261

EXCURSION TO BELGIUM AND THE F HENCH ARDENNES-BRUSSELS, GTVET, DINANT, NAMUR, GROTTO OF HAN, &c. AUGU ST 10TH TO 15TH, 1885.

Directore : M. En. DUPONT, Director of the Royal Museum, Brussels, and of th e Geological Survey of Belgium; Prof. J. G088KLET, of Lill e ; Dr. J. C. PURVES, Geological Survey of Belgium.

(R eport by THE PRESIDENT an d MIss MA RY FORSTER, Lecturer in Geology and lJenwnstrato1' in Botany, B edford College, L ondon.)

PART I, BY THE PRESIDENT. The ordinary Excursions of the Association are necessarily con­ fined mainly to the immediate neighbourhood of London. At Easter or Whitsuntide it is possible to visit the outlying Cretaceous or Jurassic areas j but it is only during the Long Excursion that we can make acquaintance with th e older rocks. Renewed interest has of late years arisen with respect to the geology of the London Basin, in consequence of the numerous discoveries beneath it of P alseozoic rocks, and especial importance attaches to such stu dies as the Associat ion can give to th e outcrops of th ese rocks. These older rocks lie with an east and west strike in th e W est of En gland; th ey pass beneath the J urassic rocks of Gloucester­ shire, are proved by borings near London, and either crop out or are proved by borings and sinkings along a winding line througb th e North uf France, the Sonth of Belgium , and far into Germany. Th e Associat.ion visited t he western outcrops of these Palreozoic rocks in 1880 at Bri stol and the Mendip s, and in 1884 in Devon­ shire j in 1878 th e Association visited the Boulonnais, and there studied the nearest outcrop on th e East of London. But it is in the South of Belgium and in the French Ard ennes that the Devonian and Carboniferous rocks are best seen, and have been most carefully studied. It was, therefore, resolved to tak e the Long Excursion of 1885 in that region. The geology of Southern Belgium is extremely interesting in itself, but is especially so to En glish geologists for the light whieh it throw s on many questions of importance to us. The memoirs by De la Vallee Poussin and R enard on the alt ered and ign eous 262 EX CURS!O:;" TO lI E I, Gl u)1 AND TH E F RENCH ARD EN NES. rocks of th e A rdennes rank among the chief authorities upon questions of this kind. Prof. Bonn ey has poin ted out how closely some of the porpb yroids of the Meuse resemble some in Charn­ wood F orest. It is interesting to note that 0111' En glish area is also in a "Forest of Arden," that being the Celtic name alike of th e g reat wood in Cent ral En gland , and of what we more commonly now kn ow as " Th e Ardenn es." The Devonian series, as described by Prof. Gosselet , is more fully developed, and h as more distinctiv e fauna s, th an with us. Various class ifications hav e been proposed for th ese beds; a synops is of th em is given in Appendix I , p. 28 l. Th e Valley of th e Meuse will probably in future be regarded as th e typical locali ty for th e Cnrb oniferous Lim estone in its full de­ velopment. We th ere may study a vast mass of strata, almost wholly calcareous, but in which clearly marked sub-divisions have been established and fully mapped out by M. Dupont, whilst their vari ous faunas are being describ ed in th e splendid monographs of M. de K oninck, In E ngland no such well-marked horizons in th e true Curboniferous Lim estone hav e yet been map ped, although the recent work of Mr. G. H. Morton, in W ales, shows us that more may be dono in this matter than has hitherto been attempted; but in these islan ds we cnn est ablish an important change in tracing th e limestone series from south to north, th e thi ck lime­ ston e of South Wales and the West of England becoming split up by shales and sand stones with coals, as we go northwards. Tho incoming of this type of the Lower Carboniferous rocks has been studied by the Association dur ing its Excursion to Derby shire, and a fnr th er advan ce in the same directi on during tho Excursion to the W est Riding of Y orkshi re." The original Ruggestions for the Belgian E xcursion included a visit to the alt ered Cambrian rocks of th e French A rdennes, with their porphyroids and amphibolites; and for thi s the paper by Prof. Bonney (p. 247), was prepared. This part of th e scheme , however, was subsequently abandoned, and we were able to give the more time to the Devon ian rocks of Belg ium. In exploring th e Valley of the Meuse, we traversed II region which has been th e scene of mUIlY important excursions. Fifty years back, in Septe mber, 1835, at an E xcursion of t he Geological

• 'Peoe. Geol. Assoc.,' Vol. v, pp. 186-100; Yolo vii, pp. 420.438. EXCURSION TO BELGIUM AND THE FRENCH ARDENNES. 263

