B E R K E L E Y I f -. r> * -^ v/ EARTH SCIENCES LIBRARY SUCCINCT ACCOUNT LIME ROCKS OF PLYMOUTH, BEING THE SUBSTANCE OF SEVERAL COMMUNICATIONS, READ BEFORE THE MEMBERS OF THE GEOLOGI- CAL SOCIETY, IN LONDON, AND PARTLY PRINTED IN THEIR TRANSACTIONS. WITH TEN LITHOGRAPHIC PLATES, OF SOME OF THE MOST REMARKABLE OF THE ANIMAL REMAINS FOUND IN THEM. BY THE REV. RICHARD HENNAH, Chaplain to the Garrison q/ Plymouth. PRINTED FOR \V. CURTIS, PLYMOUTH, AND G. AND W. B. WH1TTAKER, LONDON, BY R. BO.Yfl, PLYMOUTH. 1822. 5 v n R. BOND, PRINTER, J4, WHTMPLE STREET, PLYMOUTH. (3.7 WHEN a Book is sent into the world, of whatever sort it may be, or however trivial, it is usual to solicit a favourable reception for it, from those, for whose perusal it is intended. To the common mo- tives for such an appeal, I feel, that I have many additional reasons to induce me to request this in- dulgence from the Public, in behalf of the following pages. For, professing myself but little acquainted with Geology, as a study, and remote from those sources from whence such knowledge might be ob- tained, I have ventured on the subject ; having been invited, as it were, by the circumstances around me : at a time when there are no books of established authority, and sufficiently explanatory, within my reach, to assist me in giving names to, or, in classing the numerous varieties of Organic Remains, which I have collected in this neighbourhood. In stating, however, that I have had access to no books, I must except "Parkinson's Organic Remains of a M3589O4 IV former World/' very kindly lent me by Mr. Wool- combe, of Hemerdon. Under these disadvantages, I am conscious that I may have been guilty, although unintentional \y, of some inaccuracies ; but, when the difficulties, always attendant upon the entrance into a new field of en- quiry are considered ; and when, I, say, that it has been my anxious care to avoid speaking positively, as to any fact which I did not believe to be true, I hope to be forgiven. With regard to the accuracy of the several draw- ings, from which the accompanying plates to this little volume have been taken, I can speak with confidence, as they were made immediately under my own eye, from specimens in my possession. And, as to the plates themselves, they are sufficiently correct for every purpose for which they were de- signedthat of giving a just idea of those Animal Remains, which they are intended to represent. Be it remembered also, that it is requested, that they may not be regarded as Copper-Plate Engravings, but rather such as they really are, fair examples of Li* thographic Printing; an art which is at present only in its infancy. To some of the subjects, that were sufficiently ob- vious, I have ventured to affix names, while to others, which appeared to be new, and whose cha- racteristic marks were doubtful, or undefined, I have given none; leaving it rather to those, who by their knowledge and experience, are better able to supply the deficiency. Having been disappointed in the appearance of No. 10, when the plates arrived from the Printer, in London, I had determined on withdrawing it, and on giving No. 11 in its stead: but, as the subject was an interesting one, I considered it best, on second thoughts, to retain it, although not equal to my expectations. With this remark, that in the present stage of the new art of printing from stone, there will be sometimes a failure in the working off, without any deficiency in the artist ; and which, in the present instance, as far as regards Mr. Wors- ley, who resides at Plymouth, was far from being the case. S? B. Copies Boringdon, Lord Viscount Bayly, H. M. Esq. Hooe Heavy Bedford, Vice Admiral Bewes, Thomas, Esq Birdwood, Rev. Christopher Blackall, Captain Blackburn, Peter, Esq Borlase, Samuel, Esq Boyles, Mrs. Horndean Boyles, Rev. Charles G Brooking, Rear Admiral Butter, John, M. D. F.R.S. F.L.S. M.W.S. &c i B. W i C. Calmady, Mrs. Langdon Hall . . . . i Cleather, George, Esq i Collyer, John, Esq i Collins, Rev. C. T., Ham i Coryton, J. Tillie, Esq. Pentillie Castle i Coryton, Mrs i CoryndoD, George, Esq i Culme, Miss, Tothill i Curtis, Mr I D. De Dunstanville, Rt. Hon. Lord . . u Davis, B. G. Esq. London . . . i Copies. Dunning, R. Esq i Dunsterville, B. Esq. For the First Reading Society, Plymouth . . . . i E. Elford, Sir William, Bart. F.L.S. F.R.S. i F. Fanshawe, Mrs. Stonehall i Foot, Rev. i Fownes, I. Y. Esq. . . i Frazer, Alexander, Esq i Freeman, Richard, Esq i Fuge, Samuel, Esq i G. Gilbert, Davies, Esq. M.P. M.A. F.R.S. M.A.S j Gilbert, Mr ! Gill, Thomas, Esq i H. Halliday, Rev. Evan i Hammick, Stephen, Esq. . . . . . . i Harvey, Mr. Member of the London As- tronomical Society i Haviland, Mr i Hawker, John, Esq i Hawker, Captain, R.N i Hennah, Henry, Esq. London i Copies. Hotchkys, Charles, Esq. Prospect House i Hughes, Rev. Dr. St. Paul's i J. Jago, Edward, Esq i K. Knighton, Sir William, Bart i Knighton, Lady . . . . ] Knighton, Mr. W. W i L. Lampen, Rev. Robert ] Lockyer, Edmund, Esq i Lowe, John, Esq i Lucas, John, Esq. Torquay Luscombe, John L. Esq Luxmore, Jonathan, Esq M. Mount Edgecumbe, Rt. Hon. Earl of i Mangles, Mrs. Mutley Meade, T. Esq. Chatley Lodge, Bath i Morshead, Colonel, R.E. Widey House i O. Osborn, Mrs. Harant P. Pack, Rt. Hon. Lady Elizabeth . . . . Prideaux, Mr. John Petherick, Mr. William R. Rashleigh, Charles, Esq. Duporth .. Rodd, Francis H. Esq. Trebartha Hall Rosdew, Richard, Esq. Beechwood . . Ross, David, Esq. F.G.C. Copies. Ridgeway Reading Society . , . . i S. Seymour, Sir Michael Bart. K.C.B. . , i Seymour, Lady * Sconce, R. C. Esq I Scully, Dr. Totnes i Smith, Hervey, Esq. B. Major . . . . i Spicer, Miss i Stackhouse, Rev. William i Stokes, Charles, Esq. F.A. & L.S. &c. i T. Tonkin, Peter, Esq i Tremayne, Rev. Henry H. Heligan i Tremayne, John H. Esq. M.P i W. Warburton, Henry, Esq. F.R.S. & F.G.S H Wavel, Dr. Herwood House i Wetherell, Mrs. Newnton Longville, Bucks i Whidbey, Joseph, Esq. F.R.S. FLS. & F.A.S n White, Samuel, Esq. Gaskin-Street.. i White, Counsellor, Exeter i Wills, R. Esq i Wolf, Captain, R.N. . . i Woollcombe, George, Esq. Hemerdon i Woollcombe, Dr, i Woollcombe, Henry, Esq i Y. Yonge, Rev. Duke, Cornwood .. . . i Yonge, Rev, John, Puslinch i UiY PART I. CHAPTER 1 Page Introduction . . % 1 CHAPTER 2. Whctli er th e Li in estone of Ply m o uth con ta ined a ny Animal Remains or not ? and its relative position and extent . 