APH
Memoirs of the Geological Survey
EXPLANATIONS TO ACCOMPANY SHEETS 96, 97,106 AND 107 OF THE MAPS
OF THE GEOLOGICAL SURVEY OF IRELAND,
ILLUSTRATING PARTS OF THE COUNTIES OF GALWAY AND ROSCOMMON
Published by Order of the Lords Commissioners of Her Majesty’s treasury Dublin: Printed for Her Majesty’s Stationery Office:
Published by Alexander Thom, 87 & 88, Abbey-street, Hodges, Smith & Vo., 104, Grafton-street, London: Longmans, Green, Reader and Dyer
1867
THE GEOLOGICAL SURVEY OF THE UNITED KINGDOM
IS CONDUCTED UNDER THE POWERS OF THE
8TH & 9TH Vict., chap. 63- 31st July, 1845.
——————–
DIRECTOR-GENERAL OF THE GEOLOGICAL SURVEY OF THE UNITED KINGDOM
SIR RODERICK EMPEY MURCDHISON, BART.,N.C.B.
B.C.L., F.R.S., G.C.M.S.&C,&c
GEOLOGICAL SURVEY OFFICE & MUSEAM, PRACTICAL GEOGOGY, LONDON
————————-
IRISH BRANCH OFFICE IN THE MUSEUM OF IRISH INDUSTRY, 51, STEPHEN’S GREEN, DUBLIN
DIRECTOR; BERTIE DUKES M.A. P.R.S. & DISTRICT SURVETOR: G..V. DU NOYER M.R.I.A.
SENIOR GEOLOGISTS: W.H. BAILEY F.G.S. G.H. KINAHIN ESQ, J. O’REILLY M.A.
ASSISTANT GEOLOGISTS: (PERMANENT) R.G. SYMES, ESQ
(TEMPERORY) JAMES WARREN ESQ: S.B.N. WILKENSON ESQ; JOSEPH NOLAN ESQ, W.B. LEONARD ESQ HUGH LEONARD ESQ
R.J. CHUISE ESQ.
COLLECTORS OF FOSSILS : C J. GALVAN, MR. A. MCHENRY
The observations made in the course of the Geological Survey, are entered, in the first instance, on the Maps of the Ordinance Towland Survey, which are on the scale of six inches to the mile. By means of marks, writing, and colours, the nature, extent, direction, and geological formation of all portions of rock visible at the surface are laid down on these maps, which are preserved as data maps and geological records in the office in Dublin.
The results of the Survey are published by means of coloured copies of the one-inch map of the Ordinance Survey, accompanied by printed explanations.
Longitudinal sections, on the scale of six inches to the mile, and vertical sections of coal pits, &c, on the scale of forty feet to the inch, are also published, and in preparation. Condensed memoirs on particular districts will also eventually appear.
EXPLANATION TO ACCOMPANY
SHEETS 96, 97, 106 AND 107 OF THE MAPS OF THE GEOLOGICAL SURVEY OF IRELAND
General Description
The district included within the limits of these sheets lies chiefly in the county Galway, a small portion of the county Roscommon, occupying the eastern sides of Sheets 97 and 107. It contains the following towns and villages. In Sheet 96 are the town of Tuam, and the village of Newtown Bellew; in 97, the village of Mount Bellew, Ballygar, Athleague, Castleblakeney, and Creggs; in 106 the small town of Athenry, and the villages of Oranmore, Monivea, Claregalway, and Menlough; in Sheet 107, the town of Ballinasloe, and the villages of Ahascragh, Kilconnel, and Aughrim.
Form of the Ground
This district forms a part of the great central plain of Ireland, interrupted occasionally by low gently-sloping hills, for a few elevations of more abrupt outline, surrounded by large tracts of flat, low-lying ground often covered by extensive bogs or peat mosses.
Its mean elevation above the level of the sea would probably be below 900 feet.
Towards the east, north, and north-west large tracts of peat-bog occur, while to the south and west the country consists of bare or nearly bare crags of rock often of considerable extent
The bogs and intervening ridges of higher ground have in many places a curious approach to parallelism in their outlines, which becomes apparent by a glance at the map.
