete on the outer whorls ; aperture transverse, 
 rounded, or subquadrate ; diameter 7-J- inches. 
 
 This is one of the species noticed by Young, as ap- 
 proaching near to A. armatus, Sow. It is, however, a 
 coarser species, and beside other characters, the outer 
 whorls are narrower in proportion, the radii more dis- 
 tant and stronger, and the spines become very powerful, 
 separated by deep concavities. L.L. 
 
 97. A. SUBTEJANGTTLARIS, T. fy B. 
 
 Volutions eight, exposed ; radii very obtuse, 
 bent most near the inner margin of the whorl, 
 terminate on the outer edge in a row of strong 
 knobs ; diameter twelve inches. 
 
 The aperture of this species differs in form very 
 materially in different parts of the same specimen ; at 
 the extremity of the outer whorl of the largest specimens 
 it is triangular, with the apex truncated, and the base 
 outward ; it then becomes almost square ; in the inner 
 whorls it is transverse and elliptical ; so that the whorls 
 are separated by a deep channel. 
 
 This species is by no means uncommon in the pyritous 
 bed near Bay-town ; but the specimens are so crushed 
 and distorted, that I have not seen a perfect one. 
 
 98. A. ACULEATTTS, Simp. 
 
 Volutions six, exposed ; obsoletely radiated ; 
 armed with a row of moderate, pointed spines ; 
 striaB numerous, undulating, annular ; aperture cir- 
 cular ; diameter ten inches. Brassy-bed, L.L, 
 K.H. Bay. 
 
 The edges of the septa are exceedingly fine and in- 
 tricate ; some are pointed, others are rounded, crowding 
 the whole surface of the whorls with their delicate 
 meanderings. 
 
 They vary much in the length and number of the 
 spines. 
 
100 
 
 99. A. ARMIGKER, Simp. 
 
 Volutions seven, exposed, outer whorl one-fifth 
 the diameter ; radii bend from the aperture on the 
 inner edge of the whorl, then proceed in a straight 
 direction to the outer edge, where they end in a 
 row of knobs, equal to the intervening furrows ; 
 aperture quadrate ; diameter twelve inches. L.L., 
 R.H. Bay. 
 
 100. A. HAMILTONI, Simp. 
 
 Volutions eight or nine, exposed ; radii numerous, 
 bend slightly towards the aperture, on the outer 
 whorls, strong, obtuse, equal to the concave spaces 
 between ; on the inner whorls, fine, armed with a 
 row of strong spines along the outer margin of the 
 whorls, nearly obsolete on the back ; aperture 
 quadrate ; diameter seventeen inches. 
 
 This noble fossil is in the Whitby Museum,, and is the 
 largest Ammonite I have seen in our Lias ; but notwith- 
 standing its large size, it still retains the elegance which 
 so highly characterizes the fossils of that formation. It 
 was found in the Lower Lias at Robin Hood's Bay, at a 
 very low tide ; but in what particular bed I am unable 
 to say. Probably about the stratum t. The part to- 
 wards the aperture is much depressed. The spines on 
 the outer whorl I judge to have been three-quarters of 
 an inch long ; those on the inner whorls strongly resemble 
 those of A. aculeatus ; the greater number and slender- 
 ness of the whorls, however, clearly distinguish it from 
 that species. 
 
 There is in the Whitby Museum the outer whorl of 
 this species, seventeen inches in diameter, where the 
 part towards the aperture becomes much depressed, so 
 
101 
 
 as to render the aperture an elongated ellipse, with very 
 diminished spines. 
 
 There is a large, but very imperfect example in the 
 Scarborough Museum. 
 
 101. A. MAMMILLATUS, Simp. 
 
 Volutions five or six, exposed, with one row of 
 distant mammillae, or obtuse spines ; radii annular, 
 on the inner whorls prominent, separated by rather 
 wide concave spaces, on the outer whorls, nearly 
 obsolete; striated; aperture circular ; diameter four 
 inches. L.L., R.H. Bay. 
 
 This is at present a rare species ; the cast is smooth 
 and striated, but ohe shell is rough. The ramifications 
 of the septa are not very numerous, but rather deeply 
 serrated. 
 
 102. A. NATIVUS, Simp. 
 
 Volutions six, exposed ; outer whorl more than 
 one-third the diameter, inner margin rounded, pro- 
 minent, slightly overhanging the succeeding one ; 
 radii obtuse, irregular, more numerous on the 
 outer whorl, annular, a row of blunt tubercles on 
 the outer half of the whorl,, more distinct towards 
 the aperture, the radii connected with the tubercles 
 split in two on the back, between these are from 
 one to three radii which pass over the back undi- 
 vided ; aperture circular ; diameter two inches, 
 
 L.L., R.H. Bay. 
 
 As far as I can judge, the shell is smooth. The rami- 
 fications of the septa are very numerous, delicate, and 
 angular, occupying nearly the whole whorl. This speci- 
 men, and a fragment of a larger one, are much cracked, 
 and very fragile, arising apparently from the abundant 
 pyrites they contain. 
 
102 
 
 Two rows of Spines. 
 
 103. A. PETRICOSUS, Simp. 
 
 Volutions five or six, exposed ; radii numerous, 
 obtuse, larger than the intervening spaces, obsolete 
 on the back ; aperture nearly round ; diameter 
 three-quarters of an inch. L.L., R.H. Bay. 
 
 The radii terminate at both ends in round, flatted 
 spaces, as if knobs had been worn off. Some indistinct 
 striae may be observed on the back, which almost seem 
 fimbriated. The ramifications of the septa are numerous, 
 slender, and sometimes pointed, covering the whole 
 surface of the shell. Mr. CharlesworWs Col. 
 
 104. A. BIRCHII, Sow. PL cclxvii. 
 
 Volutions six or seven, exposed ; radii prominent, 
 armed with two rows of short pointed spines ; striae 
 annular, fimbriated ; aperture roundish, rather 
 transverse ; diameter 3^ inches. 
 
 The ramifications of the septa of this ammonite are 
 sharply pointed, and not so crowded as in some species ; 
 all the specimens which I have seen were in Mr. Bean's 
 Museum, and were obtained from the Lower Lias. Outer 
 whorl 7 inches, in the Scarborough Museum. I have 
 obtained portions of whorls about L.L., 16, E.H. Bay. 
 
 105. A. BISPICATTJS, Simp. 
 
 Volutions five, exposed, outer one one-third the 
 diameter, back rounded, two rows of strong spines 
 along the sides of the whorls ; shell coarsely 
 striated transversely ; cast smooth ; aperture 
 roundish ; diameter 10J inches. 
 
 A very coarse shell. Judging from the character of 
 the matrix, it is from an arenaceous bed of the Middle 
 Lias above the Lower Lias. Hawsker. 
 
103 
 
 106. A. SCORESBYI, Simp. 
 
 Volutions six or seven, exposed ; radii prominent 
 on the sides, with two rows of blunt tubercles, 
 obsolete on the back and on the inner margin of the 
 whorls, nearly equal to the concave spaces between 
 them; striae obsolete, annular, fringed; aperture 
 circular ; diameter eight inches. L.L., R.H. Bay. 
 
 This is principally distinguished from A. Birchii by 
 the smallness of the tubercles. 
 
 107. A. BREVISPINA, Sow., pi. dlvi. 
 
 Volutions five or six, exposed ; radii numerous, 
 straight, obsolete on the back; armed with two 
 rows of small sharp spines near either margin of the 
 whorl; aperture roundish ; diameter 1^ inch. L.L.,, 
 R.H. Bay. 
 
 In the larger specimens the spines become obsolete on 
 the outer whorls, and the radii strong and prominent,, 
 passing over the back. It appears to have been a very 
 tender shell, and is seldom found perfect. Outer whorls 
 occur five inches in diameter. 
 
 108. A. TENUISPINA, Simp. 
 
 Volutions five, exposed, outer whorl less than 
 one-third the diameter ; radii numerous, straight, 
 terminate on both sides of the whorl in a sharp 
 point, forming two rows of spines; back slightly 
 rounded ; aperture quadrate ; diameter half an inch. 
 L.L., R.H. Bay. 
 
 On the back of this ammonite may be seen, in places., 
 some indistinct transverse striae ; and, occasionally, the 
 radii are also continued over it. The shell has been 
 
104 
 
 obliterated, and the ramifications of the septa, thus 
 displayed, are very numerous, and often pointed. Mr. 
 Charlesworth/s Col. 
 
 109. A. HETEROGENES, Y. fy B. Pal. pi. xxxv.-vi. 
 Volutions five or six, exposed, thick near the 
 
 mouth ; radii annular, obtuse, separated by widish 
 concave furrows ; flatted on the back, on a part of 
 the outer whorl, numerous, fine, split over the back, 
 and armed with two rows of small spines ; aperture 
 roundish ; diameter four inches. L.L., c. 
 
 This is a most singular ammonite ; for whilst the inner 
 whorls cannot be distinguished from those of A. maculatus, 
 towards the aperture the shell becomes greatly enlarged, 
 the radii gradually become finer, until they are nearly 
 obsolete, and about half the outer whorl is armed with 
 two rows of short spines, like those on A. Henleyi. It 
 occurs in the same beds with A. maculatus. 
 
 110. A. BECHII, Sow., pi. cclxxx. 
 
 Very ventricose; inner whorls two-thirds con- 
 cealed, outer whorl more than one-half the diameter, 
 inner margin rounded ; radii numerous, obtuse, 
 annular, crossed by numerous concentric striae, 
 armed with two rows of short spines; aperture 
 ovate ; diameter eight inches ; thickness five inches. 
 M.L.,#, Hawsker, R.H. Bay. 
 
 This ammonite may be readily distinguished by its 
 thickness, in which respect it exceeds all the rest ; the 
 radii are separated by flattish spaces; they are also 
 flattened, and resemble narrow bands, which in general 
 pass undivided over the rounded back, but sometimes 
 they split in two. 
 
105 
 
 111. A. BISPICATUS, Simp. 
 
 Volutions five, exposed, outer one one-third the 
 diameter, rounded, two rows of strong spines along 
 the side of the whorls ; shells coarsely striated 
 transversely; cast smooth; aperture roundish; 
 
 diameter 10^ inches. 
 
 A very coarse shell. I got my description from a speci- 
 men in a dealer's shop. It was said to be from the Lower 
 Lias at E.H. Bay. I suspect it is from the lowest beds of 
 Middle Lias. 
 
 112. A. HENLEYI, Sow., pi. clxxii. Pal. pi. xli. 
 
 Thick ; volutions six, inner whorls half concealed, 
 outer whorl half the diameter, armed on the sides 
 with two rows of short spines ; radii numerous, 
 irregular, separated by flattish concave furrows, 
 often united at the knobs; longitudinally striated; 
 aperture roundish or heptangular; diameter seven 
 
 inches. 
 
 The outer whorl is much less than in the last, and the 
 inner ones more exposed. It is altogether a much coarser 
 shell. It is flatted or depressed between the spines., 
 which gives the aperture an angular form. Syn. A. 
 heptangularis, Y. & B. This is from one of the beds 
 which unite the Middle with the Lower Lias at E..H. Bay. 
 
 113. A. TAYLORI, Sow. PL dxiv. A. CORNTTTUS, Simp. 
 Volutions five, exposed, rather rapidly diminish- 
 ing, outer whorl two-fifths the diameter ; radii 
 annular, very prominent, slender, separated by 
 rather wide concave spaces ; two rows of blunt 
 tubercles on the back ; shell coarse and cracked ; 
 aperture circular ; diameter two inches. L.L., y, 
 R.H. Bay. 
 
106 
 
 This beautiful, highly characteristic, and rare species,, 
 is from the lower beds of lias at Robin Hood's Bay ; it 
 might have been associated with A. maculatus, but the 
 two prominences on the back, which suggest the idea of 
 horns, render it necessary to unite it with the armed 
 ones. It differs from that species, also, in the slender- 
 ness of the ribs, and in the more rapid diminution of the 
 whorls. On the back of a young specimen, five-eighths 
 of an inch in diameter, there are four rows of tubercles, 
 two of which become obsolete near the aperture. 
 
 114. A. QUADBICORNUTUS, Simp. 
 
 Volutions four or five, exposed, outer whorl more 
 than one-third the diameter; radii annular, very 
 prominent, rounded, slender, separated by wide 
 concave spaces, armed with four rows of strong, 
 blunt spines on the back; shell thick, striated 
 transversely ; aperture round ; diameter two inches. 
 L.L., R.H. Bay. 
 
 Whether it is possible that this can be merely a variety 
 of the last or not, I would not take upon me to say. The 
 whorls are less inflated, the ribs more prominent, and the 
 spines in general strongly developed, especially those on 
 the middle of the back ; and I believe it is from a differ- 
 ent bed ; but one of the radii, I observe, is in every 
 respect like those of A. Taylori. If it is^not a distinct 
 species, it is certainly a very interesting variety, and 
 worthy of a separate description. Whitby Museum. 
 
 II. With a keel on the back. 
 (a.) Outer whorl broad. 
 
 115. A. ELEGANS, F. 4" -B 
 
 Volutions four or five, inner ones six-tenths con- 
 cealed, outer whorl rather more than one-third the 
 diameter, inner edge sloping or concave ; radii twice 
 
107 
 
 bent, faint; keel sharp, prominent, entire; aperture 
 triangular ; diameter three inches. ILL., 7. 
 
 This elegant shell is rather abundant in the Jet Eock . 
 and hard shale of the Upper Lias ; the shell is thin, and 
 both it and the cast are smooth and shining. About one- 
 eighth of an inch from the inner edge of the whorl is a 
 concentric line, in some specimens distinct, in others 
 obsolete. The inner edge of the whorls of this group 
 being deeply indented by the succeding whorls, the 
 apertures have more or less the shape of arrow heads. 
 
 There is one which comes so near to this, that I am at 
 a loss to determine whether it is a variety or a distinct 
 species. The outer whorl is narrower, the inner whorls 
 more exposed, and the sides of the whorls more regularly 
 rounded ; in other respects it agrees, and is from the 
 same beds. 
 
 116. A. EXARATUS, F. 4* B. Pal. pi. Ixii. 
 
 Volutions five, inner ones two-thirds concealed, 
 outer whorl not quite half the diameter ; radii 
 numerous, distinct, uniform, twice bent; keel sharp, 
 entire ; aperture triangular, or rather ovate ; diame- 
 ter 3-^ inches. U.L., 7. 
 
 In general form this ammonite resembles the last ; but 
 the radii are much more regular and distinct, and have 
 a greater curvature; it differs from A. Mulgravius, in 
 the sides of the whorls being rounded in the middle, and 
 in having the inner margin sloping. This species is 
 rather abundant in the Jet Rock. 
 
 117. A. ELEGANTULTJS, T. 8{ B. 
 
 I can regard this only as the young of the last ; for 
 although the radii are not nearly so distinct as in the 
 older shells, yet, after placing a number of different 
 sizes alongside of each other, they passed into each other 
 by imperceptible gradations. Like other young shells, 
 they appear to have been of a gregarious nature, and are 
 
108 
 
 found in great numbers, crowded together in the flattened 
 nodular bands of lias limestone, which occur in the Jet 
 Rock. U.L., 7. Syn. A. sigmifer, Ph. 
 
 Along with these sometimes occurs one of a similar 
 form, but distinguished by the crowded foliations of the 
 septa, which are rounded. If it should not prove to be 
 the young of some known species, it might be named 
 
 118. A. MULTIFOLIATUS, Simp. 
 
 119. A. RUGATULUS, Simp. 
 
 Radii on the inner margin of the whorls straight, 
 regular, distant, separated by wide flat spaces, 
 sigmoidal on the outer half of the whorls, with 
 short ones irregularly introduced ; longitudinal 
 irregular striae, or corrugations, between the ribs ; 
 keel round, depressed ; aperture ovate ; diameter 
 one inch. U.L. 
 
 120. A. MULGBAVITTS, T. $ B. 
 
 Volutions five, inner ones one-third concealed, 
 outer ones more than one-third the diameter, with 
 a concentric depression in the middle; inner mar gin 
 an acute angle ; radii numerous, nearly straight, 
 and diverging to the middle of the whorl, then 
 suddenly bend from the aperture, and then gradually 
 bend towards it ; keel sharp, entire ; aperture ovate ; 
 diameter nine inches. U.L., 5b. 
 
 The radii of this, and some of the neighbouring 
 species, resemble reaping hooks ; the radii in this makes 
 a longer bend towards the aperture than in the rest, 
 and they are marked with a small triangular groove, 
 which is not seen on the cast ; it may be readily dis- 
 tinguished from A. excavatus, which it much resembles, 
 by the inner margin of the whorls hanging over the 
 
109 
 
 succeeding ones. It often attains a large size, and is 
 obtained from the hard shale of the Upper Lias, 56. 
 
 This is certainly not A. serpentinus, if the figures 
 given by authors of that species be correct. 
 
 121. A. LYTHENSIS, Y. fy B. 
 
 Volutions four or five, inner ones nearly con- 
 cealed, outer whorl more than one-half the diameter, 
 thick near the inner margin, which is rectangular ; 
 radii twice bent, rather prominent near the back ; 
 keel thick ; aperture ovate ; diameter four inches. 
 ILL., 1, Peak. 
 
 The whorls of this shell are more concealed than in 
 A. elegans, the radii are stronger, and it is not so much 
 depressed ; the shell also is rough, which gives it rather 
 an inelegant appearance ; the interior edge of each 
 whorl, as Young and Bird observe, being rectangular, 
 the central part appears like a small round pit, with 
 perpendicular sides. 
 
 122. A. BOULBIENSIS, F. 4- B. 
 
 Nearly the same characters as the last, from which it 
 may be distinguished by a small concave space on each 
 side of the keel, and by the inner edge of the whorl 
 sloping, so as to render the umbilicus a small hemis- 
 pherical depression ; whilst that of the last is perpendi- 
 cular ; there is also often a slightly elevated rim around 
 part of the umbilicus. Both these are from the alum 
 shale, at Peak. The edges of the septa shew very in- 
 tricate and crowded foliations ; diameter two inches. 
 U.L., 1. 
 
 123. A. SIMILIS, Simp. 
 
 This greatly resembles the last, especially in the size 
 and form of the umbilicus, but it is thicker towards the 
 back, and it wants the concave part near the keel. The 
 keel is slender, and easily knocked off, when the back 
 
110 
 
 appears regularly rounded. This last circumstance 
 strongly convinces me that it is a distinct species ; for 
 this is a structure entirely different from what is ob- 
 served in A. Boulbiensis, and the succeeding one, where 
 the keel is wedged-shaped, with a slight groove on each 
 side, and not otherwise separated from the sides of the 
 whorl. It occurs with A. elegans, exaratus, &c., in the 
 Jet Rock along the Hawsker coast ; diameter 1} inch. 
 U.L., 7. 
 
 124. A. COMPACTILIS, Simp. 
 
 Much depressed ; inner volutions nearly con- 
 cealed, outer whorl more than one-half the diameter; 
 radii waving, nearly obsolete ; obsoletely striated ; 
 keel rounded, entire ; aperture acutely triangular, 
 or ovate ; diameter 1^ inch. ILL., 7. 
 
 This, like Boulbiensis, and the next, has the keel 
 formed by a slight groove on either side, and some 
 specimens have a faint rim round the small umbilicus ; 
 but it is a much more depressed and elegant species 
 than A. Boulbiensis. The foliations of the septa are 
 also very different, being far more delicate and numerous, 
 crowding the whole surface with their ramifications ; 
 one set of lobes touching, or nearly touching one another. 
 I can count six principal lobes between the keel and the 
 margin of the whorl. 
 
 125. A. LECTUS, Simp. 
 
 Much depressed ; volutions four or five, inner 
 ones nearly concealed, outer whorl more than one- 
 half the diameter ; radii waving, nearly obsolete ; 
 striae numerous, waving ; keel slightly crenulated ; 
 aperture acutely triangular, or ovate ; diameter 
 1 inch. ILL., 7, 
 
Ill 
 
 The sides of the whorls are regularly convex, as in 
 A. ovatus ; the keel is slightly crenated by the radii 
 passing over it, and is little more than the sharp edge 
 of the back, with a slight groove on each side. In 
 this respect it resembles A. Boulbiensis ; but the inner 
 margin of the whorls is much depressed, so as to leave 
 but a very shallow umbilicus. 
 
 126. A. SUBCONCAVUS, Y. Sf B. 
 
 Volutions five, inner ones much concealed, outer 
 whorl one-half the diameter, inner margin sloping ; 
 radii twice bent, sometimes united in pairs, most 
 prominent near the back ; keel prominent, entire ; 
 aperture triangular, or ovate ; diameter 2 inches. 
 U.L., 6. 
 
 This is not so depressed as A. Boulbiensis, the radii 
 are more prominent, and the inner whorls are not quite 
 so much concealed, leaving a larger umbilicus ; the 
 whorls, too, are thicker near the back, which renders the 
 aperture rather ovate. In two specimens before me, the 
 shell appears very thick, but in a larger one (three 
 inches diameter), it is moderate. 
 
 127. A. DENOTATUS, Simp. Pal. pi. vi., f. 1. 
 Volutions five or six, inner whorls three-quarters 
 
 concealed, outer whorl less than one-half the 
 diameter, inner margin rounded, outer part de- 
 pressed ; radii straight for about three-quarters the 
 width of the whorl, then suddenly bend towards 
 the aperture, where they become obsolete, terminate 
 abruptly at a flattish groove, which relieves the 
 sides of the whorl from the keel ; which is promi- 
 nent, sharp, entire ; aperture ovate ; diameter six 
 inches. L.L. Mr. Leckenby's Col. 
 
112 
 
 128. A. OVATUS, F # B. 
 
 Volutions five, inner ones about one -half con- 
 cealed, outer whorl about one-third the diameter ; 
 radii twice bent, faint, or obsolete ; striae delicate, 
 numerous, waving ; keel sharp, entire ; aperture 
 ovate ; diameter 7^ inches. U.L., 4. 
 
 This species varies both in the breadth of the outer 
 whorl, and in the exposure of the inner whorls ; in some 
 specimens the side of the whorl is a very regular curve, 
 but in others the inner margin is rather elevated, and 
 quickly rounded. It is found in a nodular band, near 
 the first Nab at Saltwick, and in other places where the 
 bed is exposed. 
 
 129. A. OVATULUS, Simp. 
 
 Nearly the same characters, but the outer whorl much 
 broader. It cannot be the young of the last, as it 
 occurs in a bed lower in the series, along with A. ele- 
 gant ulus ; diameter 1^ inch. U.L., 7. 
 
 130. A. OBLIQUATUS, Y. fy B. 
 
 Volutions five, inner ones one-half concealed, 
 outer whorl one-third the diameter ; radii nearly 
 straight, then bend towards the aperture ; keel 
 sharp, slender, prominent, entire ; aperture ovate ; 
 diameter eight inches. ILL. 
 
 These two species in general appearance greatly re- 
 semble each other, but they may be at once distinguished 
 by the edges of the septa ; for whilst those of A. ovatus, 
 shew a serrated waving, with a space between, those of 
 this species occupy nearly the whole surface with their 
 intricate foliations ; the shell is smooth and without 
 striae, and the radii on the inner whorls are often pro- 
 minent. There are two fine specimens of this species in 
 the Whitby Museum, one eight inches in diameter, the 
 other shews the fine foliations of the septa. 
 
113 
 
 131. A. BEANIL, Simp. 
 
 Volutions four or five, inner ones much concealed, 
 outer whorl nearly one-half the diameter, sides 
 flattish, with a row of tubercles along" the inner 
 margin ; radii twice bent ; aperture ovate ; dia- 
 meter four inches. ILL., 1, Peak. 
 
 This may be readily distinguished from the rest which 
 have sigmoidal radii, by the row of tubercles on the 
 inner margin of the whorl. I have now got a specimen 
 more than seven inches in diameter, with the outer 
 whorl narrower in proportion, and the inner whorls less 
 concealed ; the keel is very prominent, thin, entire, and 
 rounded on the edge, easily knocked off, when the 
 siphuncle is clearly displayed. The ramifications of the 
 septa are very fine and numerous, and often pointed. 
 
 132. A. FABALIS, Simp. 
 
 Inner volutions one-third concealed, outer whorl 
 one-third the diameter, regularly convex ; radii, 
 distinct, rounded, equal to the intervening concave 
 spaces, proceed from a row of tubercles on the 
 inner margin of the whorl, where they are united 
 in pairs, sigmoidal, bend towards the aperture on 
 the back; keel rounded, depressed; aperture ovate; 
 diameter 5J inches. 
 
 The outer whorl is narrower than in A. Beanii, and the 
 radii much more strongly marked. 
 
 133. A. PHILLIPSII, Simp. 
 
 Inner volutions much concealed, outer whorl 
 two-fifths the diameter ; thin near the back, thick 
 at the inner margin, which is irregular with tuber- 
 cles or swellings ; radii unequal, nearly straight, 
 I 
 
114 
 
 then bend towards the aperture ; keel sharp, 
 prominent, entire ; aperture triangular ; diameter 
 2 inches. U.L., 1, Peak. 
 
 134. A. RETICULARIS, Simp. 
 
 Volutions five, inner ones more than three- 
 quarters concealed, outer whorl one-half the dia- 
 meter, most convex on the outer half ; transverse 
 striae numerous, fine, waving, crossing numerous 
 fine longitudinal striae ; keel or back rounded, and 
 slightly crenated by the striae ; aperture triangular, 
 or slightly ovate ; diameter 2 inches. M.L., e, 
 Hawsker. 
 
 This conies 'near to A. lenticularis, but the outer half 
 of the whorl is thicker. It is from the iron-stone beds 
 of the Middle Lias, along with A. Hawskerensis. 
 
 135. A. CONJUNCTIVUS, Simp. 
 
 This greatly resembles the last ; the keel is the sharp 
 edge of the back,, and it has the fine diverging striae, but 
 it wants the longitudinal striae ; it occurs in the same 
 beds; diameter about an inch. Some specimens are 
 thicker, and approach A. volutus. I may also be allowed 
 to notice here another little shell, of frequent occurrence 
 in the same beds, which I would call, 
 
 136. A. FERRUGINEUS, Simp. 
 
 The sides of the whorls are regularly convex, with 
 the inner margin truncated ; the radii are sigmoidal and 
 regular, but nearly obsolete. M.L., Ironstone. 
 
 137. A. LENTICULARIS, T. fy B. 
 
 Very much depressed ; inner whorls nearly con- 
 cealed, outer whorl more than one-half the diameter, 
 sides very slightly convex, thinning to a sharp 
 edge at the back, umbilicus small, with upright 
 
115 
 
 sides ; striae radiating, faint, and slightly waving ; 
 keel slightly crenated ; aperture acutely triangular ; 
 diameter 3 inches. M.L., e. 
 
 This approaches very near to Sowerby's A. discus,, but 
 it has a small portion of the inner whorls exposed. On 
 account of the sharpness of the back and its strong 
 resemblance to a cutting instrument, it is popularly 
 known by the name of razor-back. It is not very uncom- 
 mon in the ironstone bands of the Middle Lias ; but on 
 account of its thinness, it is with difficulty extracted 
 from the matrix. 
 
 138. A. SIMPSONI, Bean's M88. f Simp. Pal. pi. xlvii., f . 4. 
 Much depressed; volutions four or five, inner 
 
 ones seven-eighths concealed, outer whorl one- 
 half the diameter, sides undulating, inner margin 
 rounded ; radii nearly obsolete on the outer whorl, 
 bend towards the aperture ; striae diverging, nume- 
 rous, and delicate; keel sharp, prominent; aperture 
 acutely triangular ; diameter six inches. L.L., 15, 
 R.H. Bay. 
 
 This ammonite, which Mr. Bean has been pleased to 
 call A. Simpsoni, is from the Lower Lias shale at Eobin 
 Hood's Bay; the whorls swell out in thickness towards 
 the inner margin, which is finely rounded, whilst the 
 part near the keel is slightly concave; in the older 
 specimens the radii are scarcely discernible. 
 
 139. A. COMPLANATUS, Sow. ? 
 
 Inner volutions concealed, outer whorl more than 
 one-half the diameter, sides rounded ; radii nume- 
 rous, slender, diverging, straight for two-thirds the 
 breadth of the whorl, then turn gently towards 
 
116 
 
 the aperture, unequal ; keel slender, entire ; aper- 
 ture triangular; diameter Scinches. L.L., y, R.H. 
 Bay. 
 
 At the first sight, this has the appearance of a com- 
 pressed specimen of A. heterophyllus, but a closer 
 inspection shows it to be a very different shell; the 
 slender radii diverge beautifully from the centre, and 
 towards the outer margin of the whorl are separated by 
 short ones, all terminating near a very slightly elevated 
 keel j in the direction of the radii may also be seen very 
 delicate striae. If, as some think, this be different from 
 Sowerby's shell, it may be named A. complanosus. 
 Whitby Museum. 
 
 140. A. LENS, Simp. 
 
 Volutions three or four, inner ones nearly con- 
 cealed, outer whorl more than one-half the diameter, 
 regularly convex ; radii nearly obsolete, waving ; 
 keel very slender, sharp, prominent, crenated, 
 concave on each side ; aperture a very elongated 
 ellipse ; diameter one inch. L.L., RJEL Bay. 
 
 A cast of a bronze colour ; lobes of the septa numerous, 
 rounded, and finely serrated. Mr. Clarkson's Col. 
 
 141. A. LEPTOPHYLLUS, Simp. 
 
 Inner volutions nearly concealed, outer whorl 
 more than half the diameter, inner angle perpen- 
 dicular to the regularly and flatly convex sides ; 
 umbilicus a small deep pit ; radii sigmoidal, nearly 
 obsolete, entirely so on the inner margin of the 
 whorl ; keel relieved from the thin edge of the 
 back by slight furrows ; aperture triangular, or 
 ovate ; diameter 3 inches. 
 
117 
 
 A cast having the whole surface ornamented with the 
 very numerous and delicate foliations of the septa. The 
 lobes looking towards the aperture are rounded, and 
 finely serrated ; those looking from the aperture pointed 
 with long delicate fingers. Apparently from the M. or 
 L.L. Scarborough Museum. 
 
 142. A. POLYPHYLLUS, Simp. 
 
 Much depressed ; volutions five, inner ones very 
 little exposed, outer whorl one-half the diameter, 
 inner margin rounded, sides convex, then concave ; 
 back thin ; radii obtuse, depressed, waving ; keel 
 sharp, much elevated ; aperture triangular ; diame- 
 ter 3| inches. L.L., R.IL, Bay. 
 
 This ammonite is distinguished by the great number 
 and regularity of the foliations of the septa, which 
 ornament the whole surface of the whorls by their 
 meanderings ; the inner edge of the whorls are rounded, 
 and the thin back is greatly produced, so as easily to be 
 knocked off. The radii in general are nearly obsolete 
 towards the inner margin of the whorl, and become 
 gradually more distinct towards the backj but a fine 
 specimen in the possession of Mr. Bean is entirely with- 
 out radii. 
 
 143. A. MARGARITATTJS, Mont. A. STOKESi, Simp. Pal. 
 
 pi. liii. 
 
 Volutions five, inner ones two-thirds concealed ; 
 outer whorl nearly one-half the diameter, sides 
 gently rounded ; radii distinct near the inner 
 margin of the whorls, obsolete towards the keel ; 
 delicately striated ; keel strongly crenated ; aper- 
 ture triangular ; diameter six inches. M.L., Iron- 
 stone bands, Hawsker. 
 
 The diverging striae are very distinct on the inner 
 margin of the whorls, and there are also obsolete 
 concentrick lines or striae crossing these; it may be 
 
118 
 
 principally distinguished from the next by the keel, 
 which resembles a twisted rope running along the back. 
 I have seen two specimens which agree with this,, but 
 which have, on the inner whorls, rather distant spines. 
 
 144. A. CLEVELANDICUS, T. fy B. 
 
 Much depressed ; whorls five or six, more than 
 one-half concealed, sides regularly convex, inner 
 margin rounded; radii numerous, flat, nearly straight, 
 then turn to the aperture ; keel the acute angle of 
 the back, crenated by the radii ; aperture saggitate ; 
 diameter 6^- inches. M.L., , Hawsker. 
 
 This has nearly the same specific characters as the 
 last. In general the radii are almost obsolete near the 
 inner margin of the whorls, and are often rather promi- 
 nent near the keel, where they slightly bend towards 
 the aperture ; the keel is strongly crenated by the radii 
 passing over it, but it has not the cord-like form which 
 distinguishes the last ; the edges of the septa shew them- 
 selves in minute, intricate, and crowded foliations, spread 
 over the whole surface of the whorl ; diameter seven 
 inches. I have a young shell (one inch diameter), which 
 has nearly the same characters as the larger one, but 
 the radii are the most prominent near the inner margin 
 of the whorl ; under such variety, the form of the keel 
 seems to be the most certain character for distinguishing 
 this from the last. No striae. 
 
 145. A. DEPRESSUS, Simp. 
 
 Very much depressed ; volutions four or five, 
 inner ones nearly half concealed, outer whorl one- 
 half the diameter, sides flatted ; radii on the inner 
 whorls straight, prominent, equal to the spaces 
 between, obsolete on the outer whorls ; striated ; 
 keel strongly crenated ; diameter two inches. 
 
119 
 
 This ammonite is the most depressed of any I have 
 seen., not even excepting A. lenticular is. The inner- 
 whorls diminishing very little in thickness, it has a 
 very shallow umbilicus ; the keel has the cord-like ap- 
 pearance observed in A. margaritatus, of which I once 
 supposed it to be a variety ; but on account of its very 
 depressed form, and the absence of radii from the outer 
 whorl, I am obliged to consider it a distinct species. It 
 also resembles some varieties of A. Clevelandicus, but 
 the septa are much more distant, and their ramifications 
 much more simple, a circumstance which 'shews it to be 
 a distinct species. 
 
 146. A. VITTATUS, Y. and B. 
 
 Volutions four or five, inner ones slightly con- 
 cealed, outer whorl one-third the diameter ; back 
 rounded ; radii straight, prominent, diverging, end 
 in a small sharp tubercle ; keel prominent ; strongly 
 crenated ; aperture triangular ; diameter one inch. 
 
 This is a shining species, and always occurs of small 
 size ; it might be mistaken for the young of A. Stokesi, 
 but the radii occupy the whole of the disc, and the 
 tubercles shew it to be a distinct species. In some 
 specimens the radii are stronger, and separated by 
 wider grooves than usual. It is rather abundant in the 
 iron bands on the Hawsker shore. M.L. 
 
 147. A. HUNTONI, Simp. 
 
 Much depressed ; volutions three or four, inner 
 ones three-quarters concealed, outer whorl one- 
 half the diameter, gradually thinning to the keel ; 
 radii sigmoidal, obsolete ; with distant deep con- 
 strictions ; aperture acutely triangular ; diameter 
 six-tenths of an inch. L.L., ?/, E.H. Bay. 
 
 This is easily confounded with the inner volutions of 
 
120 
 
 A. Robinsoni, but it is more depressed, and the con- 
 strictions are nearly straight. The shell is very thin, 
 and faintly radiated or striated. 
 