Society of France, Belgian, English, and French geologists met at Mczieros, and explored the Valley of the Meuse to Namur. In the list of twenty-five geologists present, we find the names of Buckland, Greenough, Jameson, and Johnstone, with those of Buvignier, Constant Prevost, Dumont, d'Omalius d'HalIoy, and Schmerling. Of the whole party. probably only one-Professor Victor Hanlin, of Bordeaux-still lives. Forty-eight years later, in September, 1883, the same Society traversed almost the same route; and the Report of that Excursion" should be consulted by those who wish for fuller information respecting the Valley of the Meuse than is hereafter given. MM. Dupont and Gosselet, two of the foremost leaders in the later Excursion, were also our chief conductors. The French area traversed by us is that surveyed by Prof. Gosselet for the Geologieal Survey of France. His detailed mapping is published in sheets 'Givet' and 'Rocroi,' and his explanations of the district in numerous papers. The full offieial memoir, 'Description Geologique de l'Anlcnne,' is now in the press. On crossing the Belgian frontier we passed into the domain of M. Dupont, and traversed the region long sinee made famous by his cave-explorations. In after years he returned to the dis­ trict, as Chief of the Belgian Survey, and produced the beautiful maps to which reference will presently be made. Dr. Purves, formerly Curator of the York Museum, now on the staff of the Belgian Survey and the Brussels Museum, who had taken upon himself the chief burden of the arrangements, was constantly at thc side of MM. Dupont and Gosselet, translating their remarks. The Association is deeply indebted to these gentlemen for their services. The enthusiasm with which tho thanks of the ex­ cursionists were given to M. Gosselet at Givet, and to MM. Dupont and Purves I\t Rochefort, and the kindly manner in which these thanks were received, will not soon be forgotten by those present. The other officers of the Belgian Survey who accompanied us were MM. Hutot and Van Den Broeck; the latter, from his knowledge of English, being of much service. M. Ie Due, the special attendant of M. Dupont, well armed with pickaxe, hammer, and chisel, was always at the service of the Members for breaking .. , Bull. Soc. Geol, France,' ScI'. 3. tom. xi, pp. 625-730. 264 EXCURSION TO BELGIUM AND THE FRENCH ARDENNES. down rocks, searching for fossils, &c. M. Paul Jansen, a member of the Belgian Parliament, who has since joined the Associa­ tion, formed one of the party; as also did M. Hovelacque, Secretary of the Geological Society of France. Generally it has been possible during the" Long Excursion" to make one town (or sometimes two) the headquarters for the week, by which arrangement the loss of time and the inconveniences in­ volved in constant changes have been avoided. But it was im­ possible to do this in Belgium j the points to be visited were far apart, and it was necessary to shift quarters frequently. The officers of the Association thought that possibly from thirty to forty Members and friends of Members might be induced to make up the party if the programme were sufficiently attractive, and many fears were expressed that it would be impossible to provide with comfort even for this number in a succession of small towns. The number, however, much increased; and nearly seventy left England, whilst with the Directors and other French and Belgian geologists who joined the party in Brussels or later on, the total number amounted to about eighty. The arrangements for travelling, hotels, &c., wcre all made by MM. Dupont and Purves. So admir­ ably was the Excursion planned, that this large party travelled with comfort, and carried out in detail every item of the week's pro­ gramme j in fact, with the single exception of a change in the hotel at Namur the Circular explaining the arrangements might be taken as the "Report" by a simple alteration of the tense of the verbs. The Brussels Muscum, by permission of M. Dupont, was used as a meeting-place by the Members, as at different times and by various routes they arrived in Brussels. A book was kept by M. Beclard, the Secretary, in which names and addresses in Brussels were entered. The Museum is the headquarters of the Belgian Geological Survey, of which also M. Dupont is Chief. The methods adopted by the Survey were fully explained here and in the field, and the maps of the officers were at our service during the week. The Association bad, therefore, excellent opportunities of testing on tile ground the value and accuracy of the maps. The sheets of the Belgian 8urvey Map, which have been produced entirely under M. Dupont's direction, stand quite alone for beauty of execution and minuteness of detail. M. Dupont has solved the EXCURSION TO lIELGIUM AND THE 1"RENCH ARDENNES. 265 difficulty of indicating upon th e same map the superficial drift deposits and the underlying rocks. The maps show by deep colour the actual rock-exposures; by lines, bordered with faint washes of colour, the known or inferr ed ran ge of the rocks; by oth er tin ts the distribution of th e superficial beds. A special point with this Surv ey is the care taken to prove the solid rocks when concealed by soil or drift. The surveyors and th eir assistants carry boring­ tools, which prove the depth and nature of the drift-to a depth, if necessary, of about 30 feet, and the character of th e solid rock beneath . Each boring is marked on the map, so that almost the whole evidence present to th e mint! of the surveyor is pr esented also to th e student. The scale of the map (1 : 20,000, 01' about 3 inches to one mile) allows this to be done with ease, whereas on a smaller scale it would be impossible. The 'I Explications" accompanying the maps contain sections illustrating the structure of the country; whilst the palreontology is worked out in the' Annales ' of the Museum. Minor points, th eoretical questions, and preliminary notices are printed in th c , Bulletin.' Few palreontological discoveries in Europe of recent years have equalled in interest those made at Bernissart, where, in sinking a shaft to the Coal-Measure s, a ravine or hollow was met with, in the Carboniferous rocks, filled with deposits of W eelden age, con­ taining large quantities of Deinosaurians, Crocodiles, Chelonians, Amphibians, and Fishes. The material thus collected will give wurk for many years to come, but much pr ogress has been made in studying the objects of gr eatest interest, especially the Iguano­ dons and Crocodiles. The magnificent specimens of Iguanodon B ernissartensis and J. lrlanlelli have been restored and mounted hy M.L. Ii'. de P auw, and form striking objects, placed as they are in a special glass building in the courtyard of the Museum. Mr. L. Dollo has published figures and descriptions of th ese remarkable Deinosaurs in the Bulletins of the Musee Royal, as well as of several other forms, including some of Crocodiles, Chelonians, and Amphibians. Another species which attracted much attention was the skeleton of Hainosaurus, from th e phosphatic chalk of Mons, a form nearly allied to 1rlOSa8mI1'US . From the same locality, but from beds of Lower Eocene age, was a femur of Gastol'nis, of in­ terest to our Members as being similar to remains of the same 266 EXCURSION TO BEL GIUM AND 'filE FR~NCH ARDENNES. gigant ic bird recently discovered by Mr. Klaassen at Croydon, and descri bed by Mr. E. T. Newton. All these specimens were explained by 1\1:. Dalla, who most courteously plac ed him self at th e disposal of the mem ber s of the party who visited th e Museum j he conducted th em over the work­ shops in th e ba sement, and explained the methods by which the bones are extracted from th e matrix, restored and mounted. Part of this basement has once been a chapel, and within the lofty gothic arches of this the great Iguanodons are built up. Amongst ot her th ings for which th e Brussels Museum is famou s, reference sh ould be mad e to th e great collection of Mammalian remains, cbiefly Cetacean, from the Crag of Antwerp. These were obtained some years back, when the fortifications of that city were in course of construction; they have since been described by M, Van Beneden. On Monday afternoon, at 2 o'clock , the members assembled in the Museum, and were received by M. Stas, the Chairman of the Commission of Control, and by M. Dupont. There were also present Dr. Purves, and MM. Rutot, Van Den Broeck, Dollo, and others. After the formal rec eption th e party adjourned to the semi­ circular gallery of the Museum known as th e "Salle des Cavernes," where M. Dupont delivered an address descriptive of the contents of this department. At the conclusion of this address its sub stance was translated by Mr. Rudler, who ha s also snppli ed the following paragraph r-> "In 1864, a time when th e subject of the antiquity of man was attracting much attention, th e Belgian Government, at the solicitation of the Royal Acad emy of Sciences, commi ssion ed M. Dupont to explore the caves of Belgium. This investigation occupied about seven years, and resul ted in the collec t ion of a vast number of sp ecimens, which are systemat ically arranged in the Salle des Cavemes.· 'I'h e most litriking feature in this gallery is a series of almost entire skeletons of the great Carnivora of the caverns-the cave-bear, cave-lion, and cave-hyrena. In the upper * For a description of these caves the following works may be consnlted :- • Notices preliminairea sur les Fouill es executees sous les auspices du Gouverneinent BeIge dans les Cavernes de Ill. Belgique' Par M. Edouard Dupont. Bruxelles, 18tH. , L'Homme pendant les Ages de III Pierre dans les environs de Dinant­ aur-Meuae.' Par M. E. Dup ont. 2nd ed. Bruxelles, 1872. EXCURSION TO BELGIUM AND TH~ FRENCH ARDENNES. 267 part of the wall-cases in the semi-circular gall cry are picturesque sketches of the principle caves, accompanied in each case by a plan and geological section. The relics of human industry are dis­ played in a series of table-cases, and include a large number of worked flints, carved pieces of reindeer-antler, perforated shells, and even fossils to be worn as ornaments, a piece of fluor-spar bored for use as II decorative object, nodules of iron-pyrites for striking fire, &c. From the Cave of Frontal, near Furfooz, in the lower valley of the Lesse, were obtained several fragments of a round-bottomed urn in coarse pottery, supposed to be one of the most ancient examples of Ceramic art in existence. It is referred by M. Dupont to the Reindeer age, and was probably suspended in a sepulchral chamber, the Cave of Frontal having been a place of sepulture in late Palseolithic times. This cavern, discovered by 11. Dupont, was named in consequence of having yielded a human frontal bone; and subseq uently two human crania were disinterred from this cave. Another extremely ancient relic of man's exis­ tence in the Belgian area is preserved ill this gallery. This is the famous lower jaw-bone from the Cave of La Naulette-a Cavern situated on the left bank of the Lesse, which has yielded a long catalogue of extinct mauimalia, includiug the mammoth and woolly rhinoceros. The jaw-bone of La Naulette is supposed to have belonged to a contempoi ary of the mammoth." Before leaving this room the general business arrangements for the week were explained by the President and Secretary, after which the Members dispersed through the Museum, under the guidance of the various officers. All met again at the Station du Midi later in the afternoon, and then took train for Charleroi.

