order of the strata. The undoubted group D, or the approximate equivalent of the Upper Ludlow, is distinguished by its beautiful and variegated stratification, the prevalent colours being red, grey, and green. The strata are inclined 40° S.W., except where the strike becomes east and west. This is the case with the uppermost strata, which have been thrown in this direction by the amygdaloid trap, by which it is partly overlain. Here our Silurian fauna has attained its greatest development as regards genera, species, and individuals. The fossils are not, however, so well preserved as in other parts of the series. Of the class Cephalopoda, individuals have diminished in size, while it has received many accessions in genera and species. Heteropoda, Pteropoda, and Gasteropoda abound, the Gasteropoda being generally of smaller size than they are in the group C. Lamellibranchiata occur in greater numbers than before, especially species of Clidophorus. Brachiopoda are now generally of smaller species. Crustacea are more numerous, both in genera and species, and Homalonotus and Calymene are of rather unusual size. One pygidium of Homalonotus Dawsoni, Hall, must have belonged to an individual six or seven inches in length. An entire Calymene is four inches in length, and a glabella of another individual indicates still larger proportions. Entomostraca appear here for the first time, and in considerable variety and numbers, near the top of the series. In the earlier members of the series the organisms were generally insulated; sometimes they occurred in small groups, and in thin and small beds of limestone; here they often form limestone-bands five or six inches in thickness, which appear to have been, to a considerable extent, formed of the débris of organisms. In this member of the series the fossils are generally fragmentary. entire specimens being very seldom found. The following list shows the character of the fauna of the group : D: Clidophorus erectus, Hall. Clidophorus nuculiformis, Hall. Orthonota (like many Ludlow species, Goniophora cymbaformis, Sow. Chonetes Nova-Scotica, Hall. Spirifer subsulcatus, Hall. Discina? tenuilamellata, Hall. Homalonotus Dawsoni, Hall. These Silurian strata (see fig. 4) are succeeded by Lower Carboniferous conglomerate. § 6. Conclusion. I have thus directed attention to the results of a detailed examination of the Silurian strata of Arisaig. This being the undoubted type of a very considerable proportion of our Nova-Scotian Silurian system, and bearing so striking a resemblance, as regards its fauna, to the British Upper Silurian, is a sufficient reason for so directing attention to the subject. The conclusion thus arrived at is, that the members of the series are respectively the approximate equivalents of the Mayhill Sandstone, Lower Ludlow, Aymestry Limestone, and Upper Ludlow. Mr. Salter suggested to me the propriety of distinguishing the respective members of our series by local names. I have not been able to act on the suggestion, on account of the mode of distribution of the several members of the group. I have therefore distinguished them as Arisaig A, B, B', C, and D. I have not yet attempted to measure the entire thickness of the several strata. Supposing Dr. Dawson's estimate of the thickness of the groups B', C, D to be correct, although I consider it much below the reality, we have of them about 500 feet; I found the thickness of B 170 feet, and of A 200 feet; total, 870 feet. I have observed that strata A have a fauna well developed, too much so, indeed, to warrant the supposition that while there are sedimentary rocks in other parts of the province, which we have every reason to suppose are older than those of the Arisaig group, our A fauna is the first one represented in our Nova-Scotian geology. Before I consulted Sir R. I. Murchison and Mr. Salter, I supposed that certain unaltered strata which I had discovered in another locality, and which had, as their only fossils, hundreds of Lingulæ, beautifully preserved in small spherical and elliptical nodules, might be our Nova-Scotian Primordial zone. These appeared undoubtedly to be older than the equivalent in this locality of the Arisaig group B', or the Clinton (U. S.) equivalent of Hall and Dawson. So that, regarding this determination as correct, I considered the Lingula-bed as Middle or, possibly, Lower Silurian. This bed appears to be about the equivalent of the bed B of Arisaig, and, therefore, is not Primordial. I believe, then, that we must look elsewhere for any earlier fauna than that of the Arisaig group A. The older slates of our Gold-fields, especially in the Peninsula of Halifax, bearing a striking resemblance to the Graptolitiferous slates of Victoria, in Australia, exhibited by Professor M'Coy in the Inter national Exhibition of 1862, that was considered by me the proper region of our Primordial fauna. After a patient search, I believe that I have discovered evidence of the existence of the expected fauna in the capital of our province. 