6 CHAPTER 3. Its Colour, and Compactness * . 11 CHAPTER 4. Magnesia in the Limestone ...,.,... 14 CHAPTER 5. Quart: with the Limestone 16 CHAPTER 6. No Metallic Veins . . 18 PART II. VRGANIC REMAINS OF MARINE ANIMALS. CHAPTER 1, The Dock-Yard ............ 20 CHAPTER 2. Western side of Mount Wise, $c 23 CHAPTER 3. Page Ordnance Quarries and Devil's Point 25 CHAPTER 4. Stonehouse Hill .27 CHAPTER 5. Mill-Bay Quarry, near the Iron Foundry . . . .30 CHAPTER 6. The Rocks between Sandy-Cove and Mill-Bay ... 32 CHAPTER 7. East Hoe, under the Citadel 33 CHAPTER 8 Teates Hill and Queen Anne's Battery 34 CHAPTER 9. * Dead Mans Bay Cat-Down Quarries, and Prince Rock . . 36 CHAPTER 10. Concluding Observations on the foregoing Chapters . 38 PART III. PETRIFACTIONS AND CRYSTALIZATIONS. CHAPTER 1. Stalagmites 45 CHAPTER 2. Stalactites 47 CHAPTER 3. Dendritic Productions 49 CHAPTER 4. Crjfstalizations of Calcareous Spar 50 Miscellaneous Remarks 56 Conclusion 68 Description of the Plates A DESCRIPTION OF THE PLATES. PLATE I. FIG. 1. A branched Corallite, and other Organic Re- mains. Broken from the surface of one of the rocks at Sandy-Cove, near Mill-Bay. 2. An Anomia. Detached, and taken from the rock on the western side of Mount Wise. 3. A Terebratula. From the same place. PLATE II. The head of one of the varieties of the Encrinite, connected with its stem. Taken from the rocks at Queen Anne's Battery. PLATE III. FIG. 1. A considerable portion, consisting of about ten connected joints, of the stem of an Encri- nite. From Sandy-Cove. 2. An imperfect head of an Encrinite, partially exhibiting its interior appearance. From San- dy-Cove. 11 3 & 4. Two heads, apparently of the same species of Encrinite, but more perfect. From the same place as the former. N.B. Imperfect portions of the heads, and separate joints of the stems, of these curious Animal Remains, are in abundance, both at the place above-mentioned, and in other parts of our Lime Rocks. Yet any thing like a perfect one is very rarely to be met with ; and the head and stem connected together still more so. PLATE IV. The largest, longest, and most perfect vertebral co- lumn of the Encrinus, that I have ever seen in the Plymouth Limestone ; with the ends of several others appearing in the same spe- cimen. This was taken from the rocks near the Devil's Point. PLATE V. FIG. 1. The cast of a very large Univalve Shell. From the western end of Stone house Hill. 2 & 3. Univalve Shells, to all appearance Turbos. From the same place. 4. A very perfect Bivalve Shell, in the stone. Taken from the rocks at the western end of Mount Wise. m PLATE VI. Fro. 1. A specimen from the Quarry at the eastern end of Stonehouse Hi]], polished : SQ cut as to shew transversely and longitudinally the interior parts of one of the Madrepores which it contains. 2. A Bivalve Shell, in the stone, from Mount Wise. 3. Another Shell. From the same place. 4. Two Bivalve Shells, which seem to be Ano- mias. From Mount Wise. PLATE VII. A characteristic specimen of the Plymouth Limestone ; heing a mass of Madrepores, and Animal Re- mains, brought out to view by the action of the weather. From Sandy-Cove. PLATE VIII. FIG. 1. A specimen which has much the appearance of the Madrepora Flexuosa of Parkinson. From Teate's Hill, 2. Apparently, an Alcyonite, completely detach- ed ; and showing its gradual increase by the workings of the Polype. 3. An Orthoceratite. From Mount Wise. N.B. I have, I believe, in my possession, several fragments of others, but none so per- fect as the one figured in this Plate. tv PLATE IX. Two specimens, consisting of Trochites, Entrochites, and Shells, in a red calcareous sand stone. From Mount Wise. Also, several articulating surfaces of various Encrinal vertebrae. Found at different places. PLATE X. This appears to be a perfect flower, or head of an Encrinite. The stems are lying- in every di- rection, and running throughout the stone. The head and stems are of pure white, and form a striking contrast to the matter in which they are embedded, the colour of which is blood-red, and of a close texture. From the Devil's Point. PLATE XI. 1. Is a correct representation of a rare but sa- tisfactory specimen of the Euomphalus, found at the south-west end of Stonehouse Hill. 2 & 3. Give the transverse and longitudinal sections of what appears to be an Entrochite, which is white, while the stone itself is of a dark colour, and very compact. 4. Is another side of the same stone, on which there is a cast of a shell.^-From Mount Wise. PART I. CHAPTER 1 INTRODUCTION. IN the present state of Geological knowledge, when every fact, connected with and tending to elucidate the subject, is of importance, and, at a time when an ardent and laudable thirst for enquiry into this de- partment of Natural History so universally prevails, I venture to hope, that the following pages, giving some account of the Calcareous Rocks of Plymouth, and their contents, will meet with a favourable recep- (2) tion from all those, who are fond of this particular study; and that they will also be not entirely unin- teresting to the Public at large, particularly when I declare, that they contain no statements but such as have been founded on my own knowledge and ob- servation, and that the principal motive which has induced me to offer them to general notice, is, to invite attention to a small, but rich field for investi- gation ; a field hitherto but little regarded, or at most but cursorily examined. Among the vast number of strangers, independent of its own inhabitants, and those of its more immediate neighbourhood, who visit Plymouth during the sum- mer months, for the sake of seeing the many interest- ing objects which it affords, particularly that national and stupendous work the Breakwater in our Sound, very few perhaps have the least conception, that the immense masses of stone of which it is composed, and the quarries from whence they have been taken, as well as the whole stratum or bed of limestone, ex- tending from those quarries westward as far as the Tamar, contain, besides many beautiful and well de- fined crystallizations, various organic remains of animals, (3) which lived in ages that have long since passed away. Yet such is the undoubted fact; and, to be informed of this circumstance, I flatter myself, will not lessen that pleasure which they might otherwise receive from an excursion to this part of our Island. Without some such information, many of the most curious