PART II, BY MISS FORSTER.'" On Tuesday morning the party left Charleroi for Cerfontaine, and commenced work, under the guidance of M. Dupont, in the rail­ way-cuttings and spoil-heaps between that place and Senzeille, where excellent examples of the Frasnian and Famennian beds were seen. The Frasnian beds are nodular shales. M. Dupont pain ted out that they may be distinguished from the similar shales of Mariembourg overlying them, which also contain limestone nodules, by the absence in the Frasnian of C!Jl·tia Murchisoniana. * This report has been submitted to Prof. Gosselet, M. Dupont, and Dr. Purves for their approval or correction. :268 EX cunSION TO BELGIUM AND THE FRENCH ARDENNES.

On th e shale-heaps bordering the railway many fossils were found, that specially characteristic of the Frasnian being Rhync!lO­ nella cuboides.'" Passing into th e shales of Senzeille in the Famennian, the fossils were still more numerous. 1\1. Dupont showed that th e beds may be recognised by Rh ynchonella Omaliusi replacing R. cuboides, and by the presence of Cyr tia M urchisonia na. The dip is to the south or south- east. These shales are represented in North Devon by th e Pil­ ton Beds, but Cyrtia is not found there, th ough it occurs in Russia. Th e shales of Mari embourg, also containing Cy rtia, were shown to be distinguishable from those of Senzeille by th eir arenaceous character and by R. Dumonti replacing R. Omaliuei, Th ey also con­ tain layers of psammite, Proceeding still to th e sout h-east along the line, M. Dupont showed Frasnian beds again brought up containing R. cuboiues, and to the east of the tunnel of Senzeille, diverging into th e wood on the left, the Frasnian limestone was well seen in a marble quarry. M. Dupont explained that this mass did not show any bedding, and he considered it to have been built up as a coral-reef, it being, in fact, an atoll. It is surrounded by shales, among which it stands up in a dome-like form. The g round-mass of this limestone is pink from oxide of iron. The corals, which are whit e, consist of Stromatactis and Acervularia, and were well seen in polished blocks in the quarry. In the Frasnian shales of Matagne It few specimens of Cardium palmatum were found. After a walk of about four miles, lunch was provided at a small inn in the village of R oly, where, the accommodati on being insuffi­ cient for the party, a tent was erected. The arrangements proved most satisfactory to the geologists, and when th e g reat round tarts of th e country were brought in they greeted th em with a ringing cheer. Near Roly a detailed examination of the country WaS made, in order to hear from 1\1. Dupont, on the ground, a further explana­ tion of his theory of coral-reefs as applied to the formation of the Devonian and Carboniferous coralline limestone. The Frasnian limestone at Roly lies in the form of an elongated ring (see Fi gs. 5 and 6, p. 235), which 1\1. Dupont regards as an atoll,