 148. A. ROBINSONI, Simp. 
 
 Volutions four, inner ones nearly concealed, outer 
 whorl more than one-half the diameter, back 
 rounded ; radii slightly waving, nearly obsolete ; 
 keel blunt ; aperture acutely triangular or ovate ; 
 diameter seven-tenths of an inch. L.L., 13. 
 
 This beautiful little ammonite is from the lowest beds 
 of Lias at Eobin Hood's Bay. The sides of the whorls 
 are regularly convex, the inner margin is slightly ele- 
 vated above the succeeding whorl; the keel is merely 
 the thin edge of the back, which is rounded, but without 
 the groove on each side, as occurs in A. lectus. The 
 inner whorls frequently have waving constrictions. It 
 is peculiarly distinguished by the regular and beautiful 
 ramifications of the septa, which crowd the sides of 
 the whorls. I can count six principal, deeply-serrated 
 ramifications, or lobes, from the inner margin of the 
 whorl to the back. 
 
 149. A. SIMPLEX, Simp. 
 
 Volutions four or five, inner ones much concealed, 
 outer whorl less than one-half the diameter ; radii 
 flat, and nearly obsolete ; keel blunt ; aperture 
 acutely triangular, or ovate ; diameter three-quarters 
 of an inch. L.L., R.H. Bay. 
 
 In external form, this differs little from A. Robinsoni ; 
 but the ramifications of the septa are much more simple, 
 and altogether so different, that I am compelled to con- 
 sider it a distinct species. Mr. Charlesworth's Col. 
 
 150. A. RETENTUS, Simp. 
 
 Inner volutions nearly concealed, outer whorl 
 
121 
 
 more than one-half the diameter, sides regularly 
 rounded ; radii waving-, nearly obsolete ; keel 
 prominent, sharp, entire ; aperture acutely trian- 
 gular, or ovate ; diameter nine-tenths of an inch. 
 L.L., R.H. Bay. 
 
 This is a cast, and, like many others from the Lower 
 Lias, is of a bronze colour; the ramifications of the 
 septa are very numerous, those on the inner margin of 
 the whorl are mere serrations. It may be readily dis- 
 tinguished from A. Eobinsoni by its prominent keel, 
 and from the next, by its small umbilicus. Mr. Clarkson's 
 Col. 
 
 151. A. BUCKII, Simp. 
 
 Volutions three or four, inner ones one-half con- 
 cealed, outer whorl not one-half the diameter ; 
 radii broad, flat, waving, distinct near the inner 
 margin of the whorl, obsolete towards the keel ; 
 keel prominent, sharp ; aperture triangular, or 
 ovate ; diameter half an inch. L.L., Ind. b, 15, 
 K.H. Bay. 
 
 In the prominence of the keel, and in the general form 
 of the whorls, this ammonite resembles A. Simpsoni, but 
 the outer whorl is narrower, the inner margin is more 
 quickly rounded, and the foliations of the septa are 
 very simple, and obtuse ; the shell is rough, and the cast 
 is smooth and shining. 
 
 These small ammonites, which occur in the Lower 
 Lias, are by no means to be considered as the young of 
 the larger species; their definite and elaborate forms 
 being a certain indication of age and slow growth. 
 In this respect they are strongly contrasted with the 
 irregularity of A. elegantulus, and other shells, which 
 are so abundant in the Upper Lias. 
 
122 
 
 Var. (a.) Radii more numerous, and being continued 
 irregularly on the back, the keel becomes crenated. 
 
 Var. (6.) Whorls more tumid ; keel sharp, prominent, 
 entire, with a portion of the whorl on either side 
 concave. Probably a distinct species. 
 
 152. A. DEJECTUS, Simp. 
 
 Volutions four, inner ones one-quarter concealed, 
 outer whorl not one-third the diameter ; radii 
 separated by wide spaces, bend from the aperture, 
 obsolete towards the back ; keel indistinct, coarsely 
 crenated; aperture ovate; diameter half an inch. 
 LL., R.H. Bay. 
 
 There is something about this ammonite which creates 
 a suspicion that, after all, it may be a variety of A. 
 Buckii ; but the keel is so much depressed, and the 
 general form so different, that one would scarcely think 
 it possible. Mr. Charlesworth's Col. 
 
 153. A. ALIENUS, Simp. 
 
 Volutions four or five, inner ones one-half con- 
 cealed, outer whorl not one-half the diameter ; 
 umbilicus shallow ; radii rather numerous, waving, 
 flattened, equal to the furrows between, nearly 
 obsolete towards the keel ; keel not prominent ; 
 aperture ovate ; diameter six-tenths of an inch. 
 L.L., R.H. Bay. 
 
 This species is rather variable. In one example the 
 outer whorl is narrower, and the keel, towards the 
 mouth, becomes obliterated, and some of the radii pass 
 over the rounded back. In two smaller specimens, the 
 radii are nearly obsolete, so that they resemble what we 
 might suppose to be the young of A. ovatus, which I 
 believe is never found in the Lower Lias. They how- 
 ever all agree in the foliations of the septa being much 
 more simple than usual. Mr. Charles wort h's Col. 
 
123 
 
 154. A. FLAVUS, i 
 
 Volutions three or four, inner ones three-quarters 
 concealed, outer whorl not one-half the diameter ; 
 keel obtuse ; aperture ovate ; diameter three- 
 quarters of an inch. 
 
 This is not quite so much depressed as the last, and 
 the inner whorls diminish very little in thickness ; it is 
 quite plane, without radii or striae ; the shell is cracked ; 
 the septa are more distant than in the last, and the 
 lobes are less serrated, and not so numerous. It is also 
 from the Lower Lias at Eobin Hood's Bay, and has a 
 light metallic hue. 
 
 155. A. LIMATUS, Simp. 
 
 This greatly resembles the last, but the whorls 
 diminish more in thickness, leaving a larger umbilicus ; 
 there are also a few obsolete radii. It is entirely a cast, 
 and of a brown colour. L.L., R.H. Bay. 
 
 156. A. VOLUTTJS, Simp. 
 
 Volutions four, inner ones one-half concealed, 
 outer whorl not one-half the diameter ; radii faint, 
 obtuse, waving ; keel obtuse, slightly crenated ; 
 aperture ovate ; diameter half an inch. M.L., 
 Hawsker. 
 
 Merely taking a side view of this shell, it very much 
 resembles A. fimbriatus ; the sides of the whorls are 
 finely rounded, and the keel is merely the thin back ; 
 cast is smooth and shining, and the foliations of the 
 septa are, for the most, obtuse. Another, which I judge 
 to be of the same species, has the shell striated. They 
 occur in the marlstone. 
 
 157. A. ALTERNATUS, Simp. 
 
 Volutions four or five, inner ones one-third con- 
 cealed, sides flatted, a row of obtuse depressions 
 
124 
 
 near the inner margin, which is sloping-, outer 
 whorl two-fifths the diameter ; radii numerous, 
 twice bent ; keel sharp, entire ; aperture acutely 
 triangular ; diameter three inches. U.L., 7. 
 
 This ammonite may be easily distinguished from A. 
 elegans, A. exaratus, and others of a similar form., by 
 the depressions upon the inner margin of the whorls, as 
 as well as by the less breadth of the outer whorl, and by 
 its being thicker towards the back ; also, where the shell 
 remains, there may be observed very slender radii in 
 the furrows ; on which account it has received the above 
 name. 
 
 (6.) Outer whorl narrower. 
 
 158. A. RUDIS, Simp. 
 
 Volutions four or five, inner ones one-fifth con- 
 cealed ; radii strong, straight, then turn towards 
 the aperture, equal to the concave spaces between ; 
 aperture roundish ; diameter 2^ inches. U.L. 
 
 This is an extremely rugged shell ; the outer whorls 
 are only slightly indented by the succeeding ones. Near 
 the inner margin of the whorls are coarse, irregular 
 swellings, from whence proceed two radii, which are 
 occasionally separated by other radii, but with the great- 
 est irregularity. I have seen only one specimen, the 
 shell of which is thick, the keel broken off, and the 
 siphuncle is well displayed. 
 
 159. A. STRIATULTJS, Sow. PL ccccxxi. 
 
 Volutions five, inner ones one-fifth concealed, 
 outer whorl one-third the diameter of the shell; 
 radii twice bent ; striae numerous in the direction 
 of the radii ; keel obtuse, entire ; aperture ovate ; 
 diameter 2 inches. ILL., 1, Peak. 
 
 This smooth and elegant shell is from the Upper Lias 
 
125 
 
 at Peak, where it is found in some abundance. The sides 
 of the whorls are gently rounded, as in A. ovatus. On 
 some specimens the radii are nearly obsolete, in others 
 they are rather prominent, gradually increasing in 
 strength from the inner margin, and turn towards the 
 aperture in passing over the back ; the beautiful striae 
 observed on the shell is not seen on the cast, which is 
 smooth and shining. 
 
 160. A. NITESCENS, Y. Sf B. Pal. pi. xlix., f. 1. 
 Volutions six, inner ones very little concealed; 
 
 radii faint on the inner margin of the whorls, twice 
 bent, form a row of blunt tubercles in passing over 
 the back ; keel obtuse ; aperture ovate ; diameter 
 three inches. M.L., , Hawsker. 
 
 Var. Radii more prominent. 
 
 This greatly resembles the last, and is, like it, striated ; 
 but the ramifications of the septa are much more acute 
 and intricate; which show it at once to be a different 
 species. It occurs in the marlstone beds, which are im- 
 mediately above the Lower Lias ; but it is by no means 
 plentiful. 
 
 161. A. MACDONNELLI, Portlock; T. $ B., pi. v., f. 8. 
 Much depressed ; volutions eight, little con- 
 cealed, outer whorl one-quarter the diameter, sides 
 regularly and flatly rounded ; striae very numerous, 
 slightly bend to the aperture ; keel sharp, entire ; 
 aperture saggitate ; diameter If inch. Upper half 
 of the L.L. 
 
 This was very kindly sent me by Mr. Blake from 
 Water, where it appears to be abundant. It is much 
 more delicate than A. striatulus. 
 
 162. A. VETUBTUS, Simp. 
 
 Volutions five, inner ones nearly half concealed. 
 
126 
 
 outer whorl one-third the diameter ; radii straight, 
 obtuse, nearly obsolete on the inner whorls; keel 
 an obtuse angle; aperture ovate; diameter one inch 
 and one -tenth. 
 
 The shell is roughish, the cast smooth, and the folia- 
 tions of the septa simple. In general form it comes near 
 to the more depressed varieties of A. striatulus, but the 
 whorls are numerous, and the shell is without striae. I 
 believe it is from the Lower Lias at E.H. Bay. Mr. 
 Clarkson's Col. 
 
 163. A. SIPHUNCULARIS, Simp. 
 
 Volutions four, exposed ; radii straight, strong, 
 obtuse, separated by narrow furrows ; siphuncle 
 on the back equal to half the breadth of the whorl ; 
 diameter six-tenths of an inch. L.L., R.H. Bay, 
 
 This is a most singular species, the keel being formed 
 of a very distinct tube. In one specimen part of the 
 tube has been broken off, and the radii are seen to pass 
 over the back, strongly resembling those of A. macula tus. 
 The cast is smooth and the shell rough. 
 
 164. A. RADIATUS, Simp. 
 
 Volutions five, inner ones one-third concealed, 
 outer whorl not quite one-half the diameter, sides 
 rounded ; radii straight, numerous, sharp, regular, 
 delicate, bend towards the aperture near the back ; 
 the keel slender, rather rounded, furrows distinct ; 
 aperture ovate ; diameter three-quarters of an inch. 
 L.L., R,H. Bay. 
 
 This is an exceedingly beautiful and well-defined 
 species ; the radii are all as if drawn with geometrical 
 exactness, those near the aperture slightly waving, absent 
 in the centre ; the keel and all its parts have the greatest 
 
127 
 
 regularity. I have seen five or six, all small and uni- 
 form, and entirely unlike the young of A. geometricus, 
 Bucklandi, or any other species. 
 
 165. A. REGULARIS, Simp. 
 
 Volutions four, inner ones one -half concealed, 
 outer whorl more than one-third the diameter, with 
 the sides rounded ; radii numerous, regular, straight, 
 bend towards the aperture near the keel ; keel 
 depressed ; aperture acutely triangular, or ovate ; 
 diameter one inch and two-tenths. 
 
 This ammonite is much more depressed than A. geo- 
 metricus, the outer whorl is wider, and the radii are 
 obtuse, and less numerous; the shell is roughish, and 
 without striae. I believe it is from the Lower Lias at 
 E.H. Bay. Mr. Clarkson's Col. 
 
 166. A. GEOMETRICUS, Ph. 
 
 Volutions four or five, exposed ; radii slender, 
 very regular and distinct, straight, suddenly turn 
 towards the aperture on the back ; keel slender, 
 entire; aperture ovate ; diameter l inch. M.L., 
 Hawsker. 
 
 The radii of this shell are extremely regular ; it differs 
 from A. subnodosus, chiefly in the more regular convexity 
 of the sides of the whorls, and in the absence of tubercles 
 on the exterior part of the radii ; on some specimens, 
 however, I have seen a few tubercles like those always 
 observed on A. subnodosus ; but as these occur only 
 occasionally, I shall consider it a distinct species. 
 
 III. Keel between two furrows, 
 (a.) Furrows slight. 
 
 167. A. SPINATUS. 
 
 Volutions five or six, inner ones more than one- 
 quarter concealed, outer whorl one-third the 
 
128 
 
 diameter, sides flat, and nearly parallel with each 
 other, inner edge rounded ; radii straight, promi- 
 nent, end in a knob on the back, turn at a right 
 angle towards the aperture, not equal to the 
 intervening concave furrows; keel slender, rounded; 
 furrows on either side slight ; aperture rectangular ; 
 diameter five inches. M.L., a, Hawsker. 
 
 The radii are most prominent on the outer margin of 
 the whorls where they often form a knob, and where 
 they are separated by deeper furrows. The radii, espe- 
 cially on the inner whorls are much more numerous, 
 plain and regular than in A. Hawskerensis with which 
 it has been confounded. 
 
 In one sent me by Mr. Tate from the Cleveland mines 
 the radii are not so numerous, and the aperture is rather 
 ovate. 
 
 Another, which I suppose we must place under this 
 name, has a square aperture, the keel having been de- 
 pressed into a mere crenated line. 
 
 168. A. ELABORATUS. 
 
 Depressed ; volutions six, exposed, prominent on 
 the rounded inner margin, outer whorl less than 
 one-third the diameter, pinched towards the back ; 
 radii strong, sharp, regular, tending to form tuber- 
 cles on both margins, suddenly turn towards the 
 aperture on the back, separated by deep concave 
 grooves ; keel much depressed, sharp, smooth ; 
 aperture quadrate ; diameter two inches. M.L., a, 
 Hawsker. 
 
 This belongs to the A. spinatus family, and is from the 
 uppermost bed of the Middle Lias on the Hawsker shore. 
 It is highly finished, and well distinguished from A. 
 
129 
 
 solitarius, by the prominence of the inner margin of the 
 whorls, and the smooth keel. From the ribs rising on 
 both margins a slight hollow or groove is formed along 
 the side of the whorl. Whitby Museum, No. 302. 
 
 169. A. EXASCIATUS, Simp. 
 
 Volutions five, inner ones nearly one-half con- 
 cealed, outer whorl more than one-third the 
 diameter, inner margin prominent ; radii straight, 
 terminate in a tubercle near the outer margin, 
 separated by rather wide concave spaces ; keel 
 rounded, distinct ; aperture subquadrate, or ovate ; 
 diameter 2^ inches. 
 
 In the form of the radii, this ammonite resembles A. 
 nodosus, and, in its coarseness and general appearance* 
 A. Hawskerensis ; but the back is triangular, and with- 
 out furrows near the keel. It is from the ironstone beds 
 of the Middle Lias. 
 
 170. A. SUBNODOSUS, Y. 4" -B- 
 
 Volutions five or six, inner ones one-quarter 
 concealed, outer whorl one-third the diameter ; 
 radii straight for two -thirds their length, then a 
 small tubercle, a sharp turn towards the aperture 
 and the keel, another tubercle, then turn towards 
 the aperture ; keel crenated ; aperture subquadrate, 
 or ovate ; diameter 1^ inch. M.L., Hawsker. 
 
 This is intermediate between the last and the following 
 species ; it is a much more elegant shell than the next, 
 and the radii are more numerous, regular, and less 
 prominent. In some specimens the radii are still closer, 
 and the characteristic tubercles become nearly obsolete, 
 until it can scarcely be distinguished from A. geome- 
 tricus. 
 
 K 
 
130 
 
 171. A. HAWSKERENSIS, F. fy B. 
 
 Volutions five, inner ones very slightly concealed ; 
 radii prominent, sharp, separated by wide spaces, 
 straight on the sides, suddenly turn towards the 
 aperture on the back ; striated ; keel faintly cre- 
 nated ; aperture subquadrate ; diameter 3 inches. 
 M.L., e, Hawsker. 
 
 This approaches very closely to Sowerby^s A. multi- 
 costatus, but differs in the form of the aperture, the 
 present one being wider near the next whorl than to- 
 wards the keel; it is also more depressed. It is not 
 uncommon in the ironstone bands. There are several 
 varieties. 
 
 One,, in which the straight part of the radii terminate 
 in a tubercle ; another, which has two tubercles, as in 
 the last ; another, which has knobs also on the inner 
 margin of the whorls. 
 
 A very elegant variety, if not a distinct species, with 
 a row of tubercles on the inner margin, and the sides 
 more parallel. 
 
 172. A. TRANSFORMATUS, Simp. 
 
 Volutions five, exposed, outer whorl one-third 
 the diameter ; radii strong, prominent, sharp, sepa- 
 rated by rather wide concave spaces, nearly obsolete 
 on the back, straight until they reach the outer 
 margin of the whorls, where, on the last whorl, 
 they form a slight knob, and suddenly bend to- 
 wards the aperture ; keel much depressed, furrows 
 on either side slight ; aperture quadrate ; diameter 
 1^ inch. 
 
 The inner whorls of this species are destitute of any 
 dorsal keel or furrow, and have a good deal the character* 
 of A. arcigerens, though by no means so numerous and 
 
131 
 
 slender; but as they increase in size, they have gradually 
 formed upon the back a distinct elevated line, which 
 ultimately becomes a depressed but distinct keel between 
 two slight furrows j the radii towards the aperture be- 
 come stronger, and form distinct knobs on the outer 
 margin of the whorl, when they greatly resemble those 
 of A. Hawskerensis. I have now seen a good number of 
 specimens, which have been obtained from lias boulders 
 in the alluvium on the Holderness coast, and some also 
 from the Lower Lias at E.H. Bay. 
 
 173. A. MULTICOSTATUS, Sow. PL ccccliv. 
 Volutions five, exposed ; radii numerous, promi- 
 nent, straight ; keel depressed ; furrows on either 
 side slight ; aperture nearly square ; diameter four 
 inches. L.L. 
 
 It principally differs from A. Hawskerensis, in being 
 much thicker, the radii more numerous, the keel entire, 
 or but slightly crenated. The shell is smooth and with- 
 out striae, enlarges much towards the aperture, and the 
 sides of the whorls are rather rounded j there appears 
 to have been tubercles on the outer margin : I see a 
 very prominent one, and others appear to have been 
 broken off. This specimen is in the Leeds Museum, The 
 sides in Sowerby's figure are much natter, and the grooves 
 on either side deeper ; but his specimen was much larger 
 (fourteen inches diameter, and between three and four 
 inches thick). 
 
 174. A. BIBDI, Simp. 
 
 Volutions five, exposed ; radii very prominent, 
 sharp, separated by large concave spaces, nearly 
 straight, then make a slight turn from the aperture, 
 and form a tubercle, make another turn towards 
 the aperture on the back, where they become 
 
132 
 
 obsolete ; keel very small ; grooves on either side 
 nearly obsolete ; aperture quadrate ; diameter two 
 inches. 
 
 The radii on the rounded inner edge of the whorls are 
 nearly obsolete, then become gradually more and more 
 prominent, until they reach the outer edge, where the 
 groove which separates them is very deep. From the 
 very feruginous appearance of this specimen, I judge it 
 to be from the ironstone bands. 
 
 175. A. OBTUSUS, Sow. PL clxvii. 
 
 Volutions five, inner ones one-third concealed, 
 outer whorl one-third the diameter ; radii obtuse, 
 prominent, regularly bend towards the aperture; 
 keel blunt, much depressed ; furrows on each side 
 nearly obsolete ; aperture ovate ; diameter 3 
 inches. L.L., 22, E.H. Bay. 
 
 The shell of this species is rough, and the cast smooth 
 and shining ; the radii, where the shell is not removed, 
 are like cords laid on, and are not equal to the concave 
 spaces between ; on the cast they are sharper, and not so 
 prominent. 
 
 (&.) Furrows distinct. 
 
 176. A. ROTIFORMIS, Sow., ccccliii. Pal. pi. vii., f. 1. 
 Volutions six, exposed; radii numerous, equal, 
 
 prominent, straight nearly the whole length, then 
 suddenly bend towards the aperture; a row of 
 tubercles near the outer margin of the whorls; a 
 deep furrow on each side of a low, rounded keel ; 
 aperture quadrate ; diameter five inches. 
 
 This has a strong resemblance to A. Hawskerensis ; its 
 distinguishing character is the plane keel and the deep 
 furrows. The only one I have seen is in Mr. Bean's 
 collection. 
 
133 
 
 177. A. SOLITARIUS, Simp. 
 
 Volutions five, exposed, outer whorl one-third 
 the diameter of the shell, sides flatted ; radii 
 numerous, equal, prominent, nearly straight to the 
 outer margin of the whorl, then suddenly bend 
 towards the aperture, equal to the intervening con- 
 cave spaces ; keel rounded, strongly crenated, the 
 furrows on either side nearly obsolete; aperture 
 oblong quadrate ; diameter 1-J- inch. L.L., R.H. Bay. 
 
 On the inner whorls of this ammonite may be seen a 
 row of tubercles at a short distance from the outer 
 margin. The shell, as far as it can be observed, appears 
 very thin, and quite smooth and shining ; but very little 
 of it remains, and the cast is roughish, exhibiting the 
 ramifications of the septa rather rounded, and very 
 numerous, covering nearly the whole surface of the shell 
 with their meanderings. 
 
 178. A. SEMICOSTATUS, T. Sf B. 
 
 Volutions five or six, exposed ; radii sharp, promi- 
 nent, separated by concave spaces; delicately 
 striated ; keel entire, between two distinct furrows ; 
 aperture subquadrate ; diameter two inches. L.L., 
 25, R.H. Bay. 
 
 This often occurs in large masses. In general the inner 
 whorls are destitute of radii, but it is a variable species ; 
 in some the radii are distant and much curved towards 
 the aperture ; in others the sides of the whorls are very 
 convex, and the keel without furrows. 
 
 179. A. ACUTICARINATUS, Simp. 
 
 Volutions seven or eight, exposed ; radii separated 
 by concave spaces, sharp, faint on the inner margin, 
 gradually increasing towards the keel, where they 
 
134 
 
 suddenly turn towards the mouth; keel slender, 
 sharp, prominent, entire; aperture ovate; diameter 
 2 inohes. L.L., 25, K.H. Bay. 
 
 This greatly resembles A. semicostatus, but the sides 
 of the whorls are more rounded, the keel sharper and 
 more prominent, and without any distinct furrow on 
 either side. 
 
 I formerly named this shell A. Youngi ; but I was after- 
 wards reminded that another from the Speton clay (A. 
 rotula, Sow.) had been named A. Youngi, by Mr. Bean, 
 and described by Young previous to the publication of 
 Sowerby's description. 
 
 180. A. ATJREOLUS, Simp. 
 
 Volutions eight, exposed, outer whorl less than a 
 quarter the diameter, sides regularly rounded ; radii 
 numerous, nearly straight, sharp, not equal to the 
 intervening concave furrows, terminate on the outer 
 margin of the whorl ; keel rounded, depressed be- 
 tween two slight furrows ; aperture roundish ; 
 diameter one inch. L.L., 15, R.H. Bay. 
 
 This ammonite, on the side, greatly resembles A. aureus, 
 and the radii in places have a tendency to form two slight 
 tubercles. The cast is smooth and of a golden colour. 
 The shell is thin, smooth, and brownish, without any 
 appearance of striae ; the ramifications of the septa are 
 very simple and distant, at irregular intervals of two or 
 three radii. On comparing a description I wrote of a 
 specimen I received of Mr. Bean, labelled A. finitimis, 
 I find it identical with the above. I also believe that 
 Blake's A. spiratissimus is the same as my A. aureolus. 
 They are all from the same bed, and are strongly marked 
 to the very centre. 
 
 181. A. MULTANFRACTUS, Simp. 
 
 Volutions seven or eight, exposed ; radii of the 
 
135 
 
 cast sharp, bend slightly towards the aperture ; 
 keel rounded, much depressed, furrows on either 
 side shallow ; aperture ovate ; diameter 2| inches. 
 L.L., 25, R.H. Bay. 
 
 This comes near to A. semicostatus, but the sides are 
 more regularly convex, and the keel and furrows are 
 nearly obsolete. The little of the shell which remains 
 appears wrinkled and coarse, and irregular striae crenu- 
 late the keel. The septa are rather distant, being 
 clearly separated by each alternate rib ; the radii on the 
 innermost whorls split in two near the inner margin, and 
 are strongly marked to the very centre. The innermost 
 whorls are more slender in proportion than the outer 
 whorls. 
 
 182. A. VALIDANFRACTTJS, Simp. 
 
 Volutions, five or six, exposed ; outer whorl ,one- 
 quarter the diameter ; radii of the cast sharp, 
 straight, strong, prominent, form tubercles on the 
 outer margin, then bend towards the aperture and 
 terminate abruptly near a depressed rounded keel 
 and two slight furrows, not equal to the wide 
 concave spaces ; aperture roundish ; diameter 2 
 inches. L.L., 25, R.H. Bay. 
 
 This is a strong robust species. The little of the shell 
 which remains is of a dark colour without striae. 
 
 183. A. TURNEKI, Sow, pi. cccclii. Pal. pi. xii. 
 Volutions five or six, inner ones half concealed, 
 
 outer whorl more than one-third the diameter, 
 sides flatted ; radii numerous, regular, bend towards 
 the aperture, not equal to the intervening concave 
 spaces ; dorsal furrows very distinct ; keel entire ; 
 
136 
 
 aperture oblong subquadrate ; diameter 2 inches. 
 L.L., 24, R.H. Bay. 
 
 The little of the shell that remains is rough,, and with- 
 out striae ; and the cast is smooth. The ramifications of 
 the septa are numerous and rounded, but by no means 
 so deeply indented as may often be observed. 
 
 184. A. IMPENDENS, r. <. B. Pal. pi. xxii. 
 Volutions four or five, inner ones three-fourths 
 
 concealed, outer whorl two fifths the diameter, 
 slightly convex, inner margin overhanging the next 
 whorl; radii prominent, straight, turn suddenly 
 towards the aperture near the back ; keel very 
 prominent, furrows on either side large ; aperture 
 triangular; diameter three inches. L.L., 16, R.H. 
 Bay. 
 
 The radii on the whorls of this species vary much in 
 their distance from each other in different specimens ; in 
 some they are numerous, in others rather distant, and 
 are separated by flat spaces. The inner edge of the 
 whorls overhangs, and the outer edge is terminated 
 rather abruptly by the groove on the side of the keel. 
 
 185. A. CONYBEARI, Sow. PI. cxxxi. 
 
 Volutions many, exposed, sides rather inflated, 
 outer whorl rather less than one-quarter the dia- 
 meter ; ribs prominent, rounded, numerous, curve 
 towards the aperture, equal to the rather angular 
 spaces ; keel prominent, plane, betweeen two strong 
 furrows ; aperture subquadrate. L.L., 24, Redcar, 
 and R.H. Bay. 
 
 186. A. TARDECRESCENS, BlaJce, pi. v., f. 5. 
 
 Much depressed ; volutions seven or eight, 
 
137 
 
 exposed, sides flatly rounded, inner margin blunt, 
 outer whorl one-fifth the diameter ; radii numerous, 
 straight, or but slightly waving, bend suddenly to 
 the aperture on the back, equal to the separating 
 concave spaces, scarcely striated; keel smooth, 
 furrows on each side distinct ; aperture subquadrate ; 
 diameter 3 inches. 
 
 In the first edition of this work, I took it as a variety 
 of A. Conybeari, but I agree with Mr. Blake in con- 
 sidering it a distinct species. It occurs in a nodular bed 
 L.L. 2. of my section, on the beach near the town of 
 R.H. Bay. 
 
 187. A. TENELLUS, Simp. 
 
 Much depressed; volutions five, inner ones three- 
 quarters concealed, outer whorl less than half the 
 diameter ; radii separated by widish spaces, straight, 
 turn suddenly towards the aperture near the back ; 
 striae, or lines of growth, numerous, fine, beautifully 
 sharp and distinct upon the keel, which they finely 
 crenate; keel prominent, round, relieved from the 
 sides of the whorl by a concavity; aperture tri- 
 angular or ovate ; diameter 2| inches. L.L., R.H. 
 
 Bay. 
 
 This is a more elegant species than the last ; the radii 
 are less prominent, and the groove on the side of the 
 keel much natter. 
 
 188. A. STELLARIS, Sow., pi. xciii. Syn. A. BUCKLANDI, 
 
 Simp. 
 
 Volutions five, inner ones a quarter concealed, 
 outer whorl one-third the diameter, thinnest near the 
 back, sides rather convex, inner margin rounded, 
 
138 
 
 overhangs the next whorl ; radii nearly straight as 
 far as the outer margin, then bend towards the 
 aperture, obtuse, equal to the intervening furrows, 
 nearly obsolete towards the aperture; keel obtuse; 
 aperture quadrate; diameter 12 inches. L.L., 23. 
 
 This is one of the largest species of ammonites which 
 occurs in our lias, and is. not uncommon in the lowest 
 beds at E.H. Bay. Different specimens vary much in the 
 strength of the radii, and, in the very large ones, the 
 radii sometimes become nearly obsolete towards the aper- 
 ture ; the inner edge of the whorl is rounded in such a 
 manner as to expose the next whorl, which it overhangs ; 
 the keel is often smooth, but in some specimens it is 
 crenated. 
 
 189. A. BUCKLANDI, Sow., pi. cxxx. Pal. ]S1. 1. 
 
 The A. Bucklandi of the Whitby dealers is the A. 
 stellaris, Sow. It appears from Tate and Blake that 
 the true A. Bucklandi occurs in a lower bed at Eedcar. 
 Sowerby describes his shell as having five volutions 
 wholly exposed and the aperture quadrate ; radii large 
 and obtuse. 
 
 190. A. BISULCATU8, Bing. 
 
 I have only a fragment sent me by Mr. Tate. The 
 radii are like those of A. stellaris, the aperture square 
 with the angles rounded. L.L., Eedcar. 
 
 191. A. BROOKI, Sow., pi. cxc. Pal. pi. vi., f. 4. 
 
 In the Whitby Museum, there is a fragment from the 
 Lower Lias at E.H. Bay, which I suppose to have be- 
 longed to Sowerby 's A. Brooki. The radii are more 
 bent, and the sides of the whorls are more rounded than 
 in A. stellaris ; the aperture is transverse ; diameter of 
 aperture three inches by 3 inches. 
 
 192. A. NODTTLOSUS, F. 4* B- Pal. pi. vi., f. 2. 
 Volutions five, inner ones about one-fifth con- 
 cealed, outer whorl about one-third the diameter, 
 
139 
 
 sides flat ; radii separated by flattish concave 
 spaces, straight to the outer margin of the whorls, 
 where there is a row of tubercles, then turn to- 
 wards the aperture ; keel crenated, grooves on 
 each side distinct ; aperture subquadrate ; diameter 
 two inches. 
 
 This is from the lower beds of Lias at E.H. Bay ; the 
 radii are only slightly elevated, and slender. The shell 
 is thickish, and of a light-brown colour. 
 
 The characters by which this ammonite is described, 
 are nearly the same as those of A. subnodosus, but it 
 belongs to a different family widely separated in time, 
 and must be considered a different species. 
 
 There is, in the Whitby Museum, the outer whorl of 
 an ammonite, from the Lower . Lias at Robin Hood's 
 Bay, 13^ inches in diameter. It has straight radii 
 terminating near the angular back in blunt knobs ; the 
 keel, and the deep furrows on its side, are well denned ; 
 the aperture is oblong, and widest at the inner part of 
 the whorls. 
 
 193. A. SAUZEANUS. 
 
 Mr. Blake has sent me an ammonite under this name 
 from beyond Slow-beck, E.H. Bay, one inch diameter, 
 volutions six, innermost ones plain, slightly concealed, 
 outer whorl more than one-third the diameter, inflated ; 
 ribs obtuse, short, prominent, with blunt tubercles on 
 the outer margin, separated by rather wide concave 
 spaces ; back rounded with a slight rising or incipient 
 keel ; shell smooth. Some of the ribs incline from the 
 aperture which has induced Mr. Blake to associate it 
 with A. resupenatus. Aperture ovate. 
 
 I have two examples, an inch and four-tenths dia- 
 meter, from the same locality, L.L., band 24, which 
 greatly resemble the above, but they have a smooth keel 
 between the distinct furrows. The ribs slightly incline 
 from the aperture, and in some places split in two, so 
 that one rib unites with two tubercles. 
 
140 
 
 194. A. BIFRONS, Brug. Syn. A. WALCOTTII, Sow. 
 Volutions five or six, inner ones one-fourth con- 
 cealed, inner edge of the whorls nearly plane, 
 rounded, or rather angular, then a broadish, shal- 
 low, concentric furrow or depression, from whence 
 proceed obtuse, crooked radii, separated by widish 
 concave spaces; keel entire, furrow on each side 
 large ; aperture oblong quadrate; diameter 6^ inches. 
 
 This may readily be distinguished by the groove run- 
 ning along the side of the whorls, and by the short, 
 obtuse radii. On the inner whorls, however, the groove 
 often becomes obsolete, and then the radii commence on 
 the inner margin of the whorl ; the shell is thick and 
 coarse, and the cast is smooth. In extracting the shell 
 from the matrix, the keel often comes off, and then the 
 siphuncle is beautifully displayed with constrictions at 
 short intervals. This is one of the most abundant shells 
 in the uppermost part of the Upper Lias. 
 
 195. A. HILDENSIS, Simp. 
 
 Of the same size and type as the last ; but the back of 
 the outer whorl is obtusely triangular. It is of frequent 
 occurrence in the jet-rock, where A. bifrons is never 
 found. 
 
 196. A. LEVISONI, Simp. 
 
 Volutions five, inner ones but little concealed, 
 outer whorl one-third the diameter, inner edge 
 rounded ; radii sigmoidal, obtuse, equal to the in- 
 tervening concave spaces ; keel entire, furrow on 
 either side distinct; aperture ovate; diameter 1| in. 
 