phcenomena in nature might remain con- cealed ; and various hidden, but highly interesting circumstances, would often escape the observation of the generality of travellers: nay, it requires diligence and acuteness, even in the experienced and most in- quisitive, sometimes to discover them, and to satisfy the mind of their actual existence. Nor is it by a hasty view alone, during a short visit of a few days, but by frequent and repeated examinations, that the peculiar features of any district can be satisfactorily traced or explained. I am well aware that some highly respectable cha- racters, men more competent to the task, have already given occasional and unconnected remarks on the Plymouth Limestone ; but the result of these remarks, whether from want of time and opportunity, or per- (4) haps from some other cause, has been of a nature ra- ther to excite than to gratify curiosity in those desirous of information on the subject. At least this was the effect produced in my own mind, and tended very powerfully to prevail on me to commence a strict and minute examination of our Rocks at different points, from the Plym to the Tamar, and which I have now continued, at different intervals, for a con- siderable time, whenever the professional duties of a laborious situation afforded me leisure for that purpose. The success that has already attended my labours, and which has more than answered my expectations, will be evident from the number of Lithographic Plates of animal remains accompanying this little volume ; which have been taken from drawings of specimens, selected from a considerable number, col- lected by myself, and found in situ. Much more, however, remains yet to be done ; and I am not without a hope, that some other individuals, more experienced, and whose time and inclination will allow of it, may be induced, by seeing how far I have gone, to engage in the same pursuit, so that by united endeavours, an Account of the Limestone of (5) Plymouth, and its contents, of a much more perfect and satisfactory nature than the present brief sketch can pretend to be, may, at no very distant period, be accomplished and made public. At present I shall confine myself to that part of this neighbourhood, situated between the estuaries of the rivers Plym and Tamar, which is occupied by the lime ; and shall enter upon this, my subject, without further delay : for my views do not extend to the consideration of the widely differing and very opposite theories of the Earth, which divide modern geologists, with regard to its present external ap- pearance, and internal structure; and neither of which theories alone can explain, satisfactorily, the various phcenomena in the mineral kingdom. (6) CHAPTER 2, Whether the Limestone of Plymouth contained any ani- mal remains? and its relative position and extent. WHETHER the Limestone of Plymouth contained any animal remains, was a question, which, until a recent period, was by a very few only admitted, and then with considerable reservation ; and I had been a resident in the neighbourhood for some time, before I turned my thoughts at all to the subject. But, hearing it often mentioned among my friends and acquaintances, I was insensibly led to explore our quarries, with a view to determine a point, over which there yet seemed to hang so much doubt. The result has been, that I am now enabled to affirm, from actual observation, that unquestionable (7) proofs of the presence of these interesting relics in our Limestone are abundant; and, it appears wonderful, that they should have remained so long unnoticed, or, at least without drawing more attention. I cannot therefore better fulfil the design of this brief sketch, than by describing, in the first place, the leading features, the characteristic marks and properties of our Limestone, as they occur, in the following order. For this purpose, I shall begin with its Relative Position and Extent. The Plymouth bed of Limestone may be regularly traced, on the South side, in an uninterrupted line, forming, as it were, a barrier against the encroach- ments of the sea, from the Passage-house at Cat- Down to the Devil's Point leading into Hamoaze ;* and, on the North side, I may mention the following points, as being sufficiently exact for every purpose I have in view. Commencing then from the house at the Flying-Bridge, it may be traced westward over * I omit mentioning Mount Batten, Hooe Lake, and Oreston, where the lime extends, as being the other side of the water, and not coming within the limits I have prescribed for my present consideration. (8) Cat-Down to the Breakwater Inn, in Cat-Do wn-lane, and Fareham-place, and from thence to near the Pottery at Coxside, and into Sutton Pool: still pro- ceeding West, it is found again on the opposite side of the water, near Foxhole Quay, running near Cat- Street, and the North side of the Parade, and then it turns a little South, and appears about the entrance into Mill-Bay-lane, when it keeps its course westward, nearly in the direction of that lane, until it arrives at Mill Prison ; afterwards it may be traced, in an irregular line, towards the north-west from the Mill Prison to the Turnpike-gate at the eastern end of Union-street, Stonehouse ; then it takes a westward direction, and runs nearly parallel with that street on the South side to Stonehouse Bridge. On ascending from the bottom of the hill, at the western end of Stonehouse Bridge, towards Dock, it is visible on both sides of the road, at least over a great part of it ; but, at the top of the hill, it is lost on the North side, and is only visible on the South side. From hence it makes a short turn towards the south-west, passing near the southern corners of George's Square, and may be seen, according to circumstances, taking a direction still westward, by Pembroke-Street, which is situated between the eminence where the New Town Hall is built, and iMount Wise; it then enters the Dock- Yard, and sinks into the sea somewhere near, if not in, the Mast-pond* at its southern ex- tremity. f i : It rests on clayslate, alternating with it, at the place of junction, in a remarkably distinct .manner; tables of Limestone, of a few inches in thickness, and many feet in length, appearing- in considerable numbers, as may be seen at the western landing- place of the Flying Bridge, as well as in other situations. It has an elevation of about one hun- dred feet* above high water mark, and