It Th ese beds are probably of the same age as those discovered by borings a t Turnford and 'I'ottenham Court Road. Mr. Ether idge not iced R hYllchonelia cuboides and Spirijer disjuncta (8. VC1 "nCU li) from both borings. These shells are especially characteristic of the F ra snian. EXCURSION TO BELGIUM AND THE F RENCH ARDENNES. 269 showing all the essential characteristics of the atolls of our prese nt seas. Thi s structure consists of two larg e masses of Pachpstroma limestone, dolomitised in many parts, which emerge par allel to each oth er from the midst of F rasn ian nodular shales, over which lie Cardium -palmatum shales . A little hill ock of grey S tromatact is limestone, on which a shr ine has been built, stands a short distance off in the plain, and is immediat ely surrounded by Cardium-pal­ matum shal es. A num ber of similar small eminences continue the line of th e two principal masses lat erally, forming with th em an ellipse. The hollow, in its midst , is filled with shales from th e denudation of th e land surface , and of th e coral formed in th e sea. The exclusively corallian character of th ese limestones is clearly shown by the presen ce of the reef building corals. The mollusca are the same as th ose found in th e red marbles (seen ncar th e tu nnel), but the genera of corals are quite distinct. Th e red lime­ stone always underlies th e grey. The Paehsjstroma limestone is blue, with calcareous veins, formed of an agg lutinated coral mud. On th e margin of the masses are nodular limestones formed of a mix­ ture of shale, calcareous matt er, and cora l sand. Large pieces of hroken cora l were seen in them, with a net-work of clay in their interstices. Near th e reefs the shales contain Stromatopora , but not further off. M. Dupont point ed out that the beds of grey limestone are arranged in the shape of a dome, and th at the nodular limestone and Cal'dium-pa lmatwn shales invariably rest on them, and must therefore have been deposi ted subseq uently, and may be regarded as material filling up the spaces between th ese eminences. Before leaving thi s interesting distr ict 1\1. Dupont was able to gu ide the party to a section where the nodular limestone was to be seen lying against the reef. He explained th at numerous other examples of atoll formation occur in th e neigh bourhood, whilst the long lines of coral limestone to the north and south are regarded by him as " fringing reefs" of th o Devonian Sea. The drive from Roly to the st ation of Matagne was accomplished in conveyances remarkable for th e ent ire absence of springs. Wh en the train came in, seven of th e party, who had been lost earl ier in th e day, were found to have joined it at Mariembourg. At Givet Station a long det enti on was occasioned by the num erous bags of th e party being submitted to th e Custom-house officers. After dinner, at th e Hotel d'Or, a curious sight was witnessed 270 EXCUR SIO~ TO n EL GIU~1 AND THE FRENCH ARDEN NES . on the bridge over the Mouse. Th e gas-lamps were surrounded by thousands of white May-flies, constantly falling dying to the ground, which was covered wit h them like snow. The whole of W ednesday was spent in France. Prof. Gosselet became leader, and, before enter ing on the work of the day, con­ ducted a party to th e right bank of th e Meuse to see th e sections of th e Givet Limestone th ere visible. La rge specimens of St roma­ topora were seen on th e face of th e cliffs, and Strinqocepha lue Burtini also occnrs. Ou the hill to the south of the bridge, how­ ever, in lower beds of the Givet Limestone, Strinqocephalus is abundant and Stromatopora very rare. Professor Gosselet directed th e attention of th e party to th e section on the opposite or left side of the river, where stand the fort ifications, pointing out th e well-marked fault called " F aille de Charlemont" in the Eifclian beds of Calceola sandalina, On the way to the station, on a hill to tbe left of th e Walcourt Road, the shales of Mat ag-n e were shown; here C ardium palmatum and En tomostraca were found . Train was t.hen taken from Givet to F umay, and the rest of th e day was devoted to an exami nation of th e banks of the Meuse from Fumay to Vireux, under the guidance of Prof. Gosse1et. F ollowing the high road on the left bank of th e river, he pointed out t he Cambrian beds of Devillian and Revinian nge, equivalent.t o those of Harlech. Th ey consist of black slates resting on violet slat es and quartzites. Th e first beds seen on leaving the village were violet slates, which showed num erous plica tious. Iron has been dissolved out of th is slate, leaving cracks, which have been filled in with a siliceous mat erial, which is, ill fact , almost pnre silica. The quartzites form masses, in th e midst of which violet slates are intercalated. The second band of slates is that of St. Ann e. It is extensively worked by tu nnels further north , where it is brought up again by a fold. A fine perpendi cular rock, forming part of the third slate band, called the "Rock of thun der and lightning," is seen on the left side of the road. It has been thrust over, forming innumerable small plicatious , by a force coming from the south. This distur­ bance was anterior to the deposition of the Devonian Beds, for th ey can be seen lying horizontally on th e edg es of the se plicated rocks. Near Haybes the green shales were seen, and a successful search for Oldhamia radiata was made. EXCURSION TO BELGIUM AND THE FnESCH ARDENNES. 271