 197. A. LATESCENS, Simp. 
 
 Depressed ; volutions four or five, inner ones half 
 concealed, outer whorl two-fifths the diameter, sides 
 
141 
 
 regularly rounded ; radii waving, the last bend is 
 towards the aperture, obtuse, distinct on the outer 
 margin, on the inner whorls distant and nearly obso- 
 lete ; keel sharpish, entire, furrows on either side 
 distinct ; aperture ovate ; diameter l inch. 
 
 The breadth of the whorls, the regular convexity of 
 their sides, and the form of the radii, give this ammonite 
 a strong resemblance to A. striatulus ; but it is destitute 
 of striae, and has a distinct furrow on each side of the keel. 
 
 198. A. PINGUIS, Simp. 
 
 Thickish ; volutions five or six, inner ones half 
 concealed, outer whorl less than half the diameter, 
 inner margin nearly perpendicular, sides regularly 
 rounded; radii numerous, waving, strongest on the 
 outer half of the whorl ; keel plane, obtuse, between 
 two distinct furrows ; aperture ovate ; diameter 1| 
 inch. 
 
 This is much thicker than the last, and the radii more 
 numerous ; the keel also appears to be constructed in a 
 different way, so as to be knocked off with the shell ; 
 whilst in A. latescens it remains perfect where the shell 
 has been removed. It is of a brown colour, and shining. 
 It is from the jet-rock of the Upper Lias. Mr. Clarkson's 
 collection. 
 
 IV. With a dorsal furrow only. 
 
 199. A. ANGTJLATUS, Sch. Syn. A. EEDCARENSIS, Y. fy B. 
 Volutions five or six, inner ones, half concealed, 
 
 outer whorl rather more than one-third the diameter ; 
 radii prominent, diverging, straight along the sides 
 of the whorl, then suddenly bend towards the 
 aperture near the back, where they are terminated 
 
142 
 
 by a narrow smooth space or furrow; aperture 
 triangular, or subquadrate ; diameter three inches. 
 
 The radii proceed from the inner margin of the whorls, 
 and have the appearance of coarse plaits; the prominent 
 angles on the back, and the absence of a keel, render 
 this a highly characteristick species; the sides of the 
 whorls are slightly convex, and the inner edge quickly 
 rounded. It is very variable. 
 
 I have a fragment of a specimen, twice as thick as 
 some, and with coarse and irregular radii. I leave it at 
 present as a variety. L.L., 26. 
 
 200. A. SULCATUS, Simp. 
 
 Volutions much concealed, outer whorl nearly 
 half the diameter ; radii strong on the inner margin 
 of the whorl, then split in two or three, faint, twice 
 bent ; an angular furrow on the back ; aperture 
 triangular ; diameter three-eighths of an inch. 
 
 This interesting little ammonite may be readily dis- 
 tinguished from the rest by the angular furrow on the 
 back, which is very distinct on the outer whorls, and 
 becomes a mere line on the inner ones. It, like a great 
 many other small and beautiful species, is from the lower 
 beds of lias at Robin Hood's Bay. 
 
 MALFORMATIONS. 
 
 I may notice several malformations, which came under 
 my observation all at once : Two specimens of A. elegan- 
 tulus, which are in the form of a dish, with an ill-formed 
 keel near the hollow side; one is 1 inch in diameter, 
 the other three-quarter inch. Three more, which may be 
 of the same species, are also hollow on one side, and 
 round on the other ; the back is thin and rounded, and 
 an imperfect keel is formed on the hollow side of the 
 whorl. The inner whorls are more concealed than is 
 generally the case in A. elegantulus, and the radii are 
 less distinct. They are all from the Jet Rock. 
 
143 
 
 There is also another, which I suppose to be A. Haws- 
 kerensis ; on one side it has the characteristick radii of 
 that species, but on the other they are nearly obsolete, 
 and their place supplied with an imperfect crenated 
 keel. The inner whorls differ nothing from the ordinary 
 forms of this species. 
 
 GASTEEOPODA. 
 
 The animals which inhabit these shells, are so 
 named, because they walk on their stomach. The 
 common garden snail, and the periwinkle of our 
 shores, are familiar examples. 
 
 The muddy beds of Lias have been very un- 
 favourable to the existence of these creatures, and 
 in the previous edition of this work, I could not 
 make out more than fifteen species. But Messrs. 
 Tate and Blake, by their enthusiastick labours in 
 the main bed of ironstone, in the Middle Lias at 
 Eston, in the Tees valley, and more especially in 
 the lowest beds of the Lower Lias, in that region, 
 have recently brought up the number of species to 
 eighty-four. To these we have added a few more. 
 
 We may first notice the Trochoid or Turbinated 
 shells. They feed on vegetables. 
 
 Genus Trochus, Linn. The top-shaped shells. 
 These have more or less a quadrangular aperture. 
 
 Of many species noticed by Profr. Tate, as found by him in the 
 Yorkshire Lias, no examples could be found in the collection he 
 deposited in the Museum of Economic Geology in London, on leaving 
 for Australia. I give the names to assist future researches. 
 
144 
 
 Those with a slit in the outer margin, are called 
 Pleurotomaria. Some have the base umbilicate as in 
 Solarium, in others it is imperf orate. 
 
 Trochus proper. 
 
 1. TROCHUS THETIS, Mun., Tate. 
 
 Spire conical, height one-quarter of an inch, 
 equal to the width of the flatted base, apex 
 pointed ; whorls four or five, sides flatted, the 
 spiral strise tuberculated by coarse lines of growth. 
 L.L., w, North cheek of R.H. Bay, Huntcliff, &c. 
 
 2. T. REDCABENSIS, Tate, T. $ B., pi. x., f. 14. 
 Whorls six, deeply channelled at the suture, 
 
 decorated with three strong spiral strise ; height 
 of spire two-tenths of an inch ; diameter of the 
 concentrically striated base two-tenths of an inch. 
 Lowest beds of Lias at Redcar. 
 
 3. T. EOBIGUS, Tate, T. $ B., pi. x., f. 3. 
 
 Whorls six, with the shell angular, shewing a 
 central line ; cast of interior, smooth, round ; 
 length of spire three -tenths of an inch ; width 
 three-twentieths of an inch. L.L., upper part of the 
 indurated bands, R.H. Bay. 
 
 Pleurotomaria. A slit in the aperture. 
 
 4. T. ANQLICUS, Sow. Syn. SIMILIS, Sow. 
 Turriculated, base umbilicate, flatly rounded, 
 
 and strongly striated, width nearly equal to the 
 height of the spire; whorls five, rhomboidal, very 
 strongly crenated on the edge, a keel in the middle 
 
145 
 
 between two furrows, coarsely, spirally, and longi- 
 tudinally striated; length two inches. 
 
 The whorls of the cast are rounded; and entirely 
 smooth. It is from the lowest beds of the Lower Lias, 
 R.H. Bay ; Redcar. 
 
 5. T. PUSILLUS, Simp. 
 
 Length three-quarters of an inch, equal to the 
 width, base rounded ; five rounded tumid whorls, 
 last whorl large, having on the middle a rounded 
 keel between two concave furrows, the lower 
 
 furrow the larger. 
 
 A cast, with a small bit of the shell at the base 
 strongly striated. L.L., w, E..H. Bay. 
 
 6. T. PROCERUS, D'Orb, Tate, T. & B., pi. ix., f. 24. 
 Whorls seven or eight, rhomboidal, concentrically 
 
 and transversely striated, with a groove on the angle, 
 height one and three-quarters of an inch, width 
 seven-tenths of an inch ; base protuberant, con- 
 centrically striated. L.L., w, R.H. Bay. 
 
 This is a very beautiful and well-defined species, the 
 transverse striae are the most distinct on the upper 
 whorls, and are oblique. 
 
 7. T. FOVEOLATUS, Desl., Tate, T. $ B., pi. ix., f. 2. 
 Whorls five, strongly, concentrically, and trans- 
 versely striated ; on the upper whorls deeply 
 grooved. M.L., ironstone, Staithes. 
 
 8. T. HELICINOIDES, Ro., Tate, T, $ B., pi. x., f. 7. 
 Ovate, turriculated, width of base three-quarters 
 
 of an inch, equal to the height, apex obtuse, base 
 convex, with 16 strong T concentrick striae, inter- 
 vening spaces wider towards the centre ; whorls 
 L 
 
146 
 
 five, subquadrate, lower edge rounded, then a con- 
 cave band with six spiral striae and a narrow groove 
 on the upper margin, then a broad concave band, 
 and a narrow elevated sutural band ; the whole 
 shell is decussated by spiral, and longitudinal, wav- 
 ing striae. Uppermost part of the M.L., Hawsker. 
 
 9. T. TECTARIUS, Tate, T. Sf B., pi. ix., f . 26. 
 
 Whorls five, rather angular; upper side sloping, 
 with a distinct groove on its lower edge ; lower side 
 concave, coarsely and concentrically striated ; height 
 of spire seven-tenths of an inch, width of base five- 
 tenths of an inch. Lowest Lias, Redcar. 
 
 In another example the whorls are rhomboidal and 
 spire pointed. 
 
 10. T. UNDOSUS, Des., Tate, T. $ B., pi. ix., f. 1. 
 
 This I have not seen. It is from the ironstone at 
 Eston, and is very similar to T. Anglicus. 
 
 11. T. CONCAVUS, Martin, Tate, T. Sf B., pi. ix., f. 27. 
 Whorls four, the cast much inflated, flatted in 
 
 the middle concentrically striated ; height three- 
 tenths of an inch, width two-tenths of an inch. 
 Lowest Lias, Redcar. 
 
 12. T. RUSTICTJS, Des., Tate. 
 
 This has not been preserved in Tate's collection. It 
 occurs in the Cleveland Main Ironstone bed, and is 
 three inches in diameter, but so imperfectly preserved 
 as not to admit of particular description. Tate assimi- 
 lates it to T. Anglicus. 
 
 13. T. BASILICUS, C. # D., Tate. 
 
 Very similar to T. Anglicus, but of small size, umbi- 
 licus wide. Lowest Lias, Eedcar. 
 
147 
 
 14. T. HENNOCQUI, Ter., Tate. 
 
 Whorls five, flattish, concentrically, and irregu- 
 larly striated ; base flattish, margin rounded ; 
 height two inches and seven -tenths, equal to the 
 width. Lowest Lias, Redcar. 
 
 15. T. OBESULUS, Tate, T. & B. f pi. x., f. 6. 
 
 Whorls four, rounded, concentrically striated; 
 apex obtuse ; base flattish, umbilicate, concentri- 
 cally striated, height one inch, equal to the width. 
 Lowest Lias, Market Weighton. 
 
 Helicina, or those which approach in form to the Helix. 
 
 16. T. EXPANSTJS, Sow. Syn. HELIX CIRROIDEA, Y. & B. 
 Spire much depressed, acuminate, base deeply 
 
 umbilicate ; whorls five or six, last one large, lower 
 part rounded, upper part concave, then a ridge, 
 concave at the suture ; striae spiral, numerous,, 
 fine, distinct, often waving, crossed by lines of 
 growth ; aperture gibbous ; width of the base one 
 
 inch. 
 
 Cast smooth and shining, in which state Young com- 
 pares it with Helis ericetorum. It has had various 
 names. Sowerby first named it Helicina expansa. It 
 it is closely allied to Pleurotomaria. Uppermost part of 
 the Middle Lias at Hawsker, Eston, &c. 
 
 17. T. CONSOBRINUS, Tate, T. & B., pi. x., f . 2. 
 
 Spire very much depressed, acute ; whorls five, 
 last one large, lower part rounded, upper part 
 concave with a rounded rim at the suture ; dia- 
 meter one inch. M.L., a. 
 
 This is well distinguished from the last by its having 
 no striae, as well as by the greater flatness of the spire. 
 
148 
 
 It is from the main ironstone bands at Eston. Tate 
 says it is marked with curved transverse lines. 
 
 18. T. SOLABIOIDES, Sow ., pi. cclxxiii. ; T. & B., pi. x., f . 2. 
 Spire very much depressed, base rounded, with 
 
 a depressed central area ; whorls five or six, upper 
 part with a large concave channel ; apex acute ; 
 spiral striae obsolete ; diameter three-quarters of 
 an inch. 
 
 This is even more discoid than either of the above. 
 Lowest beds of Lower Lias at Eedcar. 
 
 19. T. R6TELL,aEFORMis, Dun., Tate. No example, and 
 / very doubtful. Lowest Lias, E-edcar. 
 
 20. T. NUCLERES, Ter., Tate. No example, and very 
 
 doubtful. Lowest Lias, Cliff. 
 Solarium ; Tate's Discohelix. 
 
 21. T. OPPELI, Ma., Tate, T. $ B., pi. x., f. 8. 
 
 Discoid, much depressed, whorls six, smooth, 
 diameter three-tenths of an inch. Lowest Lias, 
 Eedcar. 
 
 22. T. LIASINUS, Dunks., Tate. L.L. No example. 
 
 23. T. STRIATUS, Pic., Tate, T. fy B., pi. ix., f. 8, 9. 
 Much depressed, whorls five or six, exposed ; 
 
 ribs numerous, pass over the back ; diameter two- 
 tenths of an inch. Lowest Lias, Redcar. 
 
 24. T. ARATTJS, Tate, T. $ B.,, pi. ix., f. 5. 
 
 Whorls four; transverse ribs, numerous, distinct, 
 pass over the back undivided ; aperture transverse ; 
 diameter quarter of an inch. M.L., Saltburn, &c. 
 
 This is well distinguished from the next by the ribs. 
 On one specimen I observe some obsolete spiral striae. 
 The spire is scarcely so much depressed as in the next. 
 
149 
 
 25. T. BELLTTLUS, Tate. 
 
 Whorls four, with very fine, numerous, spiral 
 striae, crossed by lines of growth, amounting in 
 some places to ribs ; aperture very transverse, 
 lunate ; diameter one-fifth of an inch. 
 
 The back is regularly convex, and the spire is so much 
 depressed that it might be taken for an ammonite. 
 Lower beds of Middle Lias at Staithes. 
 
 26. T. SEMICLAUSUS, Tate, T. & B., pi. ix., f. 14. 
 
 < ' Shell small globose ; spire sunk, base convex, umbi- 
 licus narrow, not exposing the inner whorls ; whorls 
 four, convex, embracing, ornamented with numerous, 
 fine, flexuous threads; diameter and height one-tenth 
 of an inch." Tate. L.L., 27, Eedcar. 
 
 Genus Turbo, Linn. There is no well-defined 
 line of separation between the genera Trochus 
 and Turbo. In general the former has a quadrate 
 aperture and the whorls more angular. The latter 
 has the aperture more rounded and the spire more 
 perfectly and regularly turbinated. In some species 
 it is greatly lengthened. 
 
 Spire short. Turbo proper. 
 
 1. T. SOLARIUM, Pic., Tate, T. $ B., pi. ix., f . 16. 
 Height scarcely equal to the width ; whorls four, 
 
 rounded, smooth, channelled at the suture; diame- 
 ter of the base quarter of an inch. L.L., Redcar. 
 
 2. T. LATILABRUS, 8tol. t Tate, T. fy B., pi. ix., f. 15. 
 Whorls five, quickly rounded, apex obtuse ; last 
 
 whorl half the spire ; height of spire three-tenths 
 of an inch, scarcely equal to the width of the base. 
 M.L., a, Eston. 
 
150 
 
 3. T. LINEATUS, Moor, Tate, T. & B., pi. ix., f. 20. 
 Whorls six, rounded, with numerous, strong 
 
 spiral striae ; last whorl about half the length of 
 the spire, which is seven -tenths of an inch ; dia- 
 meter of base five-tenths of an inch. M.L , a, 
 Upleatham. 
 
 4. T. RETICULATUS, Moor, Tate. 
 
 Depressed, four rather angular whorls, with 
 reticulated striae ; base convex, striated, diameter 
 four-tenths of an inch, height of spire three-tenths 
 of an inch. L.L., 16, Redcar. 
 
 5. T. WILSONI, Tate, T. fr B., pi. x., f. 5. 
 Depressed; Whorls four, convex, spiral striae fine; 
 
 base convex, umbilicate, concentrically striated ; 
 width two-tenths of an inch, equal to the length 
 of the spire. L.L., 16, Redcar. 
 
 6. T. CYCLOSTOMA, Benz., Tate, T. j- B., pi. ix., f. 19, 20. 
 Conical ; whorls five, rounded below, upper part 
 
 rather flatted, channelled at the suture ; apex acute ; 
 spiral striae numerous, distinct, reticulated by trans- 
 verse lines of growth ; height of spire three-eighths 
 of an inch, greater than the width. M.L., a, and 
 ILL., 8, Hawsker, &c. 
 
 7. T. TUKBINATUS, Moor, Tate. 
 
 Conical, height three-eighths of an inch, greater 
 than the breadth ; apex acute ; base rounded, 
 umbilicate ; whorls five, regularly rounded. M.L., 
 dj Eston. 
 
151 
 
 8. T. ACICULUS, Stol., Tate, T. & B., pi. ix., f. 22. 
 
 Mr. Tate says this differs from T. turbinatus, but I 
 cannot see on what his opinion is founded. All my 
 specimens are from Mr. Tate. 
 
 9. T. PHILEMON, D'Orb, Tate, T. $ B., pi. ix., f. 25. 
 Spire much depressed ; base umbilicate, crimped, 
 
 breadth one-eighth of an inch, greater than the 
 height ; whorls four, smooth, flatted, last whorl 
 with a spiral groove on the edge. Lowest beds of 
 L.L., at Redcar. 
 
 10. T. TENTHS, T. fr P. Tate. 
 
 Whorls three, turriculated, last whorl large, 
 height of spire one-tenth of an inch. Lowest beds 
 of Lias, Foxton. 
 
 Littorina, shore shells. 
 
 11. T. NANUS, Martin, Tate, T. fr B., pi. ix., f. 17. 
 Ovate, whorls four, convex, with about eighteen 
 
 strong longitudinal ribs, crossed by very fine, faint 
 spiral striae, height of spire two -tenths of an inch, 
 greater than the width. L.L., Redcar. 
 
 12. T. SORDIDTJS, Tate, T. fr B., pi. x., f. 19. 
 
 Conical, height one-fourth of an inch, equal 
 to the width, base imperf orate, striated in the 
 middle, whorls five, rather inflated, convex, smooth 
 or obscurely and spirally striated. Lowest beds 
 of Lias at Redcar. 
 
 13. T. ELEGANS, Huns., Tate, T. & B. y pi. ix., f. 30. 
 Conical, height one-third of an inch, width at 
 
 the base one-fifth of an inch ; base convex, imper- 
 forate, concentric striae, strong, reticulated ; apex 
 obtusely pointed ; whorls seven, with two strong 
 
152 
 
 spiral ribs in the middle and a smaller one above, 
 deeply channelled at the suture, spiral striae numerous, 
 distinct, reticulated, interrupted. L.L., Redcar, &c. 
 
 14. T. CHAPTTISI, T. & P., Tate, T. & E., pi. ix., f. 29. 
 
 No example. 
 
 <( Whorls angulated, sub-imbricating,, with granular 
 ribs." L.L., 23, Redcar. Tate. 
 
 15. T. SELECTUS, C. & V., Tate. 
 
 Whorls six or seven, flat, with a strong elevated 
 ridge on the lower part, imbricating, longitudinally 
 striated ; base convex, strongly and concentrically 
 striated, width six-tenths of an inch ; height of 
 spire one inch. L.L., Marsk. 
 
 16. T. ACUMINATUS, C. & D., Tate, T. <L- B., pi. x., f . 20. 
 Conical, height of spire three-fourths of an inch, 
 
 width half an inch ; base convex, imperforate, with 
 concentrick striae strong, coarse, irregular ; apex 
 obtusely pointed ; whorls eight, acutely triangular, 
 crossed by coarse striae crenating the lower edge 
 of the whorls. Lowest beds of Lower Lias at 
 Redcar. 
 
 17. T. IMBRICATUS, Sow., pi. cclxxii. 
 
 Conical, height of spire one inch, equal to the 
 width, base elevated ; apex bluntly pointed ; 
 whorls imbricating, six or seven, triangular, the 
 upper side the broader, both sides ornamented with 
 three rows of tuberculated spiral striae, crossed by 
 very distinct irregular, longitudinal striae. Cast 
 smooth. L.L., y, R.H. Bay, Huntcliff, &c. 
 
153 
 
 18. T. Gu ADR Y ANUS, D'Orb, Tate. 
 
 Conical, height half an inch, equal to the width, 
 base -rounded, with strong- con cent rick ribs ; apex, 
 sharply pointed ; whorls six, the lower edge with 
 a strong tuberculated keel, then a flattish space 
 with a slender spiral line, and above it three rows 
 of connected tubercles. L.L., ?/, Huntcliff. 
 
 19. T. UNDULATUS, Ph., T. & B., pi. x., f. 12. 
 Conical, height of spire one inch, width at the 
 
 base seven-eighths of inch ; base rounded, coarsely, 
 concentrically and transversely striated ; whorls 
 seven, subangular, upper part flatted, ornamented 
 with about twelve spiral tuberculated ribs or 
 strong striae, decussated by strong longitudinal 
 striae. M.L., #, Hawsker. 
 
 The whorls of the cast are nearly smooth and rounded, 
 some in the ironstone beds at Grosmont have a shorter 
 spire, and may be a distinct species. 
 
 20. T. CONCINNUS, Simp. 
 
 A cast. Last whorl more ventricose than the last, 
 and regularly convex, in which respect it differs from 
 the cast of T. imbricatus, which has the upper half of 
 the whorls nearly flatted. L.L., y, E.H. Bay. 
 
 21. T. RUGOSUS, Simp. 
 
 Conical, length about equal to the width ; whorls 
 four or five, flatted, lower edge obsoletely keeled, 
 or quickly rounded; striae coarse, with numerous 
 undulations and wrinkles. M.L., Hawsker. 
 
 22. T. ADDUCTUS, Simp. 
 
 A cast. Base and lower part of the whorls 
 
154 
 
 boldly rounded, upper edge prominent, turriculated 
 by a deep channel at the suture. M.L., Hawsker. 
 
 23. T. NIREUS, D'Orb., Tate. 
 
 Whorls six, much flatted, with strong 1 tuber- 
 culated spiral striae, about six on each whorl, 
 decussated by transverse striae ; apex pointed ; 
 height of spire seven-tenths of an inch, diameter 
 of base five-tenths of an inch. M.L., Cleveland. 
 Tate. 
 
 24. T. CONSPERSTJS, Tate, T. & B., pi. x., f. 11. 
 Whorls seven, angular, deeply channelled at the 
 
 suture, spiral striae numerous ; apex acute ; base 
 convex ; last whorl about half the spire ; height 
 six-tenths of an inch, width three-tenths of an 
 inch. M.L., a, Eston. 
 
 25. T. CINGENDUS, Tate, T. & B., pi. x., f. 15. 
 Whorls six, boldly rounded ; spiral striae very 
 
 strong and coarse ; apex pointed ; height of the 
 spire five-tenths of an inch, width four-tenths of 
 an inch. 
 
 In another example the height is eleven-tenths of an 
 inch, width six-tenths of an inch. M.L. 
 
 26. T. CLEVELANDICUS, Tate, T. & B., pi. x., f. 17. 
 Subconical or ovate ; height seven-tenths of an 
 
 inch, equal to the width ; apex obtuse ; whorls 
 four or five, rounded ; base rounded, with twelve 
 crimped or fimbriated spiral striae which are con- 
 tinued over the rest of the shell. M.L., Arenaceous 
 beds, Staithes, Huntcliff, &c. 
 
155 
 
 Phasianella. 
 
 27. T. MORENCYANUS, Pic., Tate, T. & B., pi. ix., f. 21. 
 Conical ; length two-tenths of an inch, equal 
 
 to the width ; five smooth convex whorls, the last 
 whorl large. L.L., 27, Redcar. 
 
 Spire elongated. Turritella. 
 
 28. T. DEFOSSUS, Simp. 
 
 Length half an inch, three times the width ; 
 whorls thirteen, flattish, grooved at the suture, 
 reticulated with longitudinal and spiral striae. 
 
 In my most distinct example there are from five to 
 seven spiral striae, and about twenty longitudinal striae, 
 which are concave to the aperture on each whorl. 
 Whorls of the cast are rounded. L.L., B/.H. Bay. 
 
 29. T. DUNKEII, Ter., Tate, T. & B., pi. ix., f. 3. 
 
 Mr. Tate considers this a synonymous with the last, 
 but in a length of an inch it has only fourteen whorls 
 which have only five longitudinal costae, transversely 
 striated. L.L., 13, E.H. Bay, &c. 
 
 30. T. ZENKENI, Dun., Tate. 
 
 Whorls several, rounded, longitudinally striated. 
 Eather a large species. All my specimens are very 
 imperfect. L.L., Redcar. 
 
 31. T. REGULARIS, T. < P., Tate. 
 
 Whorls six or seven, nearly smooth, with a rising* 
 at the suture ; height two-tenths of an inch. 
 
 Tate says the whorls have six rows of granulations, 
 and are transversely striated, which I did not observe. 
 L.L., 15, E.H. Bay. 
 
 32. T. AUBEUS, Simp. 
 
 Height of the spire three-tenths of an inch, 
 rather more than twice the width ; whorls eight, 
 
156 
 
 moderately channelled at the suture, boldly rounded, 
 with longitudinal ribs prominent on the upper part, 
 interrupted by the sutural groove, obsolete on the 
 lower ; a varix the whole length of the shell ; the 
 last whorl with very indistinct spiral striae. L.L.,#, 
 R.H. Bay. 
 
 The cast has the whorls tumid, the last one with a few 
 obsolete ribs or varices. 
 
 33. T. BLAINVILLEI, Muns. f Tate. 
 
 Whorls seven or eight, flattish, strongly ribbed, 
 longitudinally, about ten in number, length of finely 
 pointed spire three-tenths of an inch, width of 
 base one-tenth of an inch. M.L., Hawsker, &c. 
 
 34. T. YOUNGI, Simp., T. $ B., pi. xvi., f. 6. 
 Scalariform, length l inch, about five times 
 
 the width ; eighteen rather tumid whorls, which 
 are ornamented with from twenty-six to twenty- 
 eight obtuse ribs, curving to the right, crossed by 
 faint spiral striae, most distinct near the well defined 
 suture. L.L., #, R.H. Bay. 
 
 35. T. FERREUS, Simp. 
 
 A cast ; whorls six, flatted, or concave in the 
 middle, angular near the suture ; length three- 
 quarters of an inch, width three-eighths of an inch. 
 M.L., Hawsker. 
 
 I have a fragment of what appears to be the same 
 species ; whorls of the cast round and bright, and a bit 
 of the shell, with fine longitudinal and spiral striae. 
 From the same beds. 
 
157 
 
 36. T. CITHABELLA, Tate, T. $ B., pi. x., f . 4. 
 Whorls five or six, flatted, longitudinally striated, 
 
 almost ribbed, channelled at the suture, last whorl 
 less than half the spire, length of spire seven-tenths 
 of an inch, diameter of base four-tenths of an inch. 
 M.L., Huntcliff. 
 
 Probably the same as T. ferreus with the shell on. 
 
 37. T. ACTTLA, Tate, T. Sf B., pi. x., f. 10. 
 
 Whorls eight, flatted, smooth, deeply channelled 
 at the suture ; length four-tenths of an inch, 
 breadth one^tenth of an inch. U.L., 7, Glaisdale. 
 
 Tate says, covered with fine transverse striae, which 
 my glass did not bring out. 
 
 38. T. NUDA, Hun., Tate. 
 
 Shell imperfect; eight remaining whorls, smooth, 
 nearly flat, suture deeply cut ; length one inch, breadth 
 four-tenths of an inch. M.L., Huntcliff. 
 
 39. T. TRANSVERSUS, Blake, T. fy B. f pi. x., f. 21. 
 
 I have no example. It is thus described by Tate : 
 " Shell conical, whorls nine, convex, ornamented by 
 thick and straight transverse plications, ten on the body 
 whorl; the first four apical whorls without ornament; 
 whole surface smooth ; base convex, smooth ; umbilicus> 
 minute ; total length one-sixth of an inch." L.L., 27, 
 Cliff. 
 
 40. T. BEBTHAUDI, Dum., Tate. 
 
 Whorls ten or eleven, rather inflated, with 
 numerous varices or strong striae. L.L., 25, Eedcar. 
 
 41. T. UNICINGULATUS, Ter., Tate. 
 
 Many whorls, slightly inflated, smooth. L.L., 
 26, Redcar. 
 
 42. T. CABUSENSIS, D'Orb, Tate, L.L., w, E.H. Bay. No 
 
 example. 
 
158 
 
 43. T. FOVEOLATUS, Tate, T. & B., pi. ix., f. 12. 
 
 I have no example. The following is Tate's des- 
 cription : " Shell conical, elongated ; whorls twelve, 
 nearly flat, or slightly convex, separated by a narrow, 
 but well denned suture ; the anterior whorls with thicker 
 cortse, but separated into granular nodulations by trans- 
 verse sulci." L.L., w, Ayton. 
 
 44. T. SEMITECTUS, Tate, T. fy B., pi. ix., f. 23. 
 Whorls nine, flatly covex, longitudinally striated ; 
 
 length four-tenths of an inch, diameter of base 
 
 two-tenths of an inch. M.L., a, Eston, &c. 
 
 This can scarcely be placed amongst those which have 
 the spire elongated. 
 
 45. T. COLLENOTI, T. & P., Tate. 
 
 Whorls seven, rounded, smooth, a depressed 
 plica or varix on the body whorl continued to the 
 apex where the number is increased ; apex obtuse, 
 height of spire less than three times the width, 
 three-tenths of an inch. L.L., R.H. Bay. 
 
 Genus Nerita, Linn. Spire very short, last whorl 
 large. 
 
 Nerita proper. 
 
 1. N. ALTERNANS, Tate. T. Sf B., pi. x., f. 16. 
 
 Much depressed ; whorls three, last whorls very 
 large, strongly striated spirally, with a fine strias 
 between the larger, crossed by numerous lines of 
 growth ; width of the mouth seven-tenths by six- 
 tenths of an inch ; height of spire three-tenths of 
 an inch. M.L., a, Eston. 
 
 Natica. 
 
 2. N. BUCCINOIDES, Y. $ B. T. & B., pi. ix., f. 11. 
 Spire depressed; height 1^ inch, equal to the 
 
159 
 
 width; whorls five or six, turriculated, convex; 
 last whorl very large, base and side convex, upper 
 margin angular, a broad concave band to the suture 
 which is slightly channelled, covered by fine reticu- 
 lated and punctured striae. U.L., 5, Whitby. 
 
 3. N. NEGLECTA, Simp. Syn. MINUTA ? 
 
 A minute species, having nearly the same form as the 
 last. It is ornamented with -exceedingly fine, unequal, 
 hair-like spiral striae, to be seen only under a powerful 
 lens. Cast of interior smooth. Found in the greatest 
 profusion in a band above the Jet Rock, reminding one 
 of the vast number of small turbinated shell which may 
 be seen devouring the laminaria at very low tides. U.L., 
 6, Whitby, &c. 
 
 4. N. FUSCA. 
 
 Of the same form as N. buccinoides, but entirely 
 smooth, and the whorls seem to imbricate. It is of a 
 lightish brown colour. U.L., Whitby. 
 
 5. N. PURPUROIDES, Tate. T. & B., pi. x., f. 13. No 
 
 example. 
 
 Tate describes it as "ovately globose, pyriform, spire 
 oblique, whorls few, body whorl angulated medially, 
 posterior half concave, anterior part convex; surface 
 covered with flexuous lines and rugose ; length one and 
 seven-twelfths of an inch, greatest breadth one and one- 
 twelfth of an inch. 
 
 The following small shells probably belong to 
 the Genus Tornatella, Lamark, and which Mr. Tate 
 places under the Sub-genus Actasonina. 
 
 1. TORNATELLA MARGIN AT A, Simp. 
 
 Whorls four, turriculated, last whorl two-thirds 
 the whole length, with a ridge or elevated line on 
 
160 
 
 the upper margin, subcylindrical ; length of spire 
 one-fourth of an inch. L.L., v, R.H. Bay. 
 
 2. T. SINEMUNENSIS, Martin, Tate. No example. L.L., 
 
 E/edcar. 
 
 3. T. FRAGILIS, Dun., Tate. 
 
 Whorls four, turriculated, last whorl subcylin- 
 drical, smooth, upper margin sharply defined, three- 
 fourths the length ; length one-seventh of an inch. 
 L.L., 13, R.H. Bay, Redcar, &c. 
 
 4. T. CHRYSALIS, Tate, T. <fc B., pi. ix., f . 7. 
 
 Whorls six, slightly flatted, last whorl more than 
 half the spire, length of spire eight -tenths of an 
 inch, greatest breadth four-tenths of an inch. M.L., 
 a, Eston. 
 
 The following is Mr. Tate's description : " Shell oblong 
 ovate, whorls five, sub-convex, depressed at the suture, 
 with a single impressed line on the shoulder of the 
 whorl, marked with transverse plications and fine striae ; 
 spire elongated, subacute; aperture elongated, slightly 
 effuse in front, posteriorly very narrow; base slightly 
 depressed. Dimensions: Total length three-quarters of 
 an inch ; length of last whorl half an inch, breadth five- 
 sixteenths of an inch. Eston and Upleatham mines." 
 
 5. T. ILMINSTERENSIS, Moor, Tate, T. & B., pi. ix., f . 7. 
 Whorls five or six, turriculated, spirally and 
 
 strongly striate; last whorl less than two-thirds 
 the height of the spire, which is half an inch ; 
 diameter three-tenths of an inch. M.L. 
 
 6. T. PULLA, K. & D.; Tate. No example. U.L., 1, Peak. 
 
161 
 
 Genus Buccinum, Linn. A notch or canal in the 
 
 aperture. 
 
 On a piece of Lias limestone containing Isocardia 
 nitida, there is a little white shell with a very depressed 
 spire, last whorl large with a narrow aperture. It has 
 very much the appearance of a Buccinord shell, and I 
 may name it 
 
 1. BUCCINUM NITIDUM. 
 
 Spire very much depressed, last whorl large, 
 lower part flatly convex, upper margin quickly 
 rounded, deeply grooved at the suture, on it may 
 be seen about twelve very distinct, smooth, finely 
 rounded spiral striae or ribs ; aperture narrow,, 
 transverse ; greatest width one-tenth of an inch ; 
 apex wanting. U.L., 5&, Saltwick. 
 
 Genus Cerithium. 
 
 *I retain under this head a number of small shells. As 
 the aperture is seldom displayed, it may be much 
 questioned whether some of them may not be Turritella. 
 
 1. CERITHIUM AUREUM, Simp., Syn. SLATTERI ? Tate. 
 
 A cast ; length three times the width ; eight 
 tumid whorls, the last whorl crossed by a few 
 obsolete ribs or varices; length a quarter of an inch. 
 
 Judging from impressions on the matrix, and a bit of 
 the shell on one specimen, it is spirally ribbed. They 
 are not uncommon in the pyritous band, so rich in other- 
 interesting fossils. L.L., y, R.H. Bay. 
 