runs in a direction nearly East and West ; or, to speak per- haps, with greater accuracy, it varies a little to the north-west and south-east, with an inclination or dip towards the South or south-west. In breadth it does not appear anywhere to exceed, if it approaches to, the extent of half a mile ; but, in length it extends to many miles. Sinking into the sea, at the ex- * This is the height of the Hoe, by actual measurement, which is sufficiently central to give a competent idea of the adjoining eminences, either to the East or to the West. (10) tremity of the Dock-Yard, and at the Devil's Point, it appears again, although only for a short space, below Mount Edgecumbe, and at the back of the Passage-house at Cremill Ferry ; after which I do not apprehend, that it is anywhere visible, farther West, in this neighbourhood, except in small patches or detached rocks. From the quarries at Oreston, however, it may be traced in a direct line, and with little interruption, eastward, as far as Petty Tor, in Babicomb Bay, where it finally disappears, and is lost in the sea. (11) CHAPTER 3 Colour and Compactness. THE colour of the Plymouth Limestone varies con- siderably, although the prevailing one is a light blue or grey, changing at times into a much darker shade, or nearly black ; these again are frequently inter- mixed and marbled with an infinite variety of red and other colours: this, joined to its being capable of receiving a very high polish, from its hard and close-grained nature, renders it of some consequence to the Stone-cutter, and the Public, for slabs and chimney-pieces, many of which require only to be seen to be much and deservedly admired. (12) For a proof, and satisfactory illustration of this remark, I would only refer the reader to almost all the foot-pavements in the three towns of Plymouth, Plymouth-Dock, and Stonehouse, which are com- posed of blocks taken from our quarries ; and he will find, after a shower of rain, while the stones are wet, most striking specimens of marble, curiously marked with veins of different colours, and beautifully shaded : not unfrequently, too, full of animal remains of various kinds. Amongst others, however, I cannot refrain from mentioning here, one example of our marble, of a very singular appearance, which is to be found not far from the Devil's Point. It seems to be composed principally, of the stems of the Encririite, of a colour almost pure white, embedded in a blood-red matrix. This variety is of a character, and assumes an appear- ance, when polished, so widely different from, all the other productions of our rocks, that an eminent Natu- ralist, some few years ago, after having examined a piece, which was in my posession, entertained con- siderable doubts as to its being the produce of this neighbourhood ; in consequence of which, he visited (13) the rocks near the Devil's Point, for the purpose of ascertaining the fact; and having been unsuccess- ful in his researches, he went so far as to deny its existence there, and endeavoured to account for its presence, by supposing, that it had been brought from a distant quarter, by some ship, as ballast. But, I afterwards discovered its actual situation in the rock, to be nearly about the place, where I apprehended it was to be found ; that is to say, about two hundred yards to the East of the Devil's Point, on the South side. (14) CHAPTER 4. Magnesia in the Liyiestont. WITH regard to Magnesia, the Limestone of Ply- mouth, generally speaking, contains this substance ; but in an extremely variable quantity. Although not professing myself a chymist, or pretending to great accuracy, yet I have been enabled to submit certain portions of the rock to the test ; so as to ascertain the fact, and to produce the following re- sults. From one hundred grains of the pure and very transparent crystal, I obtained a very small pro- portion of Magnesia; and, from the common grey Limestone, the produce of one hundred grains was rather more, amounting to about six or seven grains. (15) But, from a hundred grains of a brown, iron-coloured Limestone, selected from the Dock-Yard, the hollows of which were filled with small rhomboidal crystali- zations, the proportion of Magnesia was consider- ble, being nearly twenty-one or twenty-two parts in a hundred : and, lastly, from the red, calcareous stone, from the western end of Mount Wise, the quantity of this substance, although not so much as in the last-mentioned specimen, was, nevertheless, about eight parts in a hundred. (16) CHAPTER 5, Quartz with the Limestone. I HAVE occasionally found a-morphous Quartz, of a milky colour, though sometimes assuming a re- gular crystaline form, and possessing a tolerable transparency, mixed with, and lying on the surface of the Lime, at different points: particularly among the rocks at the Devil's Point, at Bunker's Hill in the Dock- Yard, and in the red calcareous stone at the western end of Mount Wise ; which latter, is full of small cavities, variously shaped, occasioned, I con- sider by the decomposition of the animal matter, with which they were once filled ; of shells, for instance, and of what much resembles the pulley, (17) or screw-stone of Parkinson. Vol. 2. P. 15. Fig. 6. These curious hollows are, not unfrequently, lined with calcareous formations, accompanied by perfect Quartz crystals, each quite distinct, the one from the other. But, the instances of meeting Quartz, in con- junction, or blended with the Lime, are not common, nor is the Quartz in large quantities. (18) CHAPTER 6. is^ N No Metallic Veins. THE bed of Plymouth Limestone appears to be entirely free from all Metallic Veins; and I have not seen, nor have I heard of any thing, tending to what Miners would call a Load, of any of the metals 3 having ever been discovered in any one of the quarries that have hitherto been opened. It is true, that indications of the presence of Iron, and also of Manganese may occasionally be seen, as a colouring matter, in particular spots; but always thinly spread, and never in any quantity. In a single instance, I have observed spots of Pyrites, in fragments of Limestone and slate, taken (19) out of a well, that was sinking at the back of the houses on the South side of Union-Street, Stone- house. And, I have been told, that in digging another well, near the Public House, on the road leading from Plymouth to Cat-Down, the sign of which gives a view of the Breakwater, particles