The eskers or tortuous gravel ridges often form conspicuous features, especially when they occur among the bogs. They will be treated of hereafter under the heading “Drift”.
The waters from a small area at the S.W. of the district find their way into Galway Bay by a few rivulets, and the remainder of the tract is now drained by rivers that flow into Lough Corrib, and thus eventually into Galway Bay. Formerly many of these rivers were partly or wholly subterranean, especially during the dry season; but in 1848 and the following years the present courses were opened by the Drainage Commissions.
In the western part of the district large ‘Turloughs’ were formed during the winter months, several of them extended formerly south of Tuam along the course of an artificial stream called on the map the Clare River. An observer during the winter months in this part of the country night have seen lake-like sheets of water in places over twenty feet in depth. Had he returned in the summer, he would have found them all green, nearly level, pasture. At the present time these pastures are rarely if ever flooded. G.H.K.
Carboniferous Limestone
This formation, which spreads over all the district except the ridge of Mount Mary, admits in the country to the south of a sub-division into two or three sub-groups, which have been called Upper Limestone, Middle Limestone or Calp, and Lower Limestone. These sub-divisions are supposed to be indicated by certain litho logical characteristics, which, of course, are followed to a certain extent by paleontological ones.
In tracing the limestones from the south and east, however, up to the area delineated in these four sheets of the map, it was found difficult to carry out these sub-divisions without violent hypotheses which could have no real foundation in nature, and I finally decided to terminate them as soon as possible, and then abandon them altogether.
If we start from the Coal-measures of Slieve Elva in the Burren country, and walk across the limestone to Oranmore, and thence northwards to Tuam and westwards to Mount Mary, where we suppose the Old Red Standstone to rise out, we should find it impossible to decide upon any general change of characters in the limestone rocks which would enable us to divide them into groups. Pale gray limestones occur over the whole area, varying slightly here and there in colour, in hardness, in thickness, in greater or less abundance of fossils, but none of these variations being of much importance or persistent over any extent of ground.
Between Athenry and Ballinasloe, indeed, black limestones and shaly beds occur, such as might be called Calp in the county Dublin, but beds of good gray crystalline limestone are interstratified with them near Ballinssloe, according to Mr. Foot’s work, and they appeared to Mr. Kinahan as if passing laterally by interstratifications into the Upper (or Burren) Limestones between Loughrea and Athenry.
Sheet 106: Which was examined by Mr. Kinahan, admits of being subdivided into our districts, for the purpose of description;-
That of Athenry
That of Monivea
Athenry District
About a mile and a quarter south-west of Athenry, the railway cutting exposes dark gray limestone, dipping at an angle of about 3° to the W. Ico scratches are perceptible here. A quarter of a mile south of this there is a large exposure of thick-bedded limestone, of a dark gray colour, in some places cherty, and for the most part lying horizontally. Near the railway station of Athenry Mr. Kinahan noticed a quarry of dark gray limestone, having a slight dip of about 3° to the south-west, the upper beds of which were polished, and some striae were also apparent, the directions which were N. 65 W. and N. 60E.
In the railway cutting, three miles east of Athenry, black limestone was exposed, dipping at an angle of 3° to the south-east. Three-quarters of a mile north of this, similar beds occur, lying nearly horizontally. Three-quarters of a mile further north there is a quarry of black flossilferous limestone, containing annelid tracks a quarter of an inch wide. The beds here dip to the north-west, at an angle of 25°. About two miles south of Athenry, between Rockfield House and Moyode Castle, a large area of thick-bedded gray limestone is exposed lying horizontally. A similar exposure is seen three miles east of this, with a dip to the N.W., varying from 3° to 25°.