 Some specimens sent me by Mr. Tate as C. Slatteri, 
 may be thus described. 
 
 2. C. SLATTERI, Tate. 
 
 Conical, length a quarter of an inch, twice the 
 width ; whorls nine, flattish, deeply channelled at 
 M 
 
162 
 
 the suture ; about five or six very delicate spiral 
 striae on each whorl, the middle one the most 
 distinct, reticulated by very faint longitudinal striae. 
 L.L., 26, Redcar. 
 
 I have a number of them on a piece of Lias limestone, 
 .'along with Turritella Dunkeri, and Astarte cinqulata, 
 sent me by Mr. Tate from Coatham. 
 
 3. C. LIASSICUM, Moor, Tate, T. & B., pi. ix., f. 18. 
 Ovate, length a quarter of an inch, about one- 
 third greater than the width ; four convex whorls 
 with a deep channel at the suture, ornamented 
 with about nine elevated, strong, spiral striae or 
 ribs which are decussated by nearly double the 
 number of longitudinal striae or ribs ; apex obtuse. 
 M.L,, a, Hawsker. 
 
 4. C. QUADRILINEATUM, Rom., Tate, U.L., 1. No example. 
 
 5. C. ACRICTJLTJM, Tate, T. fy B., pi. x., f. 1. 
 
 Whorls nine, flatted, grooved at the suture, 
 length of spire not quite three-sixteenths of an 
 inch, width one-sixteenth of an inch. M.L., a, 
 Hawsker. 
 
 6. C. ARMATUM, Gold. U.L., 1, Peak. No example. 
 
 7. C. SPIRATUM, Moor. L.L., 27, Eedcar. No example. 
 
 8. C. SEMELE,D'Or6, Tate: L.L., 23, Eedcar. No example. 
 
 9. C. GRATUM, Te*., Tate. L.L., 23, Eedcar. No example. 
 
163 
 
 ACEPHALA. 
 
 We have now come .to that numerous and im- 
 portant class of molluscous animals, which, from the 
 circumstance that they have no apparent head, 
 have been denominated Acephala. They . have 
 been divided into two orders, those with a shelly 
 appendage; or, Testaceous Acephala; and those 
 without such means of protection ; the Acephala 
 Nuda. The latter constitute comparatively few 
 genera ; and being composed entirely of soft parts, 
 however great may have been their numbers in 
 primaeval seas, it is not to be expected that much 
 of their remains can be found preserved in the 
 strata. But the remains of the former order have 
 been preserved in the greatest profusion. The 
 soft parts of these, however, have also perished ; 
 and it is only their shelly appendages which have 
 been preserved. These, for the most part, consist 
 of two pieces, which are united together by a 
 hinge, and which the animal can, in general, open 
 or shut at pleasure ; these are denominated Bivalves. 
 A few consist of more than two pieces, and are 
 denominated Multivalves. The Testaceous Acephala 
 have been divided into five groups, or Families. 
 1. The Oysters. 2. The Mussels. 3, The Chamas. 
 4. The Cockles. 5. The Inclusa. 
 
 FAMILY I. OSTRACEA, OR OYSTERS. 
 
 The shells of this family are fixed to rocks, or 
 other submarine bodies, either by their byssus , or 
 
164 
 
 by their shells being- cemented to them. The 
 shelly remains of this family form the principal 
 part of extensive beds of our strata. 
 
 Genus Ostrea, Linn. No teeth in the hinge. 
 
 1. OSTREA SALTVICIENSIS, Simp. 
 
 Ovate, longer than wide, beak small, thin, smooth, 
 with numerous undulations, or wrinkles, length 
 two inches. U.L., 5. 
 
 2. O. INFLATA, Simp. 
 
 Orbicular, tumid, smooth ; beak small, upper 
 valve flat ; diameter two inches. Arenaceous beds 
 of the M.L., Hawsker. 
 
 3. O. TUMIDULOSA, Simp. 
 
 Suborbicular, gibbous, tumid scaly ; beak very 
 obtuse ; length three inches. 
 
 This forms a principal part of the oyster beds in the 
 Arenaceous division of the M.L., Hawsker. 
 
 4. O. CONCINNA, Simp. 
 
 Elliptical, equilateral, width greater than the 
 length, angle at the beak obtuse, regularly convex, 
 with numerous, regular, roughish plaits, or lines 
 of growth ; length three inches. M.L., Hawsker. 
 
 5. O. PATELL^FORMIS, Simp. 
 
 Ovate, diameter three inches by 1J inch ; much 
 inflated, smooth. M.L., Hawsker. 
 
 6. O. UNGULA, Muns., Tate. 
 
 Ovate, upper valve waving, partially plicated ; 
 lower valve convex, irregularly plaited ; a calosity 
 at the beak ; length an inch and five-eighths, width 
 1 inch. L.L., 27, Redcar. 
 
165 
 
 7. O. LIASSICA, Stric., Tate. 
 
 " Longitudinally oblong, slightly curved, imbri- 
 cated ; the upper valve flat ; the under one 
 somewhat rounded, margin entire." Strickland. 
 Lowest beds of Lias, Rhsetic. 
 
 8. O. L^VIUSCTJLA, Mun.y Tate. 
 
 More than a semicircle, deltoid, with one side 
 concave, diameter 2^ inches. 
 
 Tate says the upper valve is slightly convex, wrinkled 
 or striated concentrically. L.L., E..H. Bay, E-edcar. 
 
 9. O. SEMIPLICATA, Mun., Tate. No example. L.L., 
 
 Eedcar. 
 
 10. O. SUBAURICULARIS, D'Orb, Tate. 
 
 Ovate, slightly pointed at the beak ; length 
 seven-tenths of an inch, width two inches. U.L., 
 1, Peak. 
 
 The difference betwen this and O. saltviciensis, is 
 that it is wider than long. In other respects they agree. 
 
 11. O. SUBMARGARITACEA, BrCLUT., Tate. 
 
 Length five inches, width two inches, rounded 
 at both ends, concave on the left side, convex on 
 the other ; three wrinkled ribs from the beak along 
 the tumid back. M.L., a, Cleveland. 
 
 Tate describes it as beautiful ; a remarkable character 
 in a fossil oyster. Oysters are past description. 
 
 12. O. SPOBTELLA, Dum., Tate. 
 
 Ovate, lower valve inflated, with a considerable 
 thickening at the hinge, which is truncated; a 
 deepish longitudinal groove on one side, and an 
 excavation near the hinge on the other. M.L., &. 
 
166 
 
 13. O. LAGANIFORMIS, Tate's MSS. 
 
 Ovate, rather gibbous ; the thickened beak 
 turned to the right, upper valve concave, smooth ; 
 lower valve convex, with many irregular rugose 
 concentrick plates ; length 2-J- inches, width two 
 inches. L.L., Redcar. 
 
 Gryphcea. 
 
 These are unquestionably Oysters, but of a more 
 regular form. The beak of the lower valve projects over 
 the upper valve, and is more or less curved. It is popu- 
 larly known as the Miller 's thumb. 
 
 14. O. ARCUATA, Lam. Syn. O. INCTJRVA, Sow. 
 Lower or larger valve ovate, right side the more 
 
 convex, the back very convex, with numerous con- 
 concentrick plates of growth, and generally, a 
 longitudinal fold on the left side, beak large, very 
 much incurved over the other valve, twisted to the 
 left, pointed. The smaller or upper valve concave, 
 truncated at the hinge on the right side ; the beak,, 
 which is immediately below the larger one, is very 
 small and finely pointed, encompassed by bright 
 lamilar striae, and turned to the left ; length 2 
 inches, width 1 inch. L.L., 27. 
 
 They have been gregarious, forming distinct beds in 
 the lowest part of the Lower Lias at Eedcar, and E.H. 
 Bay. 
 
 There is a variety, if not a distinct species, which is 
 much longer in proportion to its width. It has also a 
 strong longitudinal groove or fold on the right side of 
 the lower valve. It occurs solitary, and is scattered 
 sparingly through the upper beds of the Lower Lias, 
 Length three inches, width one and three-eighths ' of 
 an inch. 
 
167 
 
 15. O. MACULLOCHI, Sow. 
 
 Lower valve somewhat depressed, nearly equi- 
 lateral ; beak moderate, central, little incurved 5 
 length 2^ inches, width two inches. 
 
 This is much less convex than the last, narrower at. 
 the beak, and expands towards the regularly rounded 
 base. It is frequent in all the beds of L.L., from No. 1 
 to 21, E.H. Bay. 
 
 16. O. DEPRESSA, Ph. 
 
 Ovate, much depressed, gibbous, left side rather 
 concave, right side and base rounded ; beak rather 
 wide, little incurved ; upper valve very concave 
 with numerous concentrick lines of growth ; beak 
 a small colosity ; length three inches, width 2% 
 inches. Upper division of the L.L., R.H. Bay. 
 It is well figured by Phillips, pi. xiv., f. 7. Geo\ 
 Yorks., Part 1. 
 
 17. O. ORBICULARIS, Simp. 
 
 Orbicular, right side obscurely lobed ; beak small t 
 and but little incurved ; hinge line small ; diameter 
 three inches. M.L., Scarborough Museum. 
 
 This is a neat, well denned species ; the smaller valve 
 with nearly circular, well defined, lines of growth. 
 
 Genus Pecten, Scallop or Clam. 
 
 These are of the same nature as the Oyster, but 
 on account of their symetrick, and definite form, as 
 also from the beauty of many of them, they well 
 deserve to be placed under a separate head. They 
 are exceedingly abundant in some parts of the 
 
168 
 
 Yorkshire Lias. The main ironstone beds of Cleve- 
 land are chiefly composed of them. 
 
 1. PECTEN MAJOR, T. & B. 
 
 Orbicular, equilateral, with about twenty strong, 
 rounded, prominent diverging* ribs, equal to the 
 intervening concave furrows ; furrows crossed by 
 very fine, sharp striae, which are separated by flat 
 spaces, and become obsolete on the ribs ; angle at 
 the beaks very obtuse ; beaks small, pointed ; line 
 of the hinge at right angles to the central rib ; 
 tears small, nearly equal ; striae nearly perpendicular 
 to the line of the hinge ; diameter 5J inches. M.L., 
 , Grosmont, &c. 
 
 This has been confounded with Sowerby's P. equi- 
 valvis. It differs, in that it is equilateral, whilst P. 
 -equivalvis is gibbous. The angle at the beaks is also 
 much more obtuse. 
 
 A specimen half an inch in length has much the cha- 
 racters of the above, but strong concentrick strise pass 
 over the diverging ribs. 
 
 2. P. SUBL2EVIS, T. $ B. 
 
 Tumid, subequivalve ; ears moderate, finely 
 striated; with about twenty or twenty-two slightly 
 elevated, scaly, diverging ribs, not equal to the 
 Intervening concave furrows, angle at the beaks 
 less than a right angle. M.L., ironstone bands. 
 
 Yar. (a.) Orbicular, valves nearly equal, striated in 
 the direction of the ribs. 
 
 Var. (6.) One of the valves very convex. 
 
169 
 
 This is a very abundant fossil in the uppermost beds of 
 Middle Lias, but it is difficult to obtain a specimen any 
 thing like perfect. It is singular that it should have 
 been confounded with the last, from which it differs in 
 so many characters, especially in its scaly, and flattened 
 ribs. Phillips' figure agrees most with the next. PL 
 xiv., f. 5, G-eo. Yorks., pt. 1. 
 
 3. P. INTERSTINCTUS, Simp. 
 
 Depressed ; about twenty-five sharp, slender 
 triangular ribs ; angle at the beak a right angle ; 
 base nearly a semicircle ; concentrick striae numer- 
 ous, undulating, distinct ; ears moderate, length 
 three inches. Uppermost part of the M.L., 
 Grosmont. 
 
 Mr. Tate considers this to be synonymous with P. 
 priscus, Schlotheim. 
 
 4. P. DICHOTOMUS, Simp. 
 
 This agrees so closely with the last in most of its 
 characters, that if it had not been widely separated in 
 time, I should have been disposed to consider it only a 
 variety of that species. It is most distinguished by its 
 strise bifurcating. 
 
 5. P. AHENEUS, Simp. 
 
 Ovate ; with eighteen or twenty plane rounded 
 ribs, rather coarse and scaly ; angle at the beaks 
 acute ; length one inch, greater than the width. 
 L.L., y, R.H. Bay. 
 
 6. P. RTJDIS, Simp. 
 
 The lower valve rather tumid, with twenty-two 
 prominent, rounded, diverging ribs, separated by 
 concave furrows ; the other valve flat and distorted ; 
 length three inches. 
 
170 
 
 7. P. DEFOSSUS. 
 
 Depressed ; angle at the beaks more than a right 
 angle ; base more than a semicircle ; twenty-two 
 diverging ribs, equal to the intervening furrows,, 
 rounded towards the base, triangular at the beak j. 
 concentrick striae very fine and closely united ; 
 length three inches. L.L., s, R.H. Bay. 
 
 8. P. THIOLLIERI, Mar., Tate. 
 
 About twenty rounded ribs, not very equal, 
 separated by narrow grooves ; angle at the beak 
 a right angle ; length seven-eighths of an inch. 
 Lowest beds of Lias, Redcar. 
 
 9. P. MULTICOSTATUS, Simp. 
 
 Orbicular, rather inflated ; about twenty-seven 
 distinct, rounded radii, separated by concave spaces, 
 crossed by very faint concentrick striae ; radii on 
 the cast nearly obsolete ; angle at the beak less 
 than a right angle ; length seven -tenths of an inch* 
 L.L., R.H. Bay. 
 
 10. P. TEXTORIUS, Schl., Tate. 
 
 Ovate ; angle at the beak rather acute ; wings 
 small, striated; ribs about thirty-four, separated by 
 equal flatted grooves, reticulated by distinct con- 
 centrick striae. L.L., 27, R.H. Bay. 
 
 11. P. PTTNCTATISSIMUS, Quen. Tate. 
 
 Ovate, nearly circular ; angle at the beak a right 
 angle ; between thirty and forty fine diverging 
 ribs, not equal to very numerously punctured 
 separating spaces. L.L., 23, R.H. Bay. 
 
171 
 
 12. P. LOHBERIGENSIS, Em., Tate. No example. L.L., 
 
 23, E. H. Bay. 
 
 13. P. TEXTILIS, Mun., Tate. No example. L.L., Eedcar. 
 
 14. P. POLLUX, D'Orb, Tate.^ No example. L.L., Cliff. 
 
 15. P. PULCHELLUS, Simp. 
 
 Depressed, orbicular, angle at the beak about 
 a right angle ; entirely covered with fine, concen- 
 trick, slightly wrinkled striae; diameter two inches. 
 
 There are four valves on a piece of lias limestone, 
 all wanting the 'ears and imperfect in the outline, but 
 the striae are beautifully distinct. Judging from the 
 character of the nodule, it is from the uppermost beds 
 of the Lower Lias. E.H. Bay. 
 
 16. P. RETICULARIS, f $imp. 
 
 Orbicular ; lamellar lines of growth distant, reti- 
 culated with numerous and slightly waving striae, 
 which are distinct near the beak and the outer 
 margin, obsolete in the centre ; angle at the beak 
 about a right angle. M.L., Hawsker. 
 
 It comes near to P. gracilis, Sow. 
 
 17. P. PUNCTATUS, Simp. 
 
 Orbicular ; ears large, striated ; cast smooth ; 
 angle at the beak a right angle ; length 1^ inch. 
 L.L., Peak. 
 
 The shell is thin, and where it remains near the 
 margin may be observed very fine concentrick punctured 
 striae. 
 
 18. P. LUNTJLARIS, Ro., Tate. 
 
 Orbicular, depressed ; angle at the beak very 
 obtuse ; beak small pointed ; nearly smooth ; 
 lamellar lines of growth distant ; concentrick and 
 
172 
 
 diverging striae very fine, almost obsolete, numerous, 
 diameter two inches. M.L., a, Eston. 
 
 Judging from two specimens sent me by Mr. Tate, 
 from the Eston ironstone, it differs greatly from P. 
 pulchellus, or planus. It is more depressed at the beak 
 in P. punctatus. 
 
 19. P. CALVUS, Gold, Tate. 
 
 Ovate ; angle at the beak nearly a right angle, 
 rather acute ; beak pointed ; wings moderate, 
 rather small ; striae numerous, fine, concentrick, 
 separated by rather wider flat spaces, crossed by 
 faint diverging lines. L.L., w, R.H. Bay. 
 
 20. P. DISCIFORMIS, Sell., Tate. 
 
 Ovate, nearly circular, rather inflated, smooth ; 
 beak pointed ; angle at the beak acute ; wings 
 moderate ; length an inch and seven-tenths, width 
 11 inch. U.L., 1, Peak. 
 
 21. P. PUMILUS, Lam., Tate. No example. U.L., 1. 
 
 22. P. SUBSTRIATUS, Ro., Tate. 
 
 Depressed, ovate, smooth, or but faintly striated ; 
 beak pointed, angle rather acute ; right wing much 
 expanded, strongly striated. Bed immediately 
 above the M.L. 
 
 23. P. PLANUS, Simp. 
 
 Much depressed ; base and sides more than a 
 semicircle ; smooth, no striae ; lines of growth 
 distant ; beak pointed, angle about a right angle, 
 
 or slightly acute ; wings small. 
 
 Plentiful in the ironstone series of the M.L., Hawsker, 
 but always small. 
 
173 
 
 24. P. TUMIDUS, Ziet., Tate. (Hinnites.) 
 
 Length equal to the width, base regularly convex, 
 the flat valve with numerous diverging striae. M.L., 
 a, Eston. 
 
 25. P. PAPYRACEUS, Ziet. t Tate. (Hinnites.) ILL. 
 Genus Lima, Brug. Syn. Plagiostoma, Sow. 
 
 It differs from the Pecten in having a longer 
 shell, smaller ears, and in the great inequality of 
 the sides. The anterior side is more or less straight 
 and gaping, and the posterior side rounded. 
 
 1. LIMA IRREGULARIS, Simp. 
 
 Ovate, depressed ; anterior side slightly convex,, 
 posterior side and base convex, expanded, ears 
 moderate ; beak small, pointed, depressed, longi- 
 tudinal ribs about forty, unequal, irregular, inter- 
 rupted, contracted on the beak into fine, sharp, 
 closely united striae ; transverse striae irregular,, 
 obsolete towards the beak; length 2-J- inches. L.L., 
 y, R.H. Bay. 
 
 It is well distinguished from the next by its flat 
 depressed form, and irregular ribs. 
 
 2. L. HERMANNI, Voltz., Tate. 
 
 Length 3 inches, one-third greater than the 
 width, anterior side concave ; posterior side and 
 base convex ; about thirty flatly rounded ribs, 
 separated by rather wide flat spaces ; concentrick 
 striae obsolete ; plates of growth distant. M.L., 
 Huntcliff. 
 
174 
 
 Var. L. MULTICOSTATA, Simp. 
 
 Length greater than the width, with about forty much 
 depressed ribs, separated by narrow grooves. Where 
 the ribs are very narrow the wider spaces are occupied 
 by fine longitudinal striae. The concentrick striae are 
 very numerous and so strong on the upper part as to 
 crenate the ribs. The concentrick plates of growth 
 distant. M.L., Ironstone series, Hawsker. 
 
 3. L. SUCCINCT A, Sch. Syn. ANTIQUATA, Sow.., Tate. 
 Depth three inches, width two inches ; anterior 
 
 side short, base convex, posterior side convex, slope 
 behind the beaks concave ; diverging striae numer- 
 ous, fine, irregular, crossed by numerous lines of 
 growth, striae behind the beaks strong. Lowest 
 beds of Lias, Redcar. 
 These three have a strong resemblance to each other. 
 
 4. L. PECTINOIDEA, Simp. 
 
 Ovate ; beak pointed, much incurved ; nineteen 
 rounded, diverging ribs, separated by flat or slightly 
 convex furrows. M.L. 
 
 This may be L. pectinoidea, Phillips' Greo. Yorks., 
 pi. xii., f. 13. 
 
 5. L. NOVEMEOSTATA, Simp. 
 
 Ventricose ; beak pointed, much incurred ; nine 
 rounded, diverging ribs, equal to the convex inter- 
 vening spaces. 
 
 A cast ; from the the Pyritous band, L.L., y, E/.H. Bay. 
 In the same bed there is another with more ribs, but I 
 have only a fragment. 
 
 6. L. PECTINOIDES, Sow., pi. cxiv. 
 
 Depressed, longer than wide; anterior side straight, 
 posterior side and base convex ; angle at the beak 
 
175 
 
 less than a right angle ; about twenty triangular 
 ribs, with a single line in the triangular grooves ; 
 transverse striae obsolete ; length six-tenths of an 
 inch. 
 
 From a specimen sent me by Mr. Tate, L.L., Redcar. 
 The following is Sowerby's description. Min., Con., 
 p. 28, pi. cxiv., f. 4: " Depressed, a little oblique, ob- 
 ovate, rather angular at the beak, beak pointed ; surface 
 with twenty or more carinated ribs ; transversely 
 striated/' 
 
 7. L. HETTANGENSIS, Ter., Tate. 
 
 Length 1^ inch, one-third greater than the width ; 
 about twenty angular, coarsely granulated, prin- 
 cipal ribs, with smaller ones in the angular grooves ; 
 beak inflated, incurved ; angle acute. 
 
 This in some measure resembles the last, but the line 
 between the ribs is stronger, and the beak is much more 
 prominent. 
 
 8. L. TERQTJEMI, Tate. 
 
 Nine or ten coarse triangular, tuberculated ribs. 
 Specimen imperfect. Lowest beds of Lias, Redcar. 
 
 9. L. PTJNCTATA, Sow. No example. L.L. 
 
 10. L. GIGANTEA, Sow. PI. clxxvii. 
 
 Semicircular, ventricose at the beaks, depressed 
 on the posterior side and base ; anterior side con- 
 cave, excavated beneath the beaks ; surface nearly 
 smooth, decussated by fine striae ; lines of growth 
 distant. L.L., 23, R.II. Bay. 
 
 11. L. EUCHARIS, D'Orb, Tate. 
 
 Anterior side slightly concave, base and posterior 
 side convex ; diminished at the base ; beaks small 
 
176 
 
 incurved ; surface nearly smooth, or faintly striated ; 
 length an inch and two-tenths, width nine-tenths of 
 an inch. M.L. 
 
 It differs chiefly from L. gigantea in the diminution 
 towards the base. 
 
 12. L. EXCAVATA, Simp. 
 
 Very similar to L. gigantea, but the striae coarse, the 
 lines of growth numerous,, and the areola very deeply 
 excavated. 
 
 Limsea teeth in the hinge. 
 
 13. L. ACUTICOSTA, Mun., Tate. 
 
 Ovate, rather ventricose, with from 10 to 15 tri- 
 angular, diverging ribs, equal to the triangular 
 separating spaces; the areola under the beaks 
 longitudinally striated; beak prominent, pointed, 
 incurved; concentrick striae generally obsolete; 
 length six-tenths of an inch ; width five-tenths of 
 an inch. L.L., R.H. Bay, &c. 
 
 I have several specimens, and they differ very mate- 
 rially in the general outline, the sharpness of the ribs 
 and in the incur viture of the beaks. In one specimen I 
 see very distinctly the very fine waving concentrick 
 striae noticed by Mr. Tate. It is more tumid than L. 
 pectinoides. 
 
 14. L. BLAKE AN A, Tate. 
 
 Subtriangular or ovate; nearly equilateral, an- 
 terior side the less, straight ; posterior side concave ; 
 base less than a semicircle ; beaks very finely pointed, 
 incurved; ears small; surface with about 16 or 17 
 triangular diverging ribs, separated by triangular 
 grooves, slightly crenulated near the base by 
 
177 
 
 obsolete concentrick striae; width half an inch, 
 length rather less. L.L., 27, Redcar. 
 
 It is shorter in proportion than L. acuticosta. 
 
 "Shell ovate, convex, nearly equilateral, hinge line 
 straight, short, ornamented with about 20 subacute ribs, 
 transversely striated ; interspaces narrow, with or with- 
 out a rib ; lateral areas costated." Tate. T. & B., pi. xiv, f . 5. 
 
 15. L. JULIANA, Dum., Tate. 
 
 Very oblique; ears small; posterior slope con- 
 cave, anterior side convex, base convex; about 20 
 prominent, diverging ribs, separated by flat, striated 
 spaces. 
 
 In three of Tate's specimens the ribs are angular, in 
 another they are rounded. M.L., a, Cleveland ironstone. 
 
 Genus Anomia, Brug. Upper valve deeply 
 notched ; teeth in the hinge. 
 
 1. ANOMIA NUMISMALIS, Quen., Tate. 
 
 Circular, tumid, striated, and with numerous 
 irregular concentrick lines of growth. L.L., R.H. 
 Bay. 
 
 2. A. STEIATULA, Op., Tate. No example. L.L. 
 
 3. A. ALPINA, Win., Tate. No example. L.L. 
 
 Placuna. 
 
 4. A. FERRUGINEA, Simp. 
 
 Ovate, length 2^ inches, more than twice the 
 width. Ironstone, M.L., Hawsker. 
 
 I possess only one valve, which is litlle more than a 
 cast ; displaying, however, the two cardinal diverging 
 ribs, or teeth left in the matrix ; and also the round 
 muscular impression near the middle of the valve. 
 
 N 
 
178 
 
 Genus Spondylus, Linn. Teeth in the hinge ; 
 hinge complicated. 
 
 Plicatula. 
 
 1. SPONDYLUS SPINOSUS, Sow. PL ccxlv. 
 
 Ovate, depressed ; with circular lamellar plates, 
 and lines of growth, on which are arranged rows of 
 tubercles, or depressed spines. L.L., R.H. Bay. 
 M.L., Staithes. 
 
 On a larger specimen the tubercles are obsolete. 
 
 2. S. CALVUS, Tate. 
 
 More elongated, smooth, without spines or radii. 
 M.L., a, Staithes. 
 
 3. S. LIASSINUS, Ter., Tate. 
 
 " Left valve ovate-oblong, attached by a more or less 
 broad surface, with the front elevated ; ornamented by 
 numerous, slender, rounded, and serrated dichotomous 
 ribs, with linear interspaces, transversely wrinkled ; 
 interior surface with dichotomous ribs widely separated." 
 
 ' ' Eight valve flat or concave, smooth in the umbonal 
 region, outwardly larnellose, and radially striated. 
 Interior ornamented with distant dichotomous ribs, 
 crowded around the outer margin ; hinge with two small 
 teeth, parallel with the hinge line." Tate. L.L., Redcar. 
 
 4. S. INTUS-STRIATUS, Tate's MSS. 
 
 Mr. Tate has sent me some small specimens from the 
 lowest beds of Lias at. Kedcar under this name, which 
 agree very well with his description of S. liassinus, but I 
 suppose he considers them to be a distinct species. 
 
 Genus Perna, Bing. Parallel fosses in the hinge. 
 
 1. PERNA QUADRATE, Sow. PL ccccxc. No example. 
 
 2. P. INFRALIASSICA, Quen., Tate. 
 
 Triangular ; hinge line rather concave, nearly at 
 
179 
 
 a right angle with the anterior side ; base rounded ; 
 posterior side acutely triangular ; width three inches, 
 depth two inches. L.L., 23, Redcar. 
 
 Crenatula. Fossas on the edge of the hinge, oval. 
 3. P. VENTRICOSA, Sow. PL ccccxliii. 
 
 Subovate, smooth ; anterior side nearly straight, 
 truncate ; length greater than the width ; ventricose 
 towards the beaks ; beaks acute, incurved. L.L., 
 R.H. Bay. 
 
 In one specimen I observe numerous elevated con- 
 centrick ridges and lines of growth, crossed by obsolete, 
 diverging striae or lamellar. It is from the ironstone 
 bands of the Middle Lias. Of this I give the following 
 description. 
 
 Wedged shaped ; beaks acute ; base regularly rounded ; 
 shell with many concentrick ridges, most prominent 
 towards the beaks, crossed by obsolete, diverging striae, 
 and also by very oblique striae ; lengtJa 3 inches, 
 greatest width towards the base 2 inches. 
 
 It differs chiefly from the Lower Lias examples in its 
 ornamentation ; it is also less ventricose, and the beaks 
 are more acute. I had almost called it P. cumata ; but 
 Mr. Tate, who saw it, thinks it only a variety of P. 
 ventricosa. 
 
 Inoceramus. Unequivalve, ventricose, laminated; beak hooked near the hinge. 
 
 4. P. DUBIA, SOW. 
 
 Ovate, subequivalve, subequilateral, ventricose, 
 length greater than the width ; beaks acute, in- 
 curved; obsolete striae longitudinal and concentrick. 
 
 Abundant in the Jet Bock and shale above, but 
 generally in a compressed state. 
 
 5. P. SIMPSONI, Tate, T. $ B., pi. xvi., f. 10. 
 
 " Subquadrate, depressed, thin, umbo acute, 
 
180 
 
 approximately tuminal ; cardinal line straight, or 
 moderately oblique ; anterior margin, subsinuous, 
 posterior slightly arched or nearly straight ; surface 
 ornamented by concentrick imbricating lamellae 
 and folds, and by radial plications and striae." 
 
 " The shell varies in the amount of the obliquity of 
 the hinge, and in the strength of the radial plicae/* 
 Tate. ILL., 5, b. 
 
 6. P. STJBSTRIATA, Mun., Tate. 
 
 This is much less ventricose than P. dubia ; concen- 
 trick striae coarse and unequal. M.L., a, Hawsker. 
 
 7. P. CINCTA, Mun., Tate. 
 
 Subtriangular, or ovate, smooth ; beak pointed, 
 prominent ; length eight-tenths of an inch. U.L., 
 Whitby. 
 
 Gervillia, fossss and teeth of the hinge oblique. 
 
 8. P. ^JROSA, Simp. 
 
 Very oblique ; wing large ; beak obtuse ; many 
 undulations or marks of growth ; length 1| inch, 
 length of hinge one inch. L.L., y, R.H. Bay. 
 
 9. P. HAGENOVII, Dunk., Tate. 
 
 Triangular, smooth ; beak pointed ; wing large. 
 Specimen imperfect. L.L., Redcar. 
 
 10. P. PINN^FORMIS, Dun., Tate. No example. L.L., 
 
 23, E.H. Bay. 
 
 Genus Avicula. This has much the appearance 
 of a Pecten, but is oblique to the hinge, which is 
 generally long, with the expanded wings, and has 
 two or three small teeth. 
 
181 
 
 1. AVICULA CYGNIPES, T. fy B. 
 
 Orbicular, scarcely oblique ; ears sharp, one of 
 them much produced ; five prominent, rounded, 
 diverging ribs ; ornamented with fine reticulated 
 striae. M.L., k, Hawsker, Staithes. 
 
 The elevation of the ribs varies much in different 
 specimens, and in those full grown, extend more than 
 an inch from the rest of the shell, giving the appearance 
 of the foot of an aquatick bird. One of these claws, I 
 observe is turned up like a tenter hook. The other 
 valve is flat, with grooves corresponding with the ribs 
 of the convex valve. They occur sometimes as much 
 as four inches in diameter, and form a bed of ironstone 
 in the upper part of the Middle Lias six feet thick 
 at Grosmont, near Whitby. Young named it Pecten 
 cygnipes, and other naturalists, from microscopick ob- 
 servations on the shell, consider it to be more allied to 
 Pecten than to Avicula. 
 
 2. A. ROSEBURYENSIS, T. Sf B. 
 
 Moderately oblique, ears sharp ; ten slender 
 diverging ribs ; interspaces flattish, strongly and 
 longitudinally striated. 
 
 This is common in the Middle Lias, and is rather 
 variable. I would confine the name to those with dis- 
 tinct longitudinal striae ; and those which are smooth 
 I would place under A. substriatus, which are rather 
 plentiful in the lowest beds of Middle Lias. 
 
 An example, as of this species, sent me by Mr. Tate 
 from the uppermost, or Am. striatulus bed of the Upper 
 Lias at Peak, is flatter, and the ribs less prominent and 
 with three incipient ribs in the intervening flat spaces. 
 
 There does not appear to be any material difference 
 between this species and one from the Kelloway Rock, 
 described under the name of A. inaequivalvis, but as it 
 is improbable that the same species should be con- 
 tinued up so far in the Oolite, I have adopted Young's 
 name for our Lias fossil. 
 
182 
 
 3. A. SUBSTRIATUS. 
 
 Much oblique, rather tumid, ears sharp ; about 
 from fifteen to twenty very sharp, distinct diverging 1 
 ribs, strongly curved outwards on the left side; 
 with obsolete diverging striae in the intervening 
 flat spaces. The upper valve flat with broad 
 nearly obsolete ribs. 
 
 This is a very fine sharply defined species or variety. 
 I obtained several examples from the upper side of the 
 ironstone band No. d of the Lower Lias at the north 
 cheek of E.H. Bay. 
 
 4. A. CRESCENS, Y. & B. 
 
 Orbicular ; ears small ; with from fifteen to 
 thirty principal, slender ribs, which are increased 
 in number by the introduction of smaller ones 
 towards the outer margin ; the other valve nearly 
 flat, and without ribs ; length an inch and six- 
 tenths. 
 
 On the shell may be seen,, also, numerous longitudinal 
 striae, increasing, in places, to ribs ; so that their number 
 may be very inconstant. 
 
 5. A. TUMIDTJLUS, Simp. 
 
 Orbicular, hinge line short, equivalve, equilateral, 
 tumid ; beaks small, incurved, about twenty-eight 
 slender ribs on either valve, crenated by strong 
 transverse striae. U.L., 6. 
 
 It occurs in small masses above the Jet Eock. 
 
 6. A. NITESCENS, Simp. 
 
 Orbicular, ears small, striae very fine, numerous, 
 longitudinal, and transverse. 
 
 Numerous but small in the Jet Eock. ILL. 
 
183 
 
 7. A. MINIMA, Simp. 
 
 Scarcely oblique, more than a semicircle ; hinge 
 line the full diameter, passing into the point of the 
 expanded wing on the left side ; one of the valves 
 with about twelve concentrick, elevated, or slightly 
 reflexed, membranous striae, crossed by numerous 
 fine longitudinal striae ; the other valve smooth, or 
 but faintly striated at the base, with nearly the 
 same convexity ; beak a small rounded point or 
 papilla. 
 
 The general length is about two-tenths of an inch, 
 and they are very abundant in the second indurated 
 band, near the top of the first Nab at Saltwick. All I 
 have seen are single valves, and in general, the striated 
 valves. They are mingled with what I take to be young 
 A. nitescens. Some times they are detached from the 
 matrix, when they are beautifully transparent and of a 
 light yellow colour, with two concentrick black lines 
 which pass up and expand into the ears. They are best 
 distinguished from the last by the long straight hinge 
 line, and the round pointed beak. ILL., No. 3. 
 