of Pyrites were observed by the workmen employed, and also a glimpse of Copper: but, not having seen it myself, I cannot vouch for the accuracy of the statement ; and I am inclined to think, that the cir- cumstance is extremely problematical, and that the men, in reference to the last-mentioned substance, more particularly, were deceived. (20) PART XI. ORGANIC REMAINS OF MARINE ANIMALS. CHAPTER 1. The Dock-Yard. I NOW come to the mast characteristic feature of the Plymouth Limestone, namely, " the very numerous and striking varieties of Organized Remains of Marine Animals" which it contains. So generally do they pervade every part of our rocks, that it is surprizing they have not earlier drawn attention; much less, that there should ever have been any doubts enter- (21) tained of their existence in them. Visible traces of these interesting relics, meet us at almost every step ; and there is hardly a hill or quarry, where they are not to be found; or rather where they do 'not obtrude themselves to the notice of the curious, and invite investigation. According to my proposed de- sign, therefore, I shall mention, in regular order, the different places, from whence I have obtained the various specimens, which at present are in my possession, the fruits of a few years research ; and that continued at uncertain and short intervals. In this enumeration, I shall specify such only as I am able to mention with confidence ; for I profess my- self too much a novice in these pursuits, to attempt either to give a character, or to class very many that I have. We will begin then, with the most western end, the Dock-Yard. Here 1 have principally obtained Corallites, Echi- nites, Entrochites, and Shells ; the latter are all bi- valves, and often retain much of their original or shelly appearance. Amongst other varieties, I think I may venture to name the Anomia, Cardium, My- tilus, and Terebratula, But, one of the specimens F (22) found here is particularly deserving of attention ; it consists of a dark brown friable stone, strongly coloured by iron, or manganese, and in which, are cavities, having casts of shells, trochites, and of other animals. Of these animals, the original substance appears, in some instances, to be totally, and in others, partly decomposed and gone; but all the cavities are lined with a brown, flat, rhomboidal, crystal,* containing a considerable portion of Magnesia. * I obtained these specimens, a few years since, when a portion of the rock, called Bunker's Hill, was removed, for the purpose of enlarging that part of the Dock- Yard where it is situated. 23) CHAPTER 2. Western side of Mount Wise, fyc. From the Dock- Yard, advancing East, across the street by Mutton-Cove, we come immediately to the western end of Mount Wise. This place abounds with Animal Remains. Amongst the Shells, which are also of the class of Bivalves, and which retain much the same appearance as their neighbours, in the Dock- Yard, we may enumerate the Anomia, the Cardium, the Ostrea, the Tere- bratula, and the Orthoceratite. I possess also, one specimen from hence, which seems to be a variety of the Echinus; but there are vast quantities of (24) Madreporites, fragments of the vertebral column, Serpulae, and Trochites, in this place. In conclu- sion, I would particularize a beautiful variety of branched coral, in a red, calcareous, sand-stone, con- taining many minute, white, bivalve shells, all about the same size, and forming together a very interest- ing specimen. To these may be added, an abun- dance of fragments of Animal Remains, to which 1 cannot give any name. Before leaving Mount Wise, however, I would mention, that shells in situ may be seen at any time, and without difficulty, in a part of the rock that is uncovered, a little to the East of the Battery, and not far from the pathway leading from the Port Admiral's house, to the Navy Stairs, below. But, these are of a harder texture, retain less of their original character and shelly appearance, than those on the other side of the hill, and having a greater affinity or resemblance to the matter in which they are embedded, may very properly be called casts.* * By the terra casts, I mean, where the original substance has been removed by decomposition, and its place filled by the infiltration of the surrounding matter. (25) '& CHAPTER 8; 'i JMi- UI/v 11 03 ...--. . ' ^i "{4fJ dt!9T Ordnance Quarries and Devil's Point. ~ + ^ WE next arrive at the Ordnance Quarries, imme- diately to the West of Stonehouse Bridge, on the South side of the Road. In these I have never met with any shells; although the stone is fall of Madreporites, and other Organic Remains of this class : it is also, when polished, a very fine marble. The Devil's Point. DEPARTING a little from the direct line, I wish here to notice the Devil's Point. G (26) I have already spoken of the very singular red and white stone of this place,* as a striking speci- men of marble. I shall now take notice of it, in reference to its Animal Remains. The white part appears to me, to be the stems of a variety of the Lily Encrinite ; and, for this reason, viz. I have recently found a fragment of this rock, containing, with the stems, what, I believe to be a head of one of those curious and rare animals. Vide Plate 10. Fragments of the vertebral column, of different lengths and sizes, of another variety of these ani- mals, appear in great quantities, in most of the rocka of this eminence, facing the sea. A specimen of whiGM CHAPTER 4, 'i.">DF ; - rcfte ' ' , : - ; ,,- r . * ' . Stonehouse Hill. NOT many yards distant from the last houses, leading from Stonehouse to Mill-Bay, over the hill, on the South side, I have found, amongst the breccia, aboye and below the road, detached frag- ments of stone, some of considerable size, lying seTeral feet under the present surface, in seemingly undisturbed ground, and differing but little from the solid rocks near them ; containing, besides Ma- dreporites, the Euomphalus, and other Animal Re- mains, of a most singular and curious appearance ; several varieties of Univalve Shells, and amongst others, I recognise the Turbo. But these, unlike (28) those in the Dock- Yard, or at the western end of Mount-Wise, are so blended with the surrounding matter, as to form one solid and compact mass ; and it has been with some difficulty that I have succeeded in obtaining detached and perfect speci- mens. The prevailing colours of this stone, are, a