Near this point th e Devonian Beds cover th e Cambrian, and here a go od example was seen of ovcrfold and in version , for the Cam­ brian black slates ha ve been thrust. from the south over th e Dev onian conglom erate and arkose. It is not long since th e reversed order of these beds was considered th e true one j th e error ha ving been correct ed by th e evidence of the palreontologi st. Prof. Gosselc t sta led that the Cambrian had never been wholly covered by Dev onian. Her e th e Cambrian cliff stood up during Silurian ages till th e Devonian Beds were deposited on its borders. In some sections the Cambrian is seen cau ght in among the D evonian. After a halt at Fepin, the party crosse d th e riv er to the arkose quarries opposite th e villag e. From th e boat a fine view of this im­ portant section is seen, and here th e leaders explained the principles of mountain-making which have rul ed over a wide ar ea in many successi ve geological periods. In a large number of case s, as here, th e beds ha ve been thrust laterally from suuth or sout h-east to north or north-west. Between Fepin and Givet all the sub­ d ivisions of th e Lower Devonian ar e seen. From F epin, as far north as Vireu x, th er e are many minor folds in th e beds j but the g eneral success ion is an ascendin g one with a north erly dip. At Vireux, however, th er e is an isocline, and to th e north of this the beds ar e inverted as far as Givet ; th e dip is south, and the beds successively seen as we go north, thoug h apparently older, are really newer. At <1ivet there is a g reat fault in th e limestone, and beyond this the normal dip is resumed. Prof. Gosselet then fully explained th e points to be not ed in thii> secti on, and its bearing on th e general structure of the dis trict. Th e followin g parag rap hs are fr ee t ran sla tions of his desc ription of the same place g iven to th e members of th e Geologi cal Society of France at t.heir E xcursion here in September , 1883.· " All th e base of th is escarpment, as well as it s easte rn porti on to th e summit, is form ed of shales and quartzites of Cambrian age, in clin ed 32° to the sout h-east. Th ey may be seen also in th e ra ilway­ cutting in the middle of th e villag e of H aybcs, Th e F epin rock is of a different character, being a congl omer ate of rolled pebbles, some of which attain enorm ous dimensions, and weigh more than 5,000 kil ograms. It abuts against th e older rocks of th e eas tern part of th e * ' Bull. Soc. Geol. France,' Ser. 3, tom. xi, pp. G73-67G. See also the two illustrations there given. 272 EXCURSION TO DELGIUM AND THE FRENCH ARDENNES. escarpment. The line of contact, after remaining for some distance vertical, suddenly takes a horizontal direction, and the Devonian conglomerate is seen resting on the edge of the older shales, as at Linchamps, This position is maintained for more than 100 metres. Thus at Fepin, as elsewhere, there is an unconforrnability between these beds. "The conglomerate was deposited horizontally on Cambrian beds. But later, when the great thrust occurred from the south to the north, which caused the upheaval of Haina ut, its southern portion was raised, and even over-turned on to the northern side without rupturing the beds. " As to the Cambrian slates, which had been the intermediate agents of the thrust, they at first preserved their position as if they Lad acted as a mass, but afterwards continued to follow the move­ ments which they had impressed on the conglomerate. It thus happened that the layers of shale slid one over the other, but always remained parallel to each other. " The arkose quarries occupy three levels. In the lowest quarry the exceptional contact of arkose with Cambrian beds is seen. The arkose has been forced under the slates, so that the slates have been forced into the arkose and the arkose into the slates without the general stratification of the two beds being disturbed. A lateral pressure is the only one that could produce snch a result, "It would be supposed at first sight that the beds of arkose were pushed up against the fault, but the contrary is the case. All these beds dip towards the fault, and those Revinian slates nearest to it are the more recent. The condition of the quarry in 1878 did not enable me then to recognise this structure, but it is now quite obvious. ,. Towards the centre of the quarry a very irregular fault is seen, which the quarrymen have designated' The Horse's Head.' It is formed of dark arkose, alternating with shales of the same colour, and belonging to the lowest zone of the beds. Towards the south the fault continues with an irregular course till it encounters the Cambrian shales. But to the north, by reason of another fault, the white arkose abuts against the head of the horse, and on walking towards the north to the extremity of the quarry, black arkose is found, different from that of the Horse's Head. " Thus in this quarry the arkose is divided into two portions, both reversed towards the south, and each dipping towards the Devillo-Revinian Cambrian mass." EXCURSION TO BELGIUM AND THE FRENCH ARDENNES. 273

Prof. Gosselet attributed the arkose of Fepin to disintegration of tourmaliniferous pegmatites of some part of the Ardennes massif. It is comprised mainly of kaolin, quartz, clastic chlorite, and elastic tourmaline and mica. It is, in fact, a felspathic grit. It forms the lowest bed of the Lower Devonian, except the con­ glomerate of Fepin, not seen here, but occurring close by. The arkose is used for pavements, and is valuable as not becoming polished and slippery. The shales of Mondrepuits occur in the woods above the arkose. The Association had not time to visit them, and were not able to see them from the road, as harder rocks underlie them. Proceeding on the Givet road, at less than a mile from Fepin a beautiful section ill red and green shales of Oignies carne in sight. It is non-fossiliferous, and shows in a striking way the difference between stratification and cleavage often seen in the Ardennes, harder layers occurring between the cleaved beds, the former consisting of arkose and the latter of variegated shales. The metamorphism causing cleavage in the shales did not affect the harder rock ill that way, but it had a different effect, re-converting the kaolin of the arkose partially back to felspar. When occurring in a zone of metamorphism, the shales of the Lower Devonian are, like those in the Cambrian, converted into slates. The shales of St. Hubert, which are the upper beds of the Gedinnian, were passed opposite Risdon. These greenish shales are not much developed here, but are alternated with a dark grey sandstone. No fossils are fonnd in it, but they occur abundantly in the sandstones of Anor. On the right bank of the Meuse they are abundant, and some way up in the wood on the left of the road most of the fossils mentioned by Prof. Gosselet (Vide p. 2:m supra) were found. The Grauwacke of Montigny followed next above the Anor beds. Part of it is very fossiliferous. Many fossils, including encrinites, were collected. Further on, the black sandstones of Vireux are seen, which are worked for pavingstones j then the red shales of Burnot resting on them. Here they contain no conglomerates and no fossils. On arriving at Vireux, after a walk of about eight miles, there being still some time before the train left, Prof. Gosselet conducted some of the party to a point of interest west of VOL. IX., No.4. 20 274 EXCURSION TO BELGIUM AND THF. FHENCH ARDENNES. the town. The valley of Viroin here breaks through the escarp­ ment just where the red shales follow the black sandstones. In the railway-cutting the party sawall the series of red shales reversed ann highly inclined. They are reversed all the way to Givet. The sediment composing these beds is extremely £ne, so that they retain impressions, which are generally of the most temporary character. Prof. Gosselet showed a bed with im­ pressions of rain drops, others with annelid-tracks, ripple-marks, and cracks. Polygonal markings were seen on one, due to the drying up of a wet surface, and Prof. Gosselet has even found prints which he attributes to Medusee, and which may be seen by any Member of the Association who visits him at Lille. The Grauwacke of Hierges, brought up here by the inversion, is very fossiliferous, containing Spirifer cultrijugatus and S. arduenneneis, The return to Givet was then made by train. On Thursday the whole party embarked in a steamboat for Namur, The Belgian frontier was soon crossed, and M. Dupont again took the lead. The Meuse in this part of its course traverses the Devonian and Carboniferous beds transversely, and thus sections occur which show these rocks and their relations to each other in the best possible manner. (See Map, Fig 9, p. 240.) The Frasnian beds were left behind near Givet, as the river passes into the Famennian, forming escarpments consisting of shales, psam­ mites with calcareous nodules. sandstones and nodular argillaceous limestones, representing, according to Prof. Gosselet, the shales of Senzeilles and Mariembourg, the shales of Sains, and the Lime­ stones of Etrreungt. These beds have been thrown into a series of fine folds with varying dips; but their general inclination is to­ wards the north. From these limestones of the Upper Devonian, which are more or less nodular, the beds pass, as Hastiero is approached, without unconformability, into the Carboniferous Limestone. Those first seen are all crinoidal beds, the limestone of Tournai. This forms the great building stone of Belgium, called "Ie petit granit." Below Hastiere, on the left, beautiful sections are seen, showing very clearly the bedding of these rocks, with plications and faults. This region has indeed been greatly dislocated, so that in some places the Devonian psammites have been thrust in among the Carboniferous Limestone, The Waulsort limestone next seen, is not essentially crinoidal, EXCURSION TO BELGIUM AND THE FRENCH AR DEN NE S. 275