 8. A. PATTERSONI, Tate. 
 
 "Shell depressed, ovate, transverse, slightly oblique, 
 concentrically striated; anterior margin arched, and 
 superiorily sinuated j hinge line straight ; anterior wing 
 very short, acute ; posterior elongated, acuminated, exca- 
 vated behind." Tate. L.L., 27. 
 
 9. A. CALVA, 8chl. t Tate. 
 
 Orbicular, smooth ; ears small ; width an inch and 
 four-tenths. The smaller examples are more oblique. 
 M.L., a, Hawsker. 
 
 10. A. ECHINATA, Sow. PI. ccxliii. No example. 
 
184 
 
 11. A. PAPYRIA, Qum., Tate. L.L.,23,Redcar. Noexample. 
 
 12. A. CONTORT A, Port., Tate. Bhsetic. No example. 
 
 13. A. BRONNI, Volt., Tate. Posidonomya. 
 
 Ovate, very much depressed, finely striated, hinge 
 line short. U.L., 5, Saltwick. 
 
 Genus Pinna, Linn. Equivalved, wedge-shaped. 
 
 1. PINNA FOLIUM, T. fy B. 
 
 Acutely triangular, depressed; length more than 
 twice the width ; longitudinal and transverse striae 
 coarse. 
 
 Very abundant,, but very fragile. This is one of the 
 most abundant and wide-spread of Lias fossils, charac- 
 terizing a thin bed in the middle of the Lower Lias 
 throughout England and the northern regions of Scot- 
 land. L.L., w, K.H. Bay. 
 
 2. P. SPATHULATA, Tate, T. fy B., pi. xiv., f. 2. 
 Lanceolate, depressed ; apex acute ; base regularly 
 
 ovate; length eight inches, twice the width; with 
 numerous concentrick, strong ridges of growth, 
 crossed on one side by diverging rays. Lowest 
 beds of U.L. 
 
 The specimen referred to in the Whitby Museum by 
 Mr. Tate, is a small Pinna on a piece of Middle Lias 
 ironstone, along with Pecten and other shells. It is not 
 so acute as the present one, has straight sides, and 
 divided along the middle by a line ; strias obsolete ; scaly. 
 
 3. P. HARTMANNI, Zeit., Tate. 
 
 Cuneate, eight inches by four inches ; the divid- 
 ing line near the middle; crossed by irregular 
 waving striae. L.L., Redcar. 
 
185 
 
 Genus Area, Linn. Equivalve, generally wider 
 than deep, ventricose. 
 
 Area proper. Hinge line straight, teeth perpendicular. 
 No example of A. proper, except it be A. pulla. 
 
 Cucullssa. Teeth of the hinge oblique. 
 
 1. ARCA INCRASSATA, Simp. 
 
 Ventricose, transverse; beaks approximate, re- 
 curved; anterior side short, obtusely rounded; 
 posterior side elongated, diminishing, rounded; 
 hinge line extended; area large, carinated; reticu- 
 lated strias numerous, fine over the whole surface; 
 width an inch and four-tenths; depth one inch; 
 breadth across the umbones one inch. Hard iron- 
 stone bands, M.L., Hawsker. 
 
 2. A. INTERMEDIA, Simp. 
 
 This in its principal specifick characters resembles the 
 last, but the posterior side is shorter and more acutely 
 triangular ; the sides are more regularly convex, and the 
 striae also appear to me cancellated and consequently 
 smoother. It is much smaller in size ; the largest I have 
 seen is eight-tenths of an inch in width, and six-tenths 
 of an inch in depth. It is altogether a more regular 
 shell than C. cancellata, Ph., which in other respects it 
 resembles. Ironstone bands of the M.L., Hawsker. 
 
 There appears to be a difference of opinion amongst 
 the best conchologists respecting which is the anterior or 
 posterior side of a bivalve shell. In these descriptions, 
 I have considered the ligament as always on the posterior 
 side of the beaks. For the elliptical impression near the 
 ligament, so conspicuous in the genus Venus, Lin., I use 
 the term area ; and for the smaller impression in front 
 of the beaks, areola. 
 
186 
 
 3. A. OBTTTSALIS, Simp. 
 
 Ventricose, ovate; anterior side very obtuse; 
 posterior side the wider, diminished, rather trian- 
 gular, rounded ; base convex, slightly flatted in the 
 middle; concentrick striae obsolete, punctured; beaks 
 rather distant, recurved; area large, carinated; 
 width nine-tenths of an inch; depth six-tenths of 
 an inch, L.L., R.H. Bay. 
 
 4. A. CLEVELANDICUS, Taie, T. $ B-, pi. xi., f. 6. 
 
 " Shell ovate-trapezoidal, ventricose ; unibones slightly 
 portmedial, large, elevated,, approximate,, incurved and 
 directed forwards ; anterior extremely rounded, posterior 
 bluntly keeled, posterior area very narrow, subconcave,. 
 point margin gently curving ; surface ornamented with 
 concentrick furrows and lines of growth. The anterior 
 area shows faint indications of radial lines ; length 2^ 
 inches, breadth 3^ inches." Tate. M.L., a. 
 
 5. A. EXPANSA, Simp. 
 
 Very ventricose, width across the beaks much 
 greater than the depth, transverse, beaks very dis- 
 tant; a keel between two furrows at the base. 
 M.L. ironstone, Hawsker. 
 
 A flat-bottomed boat. A cast. A bit of the shell 
 shows it to be cancellated. 
 
 6. A. PULCHELLA, Tate, T. $ B., pi. xiii., f. 2. 
 Sub-rectangular transverse, anterior end rounded, 
 
 posterior truncate, much flatted ; beak wide, with a 
 central depression; rim of the base thickened; 
 width less than two-tenths of an inch. L.L., y. 
 
 7. A. PULLA, Ter., Tate. 
 
 Width about twice the depth, divided in the 
 
187 
 
 middle by a deep longitudinal constriction or fold,, 
 reticulated by longitudinal and transverse striae ; 
 width about a quarter of an inch. L.L., 23, "Redcar. 
 It probably ought to be placed under Area proper, but 
 I have not seen the hinge. 
 
 8. A. BTJCKMANI. No example. 
 
 9. A. LIASSINA. 
 
 Mr. Tate has sent me four specimens so labelled, but 
 afterwards crossed out. They correspond closely with A. 
 intermedia, but with the posterior side shorter, and the 
 anterior side more excavated under the beaks. They are 
 from the main ironstone beds at Eston. 
 
 
 10. A. CUSPIDATA, Simp. 
 
 Subtriangular, inequilateral, posterior side the 
 longer, triangular, sharp; anterior side short, sharp, 
 ovate ; beaks approximate, recurved over a concave 
 channel, hinge line more than half the width ; area 
 with a very sharp prominent keel ; width seven- 
 tenths of an inch, depth four -tenths of an inch. 
 L.L., R.H.Bay. 
 
 It is for the most part a cast of a brassy colour, smooth, 
 with indistinct striae radiating from the beaks. The 
 shell appears to be very thin and smooth. 
 
 11. A. HETANGIENSIS, Ter., Tate. 
 
 Depressed, width one inch, twice the depth ; 
 anterior side short, much excavated below the beak, 
 rounded, base nearly straight, rather concave at a 
 metial depression, or broad longitudinal constriction ; 
 posterior side rounded, the slope strongly carinated ; 
 concentrick plates, or striae, numerous, irregular, 
 
188 
 
 coarse, cancellated by diverging- striae near the 
 margin. L.L., 25, R.H. Bay, Redcar. 
 
 12. A. NAVICULA, T. fy P. No example. 
 
 Sub-genus Nucula. Earth nut. The name Leda, has been given to many of 
 of them. The distinction is not very satisfactory. They all can be 
 arranged under the Genus Area. Linn. 
 
 13. A. CORDATA, Gold., Tate. 
 
 Rather depressed, beaks nearly central, posterior 
 side the larger, it and the base convex, anterior 
 side rather angular ; concentrick plates of growth 
 few. 
 
 It is a small species, the general width and depth two- 
 tenths of an inch. In the four examples I possess, there 
 is much variety of outline. It is from the base of 
 the U.L. 
 
 14. A. NAVIS, Pict., Tate. 
 
 In general characters very like the last, but orna- 
 mented with very fine, numerous, concentrick striae. 
 Indurated bands, L.L., E.H. Bay. 
 
 I have a cast from the same beds more ventricose, and 
 the anterior side more excavated beneath the beaks. 
 There are a few concentrick lines of growth, but no 
 striae. If it proves a distinct species it may be named 
 A. nana. 
 
 Leda. 
 
 15. A. OVUM, Sow. 
 
 Ovate, ventricose ; beaks large, contiguous, re- 
 curved, turned towards the posterior side ; anterior 
 side obtusely rounded, posterior side triangular ; 
 attenuated, sharply pointed ; area behind the beaks 
 large, ovate, concave ; concentrick striae numerous, 
 
189 
 
 distinct, longitudinal striae nearly obsolete ; width 
 nine -tenths of an inch, depth seven- tenths of an 
 inch. 
 
 This neat shell is confined to the alum shale of the 
 Upper Lias, where it is abundant. 
 
 16. A. MINOR, Simp. 
 
 Globose ; beaks inflated, turn towards the 
 posterior side, which is triangular ; area behind 
 the beaks much excavated, slightly carinated ; an- 
 terior side inflated, and boldly rounded, slightly 
 carinated ; concentrick striae irregular, nearly obso- 
 lete ; general width about three-tenths or four-tenths 
 of an inch. 
 
 Very similar to the last, but much smaller, and not 
 so wide in proportion ; posterior side shorter. M.L., 
 Staithes, &c. 
 
 17. A. ZIETENI, Br., Tate. 
 
 Ovate, transverse, anterior side boldly rounded, 
 posterior side diminished, wedge shaped ; base 
 convex ; little excavated behind the beaks. L.L., 
 y, K.H. Bay. 
 
 18. A. HEBERTI, Mar., Tate. No example. 
 
 19. A. CYMBULA, Simp. 
 
 Depressed, oblong, transverse ; anterior side 
 short, rounded, sharply carinated ; posterior side 
 much the wider, truncate, depressed ; hinge line 
 nearly the whole width ; base nearly parallePwith 
 it, convex ; beaks incurved, separate ; width half 
 an inch. L.L., E.H. Bay. 
 
190 
 
 My specimens are all smooth casts. I have two with 
 the posterior side narrower. 
 
 20. A. DURA, i 
 
 Oblong* ; anterior side short, rounded ; posterior 
 side much the wider, attenuated, curves to the 
 hinge line ; base flatly convex, transverse striae 
 numerous, fine, distinct, not equal to the separating 
 flat spaces ; width six-tenths of an inch, depth 
 three-tenths of an inch. M.L, ironstone bands, 
 Hawsker, along with A. intermedia. 
 
 Mr. Tate considers this to be the same as A. galathea, 
 D'Orb : but his figure of that species is so different, that 
 I cannot think they are the same. 
 
 21. A. COMPLANATA, Ph. 
 
 Very much depressed ; anterior side ovate ; 
 posterior side subtriangular, or ovate, attenuated, 
 beaks depressed, nearly central, turn towards the 
 posterior side; base convex ; transverse striae 
 numerous, fine, irregular ; depth half an inch, 
 width about one-third more. M.L., ironstone 
 bands, Hawsker. 
 
 22. A. LONGICAUDATA, Simp. 
 
 Lance shaped ; anterior side ovate, posterior side 
 twice the width, contracting into a long narrow 
 sharp beak ; beaks rather broad, inclining to the 
 posterior side ; depth half an inch, width nearly 
 three times the depth ; shell ornamented with 
 curious, short, waving striae, or sharp edged 
 plaits ; cast smooth. M.L., ironstone bands, 
 Hawsker. 
 
 There can be no doubt this is Tate's L. graphica. 
 
191 
 
 23. A. TENUISTRIATA. 
 
 Depressed, lance shaped ; anterior side ovate, 
 about one- third the whole width ; posterior side 
 prolonged into a long- slender sharp beak ; con- 
 centrick striae very slender, numerous, form plicae 
 in passing over the posterior slope ; width one inch, 
 depth three-tenths of an inch. L.L. 
 
 It has nearly the same shape and properties as the 
 last, but is more slender and attenuated. The strise 
 are entirely different, and almost smooth. I have named 
 it A. tenuistriata, as indicating character,, though I am 
 not sure it is the L. tenuistriata of authors. It is on 
 a piece of rock,, along with A. subovalis., and I judge 
 from the L.L., E.H. Bay. 
 
 The names of the two following I give on the authority 
 of Mr. Tate, from specimens in the Jermyn Street 
 Museum. 
 
 24. A. RENEVIEREI, Op., Tate. T. $ E., pi. xi., f. 4. 
 Width more than twice the depth ; anterior side 
 
 ovate ; posterior side elongated, attenuated to a 
 point, crossed by very numerous fine striae, which 
 occupy the rest of the shell ; width six -tenths of 
 an inch. L.L., 27, Redcar, &c. 
 
 25. A. TEXTURATA, T. fy P., Tale. 
 
 Width twice the depth ; anterior side rounded, 
 posterior side elongated, attenuated into a point ; 
 base convex ; ornamented with very numerous fine 
 wavy striae, which become wrinkles on the posterior 
 side. L.L., 27, Redcar. 
 
 26. A. V-SCEIPTA, Tate. 
 
 Of the same form as the last, but with the striae in 
 the form of the letter V. L.L., 27, Redcar. 
 
192 
 
 27. A. TELLI^FORMIS, Simp. 
 
 Ovate, subequilateral, transverse ; posterior side 
 the wider, ovate ; anterior side ovate, excavated 
 beneath the beaks ; base convex ; beaks small, 
 incurved, pointed ; concentrick striae fine, smooth, 
 unequal ; width little more than half an inch. I 
 think it is from the Upper Lias. 
 
 28. A. SUBOVALIS. 
 
 The shell which I take to be A. subovalis, or equilatera, 
 is rather depressed, regularly ovate, and equilateral, 
 with fine, nearly obsolete striae. I think Corbis uni- 
 formis is not an Arc. 
 
 Genus Trigonia. Trigonal, equivalve. 
 1. TRIGONIA LITERATA, T. 4" B. 
 
 Subtri angular, gibbous; beaks contiguous; an- 
 terior side short, truncated, rounded; posterior side 
 slightly recurved; area large, oblong, subcordate, 
 impressed ; longitudinal and transverse striae or ribs 
 rugose and waving, giving an imperfect represen- 
 tation of the letter V. Uppermost beds of Lias, 
 Peak. 
 
 The following is Young's original description : " Its 
 sides are marked in the manner of the Mya literata, 
 displaying two sets of ribs, which meet in a line passing 
 obliquely from the beaks to the base. The ribs are rough, 
 irregular, partly undulated ; some of the smallest, behind 
 the beaks, are sigmoidal ; the largest, which are nearest 
 the front, are imbricated, and some of them faintly 
 tuberculated. A slight tuber culated ridge separates the 
 ribbed part of the shell from the anterior part, on which 
 there is another slightly tuberculated ridge, not far from 
 the hinge : the intermediate space is divided by a faint 
 longitudinal line, and marked with numerous cross striae/' 
 
193 
 
 2. T. LINGONENSIS, Dum., Tate, T. fy B., pi. xi v f. 2. 
 Subtriangular, width greater than the depth; 
 
 posterior side the wider; anterior slope concave,, 
 obtusely carinated, striated; posterior slope cari- 
 nated; angle at the beaks less than a right angle; 
 base very convex ; concentrick ribs numerous, 
 scarcely equal to the separating concave spaces. 
 
 It is from the main bed of Cleveland ironstone. M.L.^ 
 a, Eston. 
 
 3. T. MODESTA, Tate. 
 
 A very questionable species. L.L., y, R.H. Bay,, Water. 
 
 FAMILY II. MYTILACEA, OR MUSSELS. 
 
 The shells of this family are all equivalve, and 
 have the posterior side elongated. They fix them- 
 selves to each other, or to hard substances by their 
 abyssus. Though by no means so abundant as 
 the oysters, they are still very numerous in some 
 of the strata. 
 
 Genus Mytilus, Linn. Wedged shaped. 
 
 The species of this genus, with one or two exceptions, 
 belong to the sub-genus Modiolus. Lam. 
 
 Mytilus proper. Beaks terminal, pointed. 
 
 1. MYLILUS CUNEATUS ? Ph. 
 
 Width more than twice the length ; the hinge 
 side nearly straight ; base concave, posterior side 
 rounded, expanded ; striae diverging from the beaks 
 numerous, slightly waving, decussated by numerous 
 fine lines of growth, 
 o 
 
194 
 
 The only example I have seen was in the possession 
 of the late Richard Ripley ,, Esq. The posterior side was 
 not so expanded as in the oolitic species. It was probably 
 the same as the next. 
 
 2. M. AVIOTHENSIS, Bur., Tate. 
 
 Anterior side pointed ; posterior side rounded, 
 expanded, depressed ; base nearly straight ; width 
 one inch, depth four-tenths of an inch. M.L., a. 
 
 Modiolus. Anterior side projecting before, and enlarged beneath the beaks. 
 
 3. M. SCALPRTJM, Sow. PI. ccxliii. 
 
 Width three times the length, divided into nearly 
 two equal parts by a diagonal keel ; posterior side 
 depressed ; upper margin convex ; base straight, 
 or nearly so ; beaks pointed, separated by a 
 moderate channel ; concentrick striae, or lines of 
 growth numerous, distinct ; diverging strige very 
 
 fine. 
 
 It is frequent in the uppermost beds of Middle Lias, 
 at Hawsker Bottoms. 
 
 4. M. SILIQUA, Simp. 
 
 Subcylindrical, slender, width six times the depth, 
 sides nearly parallel, base slightly concave. Pyri- 
 tous band, L.L., #, R.H. Bay. 
 
 5. M. CURVATUS, Simp. 
 
 Slender ; width five times the depth ; much 
 curved downwards at the posterior end ; groove at 
 the hinge line large ; coarsely concentrically 
 striated. L.L., R.H. Bay. 
 
 6. M. ENSIS, F. # B. 
 
 Much depressed ; width five times the depth ; 
 sides nearly parallel. 
 
195 
 
 Very like the blade of a strong penknife. My speci- 
 mens are all casts of the interior, but on one I observe 
 a bit of the shell, which is striated. I believe it to be 
 Young and Bird's Solen ensis. It is also supposed to 
 be Myoconcha decorata, Muns. Ironstone bands of M.L., 
 Hawsker. 
 
 7. M. SUBCANCELLATUS, Bur., Tate, T. fy B. f pi. xiii.yf. 1. 
 Width less than twice the depth ; posterior side 
 
 much depressed, ovate ; anterior side short, rounded ; 
 beaks prominent, slender ; base concave ; concen- 
 trick striae and lines of growth more or less strong-, 
 numerous, decussated by numerous diverging striae. 
 M.L., Hawsker. 
 
 There is another from the Lower Lias with the beaks 
 more tumid. It is also concentrically striated. I gave 
 it the name of M. limatus, but it may be a variety of 
 the above. 
 
 8. M. L^EVIS, Sow. PI. viii., f. 4. 
 
 Oblong, sides nearly parallel, base concave ; 
 anterior side bluntly rounded, short ; posterior side 
 depressed, ovately rounded ; divided into tw r o un- 
 equal parts by a diagonal depression, the upper 
 much the larger ; concentrick striae obsolete ; 
 width nine- tenths of an inch, more than twice the 
 depth. L.L., 25, R.H. Bay. 
 
 It has a dull, hoary aspect, and in some examples there 
 are a few strong imbricating plates of growth. 
 
 9. M. PYGIVOEUS, Simp. 
 
 I may place here the cast of a neat little shell, which 
 much resembles the young of M. modiolus, Linn., but 
 the part below the beaks is larger, and the anterior side 
 
196 
 
 longer ; there are a few faint striae and lines of growth. 
 It is probably the same as M. bifasciatus. Tate, T. <Sf B., 
 pi. xi., f. 3. 
 
 10. M. THIOLLIEREI,, Dum., Tate. No example. M.L., a. 
 
 11. M. MIMMA, Sow. No example. B/hsetic. 
 
 12. M. HILLANOIDES, C. fy D., Tate. No example. L.L., 
 
 22, Kedcar. 
 
 13. M. BIFASCIATO, Tate, T. $ B., pi. xi., f. 3. 
 
 Ovate, transverse, beaks prominent ; finely and 
 concentrically striated. L.L., 23, Redcar. 
 
 14. M. SUBCANCELLATUS, Bur., Tate. Syn. M. PALLIDUS, 
 
 Simp. 
 
 Width more than twice the length, unequally 
 divided by a diagonal depression ; upper part the 
 larger, tumid ; base sinuous, upper side convex ; 
 lines of growth numerous, fine, crossed in places 
 by a few obsolete, fine diverging striae. 
 
 Judging by the matrix it is from a lower bed in the 
 Lower Lias. 
 
 15. M. NUMISMALIS, Op., Tate. Syn. M. PYGM^EUS ? 
 
 Simp. 
 
 Ovate transverse, very inequilateral, anterior 
 side short, rounded, posterior side elongated, 
 rounded ; base slightly convex ; beaks prominent ; 
 very smooth with lines of growth ; one inch, 
 depth four-tenths of an inch. M.L., Ironstone. 
 
 16. M. HILLANTJS, Sow. PI. ccxii. 
 Subcylindrical, rather curved, ventricose ; pos- 
 terior side rounded ; anterior side short, umbilicate, 
 
197 
 
 rounded ; base sinuous, striae or plaits of growth 
 coarse, imbricated ; width two inches and three - 
 tenths, depth one inch and four-tenths, breadth 
 one inch and a half. L.L. 
 
 17. M. HIPPOCAMPUS, Y. fy B. 
 
 Subquadrate, transverse, ventricose ; anterior 
 side projecting beyond the beaks, convex, com- 
 pressed to a thin edge ; base sinuous ; beaks 
 large, obtuse, prominent over a deep channel ; 
 width three inches and three-tenths, depth one inch 
 and nine -tenths, breadth one inch and six-tenths. 
 Ironstone bands, upper part of M.L., Hawsker, &c. 
 
 There is one in the Inferior Oolite, Glaisdale, having 
 nearly the same shape, but with the anterior side much 
 diminished in depth. 
 
 18. M. SIMILIS, Simp. 
 
 Of the same general form, but much less ventricose, 
 and wider in proportion to the depth ; coarsely striated. 
 L.L., E.H. Bay. 
 
 19. M. RUSTICUS, Simp. 
 
 Exceedingly vetricose, very coarsely plaited. This has 
 the general form of M. hippocampus, but is much 
 more ventricose ; anterior side approaching to that of 
 M. Hillanus ; the posterior end narrower, and with 
 coarse imbricated plaits of growth. I judge it is either 
 from the Middle or Lower Lias. 
 
 Mr. Tate considers all the last three to be varieties of 
 Hippopodium ponderosum, Sow. To me they seem very 
 different. 
 
 Myoconcha. 
 
 20. M. ENSIS. M. DECORATE. 
 
 21. M. PSELONOTI, Quen., Tate. 
 
 Wedge shaped, depressed, transverse, posterior 
 
198 
 
 side rounded, widened ; slope behind the beaks 
 straight, many rugose concentrick and longitudinal 
 striae, and lines of growth at the convex base. 
 L.L,, 23, Redcar. 
 
 22. HlPPOPODIUM PONDEROSUM, Sow. PL CCl. 
 
 Ventricose, transverse, gibbous ; anterior side 
 short ; beaks large, obtuse, recurved over a deep 
 areola, or umbilicus ; from the beaks to the base a 
 depression ; base concave ; transversely striated. 
 L.L., R.H. Bay. 
 
 23. H. GIGAS, Tate. 
 
 Subglobose, umbones very large ; anterior side 
 below the beaks about half the depth, rounded ; 
 base convex ; posterior side much the wider ; 
 posterior slope convex ; concentrick striae numerous, 
 coarse; depth three inches and eight-tenths. M.L., 
 , Cleveland ironstone. 
 
 FAMILY III. CHAMACEA. 
 
 Genus Isocardia, Lam. Heart-shaped cockle ; 
 equivalve, ventricose ; beaks subspiral. 
 
 1. ISOCARDIA L^VIS, Y. fy B. 
 
 Orbicular, ventricose ; beaks approximate, re- 
 curved ; concentrick striae or lines of growth 
 irregular. M.L. 
 
 In some specimens the sides are nearly equal, in 
 others the posterior side is the larger, and rather tri- 
 angular. Some are nearly smooth, others are distinctly 
 striated or even plicated. T. & B., pi. xi., f. 12. 
 Cardinia. 
 
199 
 
 Some specimens sent me by Mr. Tate from the main 
 ironstone seam at Upleatham, under the name of C. 
 laevis, Y. & B., which answer well enough to his descrip- 
 tions, but not with their figure, or with the examples 
 we call I. Ia3vis. 
 
 They are distinguished by a small elegant little beak 
 curving towards the front, the whole ornamented with 
 strong concentrick ribs ; width one inch and seven- tenths., 
 depth 1 inch. 
 
 2. I. NITIDA, Y. fr B. 
 
 Globular, subequilateral ; beaks recurved, con- 
 tiguous ; striae numerous, coucentrick, distinct, 
 separated by triangular grooves. U.L., 5&, Whitby. 
 
 A very beautiful, shining little shell, about the size 
 of a large pea. 
 
 3. I. PETRICOSA, Simp. 
 
 Subtriangular, ventricose, inequilateral, trans- 
 verse ; anterior side short, obtuse, rounded ; 
 posterior side subangular, depressed, rounded ; 
 base convex ; beaks recurved, approximate ; disc 
 convex, smooth, with numerous fine, unequal trans- 
 verse striae ; width If inch, little more than the 
 depth. Hard bands in the M.L., Hawsker. T. & B., 
 pi. xiv., f. 1. 
 
 Tate calls it Ceromya. 
 
 4. I. SUBI^EVIS, Tate, T. & B., pi. xii., f. 6. 
 
 Ovate, ventricose ; anterior side much excavated 
 under the beaks, rounded ; posterior side the larger, 
 sub-triangular, attenuated ; beaks moderate ; con- 
 centrick striae very numerous, fine, nearly obsolete 
 
200 
 
 on the beaks ; width three inches and four-tenths, 
 depth three inches. 
 
 5. I. GIBBOSA, Eth., Tate. No example. 
 
 6. L BOMBAX, Quen. f Tate. 
 
 Nearly equilateral, anterior side carinated ; beaks 
 small recurved ; concentrick ribs of growth strong, 
 distinct ; width five -tenths of an inch, depth four- 
 tenths of an inch. 
 
 7. I. CUCULATA, Mun.y Tate. I. SECURIFORMIS, Simp. 
 
 (Cypricardia.) 
 
 Hatchet-shaped, transverse ; beaks small, in- 
 curved, incline to the anterior side, which is very 
 concave near the beaks, the remainder regularly 
 rounded, posterior side the wider, angular, slope 
 sharply carinated ; base convex ; transverse striae 
 Or lines of growth numerous, irregular ; shell 
 bright ; width eight-tenths of an inch, depth six- 
 tenths of an inch. M.L., a, Hawsker. 
 
 8. I. REGULARIS, Tate's MSS. 
 
 Orbicular, nearly equilateral, ventricose ; beaks 
 central, tumid, recurved ; concentrick striae numer- 
 ous, strong ; diameter four-tenths of an inch. M.L. 
 
 Mr. Tate kindly sent me this under the above name,, 
 from the Main Ironstone seam at Upleatham. It comes 
 near to I. laevis, but is more orbicular, and the striae are 
 different. 
 
 Genus Cardinia. Oblong, compressed. 
 
 I am rather at a loss where to place these shells. 
 Sowerby originally placed them under the Grenus Unio, 
 the freshwater mussels ; but they are undoubtedly marine, 
 
201 
 
 and are by no means rare in the Middle and Lower Lias. 
 Most of them are much depressed, or flattened. They 
 are also well characterized by their numerous lamellar 
 concentrick plates of growth, which give them a ribbed 
 appearance. Upon the whole, I am disposed to place 
 them amongst the Chamacse, and on account of their 
 small neat beak, incurved over a small areola, or um- 
 bilicus, I place them near Isocardia. 
 
 1. CARDINIA LISTERI, Sow., pi. cliv. 
 Subtriangular, equi valve, transverse, inequilateral ; 
 
 anterior side short, rounded; posterior side trian- 
 gular ; base convex ; beaks incurved, contiguous, 
 with a shallow depression towards the posterior 
 side; transverse ribs numerous, coarse, lamellar. 
 L.L., R.H. Bay. 
 
 2. C. COSTATA, F. $* B. 
 
 A good deal like the last, but much more ventricose ; 
 the posterior slope and base less convex, the beaks wider, 
 and the umbonal depression greater. L.L. 
 
 3. C. ANTIQUA, Ph. 
 
 Subtriangular; anterior side rounded, short; 
 posterior side angular, rounded; beaks incurved 
 above a small areola; lamellar plates of growth 
 thick, imbricating. 
 
 The above description is from some specimens sent me 
 by Mr. Tate from the M.L., Huntcliff. They certainly 
 do not agree with Phillips' f. 16, pi. xiii., Yorks. Coast, 
 which is very ovate. Some sent me by the same kind 
 friend from the L.L., Eedcar, as the young of C. crassi- 
 uscula, agree better with it, though the posterior side is 
 more triangular and less expanded. 
 
 4. 0. DELICATA. 
 
 Very much depressed, Subtriangular, width about 
 
202 
 
 one-third greater than the depth; anterior side 
 short, rounded; posterior side angular, attenuated; 
 base rather sinuous; beaks small, with a broad 
 diagonal depression towards the posterior end ; con- 
 concentrick lamellar plaits numerous, flatted and 
 regular ; ornamented with fine, distinct, concentrick 
 striae. 
 
 It is from the shale below the double indurated band, 
 No. 15, L.L., E.H. Bay. 
 
 5. C. MEMBRANACEA, Simp. 
 
 Equivalve, sub triangular, transverse, depressed, 
 inequilateral ; anterior side short, truncate ; posterior 
 side slightly recurved, rounded ; base convex ; disc 
 flattish; transverse plicae numerous. 
 
 It has a soft, leathery appearance. M.L., Hawsker. 
 
 6. C. CRASSIUSCULA, SOW., pi. dxXXV. 
 
 Equivalve, inequilateral, transverse or ovate, de- 
 pressed ; posterior side the longer ; transverse striae 
 lamellar, most numerous towards the base. L.L., 
 E.H. Bay. 
 
 There is a small Cardinia, not uncommon, of a sub- 
 triangular shape, with the posterior side very much wider 
 than the anterior, which Mr. Tate thinks is the young of 
 this. T. & B., Yorks. Lias, pi. xiv., f. 4. 
 
 7. C. CONCINNA, Sow., pi. ccxxiii. 
 
 Width more than twice the depth ; posterior side 
 lanceolate, nearly four times the length of the an- 
 terior side, which is concave beneath the beaks, 
 then boldly rounded ; the flatted lamellar ribs and 
 striae are the most numerous and distinct towards 
 
203 
 
 the base. L.L., Indurated bands, Nos. 22, 23, R. 
 H. Bay. 
 
 8. C. ATTENUATE, Stu., Tate. 
 
 Much depressed ; anterior side short, regularly 
 convex ; posterior side elongated, subtriangular, end 
 ovate ; base and posterior slope convex ; concentrick 
 lines of growth irregular, nearly smooth; width two 
 inches and two-tenths, depth one inch and two- 
 tenths. L.L. 
 
 9. C. OVALIS, Stu., Tate. 
 
 Ovate, depressed ; posterior side the wider ; base 
 convex; beaks small, with a small umbilicus or 
 areola beneath ; lamellar plaits of growth and con- 
 centrick striee numerous, fine. 
 
 It is a rather smooth species ; it varies in its outline j 
 some have the posterior side elongated and angular. It 
 is from the lowest beds of Lias at Redcar. 
 
 10. C. DESHAYSESI, Ter., Tate. No example. 
 
 11. C. DESOUDINI, Ter, Tate. No example. 
 
 12. C. CRASSISSIMA, Sow. No example. 
 
 FAMILY IV. CAEDIACEA. 
 
 Mantel closed, perforate. 
 
 The greater part of this beautiful Family burrow in 
 mud, sand, and other substances, and in their organi- 
 zation approach to that of the next Family, whose habits 
 are always of that character. 
 
 Genus Cardium. The Cockles. 
 Equivalve, ventricose, cordate ; ribs radiating 
 from the beak. 
 
204 
 
 .1. CARDIUM TRUNCATUM, Sow., pi. dliii. 
 
 Deltoid ; beaks recurved, approximate ; anterior 
 side rounded ; posterior slope flat, cordate, striated ; 
 base rounded ; transverse stride numerous. M.L. 
 
 The longitudinal striae,, so distinct on the posterior 
 slope and its margin, are not observed on the remaining 
 portion of the disc. It is very abundant in the hard 
 bands of the Middle Lias. 
 
 2. C. BITTTMINOSUM. 
 
 Very ovate, rather deltoid ; nearly equilateral, 
 ftoth sides sharply carinated ; base circular ; beaks 
 incurved, approximate ; concentrick striae very 
 fine or obsolete ; very smooth and shiny. U.L., 
 5, Saltwick. 
 
 3. C. MTJLTICOSTATTJM, Ph. 
 
 Subglobular ; beaks tumid, recurved ; con- 
 centrick striae, or plaits of growth, about ten, 
 unequal, imbricating, cancellated by numerous 
 longitudinal striae radiating from the beaks ; base 
 circular, toothed. M.L. 
 
 Some are rather deltoid, and less ventricose. About 
 the size of a small pea ; not uncommon in the hard 
 bands of the Middle Lias. 
 
 4. C. HEBERTI, Ter., Tate. 
 
 Less globular than the last, the beaks longer, the con- 
 centrick plates of growth few, or none ; diverging strise 
 very numerous, distinct. L.L., 27, Eedcar, &c. 
 
 5. C. PHILIPPIANUM, Dunk., Tate. 
 
 Nearly equilateral ; beaks small, contiguous ; 
 anterior side carinated, circular ; base circular ; 
 
205 
 
 posterior side truncate, carinated ; smooth, or with 
 very fine concentrick striae ; diameter about half 
 an inch. 
 
 It is from the very lowest beds of Lias. E-hsetic. 
 
 6. C. TRIANGULARE, Simp. 
 
 Triangular, equilateral, base circular ; length half 
 an inch, equal to the width ; beaks sharp, incurved, 
 approximate. 
 
 A cast of a brassy colour, by no means uncommon 
 about the middle of the L.L., EJff. Bay. 
 
 7. C. STTBSTRIATULUM, D'Orb, Tate. No example. 
 
 8. C. GLOBOSUM, Moor, Tate. (Unicardium, Isocardia ?) 
 Ovate, nearly equilateral ; anterior side cari- 
 nated ; beaks small, recurved ; concentrick ribs 
 strong, distinct ; width five-tenths of an inch, 
 depth four-tenths of an inch. M.L., #, Staithes, &c. 
 