deep blue and brown, variegated with others of a lighter and different hue, according to the Ani- mal Remains which are respectively contained in it. This stone is likewise capable of receiving a very fine polish ; by which process also, the shells, and Madreporites, are most satisfactorily brought out to view, and rendered beautifully distinct. In breaking several of these fragments, for the purpose of examining their contents, but more par- ticularly for the sake of obtaining detached shells, other subjects have presented themselves to notice: some of which, in their forms, and in their mark- ings, bear a strong resemblance to what Mr. Park- inson, in his Second Volume of Organic Remains, Plate 10. Fig. 12, denominates an Alcyonite, found in the chalk-pits of Wiltshire. How far my conjec- ture may be right, I will not pretend to say ; . but,* (29) I should be very glad if this, and many more of the productions of our rocks, could be carefully investigated ; as I am well persuaded, that numbers of them have never yet been described, or classed, in any publication. In the fragments of Limestone, raised from pits that were opened on the North side also of this hill, while the houses were building in Union-street, which leads from Stonehouse to Plymouth, I obtained several satisfactory specimens of Bivalves and Madre- porites ; and observed, that they were abundant in different parts of these rocks. And, in masses of blue, or grey Limestone, mixed with clay-slate, taken up from some wells that were sinking at the time, at the back of those houses, both on the North and South side, Madreporites, Trochites, and other relics were in considerable quantities. In one, if not in two instances, Pyrites was mixed with them ; a sin- gular circumstance, and not unworthy of notice. These are the only places, where I have found Py. rites so blended with Animal Remains, throughout the whole distance, from the Plym to the Tamar. a (30) CHAPTER 5. Mill-Bay Quarry, near the Iron Foundry. PROCEEDING from the western end of the last- mentioned hilJ, we arrive at the quarry at Mill-Bay, situated near its eastern extremity ; a spot, which, in the first instance, arrested my attention, and led to the supposition, that the Limestone of Plymouth con- tained Animal Remains. Impressed with this idea, I proceeded to examine some large blocks of marble in this quarry ; which, after having been separated from their parent bed, had lain for a considerable time, in the same situation, and exposed to the weather. The varied figures of Madreporites, which generally marked their decomposing surfaces, left no (31) doubt on my mind, respecting the nature of their contents; and thus encouraged, I have continued my enquiries from that period to the present time. For the purpose of experiment, I made choice of several pieces, which I considered the most striking, and had them polished. One is represented in Plate 6, No. 1, of this book. Two others appear to an- swer to Figs. 1, and 2, in Plate 4, of Vol. 2, of Parkinson ; the first of which is called, a turbinated Madreporite, and the other, a fossil of the same spe- cies, but more of a discoidal form. A fourth speci- men, which I have, is evidently of the same family, and answers to Figs. 7 and 8, in the same Plate 4, Vol. 2, of Parkinson. The whole rock is com- posed of these and other Animal Remains, as may be^ yet seen ; although it is daily lessening, being carried away for various purposes. Lastly, notwith- standing shells are not particularly rare at the west- ern end of Stonehouse hill, yet here, which is the eastern extremity of the same eminence, I have never obtained a bivalve or univalve shell of any description ; which is rather remarkable. (32) CHAPTER 6. The Rocks between Sandy-Cove and Mill-Bay. CROSSING from hence the small stream of water, which runs into the sea, at Mill-Bay, all the rocks, between the Soap Manufactory and Sandy Cove, offer for examination, an extensive series of Animal Re- mains. I would refer the reader, instead of giving any particular description of them in this place, first to the branched Corallite, figured in Plate 1. Again to Plates 3, .and 7 ; and lastly, to Plate 8, Fig. 2, which will speak for themselves. (33) CHAPTER 7, East Hoe under the Citadel. THE next place, from whence I have obtained specimens, containing shells, besides Madreporites, and other organized remains, is the East Hoe, nearly under the Citadel. These are all, without exception, Univalves, principally of the class Turbo. In texture they are hard, and compact, of the colour and substance of the surrounding matter; much resembling, in their general apearance, many of the specimens from the south-west part of Stone- house Hill, (34) CHAPTER 8. Teate's Hill and Queen Anne's Battery. ON crossing the water, to Teate's Hill and Queen Anne's Battery, from the Victualling-Office Point, which joins the Citadel, a rich and plentiful field of Animal Remains presents itself to view ; more especially at the latter place. Here we see scattered in all directions, detached and in the rock, Tro- chites, Entrochites, as well as several varieties of Madreporites : here too, I have discovered, in situ, the most perfect specimen of the Encrinite, i. e. the head and stem being evident, and connected together, that I have seen, as the produce of our Limestone. Arid, so rarely are they found together, that, ex- (35) cepting one more, not so distinct, from the same place, I have never met with a second so well de- fined, in all its parts, throughout the whole range of this neighbourhood. A representation of this En- crinite is given in Plate 2, and will, 1 trust, be deemed particularly interesting- and satisfactory. With regard to Univalve or Bivalve shells, I have found none at this point. (36) Ib ri '"- " I <$ CHAPTER 9. ,^n '1*1 ...... ..... Dead Man's Bay, Cat-Down Quarries, and Prince Rock. A LITTLE distance from hence, in the surround- ing rock, and at the Quarry, in Dead Man's Bay, Trochites, Entrochites, Madreporites, and Bivalve shells, are distinctly to be seen. Cat-Down Quarries. AT the entrance of this extensive range of quarries, I have found Madreporites, Univalve shells, and other organised remains: particularly, I have observed very (37) great quantities of a peculiar sort, which appear, from their various and compressed forms, to have been originally animals of the Mollusca tribe, about an inch in length, composing frequently