2. On some REMAINS of FISH and PLANTS from the "UPPER LIMESTONE" of the PERMIAN SERIES of DURHAM. By JAMES W. KIRKBY. [Communicated by Thomas Davidson, Esq., F.R.S., F.G.S.] [PLATE XVIII.] THE object of the present paper is to record the discovery of Fishremains in the Upper Magnesian Limestone of the Permian formation, the occurrence of these fossils in that subdivision being of interest in several respects, though more especially so on account of their having there been found at an horizon considerably higher in the Permian series than any vertebrate remains had been previously known to occur. The fossils were first noticed by the workmen, in August 1861, in a newly opened quarry belonging to Sir Hedworth Williamson, Bart., at Fulwell, about a mile and a half to the north of Sunderland; and my attention was almost immediately drawn to them by Mr. Henry Abbs, of the latter town. From that period almost up to the present time, though chiefly during the autumn and winter of 1861, and the spring and summer of 1862, I have continued to collect specimens, and to pursue inquiries as to their paleontological and geological relations. In these researches I was joined by several scientific friends, who courteously allow me to use the results of their labours along with those of my own in this account of the fossils. Among these friends I ought specially to mention Mr. A. W. Dixon and Mr. W. M. Wake, of Sunderland, and Mr. R. Howse, of South Shields. I should also remark, that I am considerably indebted to the lessee of the quarry, Sir H. Williamson, with whose permission my inquiries were made; and I also owe much to the active assistance and careful observation of Mr. T. Foster, the overman of the quarry. The quarry referred to is situated on the northern slope of Fulwell Hill, and is not far distant from another more extensive and much older quarry belonging to the same proprietor. In these quarries, as well as in others on the same hill, more to the west, the Magnesian Limestone is largely worked for lime-burning, as it has been in the older quarries for the last sixty years or more. During the whole of that period, up to 1861, no traces of any organic remains had ever been found in the limestone of this hill. But about the time named, or a little before, it became necessary, in order to keep the new quarry at its proper level, to cut through some underlying beds (brought up by an anticlinal), which had never yet been quarried on account of the unvendible quality of the limestone; and it was in working these lower and inferior strata that the great bulk of the fossil Fish were discovered, most of them having been found in one bed, or zone of beds, of limestone; there, nevertheless, being several instances of their occurrence both above and below that horizon. Soon after their discovery in the new quarry, another or the same anticlinal brought up the equivalent strata in the old quarry, about half a furlong to the south; and it was not long before the same fossils were met with there, besides other species that the first locality had not yielded. The same Fish-bed would appear also to extend considerably to the north-east; for I have obtained the tail-half of a small fish from a stratum of limestone in Marsden Bay, occupying the same stratigraphical position as the Fulwell Fish-bed. The Magnesian Limestone worked in the Fulwell quarries belongs to the higher portion of the Permian series, or, to speak with precision, to the " Upper Limestone" of the classification proposed by Mr. Howse, or to the Crystalline and Concretionary Limestone of Professor King's arrangement. But it must be further observed that the Upper Limestone of Durham is composed of two portions, the higher being yellow, friable, or compact, or oolitic, and thin-bedded, while the lower is of various shades of yellow and grey, highly concretionary, compact, or friable, and thick-bedded. It is the latter portion that is worked in the quarries of Fulwell Hill, that district being situate beyond the outcrop of the higher strata. The lower portion, which, for the sake of convenience, I shall term the Fulwell beds, has been further subdivided by the quarrymen into several minor groups. These it will be well to mention, as they serve to mark with greater exactness the vertical distribution of the fossils I am about to describe. Below the higher thin-bedded yellow limestone is a series of thick beds of hard, subcrystalline, grey or whitish-grey limestone, associated with or passing into strata of conglomerated or botryoidal and very friable white limestone; this group is the "White Stone" of the Fulwell quarrymen. Immediately below is about three feet of dark-grey, highly crystalline, and conglomerated limestone, with beautiful (metastatic) crystals of calc-spar, and crystalloids of limestone; this is named the "Black Shell." Underlying it is generally a bed of soft friable limestone with conglobations; and then follows from twenty to twenty-five feet of thick-bedded crystalline and concretionary limestone, which, from its peculiar structure, is termed the " Honeycomb Limestone or Main Stone." Separated from the Main Stone by about two feet of conglobated limestone, follows nine feet of white or yellowish, very soft and friable limestone, which is the great "Marl Bed" of the quarrymen. Under it is about nine feet of thinner-bedded, often laminated, compact, yellow or brown limestone, called the "Dun Stone." This is underlain by eight feet of highly concretionary and crystalline, coralloidal, and laminated limestone, designated the "Grey Stone." Immediately under this is two feet of laminated limestone, which I |