Further down UIC river it occurs in a corallian and non-st ratified form . Th e stratified beds also conta in ddbri« of coral. M, Dup ont expla ined tha t he considers th ese corallian limestone s to ha ve origin ated as coral-reefs, recogni sed as such by their material, th eir massive st ruct ure, and th eir irregul ar characte r, showing all entire absence of symmetry and continuity. Where near the ancient coast th ey appear as frin ging reefs, and at a great er distance from land as islets. Th e difference in ge neral con­ struction between these Carbo niferous limestones and those seen by th e Association in th e Devonian, near Roly, consists in tho channels or gaps between th e Car boniferous reefs having been filled np by crinoidal remains, instead of by nodular shales, as in the Devonian. M. Dupont considers this the only way of explaining the presence of crinoidal limest one between masses of coral lime­ stone. These masses are well seen in profile as the river cut s through their wall-like forms, and th ey have been rendered more strik ing by a lateral squeeze they hav e received, making them higher and narrower, while the beds of crino idal debris between hav e been given a basin-shaped cur ve , or even crushed together so us to be almost horizontal. Th e corals which built up these reefs are the Stroma­ toporoids Strom atocus and Ptylostroma, forms nearl y allied to th e Stromatactis of Devonian reefs. This limestone has become par­ tially dolomitised. Above Waulsort a bend in the river brings it again into Famen­ nian st rata, but at Waulsort the crinoidal Carboniferous limest one, similar in character to that of Hasti ero, recur s. This is followed by a series of masses of " Const ructed Limestones " permeated by blue veins, and separa ted by channels of erin oidallimestone with distinct stratification. Th ese beds are palreontolog ically of th e Same ag e as th ose with blue veins, between which they are found. Most of the party now disembark ed and walked three miles along the left bank of th e riv er, in orde r that th e construction of the rocks might be seen to greater advantage. Caverns in th e limestone were pass ed, and were explained to be th e rema ins of a necropolis of neolithic age. The boat was rejoined at th e Chateau de Freyr. From time to time the Upper Carboniferous limestones of Vise were passed (see Figs. 9, 10, 11), brought in at several points by folds. They are form ed of foraminifera (Saccamina, E ndothyres, 276 EXCURSION TO BELGIUM AND THE FRENCH ARDENNES.

Valvulina), amongst which fragments of Stromatoporoids occur. Opposite Freyr this limestone is interposed between two corallian masses, and is markedly detrital. It resembles the debris which is formed on the edges of recent reefs from the action of the waves. Between Freyr and Moniat (see Fig. 8, p. 238) the valley con­ tinues to cut through numerous examples of coral-limestone masses, separated by channels filled with the limestone of Vise or isolated portions of the limestone of Tournai; but at Moniat an anticlinal fold brings the Upper Famennian again to the surface. These psammites are followed by the Middle and Lower Famennian in a series of psammites, " Macignos "* and shales. On the approach to Dinant the Carboniferous limestone re­ appears, the Roche-a-Bayard being in Waulsort limestone. Other crinoidal limestones with thick beds of phtanites follow. Then appears the compact Visean limestone, but no traces of the con­ structed limestones so common between Hastiere and Moniat. A little further on, close to the entrance to Dinant, the same series is brought up by a fold at the Rocher-du-Bastiou. M. Dupont regards this point as one of equal interest with the atoll of Roly. The same series reappears that was observed at the Roche-a-Bayard, agreeing with that also in the absence of corallian masses; but at the distance of about one and a half miles on the right bank of the Meuse a hillock of massive limestone, with blue veins, is to be found, surrounded by Visean limestone. After a halt of an hour at Dinant the party proceeded towards Namur, Between Dinant and Houx higher Carboniferous beds were noticed consisting of coal-shales without coals, forming the lowest beds of the Coal-Measures. Above the valley which enters on the right near the bridge at Yvoir, the Devonian beds come in again, and Famennian alter­ nates with Oarboniferous in several folds. The Red Oonglomerate of Burnot appears at Godinne, and both Middle and Lower Devonian near Burnot. In a discussion on the origin of some rocks of Devonian age, Prof. Gosselet remarked that he could not accept the state­ ment that there were no fish in the Devonian seas, but only in the fresh water of that period. Because ganoid fish are now found only in fresh water, it does not follow that it must have been the case during the Devonian epoch. The Devonian of this region * See p. 239. EXCURSIOY TO BELGIUM AND THE FRENCH ARDENNES. 277 may be compared with th e Old Red Sandstone of Scotland. No fossils ar e found in the g reenis h beds. Abou t a mile sout h of the town of Namur some of the party left the boat and visit ed a coal-pit under Prof. G osselet's guidance. He main tained the persist ency of th e Coal-Measures from here to the West of England , insisting on th eir probable presence south of L ondon. R eference was made to the great faulting and inversions to which the beds have been subjected, and especially to cases in the Boulonnais, previously visited by th e As sociation, where shafts pass through beds older than the Ooal-Measures before rea ching th e coal-seams. On Friday, arrivi ng at Grn pont from Namnr, the Association spent the day in studying th e Devonian beds in that vicinity, and had the advantage of investigating, under the direct ion of M. Dupont, those Middle and Lower Devonian beds which had not been seen at Senzeille nor by the Meuse. The party proceeded along th e railway-line, in a westerly direction from the village. Th e Calceola-shales of the E ifelian were pointed out, which were followed beneath by the Grauwacke of Hi erges (Gosselet), contain­ ing many fossils, but in a bad condition. In order to study these fossils, which are only casts, it is necessary to take a mould with putty . Theil' fossiliferous character was well seen. Among other fossils, Ph acops latifrons and Spirifer hystericus were found, as well as the characteristic Spirifer cultrijuga tus and S. m'duennensis. Under this bed the red shales of Burnot and the shales and sand­ ston es of Vireux come up . M. Dup ont explained th at the true Ardennes region, composed of rocks amongst which slates appear abundantly, commences to th e south of these red shales . The latter, easily recognisable by th eir colour, constitute a very clear line of demarcatio n in the middle of the pal eeozoic forma tion of Belgium, and the earlier observers, d'Omalius as well as Du mont were much struck by its apparent importance, Accordingly th ey traced at th e base of th e band of red deposits a stratigraphical limit of the first order, All the beds situated above thi s line, up to and including th e Ooal­ Measures, formed, according to th ese eminent geologists, a great group to which they gave th o nam e of "Terrain Anthraxifere,' suhdividing it into stages or minor groups distinguished by th eir lithological characters. More recent observers , however, stu dying these beds from a pal eeont ological point of view, were enabl ed to 278 EX CURSIO~ TO BELGIUM AND THE FRENCH ARDENNE S. corr elate them with the different terms of the modern classification, and to show, moreover, tha t although the red shales are so con­ spicuous by their colour and composition, they possess only a secondary importance in th e g rouping of the paleeozoic series, see­ ing that the fauna of the beds which surmount them is the same as that of the deposits on which they lie. Returning to Grupont by anoth er rout e, the se remarks were well borne out by the appearance of the lower part of the Grauwacke of Hi erges with Spirifer ardllennensis. As these beds rise they are found to hav e a gravelly character j but in th e high er bed of B. cultrijuga tus they do not thus change, and the beds pass on from Lower to Middle Devonian without any alt erat ion in their constitution. Again, the Grauwacke of Hierges and that of Montigny show exactly the same lithological characters, and can only be distinguished by fossils. This makes Belgian geology very laborious. After lunch at Grup ont the party proceeded along the railway­ line towards Forrisres, a dista nce of about four miles. The general arrangement and folds of the beds seen, is given in the section (Fig. 7, p. 238) . Th e E ifelian beds, g rey shales of Oouvin with Calceola sandalma, were the first seen. Th ey dip at a high angle to the south, and pass without any lith ological change into shal es con­ taining Spirifer cultrijugatus, thus showing again in a mark ed manner how important are the fauna s of the Lower and Middle Devonian in classifying the beds. The German geologists have found the difficulty in this respect to be very gr eat, and probably th e same will be th e case in Devonshire when it comes to be minutely worked out. M. Dup ont ga ve furth er particulars as to the number of species which passed on through a change of fauna, saying that as we pass from the region of Calceola into that of Spirifer cultrijugatus the fauna gradually changes till all the species are altered. There are, perhap s, from thirty to thirty-five species in the Lower Devonian ; twenty, perhaps, are special to it j and ten are common to it and to the Middle Devonian. M. Van den Broeck said that the sediments making up these rocks were deposited in comparativ ely deep water, and that the case was analogous to what was still taking place in the Atlantic, where there would be no break in stratigraphical succession since Mesozoic times, but only a change of life. EXCURSION TO BELGIUM AND THE FRENCH ARDENNE S. 27n