the greater part of the stone in which they are met with. Prince Rock and Flying Bridge. AND to complete the limits of my proposed ex- amination, advancing still eastward, I have found, at Prince Rock, and at the western landing-place of the Flying Bridge, various Animal Remains, in most respects similar to those I have already described. (38) ! . CHAPTER 10, Concluding Observations on the foregoing Chapters. I SHALL now add a few short observations, con- nected with the facts which have been stated above, and which have suggested themselves from time to time, in the course of my investigation. Permit me to remark, then, that a great variety of Organic Remains, such as Madreporites, Corallites, Trochites, Entrochites, Encrinites, Orthoceratites, Ser- pulse, and Shells, both Univalves and Bivalves, are blended with, and form a very considerable part of the contents of the calcareous rocks of Plymouth, and will justify us in assigning them a place among the Mountain Limestone, and that of an ancient, rather than of a recent date. Since the above observation was written, I have had the pleasure of conversing with a Gentleman, whose judgment, on Geological subjects, I regard as important, and having great weight. He is of opi- nion, that our rocks are of a more ancient date still, and that they ought to be arranged with the transition Limestone. And I find this opinion con- firmed by the Rev. William Buckland, Professor of Mineralogy and Geology, in the University of Ox- ford, in his recent publication, which gives an in- teresting account of an assemblage of fossil teeth and bones, discovered in a cave at Kirkdale, York- shire, in the year 1821 ; and in which, he applies the term transition, in speaking of the quarries at Oreston ; which quarries are situated near Plymouth, and are, in fact, part of the same stratum of Lime- stone ; the river Plym only, dividing the one from the other. Again, Organic Remains are more distinctly visible, and abound most, at those points where the Lime- (40) stone and clay-slate mix with and alternate with each other, previously to their entire separation, and to their taking their regular and respective courses, Madrepontes seem not to be confined to any par- ticular spot, but are discoverable in almost every part of the stratum of Limestone, from the Dock- Yard to the Flying Bridge. In some places, they are not so distinctly visible, from the circumstance of their being but thinly scattered in the stone, and from their not having been exposed to the action of the weather; while in others, they lie in families, con- sisting of large masses, and forming extensive layers; as in the Quarry at Mill-Bay; at Sandy Cove; in the rocks of the East Hoe, nearly under the Cita- del ; and in Dead Man's Bay, near Catdown. Univalve and Bivalve Shells^ wherever they occur, I have never found mixed together, but always in separate beds. Thus, for instance, the Shells of the Dock-Yard, Mount Wise, and the North side of Stonehouse Hill, are all Bivalves; while those from the South side of Stonehouse Hill, from the rocks at the end of the East Hoe, under the Citadel, and (41) from the Quarries on the eastern side of Cat-Down, are all Univalves. What is a still more curious circumstance, and corroborative of the above remark, Univalve and Bi- valve Shells^ in one particular instance, are seen to occupy parts of the same hill, although in beds perfectly distinct, the one from the other. On the South side of Stonehouse Hill, for example, (already so often mentioned) Univalves only are found ; while on the North side, Bivalves exclusively prevail. Besides, the shells from our rocks seem to have other characteristic marks, which constitute an appa- rently essential distinction between them, and which, are too obvious to be passed over in silence. Some are of a softer nature than others, are more friable, and retain more of that shelly or silky texture, fre- quently seen in the decayed shells of the present day; which would indicate, that they were of a more recent period: some, on the other hand, are fine grained, compact, hard, and capable of receiving a very high polish ; in short, participating most fully in the properties and colour of the matter in which L (42) they are embedded; and, in appearance, altogether favouring the supposition of their being of a much more ancient date. In reference to the Encrinites, it appears, that there are several species of them iu the Plymouth Limestone, and that each species had a distinct situ- ation for its habitat, or place of abode ; as the parts of the different kinds are rarely found intermixed and blended together. Thus, the one figured in Plate 2, is very different from those in Plate 3, The former, taken from Queen Anne's Battery, pre- serves a roundish, full form, such as we may suppose it to have been originally, when the animal was alive ; while the latter, all which are the produce of the rocks between the Soap Manufactory, and Sandy Cove, seem to be of a softer nature, probably of the Mollusca tribe, as the joints or portions of the stem, as well as the heads, are invariably com- pressed and flattened. Plate 4, exhibits the stem of an Encrinite of a different class again, from either of the former: this, taken from the Devil's Point, must have been of a harder substance, approaching very nearly to the nature of bone, as it has pre- (43) served, not only its original form, but even ill minute markings. The bed of Trochi, found at Mount Wise, several of which are represented in Plate 9, seem to have belonged to this class. But, not the least curious, nor the least handsome of all the Encrinites of our neighbourhood, must have been those at the Devil's Point, occupying $ situation by themselves, and apart from all the others. One of these is represented in Plate 10, the head of which is, in colour, not unlike a large white lily. At the opening, or top of these Encrir nites, as well as of many of the others, numerous small Trochi, from one-tenth of an inch in dia- meter, to a mere point, are frequently discoverable, which appear to have been the tentacula, or feelers of the animal, when alive, and which, where several joints happen to be together, gradually taper away, to the size of a thread. Lastly, it is very extraordinary, that, amongst the vast quantities of the fragments of the Encrinite, which are seen in different places, the perfect animal, i. e. the head and the stem connected