Robert Craig

XVIII. On the Post-pliocene Beds of the Irvine Valley, Kilmaurs, and Dreghorn Districts

Introduction. — On 12th January, 1882, Mr. John Young, F.G.S., and the writer, exhibited before this Society a fragment of a tusk of Elephas primigenius, Blum., and some shells, which had been found in sinking a pit on the farm of Drummuir, Dreghorn. These remains had been brought to our notice by Mr. Thomas Shore, at that time a clerk in the employment of Messrs. Merry & Cuninghame, the owners of the pit. In answer to a query, he stated that the shells, and “piece of wood,” for which the tusk was at first mistaken, had been found in a bed of sand resting upon Carboniferous strata, and below 80 feet of Boulder-clay; but as regards the statement that the shell bed rested upon Carboniferous strata, this was afterwards discovered to be incorrect. This find was an important one, Drummuir being nearly three miles south-west of the old quarry at Greenhill, where so many tusks of the Mammoth were discovered about sixty years ago, and I at once began to make further investigations. On proceeding to the place, I found that the discovery had been made in No. 5 pit, Drummuir, Warwickhill Colliery, belonging to the Glengarnock Iron Company, and I received from Mr. John Cuninghame, one of the partners, not only full permission to examine the pit, but also kind assistance by the loan of surface sections of numerous bores, which had been put down between Kilmarnock and Irvine, for comparison with pit sections put down in the same This 250-word extract was created in the absence of an abstract

XIX. Notes on the Occurrence of Seeds of Fresh-water Plants and Arctic Shells, along with the Remains of the Mammoth and Reindeer, in beds under the Boulder-Clay at Kilmaurs

The remarks which we have to bring before the Society this evening are upon certain organisms recently found in strata that underlies the Boulder-clay at Kilmaurs, near to Kilmarnock. Ever since the discovery, in the year 1816, of the remains of the Mammoth, Elephas primigenius, and the Reindeer, Cervus tarandus, at the Woodhill quarry, Kilmaurs, these beds and their remains have attracted the attention of nearly every writer on Scottish post-tertiary geology. Since the period of the first discovery, some nine or ten tusks and a portion of a molar tooth had been found, along with horns of the Reindeer. Two of the tusks and the horns of the Reindeer are preserved in the Hunterian Museum, University of Glasgow. These remains were at one time referred to the Till or drift. Mr. A. Geikie says,1 “It is singular that in this little Ayrshire valley, within the compass of a few yards, there should occur a greater number of mammalian remains than have been obtained from the drift of all the rest of Scotland; and that among these there should be well-preserved relics of the only two mammals which have yet been ascertained, beyond a doubt, to have inhabited Scotland during the drift period.” Dr. James Bryce,2 a few years ago, however, having become satisfied of the unfossiliferous nature of this deposit as it exists in the West of Scotland, made an examination of the Kilmaurs beds; and from information obtained from parties who had formerly worked in the old quarry, This 250-word extract was created in the absence of an abstract

On the Section in Cowden Glen, Neilston, Renfrewshire, with Remarks on the Upper Boulder Clay

In making the above railway throughout Cowden Glen, the excavations laid open a series of beds, consisting of stratified clayey mud, sand, gravel, and peat. These beds, evidently of lacustrine origin, commence about three-fourths of a mile south-west from Crofthead, or Neilston Station, and continue in the cutting for nearly half a mile as it proceeds towards Shelford. On the east end of the stratified beds, the glen is less than 100 feet wide; the north side forming a bold escarpment nearly 80 feet high. The south side has less height, falling back in undulating knolls, and forming a rugged but not unpicturesque landscape. But as it extends towards Shelford, the hills on each side lose their escarpment character, falling back with more regular declivity, and giving the glen more the character of a valley, until, at Shelford, the breadth of the clay deposits, forming the bottom of the valley, is nearly half a mile broad. The glen, or valley, has been caused by a large break in a ridge of trap, which divides the carboniferous strata of the Levern valley from that of the Lugton, lying to the south-west of Shelford. The break in itself is of geological interest. The trap on its north side is that soft peculiar porphyrite of the Gleniffer range of hills, while on the south side it is porphyritic claystone, intercalated with layers of greenstone, and is certainly a subsequent deposit to the porphyrite of the north side. At the point where the glen This 250-word extract was created in the absence of an abstract