About two miles farther to the north-east, in the river at Clogharavaun Bridge, a large exposure of black calpy-looking limestone, with shale partings, was noticed by Mr. Kinahan. These beds dip steadily, for about a quarter of a mile, to the south, at an angle of 3°. About two miles north-east of this, he describes similar beds as occurring in the same river at Raford Bridge, dipping to the north-west at 15° Half a mile north of Raford Bridge, black cherty beds occur in the river, dipping to the north-west at 3°. Two hundred yards still further north, similar beds were seen to dip south and east at 3° Six miles north-east of Athenry, the railway cutting exposed beds of black limestone and shale, which dipped at an angle of about 10° to the S.E.E. Similar beds, but cherty also, occurred two miles west of this, in the village of Cloonkeen, dipping to the south at angles varying from 5° to 15°.
Monivea District
In the western and south-western parts of this district but few exposure of rock occur. The principal were seen on the road from Movivea to Belleville, three miles south-west of Monivea. These rocks are said to be hard, dark, gray, and crystalline, and to lie horizontally. On the northern side of Belleville demesne, large rings of dark gray limestone occur; these rocks are traversed by numerous joints, and dip greatly to the north, at about 3°. To the north of this, and south of Ballyglooneen station, the railway cutting exposes beds of dark gray limestone; these, for the most part, lie horizontally, the only dip recorded by Mr. Kinahn being one to the south at 3°. These beds abound in fossils, especially corals (Lithostration). To the east of the railway cutting is the hill of Knockroo. This hill is for the most part bare crag on its eastern and northern sides, the rock slightly undulating. Mr. Kinahan says: “ Nearly at the summit of Knockroo, two and a half miles east of Ballyglooneen railway station, there is a spring called St. Bernard’s Well; this is said always to be supplied with water. When visited in June, 1864, after a long-continued drought, it was running freely. Whence the water supply comes it is hard to say, as the spring does not seem to occur on a line of fault, and seemingly it could only be accounted for by supposing that there is a shale or chert layer that prevents the water sinking, and along which it flows to the well. Even allowing this supposition, however, the spring is so near the summit of the hill, and consequently its catchment basin so small, that the constant supply is remarkable. In this neighbourhood traces of galens are said to have been observed, and trials have been made, but without any favourable results”
East of Knockroe, and south-east towards Monivea, large exposures of thick gray limestone occur, which gently undulates, the greatest dip being 15° to the north-west. On the road to the south of Rhyehill demesne, quarries of dark blue limestone are opened; this limestone dips at an angle of 5° to the south-west.
|
County and No. of Map |
TownlandBetween W. and N.W.Between N.W. and
N.
N. an S.Between N. and N.E.Between
N.E. and E.
E. and W.88/4Barrettspark N.10 E.N.30 E.E. & W.84/1BallybrockaghN.75 W. N.20 E. TobernaveanN.70 W. N.70 E. Ballydavid N.30 E.N.80 E. 84/5PollnagroaghN.75 W. N.45 E Ballygurraun South N.40 E. Caherroyn N.and S.
Sheets 97 and 107
Drift.
The greater portion of this district is more or less thickly covered with drift, which in many places conceals the rocks over large areas. This drift is generally composed of the debris of the subjacent rock, or of rocks which occur in situ at no great distance; occasionally, however, large blocks and boulders of rocks quite foreign to the district are met with such as Galway granite, which must have been transported from a considerable distance.
The Esker Drift
This also sometimes consists of loose boulders and angular fragments of the rocks of the district huddled together, compressed by or embedded in clay and gravel without any signs of stratification, and sometimes of coarse gravel and clay rudels, showing lines of stratification, or again of beds of fine sand, stiff clay, and gravel beautifully stratified, obliquely laminated, and often undulating as if contorted. The eskers occur either as abrupt hillocks or knolls, or as long ridges, often traceable for many miles with an unbroken but serpentine course. All the materials, coarse or fine, stratified or irregular, may be frequently seen in different parts of the same esker ridge; in fact the eskers seem to be made up of boulder drift, which was exposed to the action of waves and currents, which remodeled it into ridge-like bars and mounds. The absence of marine shells and other fossils in the eskers might be accounted for by supposing them to be smashed up and ground to powder by such violent action, or they may subsequently have rotted away and disappeared.