 9. CORBIS TJNIFORMIS, Ph.> pi. xii., f. 3. 
 
 Equivalve, subequilateral, transverse, ovate ; 
 beaks small, recurved, approximate ; disc smooth ; 
 transverse striae numerous, fine, unequal ; width 
 nearly an inch. 
 
 Like a Cyclas, or ventricose Tellina ; and there is a 
 small fold or faint depression at the base of the posterior 
 side. Hard bands M.L., Hawsker, &c. 
 
 Genus Tellina. Generally inequivalve and com- 
 pressed. 
 
 1. TELLINA FABALIS, Simp. T. $r B., pi. xii, f. 5. 
 
 Ovate, depressed, equivalve, inequilateral ; con- 
 centrick striae numerous, fine ; obsolete striae radiate 
 
206 
 
 from the beaks ; width four-tenths of an inch, depth 
 three -tenths of an inch. M.L., a, Hawsker, &c. 
 
 2. T. TENTHS, K. $ D., Venus. T. CYCLIFORMIS, Simp. 
 Suborbicular or ovate ; rather tumid at the beaks ; 
 
 transverse striae or lines of growth numerous, fine, 
 distinct. 
 
 A neat, shining little shell, like a Cyclas, from the 
 uppermost beds of Lias at Peak, where it is rather 
 plentiful. 
 
 3. T. STRIATA, Simp. 
 
 Ovate, transverse; concentrick striae, numerous, 
 with stronger lines of growth, rough ; width three- 
 quarters of an inch. L.L. 
 
 4. T. CARDINOIDES, Tate. T. fy B., pi. xvi., f. 8. 
 
 " Ovate-trapezoid, subinequilateral, subventricose, 
 concentrically ridged ; rounded in front, posterially 
 subtruncated ; ventral margin curved; umbones 
 small, intermedial, subacute; lamellae very small, 
 escutcheon linear." 
 
 5. T. PUMILA, Mun., Tate. M.L., a, Hawsker. No example. 
 
 6. T. SUBGLOBOSUM, Tate. ( Unicardium) . 
 Ventricose, beaks small, incurved, approximate ; 
 
 anterior side boldly rounded, short ; posterior side 
 the wider, diminished; concentrick striae numerous. 
 M.L., a, Redcar. 
 
 7. T. GBOCIANA, Br., Tate. No example. 
 
 Thracia. 
 
 8. T. GLABBA, Ag., Tate. 
 
 Ovate, much depressed, transverse ; anterior side 
 
207 
 
 the shorter, sharply carinated ; posterior side rather 
 expanded; base con vex; disc smooth, with unequally 
 elevated ribs of growth, the whole covered with very 
 numerous, fine, concentrick striae; width an inch. 
 ILL., Whitby. Closely allied with T. striata. 
 
 Tancredia. 
 9. T. DIONVILLENSIS, Ter., Tate, T. & B., pi. xiv., f. 12. 
 
 Rather inflated, width twice the depth ; posterior 
 side the longer, elliptical, slope convex ; anterior side 
 excavated under the beaks, then produced in a para- 
 bolick curve; angle at the beaks more than a right 
 angle ; base convex. U.L., 5&, Salt wick. 
 
 Mr. Tate gives the following notice of this specimen 
 <f In the Whitby Museum is a Tancredia with the two 
 valves in contact along the dorsal line, but separated 
 below, and deprived of the extremity of the rostral pro- 
 longation. Its shape is that of T. dionvillensis, though 
 much larger ; some slight differences in the relative 
 proportions of different parts are noticeable, but they 
 are not of such magnitude as to justify a new denomina- 
 tion. The dimensions are : length 2 inches ; length of 
 posterior side 1 inch ; height H inch. U.L., 5b, Saltwick, 
 near Whitby, along with Posidonomya Bronni. 
 
 10. T. OVATA, C. fy D., Tate. Syn. T. FERREA, Eth. 
 Triangular, depressed, nearly equilateral, base 
 
 convex; no distinct striae; length one-third the 
 width. L.L., 23. 
 
 11. T. LONGICOSTATA Bur., Tate. 
 
 Width twice the depth ; posterior side rather the 
 wider, but less deep than the anterior, nearly smooth, 
 base convex, above which may be seen two obsolete 
 elevations or longitudinal ribs ; width six-tenths of 
 an inch. 
 
208 
 
 12. T. LUCIDA, Ter. Tate. 
 
 Ovate, posterior side much the wider, and 
 rounded ; anterior side angular, rounded ; base 
 convex; concentrick striae obsolete, width one inch, 
 depth seven-tenths of an inch*. M.L., a, Redcar. 
 
 13. T. BIOLIENSIS ? Bur., Tate. No examples. M.L.,, a, 
 
 Eston. 
 
 14. T. APICISTRIA, Rol., Taie. 
 
 Ovate, posterior side the wider, smooth ; width 
 four-tenths of an inch, depth less than three -tenths 
 of an inch. L.L , 23. 
 
 Genus Venus. Ribs concentrick. 
 They all belong to the Sub-genus Astarte. 
 
 1. VENUS OPPELI, And., Tate, T. fr B., pi. xii., f. 3. 
 Ovate; length 1| inch; depth 1^ inch. 
 
 A coarse species,, concentrically and irregularly ribbed 
 and striated. It is from the lowest beds of Lias^ at 
 Eedcar. 
 
 2. V. STRIATOSULCATA, Eom., Tate. 
 
 Deltoid, with a circular base; concentrick ribs 
 rather strong; diameter quarter of an inch. L.L., 
 R.H. Bay. 
 
 3. V. CINGULATA, Ter., Tate. 
 
 Ovate, nearly circular; concentrically striated. 
 A very minute species from the lowest beds of Lias, 
 Eedcar. 
 
 4. V. OBSOLETA, Dun., Tat e. No example. L.L.., 27, Eedcar. 
 
 5. V. RUGATA, Quen., Tate. No example. M.L., a, Eston. 
 
 1. CORBULA CARDIOIDES, Ph. 
 
 Subequivalve, subequilateral, ovate, ventricose, 
 
209 
 
 in general transverse ; beaks large, incurved, 
 approximate ; many irregular transverse ridges ; 
 transverse strips numerous, rough. 
 
 They occur in the ironstone series of the L.L. to M.L., ct. 
 
 2. C. ^QUIVALVIS, Simp. 
 
 Subcylindrical, equivalve, transverse ; posterior 
 side the longer ; both sides rounded ; transverse 
 ridges rough, unequal. L.L., R.H. Bay. 
 
 Like the last,, but more transverse, and the hinge-line 
 longer. 
 
 3. C. DEi/roiDEAj Simp. 
 
 Deltoid, subequivalve, very ventricose ; beaks 
 incurved, contiguous, obtuse, inclining towards 
 the anterior side, which is rounded ; posterior slope 
 flattish ; transverse striae numerous, coarse, irre- 
 gular. L.L., R.H. Bay. 
 
 4. C. SUBGLOBOSA,, Tate. 
 
 Ventricose ; beak small, incurved, approximate ; 
 anterior side boldly rounded, short ; posterior side 
 the wider, diminished ; concentrick striae numerous. 
 M.L., a, Staithes. 
 
 FAMILY V. INCLUSA. 
 
 These are open at both ends, but closed by the 
 mantle along the base, so that the shell can be 
 only partially opened. The Mya arenaria, which 
 abound in the Whitby and other harbours, is a very 
 instructive example of this family, wl , :h bury in 
 the mud and sand, which, from their position in 
 P 
 
210 
 
 the strata, we see they have done in the remotest 
 times. 
 
 Genus Myacites. We may place here a number 
 of shells which are very plentiful in the muddy 
 beds of the Lias, and not uncommon in the Oolite 
 above. They were called Amphidesma, by Phillips, 
 but I have adopted the above name as indicating 
 their close connexion with the Mya. They have 
 more recently been excessively divided into smaller 
 genera, or sub-genera. Thus we have Myopsis, 
 Pluromya, Arcomya, Mactromya, Anoplomya, Gonio- 
 mya, Tellinomya, Ceromya, Gresslya. All indicating* 
 their close affinity with the genus Mya, Linn. 
 Whatever may be the advantages of those small 
 divisions in minute investigations, they greatly 
 embarras nomenclature. They do not appear to 
 be true Mya, the posterior end being only slightly 
 gaping, but they have habits of the Mya, boring 
 in the mud or sand, and are found with their 
 posterior end upwards, their natural position when 
 living. They are found in all the beds of Lias, 
 from the very uppermost to the lowest. They are 
 oblong, like the Unio and Pullastra ; more or less 
 ventricose, with the posterior end wedge shaped. 
 
 1. MYACITES COSTATA, T. fy B. 
 
 Subtriangular, very inequi valve ; beaks incurved, 
 approximate ; anterior side triangular ; posterior 
 side elongated, and slightly recurved; base convex; 
 transverse ribs numerous, strong, rounded, equal 
 
211 
 
 to the intervening concave furrows ; transversely 
 striated. Ironstone bands, M.L., a, Hawsker 
 Bottoms. 
 
 2. M. BITUMINOSA, Tate, T. fy B. f pi. xii., f. 9. 
 
 "Transversely ovate, elongate, with thick striated 
 concentrick ribs ; anterior side very short, convex ; 
 posterior side produced, compressed and roundly trun- 
 cated ; front margin slightly convex; unibones rather 
 large, incurved, approximate. It is less inflated in the 
 umbonal regions than M. costata, and has a shorter 
 anterior side than it, and differs from its congenus in 
 its truncated posterior margin. Dimensions : width one 
 inch and four-fifths, height eight-fifths of an inch." 
 Upper Lias, 56, Staithes. 
 
 3. M. DUBIA, Simp. 
 
 Subtriangular, inaequivalve, inequilateral ; ante- 
 rior side triangular, obtuse ; posterior side elongated, 
 compressed ; base convex ; transversely ribbed and 
 striated ; posterior slope concave behind the rather 
 wide beaks ; width 3 inches, depth two inches. 
 
 The ribs on the cast are rounded, and equal to the 
 intervening concave furrows, those on the shell more 
 angular. They are rather plentiful in the main ironstone 
 bands, in the Middle Lias at Grosmont. 
 
 4. M. SUBTRIANGTJLARIS, Simp. Area ? 
 Subtriaugular, ventricose, nearly equivalve, 
 
 transverse ; anterior side very short ; posterior 
 side wedge-shaped ; posterior slope straight ; base 
 convex ; beaks incurved, contiguous, areola be- 
 neath, deep ; transversely ribbed ; concentrick 
 striae numerous, coarse, strong. 
 
 The shell is seldom preserved, where it remains, it 
 
212 
 
 shews the striae rather broad, separated by lines. It is 
 not rare in the upper division of the Lower Lias,, near 
 Bay Town. L.L., y, E.H. Bay. 
 
 5. M. CROWCOMBEIA, MOOT. 
 
 Ovate, depressed, transverse ; anterior side short, 
 quickly rounded, sharp and cutting ; posterior side 
 much the longer, and attenuated, slightly recurved ; 
 base convex ; tumid at the beaks ; beaks small, 
 incurved, contiguous ; width an inch ; surface 
 adorned with very fine, regular, numerous, distinct 
 concentrick ribs, and between the ribs, very fine 
 concentrick striae ; on the cast faint, diverging 
 lines. 
 
 It is very numerous in the lowest beds of Lias. 
 
 6. M. GRANATA, Simp. T. ty B., pi. xiii., f. 7. 
 
 Ovate, ventricose, equivalve, inequilateral, trans- 
 verse ; anterior side short, rounded, obtuse ; 
 posterior elongated, depressed, rounded, base con- 
 vex ; beaks incurved, broad, approximate ; transverse 
 striae numerous, fine, unequal ; dotted all over 
 with minute granules ; width three inches, depth 
 two inches, thickness across the beaks JJ inch. 
 M.L., Hawsker. 
 
 7. M. SCABROSA. 
 
 Subtriangular, ventricose, transverse; anterior 
 side very short, flatly rounded, or subtruncate ; 
 base convex ; posterior side bluntly wedge shaped ; 
 rounded ; transverse ribs very flat, forming mere 
 
213 
 
 undulations ; roughened with granular striae in 
 many directions ; width 2J inches, depth 1| inch. 
 M.L., />, Hawsker. 
 
 8. M. MEDI^VA, Simp. 
 
 Subtriaugular, ventricose, transverse ; anterior 
 side very short, obtuse ; posterior side long, 
 obtusely pointed ; base convex ; beaks recurved ; 
 areola larg*e, cordate. L.L., R.H. Bay. 
 
 This has many of the characters of the last, but quite 
 smooth ; the anterior side is short er, and very obtuse ; 
 the posterior end is narrower. There is also a broad, 
 slight, longitudinal depression or constriction from the 
 beaks. 
 
 9. M. PUNCTATA, Simp. T. fy B., pi. xiv., f. 10. 
 Subtriangular, transverse ; beaks approximate, 
 
 incurved ; anterior side short, angular, with a 
 broad longitudinal constriction ; posterior side 
 elongated ; transverse striae numerous, dotted, or 
 
 reticulated. 
 
 This is rather a large shell. With a lens may be 
 observed numerous fine dots, which, in places, run into 
 each other longitudinally. It it from the pyritous band 
 in the Lower Lias at R.H. Bay, so rich in other fossils. 
 A bit has been broken off the posterior end. 
 
 10. M. DONACIFORMIS, Ph. 
 
 Subtriangular, transverse; beaks incurved, con- 
 tiguous ; anterior side short, rounded, with a 
 longitudinal plait or depression ; posterior side 
 elongated, depressed ; base convex ; transverse 
 striae obsolete. 
 
 This is one of the most abundant shells in the upper 
 part of the Upper Lias ; but it is seldom found perfect. 
 
214 
 
 It appears to have burrowed in the mud,, the sharp side 
 being generally found uppermost. The largest specimens 
 are about 2 inches wide,, and 1 inch long. 
 
 Some are much depressed, others are ventricose, and 
 the constriction nearly obsolete. 
 
 11. M. ROTUNDATA, Ph. 
 
 Ovate, ventricose, transverse, anterior side short, 
 boldly rounded ; posterior side rounded, attenuated ; 
 posterior slope convex from the beaks ; base con- 
 vex ; beaks incurved, contiguous ; areola deep, 
 transverse, reniform ; width two inches, depth 1J 
 inch, thickness an inch and one-eighth. 
 
 It occurs very sparingly in the uppermost divisions 
 of the Upper Lias, along with the last. The front of 
 some is less regularly convex, being protruded towards 
 the base. ILL., 1, 2. Whitby. 
 
 12. M. INTERMEDIA, Simp. 
 
 Ovate, transverse ; anterior side short, regularly 
 convex ; posterior side elongated, rounded, rather 
 concave, behind the beaks ; base convex ; beaks 
 rather small, contiguous ; areola narrow ; striae 
 numerous, regular, granulated, transverse; width 
 2^ inches, depth 1^ inch, thickness seven-eighth 
 of an inch. 
 
 This is rather an elegantly shaped species, in some 
 the striae amount to ribs. They also vary in the length 
 and depth of the posterior end. They are rather abun- 
 dant in the main ironstone beds of the Middle Lias. 
 
 13. M. FERRUGINEA, Simp. 
 
 Ovate, inaequivalve, inequilateral, rather de- 
 pressed about the beaks ; anterior side rounded, 
 
215 
 
 little excavated under the beaks ; posterior side the 
 longer, rounded, slope convex ; base convex. 
 
 This is a very ovate shell, the beaks being a. little 
 elevated. A smooth cast. It comes nearest, to M. 
 intermedia. Width 3 inches, depth seven-eighth of an 
 inch, thickness an inch and one-eighth. Ironstone bands 
 of the Middle Lias, Grosinont. 
 
 14. M. LEVIS, Simp. 
 
 Ovate ; beaks incurved, small; areola beneath, 
 small ; anterior side short, tumid, rounded ; pos- 
 terior side elongated, rounded, depressed ; base 
 convex ; transverse striae irregular, granulated ; 
 cast smooth ; width 2 inches, depth 1-^ inch. 
 
 This is an abundant shell in the middle of the Middle 
 Lias ; stratum p of my section. They are very regular, 
 but some are more ventricose, when they approach to 
 M. rotundata. 
 
 15. M. SUBTRUNCATA, Simp. 
 
 Anterior side shorter than in the last, and the 
 posterior side more depressed and attenuated. 
 From the same bed. M.L.,^>. 
 
 16. M. MACULATA, Simp. 
 
 Subquadrate ; anterior side short ; posterior side 
 depressed, truncate ; base convex. Lowest beds 
 of Middle Lias. 
 
 The length of this species is greater in proportion to 
 the width than is usual in this genus. The shell is thin, 
 and spotted with white, and has many irregular undu- 
 lations and lines of growth. 
 
 Mr. Tate has comprehended under this species, M. 
 sebachii, but his figure pi. xiii., f. 3., indicates a much 
 longer posterior side. The example he has sent me has 
 fine striae crossing each other in various directions. 
 
216 
 
 17. M. OVATA, Tate's MSS. 
 
 Ovate, rather ventricose, nearly equilateral ; 
 anterior side the shorter, and more obtuse, both 
 convex ; base convex ; beaks small, incurved ; 
 roughly striated. L.L., R.H. Bay. 
 
 18. ./EQUALIS, Simp. 
 
 Subgequilateral, posterior side the longer, anterior 
 side much produced towards the base, convex ; 
 beaks prominent ; middle of the side flatted, trans- 
 versely and obsoletely striated. ILL., Whit by. 
 
 19. M. CONCAVA, Simp. 
 
 Depressed, subtriangular, anterior side short, 
 angular ; posterior side long ; base more or less 
 concave ; width two inches, depth 1^ inch. 
 Pyritous band. L.L., ?/, R.H., Bay. 
 
 It much resembles a depressed variety of M. donaci- 
 forinis. 
 
 20. M. LIASINA, Sch., Tate. 
 
 Very transverse ; anterior side short, rounded ; 
 posterior side elongated, little diminished, rounded ; 
 base convex ; beaks depressed ; coucentrick striae 
 fine, smooth ; width two inches and three-eighths, 
 depth an inch and one -eighth. Lowest beds of 
 Lias at Redcar. 
 
 One sent me by Mr. Tate, very much resembles the 
 preceding one, with the concave base. 
 
 21. M. CRASSA, Ag., Tate. 
 
 Ovate, ventricose, transverse ; anterior side short, 
 bluntly rounded ; posterior side tumid, convex ; 
 
217 
 
 base flatly convex r line behind the beaks con- 
 cave; width an inch and seven -eighths, depth an 
 inch and one-eighth. Lower Lias, 23, Redcar. 
 
 22. M. GALATHEA, Ag., Tate. 
 
 Subtriangular, tumid on the anterior part, trans- 
 verse; anterior side short, boldly rounded, posterior 
 side elongated, depressed and attenuated ; base and 
 posterior slope nearly straight. L.L., 23, Redcar. 
 
 23. M. MTJNDULA, Tate, T. $ B., pi. xii., f. 11. 
 Depressed, ovate ; width nearly twice the depth, 
 
 subequilateral, anterior side the shorter, both ends 
 rounded, and of equal width ; base flatly convex ; 
 beaks small, depressed ; smoothly and concentrically 
 striated. 
 
 A handsomely shaped shell,, from the lowest beds of 
 Middle Lias. Huntcliff, Staithes, &c. 
 
 24. M. CONCINNA, Tate, T. fy B., pi. xi., f. 1. 
 
 Much depressed, width about twice the depth, 
 both ends rounded ; base flatly convex ; anterior 
 side the shorter ; beaks small, contiguous ; striated 
 and granulated. M.L., a, Eston. 
 
 25. M. CONTRACTA, Simp., T. fy B., pi. xvi.., f. 9. 
 Equivalve, for half the width sub-cylindrical ; 
 
 anterior side very short, obtuse ; posterior side 
 angular ; width more than twice the length ; width 
 1^ inch, length seven-tenths of an inch, thickness 
 seven-tenths of an inch. U L., Whitby. 
 
 26. M. LUNULATA, Tate, T. $ B., pi. xii., f. 10. 
 
 ff Transversely ovate, very oblique, umbones approxi- 
 
218 
 
 mate, small, incurved, pointed, anterior esclmcheon 
 large, cordate ; anterior side short, truncated j posterior 
 rounded and attenuated ; transverse strise numerous, 
 irregular." Tate says that it is my Pholadoniya 
 rostrata. M.L. 
 
 27. M. DUNKERI, Ter. y Tate. 
 
 Widely ovate, with obsolete transverse strise ; 
 anterior side rather attenuated, rounded ; posterior 
 side much the larger, expanded ; base convex ; 
 width one inch and seven-tenths, depth eight-tenths 
 of an inch. L.L., 27. 
 
 28. M. GIBBOSA, Eth. L.L., Eedcar. No example. 
 
 29. M. SUBL^EVIS, Tate, T. & B., pi. xii., f. 6. 
 
 " Shell subtrigonal, ventricose, thin, slightly 
 inequilateral ; urnbones inflated, depressed and 
 involute, nearly central ; anterior side rounded, 
 posterior side truncated, attenuated ; front margin 
 much curved, lunule broad, shallow ; surface with 
 fine, and closely arranged ridges of growth ; acute 
 anteriority ; depressed on the posterior side ; 
 breadth 3| inches, height three inches, thickness 
 nearly two inches." 
 
 30. M. VENTRICOSA, Simp. 
 
 Subtriangular, subequivalve, ventricose ; anterior 
 side short, obtuse ; posterior side sharp and cutting., 
 ovate ; beaks approximate, recurved, from whence 
 proceed to the base a broad, rather oblique de- 
 pression ; transverse striae obsolete ; length one- 
 inch ; width 1^ inch. L.L., R.H. Bay. 
 
219 
 
 Sanguinolaria. 
 
 31. M. ELEGANS., Ph. 
 
 Ovate, depressed, transverse ; posterior side the- 
 longer ; transverse striae coarse. 
 
 32. M. VETUSTA, Ph. 
 
 Trapezoid, transverse ; anterior side short ; pos- 
 terior side enlarged ; transverse plaits lamellar. 
 L.L., R.H. Bay. 
 
 Genus Mya, Linn. Open at both ends. Hinge 
 variable. 
 
 1. MYA ANTIQUA, Simp. 
 
 Trapezoid, depressed, transverse, posterior side 
 the longer, both ends boldly rounded ; base a little 
 convex ; beaks incurved, wide ; transverse ribs 
 nearly straight in the middle, curving round the 
 ends ; shell thin, scaly ; width 3 inches, depth 
 1-J- inch. 
 
 The hinge is not well displayed. There is another 
 smaller valve imperfect on the same nodule, along 
 with Am. Hawskerensis. Upper bed of Ironstone M.L., 
 Hawsker Bottoms. 
 
 2. M. ^QUILATERALIS, Simp. 
 
 Subequilateral, very transverse ; beaks small r 
 incurved ; area behind the beaks very wide and 
 spreading ; anterior end attenuated, rounded, pos- 
 terior end imperfect ; width 2^ inches, depth 
 three-quarters of an inch, width across the beaks 
 three-quarters of an inch ; shell transversely and 
 numerously striated. 
 
220 
 
 Probably from the Lower Lias, with Lima novem- 
 costata. 
 
 3. M. HISPIDA, Simp. 
 
 Very inequilateral, very transverse ; posterior 
 side much produced, slightly curved upwards, 
 upper and lower sides nearly parallel ; transversely 
 striated, and covered over with fine points ; width 
 nearly four times the length. M.L., Ironstone 
 bands, Hawsker Bottoms. 
 
 This is so transverse, that it has a good deal the ap- 
 pearance of a blade of a knife ; but rather tumid about 
 the beaks. 
 
 4. M. LITERATA, Sow., pi. CCXXiv. 
 
 Ovate, subequilateral, posterior side the longer ; 
 beaks approximate ; striae meeting in the middle of 
 the disc at an acute angle, form the letter V. L.L., 
 K.H. Bay. 
 
 5. M. ELONGATA, Eomer, Tate. 
 
 Subrectangular, very transverse, anterior side 
 short, rounded, posterior side elongated, beaks 
 small, incurved ; upper and lower sides nearly 
 parallel ; transversely striated ; width 2 inches, 
 depth one inch. L.L., ?/, R.H. Bay. 
 
 6. CONCINNA, Tate, T. $ B., pi. xi., f. 1. 
 
 Rather depressed, anterior side the shorter, 
 boldly rounded more than a semicircle, posterior 
 side the narrower, rounded, base flatly convex ; 
 beaks small; width two inches and three-tenths, 
 depth one inch. M.L., , Eston. 
 
221 
 
 7. M. LONGA, Bur., Tate, T. Sf B. f pi. xi., f. 11. 
 
 Ovate, anterior side much the shorter, full and 
 boldly convex ; posterior side narrower, convex ; 
 line behind the hinge concave ; beaks large, trans- 
 versely striated ; length four inches, depth two 
 inches. M.L., a, Eston. 
 
 Genus Pholadomya. Intermediate between My a 
 and Pholas, as the name indicates. Anterior side, 
 for the most part, ventricose, with ribs radiating 
 from the beaks ; posterior side depressed. Rather 
 common in the Lower Lias. 
 
 1. PHOLADOMYA CONCINNA, Simp. 
 
 Ovate, transverse ; beaks strong, obtuse ; an- 
 terior side short, obtuse ; posterior side produced, 
 depressed, angular ; base convex ; transverse striee 
 numerous, distinct, unequal ; width twice the 
 length. 
 
 A handsome shell from the L.L., 23, E-.H. Bay. 
 
 2. P. AMBiGUAj Sow, pi. ccxxii. Syn. P. PRODUCTA,, Simp. 
 Subrhomboidal, transverse ; anterior side short, 
 
 rounded ; posterior side produced, rounded, gaping ; 
 beaks small ; oblique ribs radiating from the beak, 
 obsolete ; transverse ribs obsolete ; width four 
 inches, length 2 inches. M.L. 
 
 3. P. RECURVA, Simp. 
 
 Ovate, transverse, beaks incurved, approximate 
 over a deepish posterior sinus, or channel ; anterior 
 
222 
 
 side short, obtusely rounded ; posterior side 
 lengthened, diminished, slightly recurved ; base 
 convex ; transverse striae irregular ; six or seven 
 ribs diverging from the beaks, indistinctly muri- 
 cated ; width three inches ; depth one inch and 
 seven-eighths ; thickness 1^ inch. Ironstone bands, 
 M.L., Hawsker. 
 
 4. P. SIMPSONI, Tate, T. fy B., pi. xii., f. 1. Syn. P. 
 
 GIBBOSA, Simp. 
 
 Oblique, transverse, gibbous ; beaks approximate, 
 incurved, prominent, obtuse ; anterior side very 
 .short, obtuse ; posterior side recurved, attenuated ; 
 about eight or nine muricated ribs diverging from 
 the beak ; coarsely, transversely striated ; width 
 2^ inches, depth two inches, thickness across the 
 beaks 1 inch. M.L., a, Hawsker. 
 
 Mr. Tate has given the following description of this 
 shell : " Shell ovately triangular, the ventral margin 
 much arched and strongly incurved behind the umbones ; 
 umbones nearly terminal, and incurved, obtuse ; es- 
 cutcheon very large; surface ornamented with about 
 seven oblique diverging and nodulous ribs, and with 
 concentrick folds and striae/' P. 399. 
 
 5. P. DECORATA, Ziet., Tate. 
 
 Yentricose, transverse ; anterior side short, boldly 
 rounded ; posterior side obtuse, rounded ; base con- 
 vex; upper side concave; beaks short, incurved, 
 contiguous ; decorated with numerous transverse 
 strige, and about ten slightly muricated diverg- 
 ing ribs ; width 3| inches ; depth three inches ; 
 
223 
 
 thickness two inches and three-eighths. L.L., ?/, 
 Huntcliff, &c. 
 
 6. P. LUNATA, Simp. 
 
 Gibbous, transverse ; beaks very large, incurved, 
 contiguous, obtuse ; anterior side obtuse ; posterior 
 -side large, depressed, rounded ; transverse strise 
 fine, numerous, distinct ; longitudinal striae on the 
 beaks only. The anterior side, base, and posterior 
 side a regular curve ; width five inches, length 3-J- 
 inches. M.L., a, Hawsker. 
 
 Mr. Tate's description : " Transversely oval, elongated ; 
 .umbones gibbous, very large, ante-medial ; anterior side 
 produced, inflated ; margin regularly rounded, front 
 margin much curved ; posterior side attenuated, elon- 
 gated, obtusely pointed ; dorsal line deeply incurved 
 behind the umbones. Surface ornamented with three 
 faint oblique ribs, and concentrick rugse and strise. 
 Distinguished by its elongated form, few ribs, and the 
 deep saddle-like depression behind the umbones. " 
 
 Another very like this . in general form, occurs in the 
 Lower Lias at Robin Hood's Bay. It is less deep in the 
 anterior half, and broader and more compressed in the 
 posterior. With the exception of a few obsolete radii 
 on the beaks, it is without ribs or strise ; width four 
 inches and seven-eighths, depth 2| inches, thickness one 
 inch and seven-eighths. It may be named P. selenata. 
 
 .7. P. LJEVIS, Simp. 
 
 Triangular, transverse; anterior side ventricose; 
 posterior side acutely triangular, much compressed ; 
 base convex ; beaks moderate, incurved, contiguous ; 
 areola beneath, small ; width three inches, depth 
 two inches: thickness an inch and four-tenths at 
 
224 
 
 the anterior side; transverse strise obsolete; shell 
 coarse and scaly. M.L., ironstone, Hawsker. 
 
 8. P. OBTTJSALIS. 
 
 Rhomboidal, ventricose, transverse; anterior side 
 short, obtuse, oblique, curving regularly with the 
 convex base; beaks small, approximate, incurved 
 over a small areola; width 1 inch; depth nearly 
 the same. M.L., p, Hawsker. 
 
 9. P. GLABRA, Ag., Tate. 
 
 Subquadrate or ovate, ventricose; anterior side 
 boldly convex; base slightly convex; beaks con- 
 tiguous, rounded ; concentrically ribbed on the upper 
 part, and with about seven obsolete ribs radiating 
 from the beak; conceritrick stria? numerous, fine. 
 Lowest beds of Lias at Redcar and R.H. Bay. 
 
 10. P. COSTATA, Simp. 
 
 Sub-rhomboidal, ovate ; beaks incurved, obtuse ; 
 areola very large, cordate, with two or three 
 obsolete ribs ; about nine oblique, diverging ribs on 
 the disc, separated by widish concave furrows ; 
 transverse striae coarse, irregular. M.L. 
 
 11. P. GALLINA, Simp. 
 
 Sub-rhomboidal or ovate, ventricose ; beaks con- 
 tiguous, incurved, pointed, small, oblique ; anterior 
 side very short ; areola very large, impressed, 
 cordate, divided by a prominent keel ; posterior 
 slope convex ; base convex ; length and breadth 
 about l inch. M.L., jt>, Hawsker. 
 
225 
 
 12. P. ROSTELLATA, Simp. 
 
 Transverse, ovate, very oblique ; beaks incurved, 
 pointed, very oblique ; anterior side short, oblique, 
 with a sharp process, or keel beneath the beaks ; 
 posterior side long, rounded ; . transverse striae 
 numerous, irregular ; width nearly equal to the 
 length. M.L. 
 
 With the exception of the process in the front, it 
 corresponds with Phillips' figure of P. obliquata. PL 
 xiii., f. 15., Yorks. 
 
 13. P. ROSTRATA, Simp. 
 
 Subquadrate ; beaks contiguous, small, incurved, 
 pointed, projecting over the front ; areola large, 
 cordate, keeled towards the base ; anterior side 
 truncate, nearly a right angle with the line of the 
 hinge ; base and posterior side rounded. M.L., s. 
 
 14. P. SCUTULATA. 
 
 Subtriangular ; anterior side truncate, forming 
 a large, flat, heart-shaped shield, with a keel 
 towards the base, and two or three coarse ribs 
 on the outer edge, with numerous, concentrick 
 striae ; beaks much elongated, incurved, with a 
 cutting edge, contiguous, with a concavity behind ; 
 posterior side circular, much compressed ; base 
 convex ; three or four coarse, muricated, trans- 
 versely striated ribs, diverging from the beaks ; 
 width one inch and five-eighths, depth one inch 
 and seven-eighths, breadth across the shield one 
 inch and three-eighths. L.L., R.H. Bay. 
 Q 
 
226 
 
 Longer than wide. 
 
 15, P. ELONGATA, Simp. 
 
 Ovate, ventricose ; beaks long 1 , contiguous ; 
 posterior side angular; indistinctly striated ; length 
 If inch, width l inch. L.L., R.H. Bay. 
 
 Another four inches long, and two inches wide, may 
 be the same. 
 
 16, P. TRUNCATA, Simp. 
 
 Ventricose, beaks long, contiguous ; anterior side 
 truncated ; areola large, cordate ; posterior side 
 short ; transverse stride numerous ; four longitu- 
 dinal ribs, diverging from the beaks ; length 3^- 
 inches, width 2^- inches. L.L., R.H. Bay. 
 
 Much resembling the last. 
 
 17, P. ANTIQUATA, Simp. 
 
 Triangular, oblique, ventricose ; anterior and 
 posterior sides flat ; longitudinally and transversely 
 striated ; length 3^ inches, width two inches. 
 
 This is by no means uncommon in the Lower Lias, at 
 Peak ; but the characters are generally much obliterated. 
 
 BRACHIOPODA. 
 
 Instead of a foot, two fleshy arms. 
 
 Genus Lingula. An oblong", nearly equivalved 
 compressed shell, resembling a little tongue. 
 
 1. LINGULA VENTJSTA, Simp. 
 
 Length twice the width, narrowest at the hinge, 
 ovate ; beak small, near the margin ; concentrick 
 lines of growth, or striae, numerous, faint ; length 
 three-tenths of an inch. 
 
227 
 
 This is an exceedingly neat, shining, little shell; 
 shewing only one valve on a piece of lias limestone. 
 Where a part of the shell has been removed,, the cast of 
 the interior is equally smooth and shining. ILL. 
 
 Since writing this description,, I have found them 
 rather plentiful in the shale , a little below the second 
 indurated band, ILL., but not so perfect. 
 
 2. L. SACCULUS, C. fy D., Tale. 
 
 Ovate, beak rather tumid, and pointed. 
 
 Mr. Tate compares this with L. Beanii, which occurs 
 in the inferior Oolite, immediately above the Lias. L. 
 Beanii, more pointed towards the apex, is ovate, oblong ; 
 shell thick, of a light blue colour. L. sacculus, subovate, 
 shell thin, and black-blue. A few specimens are recorded 
 from the uppermost beds of the Middle Lias. M.L., a. 
 
 Genus Terebratula. Valves unequal ; beak per- 
 forated. 
 
 1. TEREBRATULA PUNCTATA, Sow., pi. xiv. 
 
 Ovate, elongated, and acutely triangular at the 
 beaks, moderately gibbous, smooth, with a few 
 concentrick lines of growth near the base; base 
 rounded. 
 
 This has passed for T. ornithocephala ; but there is no 
 flattened or truncated part at the base, which distin- 
 guishes that shell ; neither has it the three diverging 
 lines at the beak, as in T. trilineata, Y. & B. M.L. 
 