Passing into lower beds M. Du pont showed how th e lithological characters begin to change, while th e fauna remains th e same. The shale is more fissile t o th e north, and more calcareous and nodular. The sandy beds (Psnmmites, C., Fig. 7, p. 238), which succeed the last in th e section, can be traced over a large area. One of the beds is a g rit, but contains th e same fauna as th e oth ers, and its character seems to be accidental. Ka olin occurs in it" causing white particl es in th e rock. Spirifer hystericus was found here. Th e fossils of th e sandy beds and those of shale differ slightly. The red shales appear again from under the psammites, being brought up by a fold. Referring to the physical geog raphy of tho Middle Devonian period , M. Dupont said that there existed towards th e south a sub­ marine plateau upon which the corals could construct their reefs. In the same direction well-developed fringing reefs may he observed, and more towards the interior of th e basin, isolated coral-islands, of which a remark able example had been visited at Roly. Towards th e north, however, the depth of th e sea was too g reat for tho reef­ building corals, and this part was filled up by sediments during th e periods of th e Upper Devonian, the Carboniferous Limestone, and th e Coal-Measures. In th e northern border of th e basin a chain of narrow reefs was established by the corals. After passing the anticlinal shown in Fig. 7, th e shales and psammites with Pte rinea costata and Spirifer cultrijuqatus, a coarse sandstone or conglomerate was observed in the midst of these shales with only a local change of fauna. The greatest change of fauna is where no cong lomerate occurs. On approaching F or rieres M. Dupont said WQ were stilI near th e edge of th e Ardennes, and he again pointed out how much th e differences in th e gr ouping of th e Belgian palreozoio strata had depended upon th e data which th e several auth ors had adopted for their system of classification. On the one hand d'Omalius, and after him Dum ont, formed th eir divisions from th e differences observed in th e lith ological characters principally, whereas th e groups now generally recognised have been established almost entirely upon palreontological grounds. The Members of th e Association had had thc opportunity of observing that the red shales, which seem to have 50 remarkable a stratigraphical importance on account of their well-marked litho- 280 EXCURSION TO BELGIUM AND THE FRENCH ARDENNES. logical characters, have, in reality, none at all when their fossils come to be studied; as it can easily be shown that the fauna begins to vary only in the beds considerably above them. Thus it may clearly be seen, in the neiglibourhood of Grupont, that a distinct change takes place in the characters of the fauna; that the fossils of the Lower Devonian are rapidly replaced by those of the Middle Devonian, and yet that the mineral characters, which vary frequently and remarkably both above and below the beds in which the paleeontological change has occurred, remain lithologically the same where the fauna of the Lower Devonian gives place to that of the Middle Devonian. The same phenomenon may also be observed between the Middle and Upper Devonian. So much do their beds resemble each other in their lithological characters, that no one would have thought of tracing a limit between them had not paleeontology shown a great change in their fossils. On the other hand, where the lithological variations are most clearly marked, the fauna varies litile, if at all. Consequently it may be said that in the paleeozoio deposits of Belgium, there are no intimate relations between the changes in the characters of the sediments and the changes in the fauna. There is, in fact, a complete discordance between these two phenomena. The Association then proceeded by train to Rochefort. On Saturday morning the Grotto of Han, a few miles from Rochefort, was visited. This is the largest of a number of caverns occurring in this vicinity. It consists of a series of intersecting galleries, excavated in Eifelian limestone. The river Lesse has forsaken its former channel, and now flows through these caverns, but its course underground has not been fully explored. When the river is unusually high all the galleries are filled with water, and the overflow then escapes down the old river-bed. The plan of the passages presents a rough rectangular arrangement, which sug­ gests that the limestone has been eroded along joints. The river enters the caverns at the "Trou de Belvaux," and leaves it at the " Trou de Han." These points are 1,100 metres apart, while the course of the former river-bed is about 4,000 metres. After returning to Rochefort the Calceola-shales at Jemelle were visited, and the afternoon was spent in collecting the numerous fossils occurring there. The party then, assembling at the Jemelle railway-station, broke up, some returning to Brussels while others carried their investigations further into the Ardennes. APPENDIX I. TABLE SHOWING THE VARIOU S CLASSIFICATIONS OF THE DEVONIAN BEDS OF BELGIUM ,