Sheet 106
Mr. Kinahan notices two exposures in this sheet, which show the “boulder clay”, or that which is presumed to represent it, capped by the more recent and generally more stratified gravels, of which the esker ridges appear to form a part. He says that the surface of the “boulder clay” drift is denuded into irregular hollows, on which the “esker drift” has been deposited, and then goes on as follows:-
“In this area only two junctions were noted, one being where the Athenry and Tuam railway cuts through the esker that runs N. of the former place, and the other is the cutting for the same railway at the road between Belleville and Castle Ellen. The esker drift seems to be the boulder drift well washed, and is best developed in the low country. We, therefore, should expect that on the higher ground which only partially came under the influences that formed the esker drift, boulder drift only partially washed should occur. This seems to be the case in this part of the district on land over 250 feet higher than the sea level. It also occurs at the ends of an esker ridge where the ridge joins into a boulder drift country.
The western part of the set of eskers that extends by Ballinasloe, Kilconnel and Athenry: – The principal esker in this portion of the district is part of one that stretches across the central plain of Ireland. Mr. Foot has described the eastern part (see page 26) as far west as Bellafa (Sheet 107) where it enters the area I have examined ten miles E. of Athenry, and runs S.W. through the bogs and flats there situated. To the north and south of this ridge the boulder drift is denuded more or less into ridges and mounds, “Dunlins” more especially on the south in the neighbourhood of Benmore (Sheets 107), where we find mounds of both boulder and esker drift. On the west of the bogs and flats before mentioned there is high ground south of Raford and Kiltullagh, five miles E.S.E. of Athenry, and hereabouts the esker is not in a defined ridge, but the country is covered with mounds and short ridges composed both of esker and boulder clay drift.
From this part three well marked ridges extend; one runs S.W. into the district included in Sheet 115, and has there been mentioned as the north Dunsandle Esker; another runs west to Moyode demesne, in the neighbourhood of which it breaks into irregular mounds and ridges; and the third goes N.W. to Athenry. The last named seems to be the principal branch, and in the neighbourhood of Loughaun consists of a number of well marked mounds, from which two ridges strike to the N.W., and the most southern of these extends for about a mile, and ends in the high undulating stony drift that covers the country S.W. of Athenry, while the northern branch runs in a semicircle to Athenry. This latter is very well developed on the south of Grover House, where it is over thirty-five feet high, and in a sand pit opened in it a remarkable bed of clay seven inches thick was observed, which forms a nearly semicircular arch. On the S.W. of Athenry we can trace the esker as far as Newford House, where it disappears; but a mile farther S.W. to the W. of Castleturvcin, we again find it forming a number of gravel mounds and ridges, and about Greethill the country is occupied with a stony drift which is inclined to form ridges and mounds. Further west there is a nearly bare limestone crag for nearly a mile, but beyond that, on the south of Templegal, the esker again appears regular for some distance, and is succeeded by a line of gravel dunes and short ridges which run southwards until they join into the Kilcorman esker, which is described in the Explanation of Sheets 115 and 116.
Menlough and Athenry Esker
This esker occupies a long tract of country, but the different parts are not as well connected as those of the esker as described. On the east of Menlough the drift is in irregular ridges and mounds, some of it being ‘boulder clay’, and the rest esker drift. On the west of Menlough there is a good esker that breaks into two branches, the most northern of which extends S.W. on the north of the road from Menlough to Monivea as far as Garbally Castle. From that for about a mile toward the west, the country is occupied by slightly undulating drift but immediately west of Killaclogher River a well marked ridge sets in and makes a good feature as far as Ryehill demesne, where it is lost in the undulating drift that occupies the slopes of the hills thereabouts. Although between Garbally Castle and the Killaclogher River there is boulder clay drift, yet the ridges are nearly connected by esker drift, which forms an undulating country all along the bog that lies S.E. of the castle, and that round Ballybawn to the flats by the river. Some of the hills west of Ballybawn are formed of boulder clay drift, against which esker drift is banked up.