 2. T. HISPIDULA, Simp. 
 
 Ovate, beaks wide; both valves flattened at the 
 base, and very slightly on one side ; the whole 
 covered with exceedingly numerous, fine, micro- 
 scopic points. L.L., ?/, R.H. Bay. 
 
 In general form, this comes very near to T. ornitho- 
 cephala ; but, when examined with a lens, it is found to 
 
228 
 
 be covered with exceedingly fine points, resembling the 
 skin of a shark. It occurs both in the Middle and Lower 
 Lias. The largest I have seen is about three-quarters of 
 an inch leng. Those from the Lower Lias are of a brassy 
 hue. The former has the base regularly rounded,, without 
 the flattening in the middle ; though both are covered 
 with the minute points. They may possibly be distinct 
 species. 
 
 3. T. RESUPINATA, Sow., pi. cl. T. Sf B., pi. xv., f. 12, 13. 
 Three sided, sharply pointed at both ends; length 
 
 greater than the width, the larger valve convex, 
 the other with a deep broad furrow ; concentrically 
 striated. 
 
 Common in the Eston ironstone mines. M.L., a. 
 
 Rhynconella. 
 
 4. T. TETRAHEDRA, Sow., pi. Ixxxiii. 
 
 Subglobular, four-sided; beak of the longer valve 
 pointed, incurved, a deep broad depression, or chan- 
 nel, in the middle of the valve, curved inwards at 
 the base, containing about four angular ribs, and 
 about four on either side; beak of the smaller valve 
 obtuse, incurved beneath the other, an elevation in 
 the middle corresponding to the depression in the 
 other valve, containing about four more sharp ribs 
 on either side. 
 
 These are exceedingly common, forming large masses 
 in the marly beds of the middle lias ; but they can seldom 
 be obtained with the shell on. They present great variety., 
 from the typical form with the deep central depression 
 in the larger valve, to those where it has almost been 
 obliterated, and the shell has become much depressed, 
 and regularly radiated over the whole surface. 
 
229 
 
 5. T. TRIPLICATA, Ph. Geo. Yorks. 
 
 Obscurely four-sided ; larger valve with a deep 
 middle depression, containing two sharp ribs, and 
 two or three more on each side ; the smaller valve 
 much inflated, with three sharp ribs in the middle, 
 and three more on each side. M.L., Hawsker. 
 
 It may possibly be a variety of T. tetrahedra. 
 
 6. T. LINEATA, T. 4- B. T.fr B., pi. xv., f. 21, 22, 23. 
 
 ' ' It differs from T. tetrahedra not only in being smaller 
 but in having only two elevated plaits at the base, and a 
 sunk line on the lesser valve, running from the beak to 
 the groove between these plaits/' Young. 
 
 7. T. BIDENS, Ph. 
 
 Triangular ; the larger valve with a deep concave 
 groove occupying the whole side, containing one 
 strong rib down the middle, bounded on either side 
 by a strait edge ; the smaller valve smooth and 
 inflated below the beak, two short elevated ribs or 
 teeth at the base, and two plicae on either side. 
 L.L., R. H. Bay. 
 
 8. T. ACUTA, Sow., pi. cli. 
 
 Subtriangular, length rather more than the width ; 
 larger valve with a deep smooth depression or 
 groove the whole length ; the other valve with one 
 large groove and two or three small ribs on either 
 side. M.L., Hawsker. 
 
 It differs chiefly from the last by having only one tooth 
 at the base. They are both sharply defined species, and 
 have no connection with any variety of T. tetrahedra. 
 
230 
 
 9. T. VARIABILIS, Sch., Tate. 
 
 Triangular, base convex, often depressed, with 
 from seven to nine coarse ribs on each valve; beak 
 very small, foramen circular. L.L., #, R. II. Bay. 
 
 10. T. MUNDULA, Simp. 
 
 Deltoid, regular, transverse ; beak of the larger 
 valve pointed, incurved, either side of which is 
 concave and excavated ; middle of valve with a 
 broad depression, containing five or six rounded ribs, 
 and five or six on either side ; the smaller valve 
 has about eighteen rounded ribs, and the middle is 
 but little elevated, and turns quickly over, so as to 
 make the rounded base appear truncated in the 
 middle. M.L., y, R, H. Bay. 
 
 Although this has a good deal the shape of some 
 varieties of T. tetrahedra, yet its neat form, its being 
 transverse, and more excavated on the sides of the beaks, 
 and from the smaller valve bending over in the middle 
 to meet the depression in the other ; and being also from 
 the lower lias, where, as far as I know, T. tetrahedra does 
 not occur, I consider it a distinct species. In the round- 
 ness of the ribs, it also appears to differ from T. media. 
 
 Another specimen has the middle depression in the 
 larger valve deeper. 
 
 Mr. Tate identifies it with T. plicatissima, and also 
 allies it with T. Juransis, but the examples he sent me of 
 T. plicatissima are depressed, ribs sharply angular, and 
 the excavations on the sides of the beaks are wanting. 
 
 11. T. CALCICOSTA, Quen., Tate. T. $ B., pi. xv., f. 10. 
 
 Mr. Tate associates this with the preceding species, 
 and describes it as " Triangular obovate, with an elevated 
 mesial fold carrying two or three plaits bordered on each 
 
231 
 
 side by two or three equally strong folds, all of which 
 proceed to the unibo. The beaks are large and erect j 
 and the foramen is elongated." 
 
 It is a coarse, rather irregular species, with coarse 
 lamellar plaits of growth towards the base. M.L., 
 Huntcliff, &c. 
 
 12. T. SUBCONCINNA, Ddv., Tate. T. fy B., pi. xv., f . 18. 
 Ovate, depressed beak broad, elongated; base 
 
 convex ; larger valve with about fourteen smooth 
 diverging ribs ; length four-tenths of an inch ; width 
 three-tenths of an inch. L.L., ?/, Huntcliff. 
 
 13. T. CAPITULATA, Tate. T. fy B., pi. xv., f. 24. 
 Subtri angular, or ovate ; larger valve with a deep 
 
 groove at the base, containing from three to five 
 plaits, with two or three on either side ; beak small ; 
 the other valve tumid, plaited. M.L., ironstone, 
 Eston. 
 
 It is a neat little shell. Mr. Tate gives the following 
 description of this new species. " Shell ovate-triangular, 
 slightly transverse, with an elevated angular mesial fold, 
 anterior third of the shell plaited ; two to four (usually 
 three) plaits in the mesial fold, and about five on each 
 lateral area ; the umbones gibbous. Beak thick, small, 
 suberect. The shell never attains any considerable size." 
 
 14. T. BIMOSA, Von Buch, Tate. 
 
 Obovate, three plaits in the centre and four or 
 five on either side ; beak flatted. L.L., y, Huntcliff. 
 
 15. T. FURCILLATA, Von Buck, Tate. 
 
 Ovate, angular towards the small beak, three 
 plaits in the centre at the base, five or six on each 
 side. L.L., y, Huntcliff. 
 
232 
 
 16. T. COMPRESSA, T. Sf B. T. FODINALIS, Tate. T. 4* B., 
 
 pi. xv., f. 16. 
 
 Ovate, rather transverse, depressed ; sides and 
 base regularly convex ; dorsal valve convex, the 
 wing-s moderately elevated ; the other valve convex, 
 tumid at the beak; beak small, incurved; both 
 valves covered with about twenty fine, equal ribs, 
 concentrically striated. M.L., ironstone. 
 
 This well-defined species corresponds with the descrip- 
 tion Young gives of his T. compressa. "The beaks 
 smooth, and the whole margin plaited, in an unbroken 
 series of twenty or twenty-two small plaits. The margin 
 rises at the base, not abruptly, as in T. tetrahedra, but 
 with a gentle undulation." Young's specimen was from 
 the Oolite. 
 
 17. T. BOUCHARDI, Davidson, Tate. 
 
 Mr. Tate describes it as having "" usually three plaits 
 on the depressed mesial fold, flanked on each side by ten, 
 which extend nearly to the umbonal region. The beaks 
 are small, acute and erect. Its numerous ribs and sub- 
 globose shape serve to distinguish it." 
 
 Genus Spirifer, Sow. Beaks imperforate. Two 
 spiral cones in the interior. 
 1. SPIRIFER WALCOTTI, Sow., pi. ccclxxvii. 
 
 Circular, rather tumid ; hinge-line about half the 
 width ; beaks prominent, approximate ; on the 
 smaller valve the middle fold about one-third the 
 width, prominent, four smaller obtuse ribs on either 
 side, a few longitudinal striae, concentrick striae, or 
 lines of growth, irregular ; on the larger valve, a 
 broad central furrow, five or six obtuse ribs on 
 either side, longitudinally striated; length 1-J- inches. 
 
233 
 
 2. S. ROSTRATUS, Sch., Tate. 
 
 Width seven-tenths of an inch, equal to the 
 length, with a deep, concave mesial depression ; no 
 ribs, beak much elongated, rather small, excavated 
 on either side. The larger valve only. L.L., 27. 
 
 3. S. LIASSICUS, Simp. 
 
 Tumid, more than a semicircle ; hinge-line less 
 than the width ; sinus concave ; beaks depressed, 
 rather distant ; a broad, nearly obsolete, fold on the 
 middle of the smaller valve, and a corresponding 
 wide concave furrow on the larger valve ; width 
 eight-tenths of an inch. L.L., R. H. Bay. 
 
 4. S. RECENTIOR, Simp. 
 
 Width twice the length, minutely rugose; hinge- 
 line nearly the whole width ; beaks much depressed, 
 distant ; sinus triangular, slightly concave, finely 
 striated ; on the smaller valve, thirteen strong ribs, 
 equal to the intervening concave spaces, the middle 
 one largest; in the middle of the larger valve, a 
 deep wide furrow, with seven strong ribs on either 
 side ; width nine-tenths of an inch. 
 
 On a portion of the sinus 'may be observed reticulated 
 striae ; the rest of the shell is roughened with minute 
 prominences, greatly resembling the skin of the shark. 
 L.L., R. H. Bay. 
 
 Mr. Tate makes these two last only varieties of S. 
 Walcotti, but, besides other characters, they have the 
 hinge-line much wider ; the beaks widely separated, 
 small, and depressed; the sinus, or area, large. S. 
 recentior is remarkable for its width. 
 
234 
 
 5. S. SIGNIENSIS, Bur. } Tate. T. fy B., pi. xv., f. 7. 
 Width one inch, length eight -tenths of an inch ; 
 
 base convex, medial depression deep, triangular, 
 with nine angular ribs on each side, imbricated by 
 plates of growth ; beak wide ; hinge-line nearly 
 the width of the shell. M.L., c. 
 
 6. S. OXYPTERUS, Bur., Tate, T. fr B., pi. xv., f. 8. 
 Width greater than the depth ; a deep furrow in 
 
 the middle of the larger valve, and five strong ribs 
 on each side ; on the other valve a strong central 
 lobe, with five ribs on each side ; beak not much 
 incurved. L.L., ?/, Huntcliff. 
 
 7. S. VERUCOSUS, Tate's MSS. 
 
 Width greater than the depth ; a deep central furrow 
 from the beak to the base, with five or six ribs on each 
 side ; a central lobe and ribs to correspond on the other 
 valve ; the whole rough with pointed granules. L.L., w, 
 B. H. Bay. 
 
 Genus Orbicula. 
 
 1. ORBICULA REFLEXA, Sow., pi. dvi. 
 
 Base ovate, height more than half the length, 
 apex a little out of the centre ; radii nearly obsolete ; 
 length half an inch. 
 
 This shell is of frequent occurence in the Upper Lias, 
 and often attached to other shells, especially to 
 Ammonites fimbricatus. It often happens that the lower 
 valve only remains, which has the appearance of a very 
 small oyster. 
 
 2. O. HOLDENI, Tate. 
 
 Apex central, concentrick ridges well marked. 
 L.L., Marske. 
 
235 
 
 ARTICULATA. 
 
 The Articulated Animals have been distributed 
 into four Classes. The Annelides, or Red-blooded 
 Worms. The Crustacea. The Arachnida, or Spiders* 
 The Insects. 
 
 ANNELIDES. 
 
 The Annelides, of which the common Earth Worm 
 is a familiar example, are composed of numerous- 
 rings united together. They are soft animals, and 
 almost all, with few exceptions, live in water, and 
 seek protection by burrowing in mud. All such 
 have perished without leaving any traces of their 
 existence. Others agglutinate grains of sand, and 
 other earthy matter, and form hard cases in which 
 they live. Of these we have many examples pre- 
 served in our strata. Some secrete a calcareous 
 substance, with which they form a sort of tubular 
 shell. Of these we have the remains of two 
 Genera in our strata, Serpula and Dentalium. 
 
 Genus Serpula, Linn. 
 
 These, in their living state, are amongst the most 
 beautiful objects in nature. The tubes, which they 
 form for their habitation, have not the regularity of 
 those of the Dentalium. They are often twisted 
 about stones and other hard substances ; and some 
 fabricate their tubes by agglutinating mud or any 
 other suitable substances. 
 
 The muddy state of the Upper Lias appears to 
 
236 
 
 have been very unfavourable to their existence, and 
 their remains are very rare. I have a thin plate of 
 Jet which has on it a number of short Serpulse. 
 
 Ditrypa. These approach closely to Dentalium. 
 
 1. SERPULA CAPITATA., Ph., T. $* B., pi. xi., f. 8. 
 Nearly straight, with irregular, rugose rings; 
 
 aperture irregular. L.L. 
 
 2. S. GLOBICEPS, Quen., Tate, T. fy B., pi. xii, f. 2. 
 Much curved, smooth, with well separated, rounded 
 
 rings; aperture circular. L.L., 27, Redcar. 
 
 3. S. CIRCINATA, Tate, T. fy B., pi. xiv., f. 11. 
 
 The smaller end convolute, ending in a straight 
 smooth tube; aperture circular. L.L., 15, R.H. Bay. 
 
 4. S. QUINQU-ESULCATA, Mun., Tate. 
 
 A semicircle, with an angular aperture. L.L., 
 R. H. Bay. 
 
 Serpula proper. 
 
 5. S. SOCIALIS, Gold, Tate. 
 
 Branched, smooth ; aperture circular. L.L., 27, 
 Redcar. 
 
 6. S. LIMAX, Gold, Tate. 
 
 Much curved; aperture angular. L.L., 27, Redcar. 
 
 7. S. LITUIFORMIS, Mun., Tate. 
 
 A wreath of four diminishing coils, partially cor- 
 rugated ; aperture circular ; diameter of coil two- 
 tenths of an inch, equal to the height. 
 
 8. S. DEFLEXA, Ph. Geo. Yorks., pi. xi., f. 26. 
 
 Many, varied, smooth convolutions. L.L., R. 
 H. Bay. 
 
237 
 
 Genus Dentalium, Linn. 
 
 These have a shell in the form of an elongated 
 cone, more or less bent, and open at both ends, and 
 may be compared to an elephant's tusk in miniature. 
 
 1. DENTALIUM GIGANTETJM, Ph., T. Sf B., pi. ix., f. 10. 
 Large, smooth, and moderately bent ; aperture 
 
 ovate ; length 3^ inches, diameter a quarter of an 
 inch. 
 
 It is very abundant in the lowest stratum (q) of the Iron- 
 stone series of the Middle Lias at Hawsker, Staithes, &c. 
 
 2. D. ETALENSE, T. &? P., Tate, T. $ B., pi. ix., f. 13. 
 Very slender, smooth, no striae, nearly straight; 
 
 aperture circular. 
 
 Mr. Tate has kindly sent me several examples of this 
 species from the lowest beds of Lias at Redcar. The 
 length of the largest is 1.2 inch, diameter .075 inch. 
 
 3. D. ARCUATUM. 
 
 Slender, smooth, bright, no striae, much curved, 
 especially towards the posterior end ; posterior part 
 finely attenuated; aperture circular, or obscurely 
 pentagonal ; length 11 inch, greatest diameter one- 
 eighth of an inch. 
 
 This agrees very much with the last, except in its great 
 curvature, and in being stronger. I found several on a 
 piece of shale, all much arcuated, but not equally so. L.L.., 
 s, north cheek of E. H. Bay. 
 
 4. D. ELONGATUM, Mun., Tate, T. <$f B., pi. ix., f . 28. 
 Long, slender, and nearly straight, with some 
 
 obsolete concentrick rings, or distant striae ; aperture 
 circular ; length 3^ inches, diameter one-eighth of 
 an inch. M.L., a, Hawsker. 
 
238 
 
 5. D, LIMATULUM, Tate, T. & B., pi. x., f. 18. 
 Slightly carved, with very fine, acute, transverse, 
 
 rather oblique ribs or elevated lines'; aperture ovate, 
 tapering to a fine point. Lowest beds of Lias, Kedcar. 
 
 6. D. LIASSICUM,, Moor, Tate. 
 
 " Cylindrical, longitudinally striated." ILL., 8. Tate. 
 
 CEUSTACEA. 
 
 No remains of short-tailed Crabs (Cancer} have 
 been discovered in the Yorkshire Lias. They all 
 belong to the long-tailed. (Astacus). They are 
 comparatively small, resembling the Prawns rather 
 than the Lobsters. Their remains are rare, and 
 very fragmentary ; and are chiefly found in the 
 uppermost beds of Lias. 
 
 1. ASTACTJS HARTMANI, Meyer. (Ergon). 
 
 This rare and interesting fossil was discovered by 
 J. W. Kershaw, Esq., F.G.S., in the second Indu- 
 rated band of the Upper Lias at Salt wick, along 
 with Lingula venusta. I have since torn up much 
 of this band in search of it, but without success. 
 Mr. Blake places it under the sub-genus Ergon, 
 which has the carapace very broad, and with very 
 deep lateral incisions. The carapace of this speci- 
 men, however, has not been preserved ; and Mr. 
 Blake seems to depend for specifick characters on 
 the caudal plates, which are broad, with a central 
 ridge ; and the edges are rounded. Claws narrow 
 and small. 
 
239 
 
 Some think it to be A. Barrowviensis. 
 
 2. A. WILLIAMSONI, Simp. 
 
 Carapace robust, roughened with numerous tuber- 
 cles ; rostrum long ; joints of the abdomen nearly 
 smooth ; first pair of legs very long, and strongly 
 tuberculated ; claws of the pincers slender. 
 
 Syn. A. rostratus, Simp. I find that under this name 
 I have described the joints of the abdomen as nearly 
 smooth^ whilst A. Williamsoni is described as having 
 seven rugose plates with smooth constrictions at the 
 joints, and the ridges at the front of the carapace less 
 elevated. Probably they are the same species. I think 
 the specimens were in Mr. Bean's collection, from the 
 Lower Lias at E-. H. Bay. . 
 
 3. A. L^SVIGATUS, Simp., Bean. 
 
 Carapace and abdomen smooth, slender. 
 
 Two claws (hands) in a separate nodule, probably of 
 this species, have the last joint inflated; a few distant 
 tubercles ; claws of the pincers rather wide at the base. 
 Upper Lias. 
 
 4. A. BANKSII, Simp., Bean. 
 
 Carapace broad, channelled with many wrinkles ; 
 tubercles numerous, small. 
 
 A robust species. L.L., E. H. Bay. Bean's col. 
 
 ENTOMOSTRAC.ZE. 
 
 Of these Mr. Blake has described seventeen species, 
 chiefly from the very lowest beds of Lias. They are 
 numerous and important as instruments of geological 
 research; but they are very tiny things, and for the 
 present we must leave them to the microscopist. 
 
 INSECTA. 
 
 The only remains of Insects discovered in our Lias 
 are a wing-case of a beetle, and two Neuropterous wings. 
 
240 
 
 RADIATA. 
 
 Genus Asterias. Star- Fish. 
 
 1. ASTERIAS MEDIA, Simp. A. CARINATA, Wright. Pal., 
 
 pi. ii, f. 1. 
 
 With five triangular rays, resembling* the common 
 A. rubens. Scarbro' Museum. 
 
 2. A. MURCHISONI, Williamson. A. POLYNEMIA, Simp. 
 With about twenty triangular pointed rays ; 
 
 diameter nine inches ; central disc one inch. 
 
 An impression upon a very frail marly substance, from 
 the Middle Lias. Scarbro' Museum, 
 
 3. A. HASTINGS, Forbes. M.L., Staithes. 
 
 4. A. OPHINUROIDES, Wright. Pal., pi. v., f. 1. 
 
 Ophiv.ra. Rays long and slender. Snake tail. 
 
 5. A. MILLERI, Ph. 
 
 Five strong, imbricated rays, with the scales in 
 three rows ; disc pentagonal. 
 
 Rather common, but seldom perfect, in the sandy beds 
 of the M.L. 
 
 6. A. GRACILIS, Simp. A. CARINATA, Wr. Pal., pi. xvi. f. 1. 
 Five slender rays ; disc round. 
 
 It very much resembles O. texurata, Lam. M.L., 
 Scarbro" Museum. 
 
 I have seen a great number on a slab of Lias, very 
 similar. 
 
 7. A. MURRAVII, Forbes. M.L., Staithes. 
 
 8. A. COLUMBA, Tate, T. & B., xvi., f. 1. 
 
 Pentacrinus. 
 1. PENTACRINUS CAPUT-MEDUS^E, Miller. 
 
 Joints of column strongly pentangular, with 
 
241 
 
 articulating surfaces pentapetalous, ovate, striated 
 markings. L.L., R. II. Bay. 
 
 Probably this is the same as P. tuber culatus. There is 
 in the Whitby Museum a fine slab of Pentacrinites with 
 very numerous delicate arms, but no stem. I suppose 
 they must have been the heads of this species. I procured 
 a smaller slab of the same for Mr. Bean, which is pro- 
 bably in the Bean collection in the British Museum. 
 They were from the Lower Lias at Eobin Hood's Bay. 
 
 2. P. BRIAREUS, Miller. 
 
 Joints of column, pentangular, alternately larger 
 and smaller ; pentapetalous, striated, articulating 
 surfaces nearly linear. U.L., Saltwick. 
 
 3. P. BASALTIFORMIS, Miller. 
 
 Column neat and slender ; joints of a uniform 
 size and thickness. L.L., R. H. Bay. 
 
 4. P. GRACILIS, Charlesworth. 
 
 Stem with a few small side branches ; head with 
 seven or more long branches, which at length 
 bifurcate. M.L., Staithes. 
 
 Echinus. Sea Hedgehog or Urchin. 
 
 1. ECHINUS ANTIQUUS, Simp. 
 
 In the Scarbro' Museum, there is a crushed portion of 
 an Echinus, with some of the spines attached, but broken. 
 The shell is covered with tubercles, and also strongly 
 mammillated, with a depressed circular channel for the 
 reception of the spines. The spines are smooth, have a 
 broad, thin base, and probably were pointed. M.L., 
 Skinningrove. 
 
 2. E. OBSOLETUS, Simp. 
 
 In the same Museum, there is a spine like the one 
 figured by Phillips, pi. xiii, f. 17. Base a truncated cone, 
 
 K 
 
242 
 
 toothed ; it then swells into a knob, and diminishes, then 
 the appearance of a joint ; all this occupies one quarter 
 the length ; the rest regularly tapers. 
 
 8. E. EDWARDSII, Wright. 
 
 CORALS. 
 
 THERE are very few Corals in the Yorkshire Lias, 
 and these are confined to the lowest beds. Mr. 
 Blake notices three species. 
 
 1. MONTLIVALTIA HAiMEi, C. <$f D., Blake. 
 Button-shaped, depressed, numerous muricated 
 
 rays proceeding from the central pit. Rays beneath 
 finely decussated by concentrick striae. 
 
 2. M. GUETTARDI, Slain, BlaTce. 
 
 Button -shaped, turreted, concentrick rings and 
 striae coarse, irregular. 
 
 8. M. POLYMORFHA, T. fy P., Blake. 
 1. SEPTASTRJEA EXCAVATA, Fr., Blake. 
 1. GALEOLANA SOCIALIS, Tate. 
 
 VEGETABLES. 
 
 WOOD is found plentifully in all the^beds of Lias, 
 but always in a fragmentary state ; lying in the 
 direction of the strata, and often bruised and 
 compressed. Some of it appears to be monocotyle- 
 donous ; but the greater part is dicotyledonous and 
 
243 
 
 coniferous ; and, when cut into thin slices, and fixed 
 on glass, its structure can be beautifully observed. 
 There can be no doubt that large quantities of 
 vegetable matter have been deposited in the Lias, 
 which have entirely perished. The only distinct 
 plant, which I have observed, is 
 
 1. ARAUCARITES PEREGRINUS, Lind. & Hut. 
 
 Pinnate ; pinnulae broad at the base, curving and 
 tapering upwards, accuminate, thickly set on the 
 rachis. 
 
 It is not uncommon in the upper part of the jet-rock, 
 at Saltwick. Syn. Pachyphyllum. 
 
 In various beds of the Lias, 4 and especially in a 
 bed in the Lower Lias, near Mill-beck, at Robin 
 Hood's Bay, may be observed, numerous branching, 
 cylindrical bodies, which we must consider as having 
 been Marine Plants. Their organic structure is 
 , clear enough, but we can determine nothing 
 respecting their species. 
 
 The casts of a long cylindrical Marine Plant, 
 abundant in the uppermost bed of the Middle Lias, 
 near Staithes, noticed by Young & Bird "as 
 bearing a striking resemblance to the stalks of the 
 common Tangle " has been named by Mr. Tate, 
 
 2. CHORDOPHYLLITES CICATRICOSUS, T. & B., pi. xiv., f. 9, 
 
244 
 
 MINERALS. 
 
 THE most important minerals which occur in the 
 Yorkshire Lias are Iron and Jet. 
 
 IKON enters largely into all the strata, but more 
 abundantly into the Middle and Upper portions of 
 the Lower Lias. It occurs generally in thin seams, 
 associated with organick remains, to which it appears 
 to have been attracted. The most important deposit 
 of iron is in the oyster beds at the top of the Middle 
 Lias, in Cleveland, where the ironstone beds amount 
 to from nine to seventeen feet in thickness, yielding 
 from thirty to thirty-two per cent, of metallick iron. 
 These beds soon become deteriorated, both to the 
 south and west, so as to be scarcely recognizable. 
 
 The other deposit of economick value is in the 
 Esk valley, near Whitby, and consists of two beds, 
 lower in the order of the strata than those of Cleve- 
 land. These beds also deteriorate, and thin out 
 both to the north and south. At Grosrnont, where 
 they are wrought, the upper beds are about three 
 feet in thickness, and the lower nearly the same ; 
 yielding about the same per cent, in iron as those 
 of Cleveland. 
 
 JET. 
 
 The stratum from which the hard or most valu- 
 able Jet is extracted, is a bed in the Upper Lias, 
 about twenty feet thick, called by way of eminence 
 the Jet Rock. It is about J40 or 150 feet from the 
 
245 
 
 top of the Lias formation, and about 50 feet above 
 the main bed of ironstone. Much good jet has 
 also been occasionally found in the shales above the 
 jet rock, and also in the bed beneath, and even in 
 the main bed of ironstone in the Middle Lias ; but 
 it is only .in the jet rock that the miner carries on 
 any systematick operations. This bed extends 
 from the sea cliffs to its western outcrop in the 
 the vale of Cleveland, and from Robin Hood's Bay 
 to the mouth of the Tees. 
 
 Jet lies parallel with the plane of the strata, in 
 flattened, detached masses of various form and 
 magnitude ; the larger are about ten or twelve feet 
 long, twelve or eighteen inches wide, and from 
 three inches to a mere film in thickness. One famous 
 mass was reported to be twenty feet long by six 
 feet wide, and in places three inches thick; but 
 masses approaching at all to such dimensions are 
 exceedingly rare. In extracting the jet from the 
 rock, it is generally broken into small pieces, but 
 occasionally some are obtained three or four feet 
 long by about a foot wide. 
 
 The best Whitby jet has a conchoidal fracture, 
 gives a brown streak, takes a beautiful deep, velvet- 
 black polish, is highly elect rick, rather lighter than 
 coal, its specifick gravity being 1.238 ; it is com- 
 bustible, and burns with a light greenish flame, and 
 strong bituminous odour. It varies much in hard- 
 ness and tenacity, some pieces being very brittle 
 
246 
 
 and difficult to work, while other pieces possess 
 much elasticity. 
 
 It has been very generally concluded that jet is 
 of ligneous origin, but this opinion is supported 
 neither by chemical analysis, nor microscopic inves- 
 tigation ; and, now that the material is better 
 known, the weight of evidence is decidedly against 
 it. It is not unlikely that vegetable matter may 
 have become jet, for we find wood, and the scales 
 of fishes, converted into something like it ; but it 
 is far more probable, that the best jet is an aggre- 
 gation of bituminous matter, which abounds in the 
 jet rock of the Lias. Mr. Louis Hunt on, of the 
 Lofthouse Alum Works, states in the Geological 
 " Transactions" for 1836, " that when a small heap 
 of this rock was calcined at the works, the melted 
 bitumen and sulphur flowed in flaming streams." 
 It is also well known that petroleum or mineral oil 
 frequently occurs in the cells of belemuites and 
 ammonites, and in cavities of nodules in the jet 
 rock, which at first is a greenish liquid, but when 
 exposed to the air soon hardens into a kind of pitch, 
 which burns with a crackling flame. 
 
 It is not improbable that the bitumen itself may 
 have had a vegetable origin, as coniferous wood 
 abounds in the Lias, and the leaves of Araucarites 
 are frequent in the strata above. 
 
247 
 
 INDEX. 
 
 Those marked thus * 
 
 indicate corrections made in 
 
 
 Page 
 
 VERTEBKATA 
 
 ... 5 
 
 Hybodus 
 
 REPTILES 
 
 ... 5 
 
 minor 
 reticulatus 
 
 Ichthyosaurus . . . 
 acutirostris ... 
 crassimanus ... 
 intermedius . . . 
 
 ... 11 
 ... 12 
 ... 12 
 ... 13 
 
 Lepidotus 
 pectinatus ... 
 semiserratus 
 
 longirostris ... 
 platyodon . . . 
 tenuirostris ... 
 
 ... 13 
 ... 12 
 ... 13 
 
 rugosus 
 Leptolepis 
 Saltviciensis 
 Notidamus 
 
 Plesiosaurus . . . 
 
 ... 8 
 
 amalthei 
 
 brachycephalus 
 cselospondylus 
 Cramptoni . . . 
 
 ... 10 
 ... 9 
 ... 9 
 
 Pachycormus . . . 
 acutirostris 
 curtus 
 
 grandipennis 
 homolospondylus 
 
 ... 9 
 ... 9 
 
 gracilis 
 latirostris ... 
 
 propinquus . . . 
 
 ... 10 
 
 latus 
 
 rostratus 
 
 ... 10 
 i n 
 
 macropterus 
 
 rugosus 
 Zetland! 
 Teleosaurus 
 brevior ... 
 Chapmanni ... 
 
 ... 10 
 ... 10 
 ... 5 
 
 ... 7 
 ... 6 
 
 Ptycholepis . . . 
 Bollensis . . . 
 Sauricthys 
 apicalis 
 Tetragonolepis 
 
 FISHES 
 
 ... 13 
 
 ovalis 
 
 Acrodus 
 
 ... 14 
 
 
 minimus 
 
 ... 14 
 
 MOLLUSC A... 
 
 nobilis 
 
 ... 14 
 
 CEPHALOPODA 
 
 Aspidorhyncus 
 
 ... 16 
 
 Ammonites . . . 
 
 anglicus 
 
 ... 16 
 
 aculeatus . . . 
 
 Belonostomus 
 
 ... 16 
 
 acuticarinatus 
 
 acutus 
 
 ... 16 
 
 asqualis 
 
 Dapedius 
 
 ... 15 
 
 alienus 
 
 micans 
 
 ... 15 
 
 alternatus ... 
 
 Eugnathus 
 
 ... 15 
 
 Andrese 
 
 fasciculatus 
 
 ... 15 
 
 Andersoni ... 
 
 Gyrolepis 
 
 ... 15 
 
 anguiformis 
 
 Alberti 
 
 ... 15 
 
 angulatus ... 
 
 Gyrosteus 
 
 ... 17 
 
 annulatus . . . 
 
 mirabilis 
 
 ... 17 
 
 annuliferus 
 
 Page 
 
 .. 14 
 
 ,. 14 
 
 .. 14 
 
 .. 14 
 
 .. 14 
 
 .. 14 
 
 .. 15 
 ... 16 
 
 .. 16 
 
 .. 14 
 
 .. 14 
 
 .. 16 
 
 .. 16 
 
 .. 16 
 
 .. 16 
 
 .. 16 
 
 .. 16 
 
 .. 16 
 
 .. 15 
 
 .. 15 
 
 .. 15 
 
 .. 15 
 
 .. 15 
 
 .. 15 
 
 .. 17 
 
 .. 17 
 
 .. 61 
 
 .. 99 
 
 .. 133 
 
 .. 80 
 
 .. 122 
 
 .. 123 
 
 .. 91 
 
 .. 90 
 
 .. 70 
 
 .. 84 
 
 .. 81 
 81 
 
248 
 
 Ammonites 
 
 _ -"^j-' 
 
 Ammonites 
 
 ,~ 
 
 antiquatus ... 
 
 ... 64 
 
 decussatus . . . 
 
 ... 95 
 
 arcigerens ... 
 
 ... 77 
 
 def ossus 
 
 ... 78 
 
 arctus 
 
 ... 66 
 
 dejectus 
 
 ... 122 
 
 armatus 
 
 ... 97 
 
 delicatus . . . 
 
 ... 86 
 
 sirmiger 
 
 ... 100 
 
 Dennyi 
 
 ... 86 
 
 athleticus . . . 
 
 ... 82 
 
 denotatus . . . 
 
 ... Ill 
 
 attemiatus . . . 
 
 ... 85 
 
 depressus . . . 
 
 ... 118 
 
 aureolus 
 
 ... 134 
 
 diversus 
 
 ... 75 
 
 aureus 
 
 ... 74 
 
 Easingtonensis 
 
 ... 63 
 
 Beanii 
 
 ... 113 
 
 elaboratus ... 
 
 ... 128 
 
 Bechii 
 
 ... 104 
 
 elegans 
 
 ... 106 
 
 Belcheri 
 
 ... 72 
 
 elegantulus 
 
 ... 107 
 
 bif rons 
 
 ... 140 
 
 erratus 
 
 ... 65 
 
 Birchii 
 
 ... 102 
 
 erugatus 
 
 ... 71 
 
 Birdi 
 
 ... 131 
 
 exaratus 
 
 ... 107 
 
 bispicatus . . . 
 
 ... 105 
 
 exasciatus ... 
 
 ... 129 
 
 bisulcatus ... 
 
 ... 138 
 
 exortus 
 
 ... 73 
 
 Boulbiensis 
 
 ... 109 
 
 f abalis 
 
 ... 113 
 
 brevispina ... 
 
 ... 103 
 
 fabricatus ... 
 