XXI.—Remarks upon “Joints” or Natural Fractures in Limestones

Introduction.—There are few observers, whether geologists or not, who when visiting a limestone quarry have not perceived that the rock is often full of fractures which have cut the strata into large tabular blocks. At first sight these fractures appear to be confused and without any definite arrangement, but, after examination, they will be seen to bear a great amount of regularity. Although two main sets of them are the causes of the limestone being cut into tabular blocks—the “posts” of the quarrymen—there are, at least, five different sets of fractures all varying more or less in age and character. The First—or Oldest—Set.—This set is characterized by little or no regularity, the limestone having been split in all directions, most probably through contraction. None of the fractures now remain open, but are generally filled with calcite and other minerals, which have re-cemented the rock into a compact and solid mass. These filled fractures are called by the quarrynien “ glass-bands,” and when the calcite approaches rock-crystal, the name is appropriate enough, as it appears very like plates of glass running through the limestone. When broken up by blasting, the rock generally gives way at the old fractures, although I have seen a new split made in the rock, before the old re-cemented one would yield. Such re-joined fractures are found in all varieties of rock, and doubtless owe their formation originally to contraction. The Second and Third Sets.—I have placed these two sets together as they are naturally closely allied; This 250-word extract was created in the absence of an abstract

III. Notes upon a Cutting in the New Kilbirnie Branch of the Lanarkshire and Ayrshire Railway, on the Farm of Gurdy, Beith

Introduction.—The cutting on the above-named railway to which I wish to direct your attention is on the farm of Gurdy, Beith. It commences near where the railway crosses the Beith and Kilbirnie road, and extends for about three-fourths of a mile in an east-by-south direction, finally running out on the farm of Coalburn, Dalry. The greatest depth is on Gurdy farm, where it is nearly 30 feet deep; and as it intersects the strata at an oblique angle, it has cut through and exposed from 20 to 25 fathoms of the strata which lie above the lower limestone and below the workable clayband ironstone. The intersection of these strata is at the west or Kilbirnie end of the cutting, and terminates at a fault and downthrow where it crosses the Kerrsland glen and Pogree burn. The strata met with in the cutting, from this burn to its termination on Coalburn, belong to those which lie above the main coal of the Dalry field. Except vegetable markings, the sandstone and shales on the east end of the cutting are apparently non-fossiliferous. The mineral and fossiliferous characters of the strata west of the Pogree burn have been closely anticipated in a previous paper by the author, “On the Strata between the Lower and Upper Limestones” (Transactions, vol. vii., page 86). In that paper is given a section of the strata exposed in Kerrsland glen, and in the Gurdy railway cutting the same strata are found. In the following notes regarding them I This 250-word extract was created in the absence of an abstract

II. On the Upper Limestones of North Ayrshire, as found in the District around Dalry, and elsewhere

Introduction.—The Upper Limestones of North Ayrshire are divided into four distinct series of beds by the intervention of shales and flaggy sandstones, giving to each an independent character, both physically and in extent of area. They are all rich in fossil remains, but, with the exception of the lower bed of the series, they are of small commercial value, and the collector has not therefore the opportunity of searching quarries, as in cases where the limestones are more extensively worked. However, from the openings made by, and the sections exposed in, the various water-courses, a fair collection of their fossils has been obtained, and to all appearance the series are as rich as the Lower Limestone beds, both in quantity and variety of their organic remains. They differ, however, from them in the proportions they contain of the same classes of fossils, as for instance corals and crinoids, in which the Upper beds are poor both in genera and species when compared with the rich deposits of the Lower Limestones. Full lists of the fossils are appended to this paper. Highfield Limestone.—The first, or lower, bed of the series is a deposit of limestone and calcareous shales known as the Highfield Limestone, from being largely wrought at the place of that name. From a similar reason it is also known in a neighbouring locality as the Swindridge Limestone. It is divided from the Lower Limestone series by about 120 fathoms of strata, which hold the workable coals and ironstones of This 250-word extract was created in the absence of an abstract

XIII. On the Fossiliferous Strata lying between the Lower and Upper Limestones in the Beith and Dalry District

Continuing my investigation into the fossiliferous character of the rocks of this locality, the present paper in advancing order treats of the strata that intervene between the lower and the upper limestones. This includes about 100 fathoms, made up of shales, sandstones, thin beds of coarse limestones, ironstones, and coal; and contains all the coals and ironstones worked in the Dalry mineral field. As in my former papers, my object is to give a short notice of the physical and fossiliferous characters of the strata so far as known. Without attempting an exhaustive list of the fossils found, still the list appended gives the whole that have as yet come under my knowledge without having recourse to microscopical examination. I do not say anything at present upon the contemporaneous age of these coal and ironstone measures, as to do so to any purpose would overburden the paper. Intending to discuss this subject in a supplementary paper, I leave it in the meantime with the following remark from Sir Charles Lyells “Students Elements of Geology,” page 377 :—“These Scotch sedimentary beds containing coal may be older than any of the coal measures of central and southern England, as being coeval with the mountain limestone of the south.” The fact that the strata, which are the subject of my remarks, lie in the middle of the Carboniferous limestone, and are therefore older than those which overlie them, bears out the correctness of the above quotation. To simplify the paper as much as This 250-word extract was created in the absence of an abstract