The southern branch from Menlough consists of numerous sand dunes and short ridges that extend in an irregular line as far S.W. as Tiaquin demesne, where they join into the drift thereabouts, which undulates in well–defined mounds, some of which are esker drift, the others boulder clay. This undulating drift continues S.W. from Tiaquin for about three miles to the Roman Catholic Chapel at Newcastle, where good ridges occur that run for about a mile in a semicircular line to the high undulating ground on the E. and N.E. of Knockbrack House, and on the west of this, in the neighbourhood of Knockbrack, there is the continuation of the ridge which extends for about a mile toward the W., and after diving into two branches, is lost in the stony undulating drift that occupies the country immediately E. of the Tuam and Athenry Railway. This part of the esker is on very high ground, as the average height at Knockbrack is 250 feet, and the highest part of the esker 270.
On the south of the bog that lies S.W. of Newcastle, there is another branch of the esker which extends in a circular line a little N. of Athenry to Castle Lambert demesne. This part is very well developed, being a well marked ridge, as far as the road from Monivea to Athenry, immediately west of which it bifurcates, and farther west, on the N. and N.W. of Athenry it becomes very extensive, breaking into various ridges which enclose small tracts of flat country, as will be seen by the accompanying map (Fig.6), copied from the six-inch working map.
On the west of the road from Athenry to Castle Lambert, we find it again dividing into two lines of sand dunes that run towards the west for about a mile, and are lost among the undulating and stony drift that occupies the high land S.W. of Castle Lambert. This hill is from 150 to 270 feet high, but the undulating hilly drift does not extend higher than about 220 feet. On the N.W. of this high land there is a N.W. and S.E. ridge about a mile long, immediately N.E. of Cloghmoyle Castle. This ends in undulating sandy drift which, farther N.W. is succeeded by ‘rocky drift’ and bare limestone crags that occupies most of the high ground S.E., S., and S.W. of Lydacan House. On the N.W. of this ground, and N. of Rocklawn House, there is a short N.W. and S.E. esker that ends at the bog which bounds Lough Corrib. Whether this latter is part of the eskers we have just described or not it is hard to say, but it is in the direction of the esker that lies N.E. of Cloghmoyle Castle, and in the same line of direction on the west of Lough Corrib, in the district contained in Sheet 105, there is an esker which extend to the mountainous land that lies farther west.
This esker, if we consider the ridge N. of Rocklawn to be part of it, forms a rude V. while eskers usually preserve a general bearing in one direction. However, its peculiar course may be due to the high land north of Monivea, round which it fringes, and as a ridge extends from this high land toward the south, this fringe of eskers had to be V shaped, in order to follow it. The compound part of the esker which is situated N. of Athenry, and is mapped in Fig. 6 lies due south of the ridge that extends from this high ground, and the irregularities may have been caused by two currents meeting thereabouts.
A mile N.W. of Turoe there is a very large granite boulder on a small gravel mound in the alluvial flat immediately W. of Ballykeena Bridge. North-east of Athenry, in the neighbourhood of Bingarra House, many of them were observed. A little W. of Greethill, which lies about three miles S.W. of Athenry, there is one 18 feet by 15 feet. About three and a half miles N.W. of this, about Lisheenkyle, they are also numerous. Five miles N.N.W. of Lisheenkyle, and a little south of Cregmore Bridge there is a very large block. Four miles, N.N.W. of Lisheenkyle, and immediately N. of the cross-roads there situated, there is a cluster of erratic blocks, most of which are granite or metamorphic rock 10 feet by 8 feet by 5 feet. To the south of this, on the north-east slope of the high ground, which lies west of Glennascaul, there are remarkable clusters of those blocks. One cluster, about a mile and a half west of that village, contains four large and two small blocks; they are all pieces of the metamorphic rocks from Maroonnaught, and the largest is about 12 feet by 10 feet by 11 feet. A little to the N.W. of these there is a cluster of small blocks, and about 200 yards to the S.W. there is a most remarkable assemblage of them, consisting of about thirty blocks, the largest being about 7 feet by 12 feet by 8 feet, another is nearly as large, four are only a little smaller, and the rest range from 5 feet to 1 foot in diameter. To the N. and N.W. of these are other clusters, generally of small blocks, and numerous blocks are scattered about. These clusters might possibly have proceeded from icebergs stranded on the hillside, while many of the scattered blocks may be the residue of the boulder drift. A remarkable line of blocks runs nearly W. and E. on the north side of the village of Doughiska; they may have been dropped from a passing berg.