together, (44) should be so rare in the rocks of this particular district. To facilitate the labour of those, who may be inclined to look into the contents of our Limestone, it may not be amiss, before quitting the subject, to intimate, that although Animal Remains are gene- rally visible in the body of the rock, and when newly broken, yet, the most satisfactory specimens are to be obtained from those parts of it which have been longest exposed to the changes of the atmo- sphere, and the action of the weather ; because, the animal substances, being of a more durable quality, do not decompose so rapidly as the materials in which they are embedded. (45) fc %ii 'iO |B * PART XIX, PETRIFACTIONS AND CRYSTALIZATJONS. CHAPTER 1. Stalagmites. AFTER the consideration of its Animal Remains, our curiosity naturally turns towards another, and that, no inconsiderable or unimportant division of the contents of the Plymouth Limestone; namely, to its Petrifactions, and various Crystalizations of Cal- careous spar. M (46) Of its Stalagmites, not much need be said ; only, that they differ from the Stalactites in this particular; being formed at the bottom, and not on the sides, or at the top of those cavities in which they are found. They present but little for observation, being, for the most part, of the same shape, although varying occasionally in their colours. I have them of different tinges, from a pale white to a deep reddish pink. (47) CHAPTER 2. Stalactites. THE Stalactites, however, are much more numerous and interesting, and are worthy of attention from their multiplied, and often fanciful, groups and figures. We find them in great abundance, in most of our quarries, ornamenting the roofs and sides of the caves and hollows; where they are produced by the water, which makes its way into those hollows, and which, becoming impregnated with calcareous matter, in its passage from the surface, gradually evaporates, and deposits it in those forms. They sometimes possess a tolerable degree of transparency, and are of various sizes, increasing from that of a (48) small reed to a considerable bulk. Some are hollow, like a quill, whilst others are solid, and their tran- rerse fracture generally displays a radiated surface, the rays regularly shooting from the centre to the circumference ; while sometimes they present brilliant angular facettes, corresponding, in their shape, with the crystaline Rhomb. Others, again, continue hol- low, and yet become the centre of new concretions, which, increasing from time to time, offer to the view, a crystalized surface. Another pleasing effect, observable in many of these stalactites, is, that al- though they are too soft for useful purposes, yet, when polished, they display the different and con- centric layers or incrustations, formed by the per- colating water, like the annual accretions of a tree. (49) CHAPTER 3. Dendritic Productions. THE Dendritic Productions, which are constant attendants on the Lime, seem to be a sort of con- necting link between the Stalactite and the regularly formed crystal ; putting on more of the appearance of perfect crystalization than the former, but not so much as the latter. They are frequently arranged in branch-like groups, and shoot out on all sides, as the term imports, similar to the minute ramifica- tions of a delicate shrub. N (50) CHAPTER 4. Crystalizations of Calcareous Spar. THE number and varieties of form, which the Crystals of our rocks assume, are very great, and much might be said on the subject, were I dis- posed to go into detail; but, without some repre- sentation or figure to assist, I fear, any description of them, would be far from satisfactory, and, to the generality o my readers, would convey but a poor and inadequate idea of their regularity and beauty. J should have been glad to have given delineations of the most remarkable, had I time and leisure for the purpose, but which is not the case at present. They are, however, a most striking class, and can- (51) not fail to excite an interest in the ininds of all those who possess any taste for productions of this sort, and who occasionally indulge themselves in the study of Crystalography. The Count de Bournon, in his elaborate Treatise on the Crystalizations of the Carbonates of Lime, has enumerated upwards of Seven Hundred modifi- cations, and exemplified them also by numerous Plates. Two or Three Hundred modifications, at least, may certainly be mentioned, as occurring in our Limestone ; many of them are beautifully perfect and transparent ; and are not figured in his book. I would enumerate the Rhomboid r , the Prism, and the Dodecaedron, as the three primitive forms, on which, with the elongation of their angles, all the other modifications are dependant, and to which, it strikes me, they may be generally referred, or traced back: but, these are so multiplied by truncations, by bevellings, by their position in their matrix, by their union with each other, and also, by other accidental circumstances, to which they are continu- ally liable, that it is frequently very difficult to (52) make them out with certainty. As if Nature intended to elude our utmost penetration and research ; and to hint, that it would be in vain for us to attempt to follow her through all her changes, and dresses, which she is constantly putting on. We have the three and six-sided pyramid ; the six-sided prism ; the six-sided plate ; which I so call for want of a more descriptive term, being the ends of the six-sided prism united, without the interme- diate column or shaft ; the dodecaedron, consisting of two six-sided pyramids united, whose bases alternately advance and recede in angular lines, and which has been denominated by Haiiy, Metastatique ; the Dode- caedron, in which the bases of the pyramids are marked by one or two transverse lines of division ; the Lance and Mitre-shaped crystals, formed by the junction of very curious variations of the rhomb, and six-sided pyramids, and having a four-sided rhomboidal base, and a four-sided shaft, with a pro- portionably lengthened point. One of these, in my possession, measures in length an inch and half; and another, three inches, with a diameter of three- 642-2997 LOAN PERIOD 1 1 MONTH 2 3 4 5 6 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS Books needed for class reserve are subject to immediate recall DUE AS STAMPED BELOW FORM NO. DD8 UNIVERSITY OF CALIFORNIA, BERKELEY BERKELEY, CA 94720