 ... 65 
 
 Brooki 
 
 ... 138 
 
 f asciatus 
 
 ... 70 
 
 Bucki 
 
 ... 121 
 
 ferrugineus 
 
 ... 114 
 
 Bucklandi ... 
 
 ... 138 
 
 fibulatus 
 
 ... 90 
 
 oapricornus 
 
 ... 78 
 
 figulinus 
 
 ... 78 
 
 cereus 
 
 .. 77 
 
 fiinbriatus ... 
 
 ... 68 
 
 Charmassei... 
 
 ... 80 
 
 flavus 
 
 ... 123 
 
 Clevelandicus 
 
 ... 118 
 
 fonticulus ... 
 
 ... 89 
 
 communis ... 
 
 ... 82 
 
 f oveatus 
 
 ... 89 
 
 compactilis... 
 
 ... 110 
 
 gagateus . . . 
 
 ... 75 
 
 complanatus ? 
 
 ... 115 
 
 geonietricus 
 
 ... 127 
 
 conjunctivus 
 
 ... 114 
 
 gracilis 
 
 ... 85 
 
 convolutus ... 
 
 ... 73 
 
 Hamiltoni ... 
 
 ... 100 
 
 Conybeari ... 
 
 ... 136 
 
 hastatus 
 
 ... 98 
 
 cornucopia . . . 
 
 ... 69 
 
 Hawskerensis 
 
 ... 130 
 
 crassescens... 
 
 ... 87 
 
 Henleyi 
 
 ... 105 
 
 crassibundus 
 
 ... 87 
 
 heterogenes 
 
 ... 104 
 
 crassifactus 
 
 ... 87 
 
 heterophyllus 
 
 ... 62 
 
 crassiusculosus 
 
 ... 88 
 
 Hildensis . . . 
 
 ... 140 
 
 crassiusculus 
 
 ... 88 
 
 Huntoni 
 
 ... 119 
 
 crassoides . . . 
 
 ... 86 
 
 ignofrus 
 
 ... 94 
 
 crassulosus . . . 
 
 ... 86 
 
 illatus 
 
 ... 67 
 
 crassulus . . . 
 
 ... 86 
 
 impendens . . . 
 
 ... 136 
 
 crassus 
 
 ... 86 
 
 incrassatus... 
 
 ... 86 
 
 crenularis ... 
 
 ... 80 
 
 involutus . . . 
 
 ... 67 
 
 Crosbeyi . . . 
 
 ... 90 
 
 integricostatus 
 
 ... 76 
 
Ammonites 
 
 Jamesoni ... 
 
 Johnstoni ... 
 
 jurensis 
 
 Sabratus 
 
 latescens . . . 
 
 lectus 
 
 lens ... 
 
 lenticularis 
 
 leptophyllus 
 
 Levisoni 
 
 limatus 
 
 loscombei . . . 
 
 luridus 
 
 Lythensis ... 
 
 Macdonnelli 
 
 maculatus ... 
 
 mammillatus 
 
 margaritatus 
 
 Marshallani 
 
 miles 
 
 Mulgravius 
 
 multanfractus 
 
 multicostatus 
 
 multifoliatus 
 
 mutatus 
 
 nanus 
 
 nativus 
 
 neglectus ... 
 
 nitescens . . . 
 
 iiitidus 
 
 nodulosus . . . 
 
 obliquatus ... 
 
 obtusus 
 
 obsoletus . . . 
 
 omissus 
 
 ovatulus 
 
 ovatus 
 
 Owensis 
 - peregrinus . . . 
 
 personatus . . . 
 
 petricosus ... 
 
 Phillipsii ... 
 
 pinguis 
 
 planicostatus 
 
 249 
 
 
 Page 
 
 
 Page 
 
 
 Ammonites 
 
 
 79 
 
 .. 72 
 
 polyphyllus 
 puteolus 
 
 . 117 
 ... 90 
 
 .. 68 
 
 quadricornutus 
 
 ... 106 
 
 .. 63 
 
 radiatus 
 
 ... 126 
 
 .. 140 
 
 Redearensis 
 
 ... 141 
 
 .. 110 
 
 regularis . . . 
 
 ... 127 
 
 .. 116 
 
 resupinatus 
 
 ... 73 
 
 .. 114 
 
 retentus 
 
 ... 120 
 
 .. 116 
 
 reticularis ... 
 
 ... 114 
 
 .. 140 
 
 retusus 
 
 ... 94 
 
 .. 123 
 
 Ripleyi 
 
 ... 74 
 
 .. 64 
 
 Kobinsoni ... 
 
 ... 120 
 
 .. 76 
 
 rotiformis ... 
 
 ... 132 
 
 .. 109 
 
 rudis 
 
 ... 124 
 
 .. 125 
 
 rugatulus . . . 
 
 ... 108 
 
 .. 79 
 
 rutilans 
 
 ... 72 
 
 .. 101 
 
 Sagittarius . . . 
 
 ... 73 
 
 .. 117 
 
 sauzeanus ... 
 
 ... 139 
 
 .. 94 
 
 Scoresbyi . . . 
 
 ... 103 
 
 .. 97 
 
 semiarmatus 
 
 ... 92 
 
 .. 108 
 
 semicelatus 
 
 ... 81 
 
 .. 134 
 
 senricostatus 
 
 ... 133 
 
 .. 131 
 
 similis 
 
 ... 109 
 
 .. 108 
 
 simplex 
 
 ... 120 
 
 ... 96 
 
 Simpsoni . . . 
 
 ... 115 
 
 ... 66 
 
 sinuatus 
 
 ... 94 
 
 ... 101 
 
 siphuncularis 
 
 ... 126 
 
 .. 76 
 
 socialis 
 
 ... 67 
 
 .. 125 
 
 solitaries . . . 
 
 ... 133 
 
 .. 70 
 
 spicatus 
 
 ... 98 
 
 .. 138 
 
 spinatus 
 
 ... 127 
 
 ..112 stellaris ... 
 
 ... 137 
 
 .. 132 striatulus ... 
 
 ... 124 
 
 .. 91 
 
 subarmatus 
 
 ... 92 
 
 .. 77 
 
 subcarinatus 
 
 ... 65 
 
 .. 112 
 
 subconcavus 
 
 ... Ill 
 
 .. 112 
 
 subnodosus... 
 
 ... 129 
 
 .. 96 
 
 subtriangularis 
 
 ... 99 
 
 ... 64 
 
 sulcatus 
 
 ... 142 
 
 .. 65 
 
 tardecrescens 
 
 ... 136 
 
 .. 102 
 
 Taylori 
 
 ... 105 
 
 .. 113 
 
 tenellus 
 
 ... 137 
 
 .. 141 
 
 tenuicostatus 
 
 ... 69 
 
 .. 75 
 
 temiispina ... 
 
 ... 103 
 
250 
 
 Ammonites 
 
 .rage 
 
 Belemnites 
 
 rage 
 
 transformatus 
 
 ... 130 
 
 dorsalis 
 
 ... 34 
 
 trivialis 
 
 ... 73 
 
 elegans 
 
 ... 47 
 
 tubellus 
 
 ... 71 
 
 erosus 
 
 ... 27 
 
 Turner! 
 
 ... 135 
 
 exiguus 
 
 ... 34 
 
 turriculatus 
 
 ... 91 
 
 expansus 
 
 ... 35 
 
 validanfractus 
 
 ... 135 
 
 f erreus 
 
 ... 43 
 
 validus 
 
 ... 95 
 
 fusteolus ... 
 
 ... 54 
 
 vermis 
 
 ... 82 
 
 glaber 
 
 ... 28 
 
 vetustus 
 
 ... 125 
 
 grandee vus... 
 
 ... 44 
 
 vitreus 
 
 ... 76 
 
 inaequalis . . . 
 
 ... 43 
 
 vittatus 
 
 ... 119 
 
 insequistriatus 
 
 ... 27 
 
 volutus 
 
 ... 123 
 
 incisus 
 
 ... 30 
 
 vorticellus ... 
 
 ... 93 
 
 inclusus 
 
 ... 27 
 
 vortex 
 
 ... 92 
 
 infundibulus 
 
 ... 51 
 
 Belemnites . . . 
 
 ... 21 
 
 laevigatus . . . 
 
 ... 44 
 
 acuminatus 
 
 ... 37 
 
 lentus 
 
 ... 34 
 
 acus... 
 
 ... 48 
 
 leptos 
 
 ... 44 
 
 acutus 
 
 ... 51 
 
 levidensis . . . 
 
 ... 41 
 
 alveolatus ... 
 
 ... 55 
 
 limatulus . . . 
 
 ... 28 
 
 aptus 
 
 ... 36 
 
 levis... 
 
 ... 35 
 
 araris 
 
 ... 50 
 
 longiconus ... 
 
 ... 45 
 
 arenaceous . . . 
 
 ... 45 
 
 longiformis 
 
 ... 46 
 
 athleticus ... 
 
 ... 38 
 
 *microstylus 
 
 ... 54 
 
 attenuatus . . . 
 
 ... 47 
 
 Milleri 
 
 ... 55 
 
 bituminosus 
 
 ... 31 
 
 Mulgravius 
 
 ... 31 
 
 calcar 
 
 ... 53 
 
 oblongus . . . 
 
 ... 48 
 
 carinatus . . . 
 
 ... 42 
 
 obtusus 
 
 ... 40 
 
 charmouthensis 
 
 ... 55 
 
 optatus 
 
 ... 29 
 
 cinereus 
 
 ... 33 
 
 palliatus 
 
 ... 52 
 
 clavatus 
 
 ... 54 
 
 perforatus ... 
 
 ... 49 
 
 compressus... 
 
 ... 26 
 
 pessulus 
 
 ... 46 
 
 concavus ... 
 
 ... 29 
 
 *pinguis 
 
 ... 36 
 
 conicus 
 
 ... 52 
 
 planulatus . . . 
 
 ... 44 
 
 curtus 
 
 ... 39 
 
 politus 
 
 ... 39 
 
 *cuspidatus ... 
 
 ... 50 
 
 pollex 
 
 ... 40 
 
 cylindricus... 
 
 ... 37 
 
 procusus 
 
 ... 55 
 
 dactylus 
 
 ... 42 
 
 pyramiformis 
 
 ... 49 
 
 delicatus . . . 
 
 ... 50 
 
 repandus . . . 
 
 ... 35 
 
 dens 
 
 ... 52 
 
 retusus 
 
 ... 45 
 
 densus 
 
 ... 32 
 
 robustus 
 
 ... 40 
 
 demissus . . . 
 
 ... 46 
 
 rostratus . . . 
 
 ... 36 
 
 depressus . . . 
 
 ... 51 
 
 rudis 
 
 ... 43 
 
 digitus 
 
 ... 42 
 
 scabrosus ... 
 
 ... 53 
 
 distortus ... 
 
 ... 30 
 
 scollops 
 
 ... 48 
 
251 
 
 
 Page 
 
 Page 
 
 Beleninites 
 
 
 Nerita 
 
 ... 158 
 
 Spadix- Ari . . . 
 
 ... 53 
 
 alternans ... 
 
 ... 158 
 
 spicatus 
 
 ... 33 
 
 Natica 
 
 ... 158 
 
 substriatus... 
 
 ... 32 
 
 buccinoides 
 
 ... 158 
 
 sub tenuis . . . 
 
 ... 33 
 
 fusca 
 
 ... 159 
 
 telum 
 
 ... 32 
 
 neglecta 
 
 ... 159 
 
 tenuis 
 
 ... 34 
 
 purpuroides 
 
 ... 159 
 
 teres 
 trisulculosus 
 trivialis 
 
 ... 44 
 ... 30 
 ... 34 
 
 Tornatella 
 chrysalis . . . 
 f raff ilis 
 
 ... 159 
 ... 160 
 ... 160 
 
 truneulus . . . 
 
 ... 49 
 
 ilminsterensis 
 
 ... 160 
 
 tubularis . . . 
 turris 
 urbanus 
 
 ... 26 
 ... 49 
 ... 39 
 
 marginata ... 
 pulla 
 *sinemuriensis 
 
 ... 159 
 ... 160 
 ... 160 
 
 validus 
 
 ... 41 
 
 
 
 vulgaris 
 
 ... 38 
 
 Trochus 
 
 ... 143 
 
 Woolleri ... 
 
 ... 37 
 
 Anglicus ... 
 
 ... 144 
 
 Nautilus 
 
 ... 56 
 
 aratus 
 
 ... 148 
 
 annularis . . . 
 
 ... 59 
 
 basilicus 
 
 ... 146 
 
 araris 
 
 ... 60 
 
 bellulus 
 
 ... 149 
 
 astacoides . . . 
 
 ... 58 
 
 concavus . . . 
 
 ... 146 
 
 heterogenus 
 
 ... 60 
 
 consobrinus 
 
 ... 147 
 
 Youngi 
 
 ... 59 
 18 
 
 expansus . . . 
 *foveatus 
 
 ... 147 
 ... 145 
 
 cuspidata . . . 
 haustrum . . . 
 incomposita 
 obtusalis 
 Trigonolites ... 
 Whitbyensis 
 
 '.'.'. 19 
 ... 19 
 ... 20 
 ... 18 
 ... 20 
 ... 20 
 
 Helicina 
 helicinoides 
 Hennocqui . . . 
 *liassinus 
 *nucleus 
 obesulus 
 oppeli 
 
 ... 147 
 ... 145 
 ... 147 
 ... 148 
 ... 148 
 ... 147 
 ... 148 
 
 GASTEROPODA 
 
 ... 143 
 
 Pleurotomaria 
 procerus 
 
 ... 144 
 ... 145 
 
 Buccinum 
 nitidum 
 
 ... 161 
 
 ... 161 
 
 pusillus 
 Redcarensis 
 
 ... 145 
 ... 144 
 
 Cerithium 
 
 ... 161 
 
 Eobigus 
 
 .. 144 
 
 acriculum . . . 
 
 ... 162 
 
 *rotelliformis . 
 
 ... 148 
 
 armatum . . . 
 
 ... 162 
 
 rusticus 
 
 ... 146 
 
 aureum 
 
 ... 161 
 
 semiclausus 
 
 ... 149 
 
 gratum 
 
 ... 162 
 
 solarioides ... 
 
 ... 148 
 
 liassicum . . . 
 
 ... 162 
 
 Solarium ... 
 
 ... 148 
 
 quadrilineatuin 
 
 ... 162 
 
 striatus 
 
 ... 148 
 
 semele 
 
 ... 162 
 
 tectarius . . . 
 
 ... 146 
 
 spiratum . . . 
 
 ... 162 
 
 Thetis 
 
 ... 144 
 
 Slatteri 
 
 ... 161 
 
 undosus 
 
 ... 146 
 
252 
 
 
 Page 
 
 
 Page 
 
 Turbo 
 
 ... 149 
 
 Turbo 
 
 
 *aculus 
 
 ... 157 
 
 undulatus ... 
 
 ... 153 
 
 aciculus 
 
 ... 151 
 
 unicingulatus 
 
 ... 153 
 
 acuxninatus 
 
 ... 152 
 
 Wilsoni 
 
 ... 150 
 
 adductus . . . 
 
 ... 153 
 
 Youngi 
 
 ... 156 
 
 aureus 
 
 .,. 155 
 
 Zenkeni 
 
 ... 155 
 
 Berthaudi ... 
 Blainvillei . . . 
 
 ... 157 
 ... 156 
 
 ACEPHALA 
 
 ... 163 
 
 carucensis ... 
 
 ... 157 
 
 Anomia 
 
 ... 177 
 
 Chapuisi 
 
 ... 152 
 
 alpina . . 
 
 ... 177 
 
 citharella . . . 
 
 ... 157 
 
 ferruginea ... 
 
 ... 177 
 
 cingendus ... 
 
 ... 154 
 
 numismalis 
 
 ... 177 
 
 Clevelandicus 
 
 ... 154 
 
 Placuna 
 
 ... 177 
 
 Collenoti . . . 
 
 ... 15s 
 
 striatula 
 
 ... 177 
 
 concinnus . . . 
 
 ... 153 
 
 Area ... 
 
 ... 185 
 
 conspersus ... 
 
 ... 154 
 
 Buckmani ... 
 
 ... 187 
 
 cyclostoma . . . 
 
 ... 150 
 
 *Clevelandica 
 
 ... 186 
 
 def ossus 
 
 .. 155 
 
 complanata 
 
 ... 190 
 
 *Dunkeri 
 
 ... 155 
 
 cordata 
 
 ... 188 
 
 elegans 
 
 ... 151 
 
 Cucullcea 
 
 ... 185 
 
 f erreus 
 
 ... 156 
 
 cuspidata . . . 
 
 ... 187 
 
 foveolatus ... 
 
 ... 158 
 
 cymbula 
 
 ... 189 
 
 Guadryanus 
 
 ... 153 
 
 dura ... 
 
 ... 190 
 
 imbricatus... 
 
 . . 152 
 
 expansa 
 
 ... 186 
 
 latilabrus . . . 
 
 ... 149 
 
 Heberti 
 
 ... 189 
 
 lineatus 
 
 ... 150 
 
 hetangiensis 
 
 ... 187 
 
 Littorina ... 
 
 ... 151 
 
 incrassata ... 
 
 ... 185 
 
 Morencyanus 
 
 ... 155 
 
 intermedia . . . 
 
 ... 185 
 
 nanus 
 
 ... 151 
 
 liassina 
 
 ... 187 
 
 Nireus 
 
 ... 154 
 
 longicaudata 
 
 ... 190 
 
 nuda 
 
 ... 157 
 
 Leda 
 
 ... 188 
 
 Phasianella 
 
 ... 155 
 
 minor 
 
 ... 189 
 
 Philemon . . . 
 
 ... 151 
 
 navicula 
 
 ... 188 
 
 regularis . . . 
 
 ... 155 
 
 navis 
 
 ... 188 
 
 reticulatus . . . 
 
 ... 150 
 
 obtusalis . . . 
 
 ... 186 
 
 rugosus 
 
 ... 153 
 
 ovum 
 
 ... 188 
 
 selectus 
 
 ... 152 
 
 pulchella . . . 
 
 ... 186 
 
 semitectus ... 
 
 ... 158 
 
 pulla 
 
 ... 186 
 
 solarium 
 
 ... 149 
 
 Eenevierei . . . 
 
 ... 191 
 
 solidulus . . . 
 
 
 subovalis . . . 
 
 ... 192 
 
 sordidus 
 
 "'. 151 
 
 telliseformis 
 
 ... 192 
 
 tenuis 
 
 ... 151 
 
 tenuistriata 
 
 ... 191 
 
 transversus . . . 
 
 ... 157 
 
 texturata ... 
 
 ... 191 
 
 turbinatus ... 
 
 ... 150 
 
 v-scripta 
 
 ... 191 
 
 Turritella . . . 
 
 ... 155 Zieteni 
 
 ... 189 
 
253 
 
 
 Page 
 
 Page 
 
 Avicula 
 
 ... 180 
 
 Hippopodium 
 
 .., 198 
 
 Bronni 
 
 ... 184 
 
 ponderosum 
 
 ... 198 
 
 calva 
 
 ... 183 
 
 gigas 
 
 ... 198 
 
 contorta 
 
 ... 184 
 
 Inoceramus 
 
 ... 179 
 
 crescens 
 
 ... 182 
 
 Isocardia 
 
 ... 198 
 
 cygnipes . . . 
 
 ... 181 
 
 bombax 
 
 ... 200 
 
 echinata 
 
 ... 183 
 
 cuculata 
 
 ... 200 
 
 minima 
 
 ... 183 
 
 Cypricardia 
 
 ... 200 
 
 nitescens . . . 
 
 ... 182 
 
 gibbosa 
 
 ... 200 
 
 Pattersoni ... 
 
 ... 183 
 
 laevis 
 
 ... 198 
 
 papyria 
 
 ... 184 
 
 nitida 
 
 ... 199 
 
 Eoseburiensis 
 
 ... 181 
 
 petricosa 
 
 ... 199 
 
 *substriata . . . 
 
 ... 182 
 
 regularis . . . 
 
 ... 200 
 
 *tuniidula 
 
 ... 182 
 
 securii'ormis 
 
 ... 200 
 
 Cardinia 
 
 ... 200 
 
 sublsevis 
 
 .,. 199 
 
 antiqua 
 
 ... 201 
 
 Lima ... 
 
 ... 173 
 
 attenuata . . . 
 
 ... 203 
 
 acuticosta ... 
 
 ... 176 
 
 costata 
 
 ... 201 
 
 Blakeana . . . 
 
 ... 176 
 
 concinna . . . 
 
 ... 202 
 
 Eucharis ... 
 
 ... 175 
 
 crassissima... 
 
 ... 203 
 
 excavata 
 
 ... 176 
 
 crassiuscula 
 
 ... 202 
 
 gigantea ... 
 
 ... 175 
 
 delicata 
 
 ... 201 
 
 Hermanni ... 
 
 ... 173 
 
 Deshaysesi . . . 
 
 ... 203 
 
 hettangensis 
 
 ... 175 
 
 Desoudini ... 
 
 ... 203 
 
 irregularis ... 
 
 ... 173 
 
 Listeri 
 
 ... 201 
 
 Juliana 
 
 ... 177 
 
 inembranacea 
 
 ... 202 
 
 Limcea 
 
 ... 176 
 
 ovalis 
 
 ... 203 
 
 multicostata 
 
 ... 174 
 
 Cardium 
 
 ... 203 
 
 novemcostata 
 
 ... 174 
 
 bituminosum 
 
 ... 204 
 
 pectinoides... 
 
 ... 174 
 
 globosum . . . 
 
 ... 205 
 
 pectinoidea 
 
 ... 174 
 
 Heberti ... 
 
 ... 204 
 
 punctata . . . 
 
 ... 175 
 
 multicostatuin 
 
 ... 204 
 
 succincta ... - 
 
 ... 174 
 
 Philippianuni 
 
 ... 204 
 
 Terquemi . . . 
 
 ... 175 
 
 sub str iatulum 
 
 ... 205 
 
 Mya ... 
 
 ... 219 
 
 triangulare 
 
 ... 205 
 
 sequilateralis 
 
 ... 219 
 
 truncatum ... 
 
 ... 204 
 
 antiqua 
 
 ... 219 
 
 Chamacea 
 
 ... 198 
 
 concinna 
 
 ... 220 
 
 Corbis ... 
 
 ... 205 
 
 elongata 
 
 ... 220 
 
 unif ormis , . . 
 
 ... 205 
 
 hispida 
 
 ... 220 
 
 Corbula 
 
 ... 208 
 
 literata - ... 
 
 ... 220 
 
 sequivalvis . . . 
 
 ... 209 ' 
 
 longa 
 
 ... 221 
 
 cardioides ... 
 
 ... 208 
 
 Myacites 
 
 ... 210 
 
 deltoidea . . . 
 
 ... 209 
 
 sequalis 
 
 ... 216 
 
 subglobosa . . . 
 
 ... 209 
 
 bituminosa 
 
 ... 211 
 
 Crenatula 
 
 ... 179 
 
 concava 
 
 ... 216 
 
254 
 
 Myacites 
 concinna 
 contracta . . . 
 
 Page 
 ... 217 
 ... 217 
 
 Mytilus 
 pygmseus ... 
 rusticus 
 
 Page 
 ... 195 
 ... 197 
 
 costata 
 crassa 
 crowcombeia 
 
 ... 210 
 ... 216 
 ... 212 
 
 scalprum . . . 
 siliqua 
 similis 
 
 ... 194 
 ... 194 
 ... 197 
 
 donaciformis 
 
 ... 213 
 
 subcancellatu s 
 
 ... 195 
 
 dubia 
 
 ... 211 
 
 Thiollierei ... 
 
 ... 196 
 
 Dunkeri 
 
 ... 218 
 
 Ostrea ... 
 
 ... 164 
 
 elegans 
 ferruginea ... 
 galathea . . . 
 gibbosa 
 granata 
 intermedia . . . 
 
 ... 219 
 ... 214 
 ... 217 
 ... 218 
 ... 212 
 ... 214 
 
 arcuata 
 concinna 
 depressa 
 Gryphcea 
 inilata 
 laeviuscula .... 
 
 ... 166 
 ... 164 
 ... 167 
 ... 166 
 ... 164 
 ... 165 
 
 levis 
 liassina 
 
 ... 215 
 
 ... 216 
 
 laganiformis 
 liassica 
 
 ... 166 
 ... 165 
 
 lunulata 
 
 ... 217 
 
 Macullochi . . 
 
 ... 167 
 
 maculata . . . 
 
 ... 215 
 
 orbicularis . . . 
 
 ... 167 
 
 mediseva 
 
 ... 213 
 
 patellaeformis 
 
 ... 164 
 
 mundula ... 
 
 ... 217 
 
 Saltviciensis 
 
 ... 164 
 
 ovata 
 punctata ... 
 rotundata . . . 
 
 ... 216 
 ... 213 
 ... 214 
 
 serniplicata... 
 sportella 
 subauricularis 
 
 ... 165 
 ... 165 
 ... 165 
 
 Sanguinolaria 
 scabrosa 
 
 ... 219 
 ... 212 
 
 submargaritacea 
 tumidulosa... 
 
 ... 165 
 ... 164 
 
 sublevis 
 subtriangularis 
 subtruncata 
 
 ... 218 
 ... 211 
 ... 215 
 
 ungula 
 Pecten 
 aheneus 
 
 ... 164 
 ... 167 
 ... 169 
 
 ventricosa ... 
 
 ... 218 
 
 calvus 
 
 ... 172 
 
 vetusta 
 
 ... 219 
 
 def ossus 
 
 170 
 
 Mytilus 
 aviothensis... 
 
 ... 193 
 
 ... 194 
 
 dichotomus 
 discif orinis . . . 
 
 ... 169 
 ... 172 
 
 *bifasciatus . . . 
 
 ... 196 
 
 Hinnites 
 
 ... 173 
 
 cuneatus . . . 
 
 ... 193 
 
 interstinctus 
 
 ... 169 
 
 curvatus 
 ensis 
 
 ... 194 
 ... 194 
 
 lohberigensis 
 lunularis . . . 
 
 ... 171 
 ... 171 
 
 Hillanus 
 
 ... 196 
 
 major 
 
 ... 168 
 
 Hillanoides 
 
 ... 196 
 
 multicostatus 
 
 ... 170 
 
 hippocampus 
 Ifievis 
 *minimus 
 Modiolus 
 Myoconcha ... 
 numismalis 
 *psilonoti 
 
 ... 197 
 ... 195 
 ... 196 
 ... 194 
 ... 197 
 ... 196 
 ... 197 
 
 papyraceus... 
 planus 
 pollux 
 pulchellus ... 
 pumillus ... 
 punctatus . . . 
 punctatissimus 
 
 ... 173 
 ... 172 
 ... 171 
 ... 171 
 ... 172 
 ... 171 
 ... 170 
 
255 
 
 
 Page 
 
 Page 
 
 Pecten 
 
 
 Spondylus 
 
 ... 178 
 
 reticularis ... 
 
 ... 171 
 
 calvus 
 
 ... 178 
 
 rudis 
 
 ... 169 
 
 intus-striatus 
 
 ... 178 
 
 sublaevis ... 
 
 ... 168 
 
 liassinus 
 
 ... 178 
 
 substriatus... 
 
 ... 172 
 
 Plicatula 
 
 ... 178 
 
 textilis 
 
 ... 171 
 
 spinosus 
 
 ... 178 
 
 textorius . . . 
 
 ... 170 
 
 Tellina 
 
 ... 205 
 
 *Thioellieri ... 
 
 ... 170 
 
 apicistria . . . 
 
 ... 208 
 
 turnidus 
 
 ... 173 
 
 bioliensis . . . 
 
 ... 208 
 
 Perna ... 
 
 ... 178 
 
 cardinoides 
 
 ... 206 
 
 serosa 
 
 ... 180 
 
 cycliformis... 
 
 ... 206 
 
 cincta 
 
 ... 180 
 
 dionvillensis 
 
 ... 207 
 
 Crenatula ... 
 
 ... 179 
 
 fabalis 
 
 ... 205 
 
 dubia 
 
 ... 179 
 
 glabra 
 
 ... 206 
 
 Gervillia 
 
 ... 180 
 
 grociana 
 
 ... 206 
 
 Hagenovii ... 
 
 ... 180 
 
 longicostata 
 
 ... 207 
 
 infraliassica 
 
 ... 178 
 
 lucida 
 
 ... 208 
 
 Inoceramus . . . 
 
 ... 179 
 
 o vata 
 
 . , 207 
 
 pinnaeformis 
 
 ... 180 
 
 pumila 
 
 ... 206 
 
 *quadrata . . . 
 
 ... 178 
 
 striata 
 
 ... 206 
 
 Simpson! . . . 
 
 ... 179 
 
 *subglobosa . . . 
 
 ... 206 
 
 substriata ... 
 
 ... 180 
 
 Tancredia . . . 
 
 ... 207- 
 
 ventricosa ... 
 
 ... 179 
 
 tenuis 
 
 ... 206 
 
 Pinna 
 
 ... 184 
 
 Trigonia 
 
 ... 192 
 
 folium 
 
 ... 1S4 
 
 lingonensis 
 
 ... 193 
 
 Hartmanni... 
 
 ... 184 
 
 literata 
 
 ... 192 
 
 spathulata ... 
 
 ... 184 
 
 modesta 
 
 ... 193 
 
 Pholadomya ... 
 
 ... 221 
 
 Venus ... 
 
 ... 208 
 
 ambigua 
 
 ... 221 
 
 cingulata ... 
 
 ... 208 
 
 antiquata . . . 
 
 ... 226 
 
 obsoleta 
 
 ... 208 
 
 concinna 
 
 ... 221 
 
 Oppeli 
 
 ... 208 
 
 costata 
 
 ... 224 
 
 rugata 
 
 ... 208 
 
 decorata 
 
 ... 222 
 
 striato-sulcata 
 
 ... 208 
 
 elongata 
 
 ... 226 
 
 BRACHIOPODA 
 
 ... 226 
 
 gallina 
 
 ... 224 
 
 Lingula 
 
 ... 226 
 
 glabra 
 
 ... 224 
 
 sacculus 
 
 ... 227 
 
 Isevis 
 
 ... 223 
 
 venusta 
 
 ... 226 
 
 lunata 
 
 ... 223 
 
 Orblcula 
 
 ... 234 
 
 obtusalis . . . 
 
 ... 224 
 
 Holdeni 
 
 ... 234 
 
 recurva 
 
 ... 221 
 
 renexa 
 
 ... 234 
 
 rostellata . . . 
 
 ... 225 
 
 Spirif er 
 
 ... 232 
 
 rostrata 
 
 ... 225 
 
 liassicus 
 
 ... 233 
 
 scutulata . . . 
 
 ... 225 
 
 oxypterus ... 
 
 ... 234 
 
 Simpson! . . . 
 
 ... 222 
 
 recentior . . , 
 
 ... 233 
 
 truncata 
 
 ... 226 
 
 rostratus ... 
 
 ... 233 
 
256 
 
 Spirifer 
 
 Page 
 
 
 Page 
 
 signiensis . . . 
 
 ... 234 
 
 Astacus 
 
 ... 238 
 
 verucosus . . . 
 
 ... 234 
 
 Banksii 
 
 ... 239 
 
 Walcotti ... 
 
 ... 232 
 
 Hartmani . . . 
 
 ... 238 
 
 Terebratula . . . 
 
 ... 227 
 
 Isevigatus ... 
 
 ... 239 
 
 acuta 
 
 ... 229 
 
 Williamson! 
 
 ... 232 
 
 bidens 
 
 ... 229 
 
 INSECTA 
 
 ... 239 
 
 Bouchard! ... 
 
 ... 232 
 
 
 
 calcicosta . . . 
 
 ... 230 
 
 EADIATA ... 
 
 ... 240 
 
 capitulata ... 
 
 ... 231 
 
 Asterias 
 
 ... 240 
 
 compressa ... 
 
 ... 232 
 
 Columba . . . 
 
 ... 240 
 
 f urcillata . . . 
 
 ... 231 
 
 gracilis 
 
 ... 240 
 
 hispidula . . . 
 
 ... 227 
 
 Hastingise ... 
 
 ... 240 
 
 lineata 
 
 ... 229 
 
 media 
 
 ... 240 
 
 inundula 
 
 ... 230 
 
 Milleri 
 
 ... 240 
 
 plicatissima 
 
 ... 230 
 
 Murchisoni 
 
 ... 240 
 
 punctata 
 
 ... 227 
 
 Murravii 
 
 ... 240 
 
 resupinata . . . 
 
 ... 228 
 
 Ophiura 
 
 ... 240 
 
 Rhynconella 
 
 ... 228 
 
 *Ophiuroides 
 
 ... 240 
 
 rimosa 
 
 :.. 231 
 
 rubens 
 
 ... 240 
 
 subconcinna 
 
 ..: 231 
 
 Pentacrinus . . 
 
 ... 240 
 
 tetrahedra . . . 
 
 ... 228 
 
 basaltiformis 
 
 ... 241 
 
 triplicata . . . 
 
 ... 229 
 
 briareus 
 
 ... 241 
 
 variabilis . . . 
 
 ... 230 
 
 caput-medusae 
 
 ... 240 
 
 
 
 gracilis 
 
 ... 241 
 
 ARTICULATA 
 
 ... 235 
 
 Echinus 
 
 ... 241 
 
 ANNELIDES ... 
 
 ... 235 
 
 antiquus 
 
 ... 241 
 
 Dentalium 
 
 ... 237 
 
 Edwardsii ... 
 
 ... 242 
 
 arcuatum . . . 
 
 ... 237 
 
 obsoletus . . . 
 
 ... 241 
 
 elongatum ... 
 
 ... 237 
 
 CORALS 
 
 ... 242 
 
 etalense 
 
 ... 237 
 
 Galeolana 
 
 ... 242 
 
 giganteuni . . . 
 
 ... 237 
 
 socialis 
 
 ... 242 
 
 liassicuin . . . 
 
 ... 238 
 
 Montlivaltia 
 
 ... 242 
 
 limatulurn ... 
 
 ... 238 
 
 Guettardi ... 
 
 ... 242 
 
 Serpula 
 
 ... 235 
 
 Haimei 
 
 ... 242 
 
 capitata 
 
 ... 236 
 
 polymorpha 
 
 ... 242 
 
 circinata . . . 
 
 ... 236 
 
 Septastrsea 
 
 ... 242 
 
 *deplexa 
 
 ... 236 
 
 excavata 
 
 ... 242 
 
 globiceps . . . 
 
 ... 236 
 
 PLANTS 
 
 ... 243 
 
 limax 
 lituif ormis . . . 
 quinquesulcata 
 socialis 
 
 ... 236 
 ... 236 
 ... 236 
 ... 236 
 
 Araucarites . . . 
 peregrinus . . . 
 Chordophyllites 
 cicatricosus 
 
 ... 243 
 ... 243 
 ... 243 
 ... 243 
 
 CRUSTACEA ... 
 
 ... 238 
 
 MINERALS ... 
 
 ... 244 
 
 FORTH AND SON, PRINTERS. WHITBY. 
 
A ! 
 
 -114 
 
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