Dressed, Polished, and Scratched Rocks
Mr. Kinahan also notices the occurrence of rocks dressed and scratched, as if by the passage of ice over them. It has become, indeed, a prevalent opinion among geologists of late years that our islands were once coated by one vast ice cover, a supposition to which such facts as the following, described by Mr. Kinahan, lend support. He says that ‘in the neighbourhood of Ryehill, north of Monivea, many of the quarry stones which were used in building the wall along the road are naturally polished, and in the quarries scratched fragments of rock occurred, but the direction of the striae was not recorded, as the rocks were covered with drift when the country thereabouts was examined; however, in the railway cutting between Galway and Athenry they can be well observed; and the following is a table of all the rock exposures, giving the dip of the surface of the rock, its present condition, the direction of the striae, and the depth of the drift. All the other places in this sheet where dressed rocks were observed are also included in the table.
In the last locality mentioned in the list (Lackaghmore) the direction of the striae is different from that of say of the others; but as the place where they were noted is situated on the west of Knockdoe, the ice would perhaps be inclined to slip down the hill, which would throw their direction more to the north-west, as we find to be the case. In the railway cuttings on the Athenry and Tuam Railway, between Athenry and Ballyglooneen, no polishing or striae were remarked, although in places there is a large head of drift, and the underlying rock looks as if at one time it had been planed down. In the cutting S.E. of Castle Ellen there is from one to five feet of boulder clay, and between that and the rock a peculiar drift, made up of angular fragments of the underlying rock, some of which are tons in weight, but generally averaging about one or two cubic feet. Between this and the overlying regular boulder clay there is no well marked boundary, as they pass gradually into one another, and the upper blocks in the lower deposition are sometimes a little polished and scratched. In the cutting south of the Ballyglooneen station this angular drift is over fifteen feet deep, but here there is no regular boulder clay drift over it. This angular drift has been remarked in other places also, and when it comes to the surface it forms a rocky broken country, and has been noted on the six-inch maps as rocky drift.
In the railway cuttings between Athenry and Woodlawn no polishing or striae were noted, but the rocks there, being of the earthy kind of limestone, would not so readily retain them. Everywhere the rocks, however, have those rounded and flowing outlines which would seem to indicate that they were once covered with an ice-flow.
In places the regular boulder clay drift has been denuded into ridges and mounds, some of them, to all outward appearances, like regular eskers: for these the Rev. M.H. Close, in a paper read before the Royal Geological Society of Ireland has proposed the name ‘Dunlins’, by which they are locally known in the North of Ireland. These can be well examined in the country N.E. and E. of Monivea and Athenry. In other places we find a sandy, clayey drift, like as if the boulder clay was partially washed; a good example of this was seen in the country S.W. of Castle Lambert.
Sandy drift, possibly of atmospheric origin. Occupying a part of the country over the thick bedded limestones, like those of the Burren country, are large heathery tracts. The drift in these places is very siliceous, or for the most part made up of particles of chert. This kind of drift sometimes lies on the limestone, at other times on the older kinds of drift; but wherever it occurs, there are ‘swallow-holes’, ‘pot-holes’ or ‘sluggies’, varying from a few feet to many yards in diameter, in some places close together, in others scattered about. From this it would seem that the limestones, or the limestone gravels, have been dissolved by atmospheric agencies, that the calcareous matter has been carried off in solution through the sluggies, that the sandy drift is formed from the insoluble siliceous matter contained in the chert and the clayey matter in the limestone, and as the siliceous matter is the most abundant it gives the character to the drift. In a few places we find a good brick clay in the hollows round sluggies. When the sandy drift overlies the boulder clay or other gravels, it destroys their natural fertility. In some low-lying places this sandy drift may have been carried down from the adjacent high land on to the boulder drift; but when we find it occupying high land, it seems to have been formed where we find it. A good example of this occurs about a mile north of Belleville. Here, in the cutting for the Tuam and Athenry Railway, we find the boulder drift, over thirty-five feet thick, is capped with sandy drift. It is full of swallow-holes, and occupies high ground, so that the sandy drift would seem to have been formed where we find it. To the north of Monivea there is a wild heathery tract on this sandy drift, miles in extent. Here it can be well examined, sometimes lying on the rock, and at other times having one of the older drifts intervening between them. It is also found in various other places in Sheet 106, more especially to the N.W. of Athenry, between that place and Turloughmore.