I. On the Fossils of the Upper Series of the Lower Carboniferous Limestones, in the Beith and Dalry Districts of North Ayrshire

The beds under review.—The upper series of the lower Carboniferous limestone consists of a series of beds varying in thickness from one foot and upwards, rarely reaching above 4 feet. At Trearne, Beith, their total thickness, when all on, is about 40 feet. The beds in this section, which may be taken as a typical one, are of a lenticular character, interbedded with thin bands of shale, which partake of the same irregularity. These irregular bands of intervening shale are characteristic of the series, whereever found, and are more abundant in the lower half of the group, dying out as the upper beds are reached. The return, at lesser or greater periods, to the shale-producing conditions, has caused this fine deposit of marine limestone to be divided into a series of beds; the shale bands being often not more than half an inch in thickness, and, with few exceptions, never rising above 6 inches. It is beyond the scope of this paper to inquire into the cause of these changes in the ancient Carboniferous sea which have produced these shales, but, in passing, it may be remarked that, after much observation, I have come to the conclusion that volcanic dust has had more to do with their formation than geologists have yet given credit for. Many of them have a greenish tinge, and others, when newly split up, are strongly marked with the same colour, while their composition is calcareous to the extent of one half. Physical aspect and extent This 250-word extract was created in the absence of an abstract

IV. On the First Appearance of certain Fossils in the Carboniferous Strata around Beith and Dalry

Having for a considerable period investigated the mode of occurrence and distribution of the fossils found in the carboniferous strata in the Beith and Dalry districts, I have thought that a few remarks upon the subject may not be without interest to the Society. It is not, however, so much the purport of this paper to give an exhaustive list of the organic remains found in the above districts, as to point out the beds in which the more common species make their first appearance, so far as has been observed. The better to understand this, it will be necessary to give a short description of the strata, while noting the principal fossils found in each bed. The Carboniferous group of strata in the district average about 150 fathoms in total thickness, their base resting upon an accumulation of ash beds. This ash has been bored into for about 80 fathoms without finding its base, and it consists of red and green ash, more or less indurated, with intervening beds of doleritic greenstone. The first appearance of organic remains in the district occurs in this ash, a few fathoms below its upper surface, in the shape of carbonaceous impressions, but too much decayed for correct identification. These, as found at Tandlehill, Beith, in a railway cutting, were associated with thin layers of sedimentary deposits intercalated in the ash. A clay ash of uneven thickness completes the series, upon which lies a thin layer of coal, 4 inches thick, overlaid by This 250-word extract was created in the absence of an abstract

XI. On the Glacial Deposits of North Ayrshire and Renfrewshire

In the north of Ayrshire, the glacial deposits are well represented, especially around Kilmarnock, where they reach a depth of from 50 to 100 feet. In the higher localities they are found less regularly dispersed, chiefly filling hollows and ravines in the Trap hills, and “wants” along the outcrop of the Carboniferous strata. In the lower, or seaward end of the valleys, they are more regular, having an average depth of about 50 feet. The Renfrewshire deposits are very similar to those of Ayrshire. The glacial epoch, according to a division first proposed by Professor Ramsay, and now all but generally concurred in, may be viewed as embracing three distinct periods:—1st, a period of land ice; 2nd, a period during which the land was submerged, and drift ice prevailed; 3rd, a period during which the land was re-elevated and local glaciers existed, producing a restricted or local glaciation. In the district under review, the glacial deposits belong to the first and second periods, and may be roughly divided into the following groups:— 1st, Lower till—the produce of land ice; subjacent rocks all polished and striated; general striation from N. by E. to S. by W.; the mineral constituents agreeing with this, except a few erratics. This bed has suffered greatly from denudation, being now found in fragmentary bosses and patches. 2nd, Sedimentary beds—fragments of old land surfaces, and lacustrine remains; fossiliferous; fossils, all belonging to the land or fresh water; existing in very small patches, having been all but swept This 250-word extract was created in the absence of an abstract