Bogs and Alluvial Flats
These are very numerous toward the east in the country occupied by earthy or calpy limestones, in fact most of that country is covered by them. They also occur to the N.W., in the neighbourhood of Claregalway and Turloughmore. Those to the east consist of deep, extensive peat bogs, with alluvial flats along the river. Parts of the bogs are very wet and soft, and small lakes are numerous in them. In one of these called Lough Nahinch, there is a small island that looks like a crannog, but unfortunately no boat could be procured to examine it. This lake is situated immediately outside the N.E. margin of Sheet 106.
In places there is a marked difference between the levels of the surfaces of the bogs. About three miles east of Monivea, for instance, the bog round Lough Cornal is sixty feet higher than the bog half a mile to the westward. The bog about two miles S.E. of Athenry is remarkable, as it lies on shell marl, having a most uneven surface, being all in hills and hollows; some of the former going up over three feet into the bog. A good section of them is exposed in the new cut along the parish boundary.
In these bogs the principal trees found are oak, fir, sallow, yew, and birth. Thomas Underwood, Esq., M.D., of Loughrea, informed me that in Clooncah bog, which is situated about the centre of the junction of Sheets 106 and 107, red deer horns were found. A branch of an antler he had in his possession is most remarkable, as the tines form a cup-shaped bunch at the top, and there is only one at the side. Dr. Melville, of Galway, to whom I showed it, is inclined to think that it belonged to a very old animal.
While opening the new river through the Turloughs, at Turloughmore, numerous deer’s horns and bones were found above the rock cutting west of Knockdoe. My informant, Mr. Roberts, County Surveyor for the West Riding of Galway, was not able to tell me what kind of deer they belonged to, or what has become of them.
The flats and bogs W. and N.W. of Claregalway are part of the flats around Lough Corrib, which extend out of the district to the west (Sheet 105), in which the south part of that lough is situated. Coarse bricks are made out of some of the clays raised here. The shell marl is most beautifully laminated in some places. This can be well seen in a cut two miles W. of Claregalway. Dr. Mellville kindly furnished me with the following list of the fossil shells found in these marls;
Limnes, stagnalls,
—— peregra,
Bithynia, teutaculats,
Valvata piscinalis,
Planorbis marginatus,
Cyolas cornea,
Succines, putris.
From this it will be seen that they all inhabit the lakes and marshes of the country hereabouts at the present day. In the new cut for the river about two miles eastward of Claregalway, the following section was noted;-
Feet
5 Alluvium, 1.25
4 Peat 0.75
3 Unstratified marl from 4 ft to 5.00
2 Stratified marl from 3 ft to 4.00
1 Boulder drift over 5.00
16
In bed No. 2 there are blocks of limestone round which the marl ‘curls’ in lamina; it also curls round the blocks that protrude up out of bed No. 1.
Brick Clay: Coarse bricks are made out of clay raised east of Cross House, which lies near the N.E. corner of Sheet 106, and out of clay raised in the flat on the N.E. of Athenry. They are also made from clay found in the alluvial flats along the Cregg River, at the west of the district. In the latter place they get from 7s. to 10s. a thousand for them. The brocks are coarse and ill-favoured on account of the calcareous matter contained in the clay.
The age of the clay near Cross House is uncertain, but the clays in the other localities have undoubtedly been deposited during the formation of the alluvial flats and bogs.