A N D T IIE I R PROB A BLll C ORR EI .A TION WITH TII OSE OF T il E BOULO NNAI S AND D EVONSHIRE .

>" • <.i :; E .. Systern es " of 1i ] ]- ~ ~ .~ BOULON NA IS. D EVO NSIlIRE. Dumont. ~ ;; ~ ] ~~ ~ ~ ~ ~ ~ C) ~ i=I ::E C)'O '" f { f {P samm ites of Condroz Ficnnes Sandstone Pickwell Down Sand- · b .{ d ..: Lim estones of Etroeungt. stones a nd Cocking- S o ~ '" h I. B Condrusien* :i 0 ~ b'§ t "S:5: a es of Sam.s. ton eds, quartzo-schisteux l'-<'O.:5: c :5:;:> "o f Mane~bourg. )...... ·It{;:>l~0 l " of Senzeille PIlton Beds. {...... c.. ~ of Matagn e• .. 0 . {" Limestones of Ferques .. . ." L. • Lim estones and Shales of Fras ne J B lieu a d N } Rarn sleigh LImestone. Eifelian Calca reux ;g :::l ,g { ..,; J:::l . l eau n oces. e: ~ ~:iii l:a "of Glvet : } Lime stoneof Blacourt. {P lym outh . and I1fra- Eifc1ian quartzo- ~ ( r~ " and ? ha les of COUVln combe Limestone. hi t I r rGra uwa cke of Hierges , Sandstone Shales and sc IS eux I Red Sha les (and Conglom erat e) of Burn et. Conglom erates of Ahrien .. .. . I.II Sa nds tone of Vireu,,: 1 Blacourt, oblent ien { t ..: ::: . I Grauwacke of Montign y. C bo) " )

APPENDIX II.

LIST OF SOME WORKS ON THE GEOLOGY OF SOUTHERN BELGIUM.

By W. TaPLEY.

(Especially referring to the Palseozoic Rocks of the district visited by the Association. For a fuller list see MouRLON's " Geologie de la Belgique," Vol. ii, pp. 3.P-392; 188 i •)

MAPS.

I-Carte Geologique de la Belgique, I: 20.000; sheet Dinuut, by E. Dupont and M. Mourlon, 1883. 2-Carte Geologique de la Belgique, I: 160.000; by A. Dumont, in 9 sheets (in two editions-soil and rock), 1854- 40 fro each. New issue in [877· 3-Reduction of Dumont's Map, I: 800.000. (Re-issues in 1855, 1876.) 4- I: 380.000; by Lelorrain and Henry, 1877. 5-Carte Geologique de la Belgique, I: 5°0.000; by G. Dewalque, 1879. 8fr. 6-Carte generale des Mines (Bassin houiller de Liege), I: 20.000, 1880. 4 sheets. 7-Carte Geologique detaillee de la France, I: 80.000; sheet 15, Civet, by ]. Gosselet, 1882. 4i fro 8-Carte Geologique du Departernent des Ardennes, I: 80.000; 5 sheets; by C. Sauvage and A. Buvignier, 1841.

MEMOIRS, &c. 9-Reunion Extraordinairea Liege. Bull. Soc. Ceol. France, ser. 2, xx, 761­ 879; 1863. (Separately published. Price 4~ fr.) to-e-Reunion Extraordinaire a Charleville et Givet, Sept., 1883. Bull. Sue. cs«. France, ser. 3, xi, 625-730; 1884. This contains papers by Dupont, Gosse1et, Mourlon, Renard, and Von Lasaulx, (Separately published. Price 3-2' fr.)

11-BA R RO I S, C., Mernoire sur le Terrain Cretace des Ardennes et des regions voisines, Ann. Soc. CeDI.Nord., v, H7·487.; 1879. 12---A Geological Sketch of the Boulonnais. Proc, Geol, Assoc., vol. vi, 1-37; 1879. APPENDIX H. 283

13-CORNET, F. L., and A. BRIAIlT, Sur Ie Relief du sol en Belgique apres les temps paleozoiques. Ann. Soc. Geol. Belg., iv (Memoires), 71-1I5; 18 77. 14-DE KONINCK, L. C., Description des Animaux Fossiles, que se trouvent dans le terrain carbonifere de Belgique. ato., Liege, Pl" 716; 60 PI.; 184 2 -5 " Is---Faune du Ca1caire Carbonifere de 101 Belgique. Ann. Musee Roy. d' Hist, Nat. Belgique, tome ii. (Poissons et Nautiie), pp. 152, 31 PI.; tome v. t Cephatopodes), pp. 133, 19 PI.; tome vi, Pl" 170,21 PI.; and tome viii, Pl" 240, 36 PI. (Gtlsteropodesj; 1883. 16-DELANOUE, ]., Des terrains paleozoiques du Boulonnais et de leurs rap­ ports avec ceux de la Belgique. Bull. Soc. Geol. France, ser. 2, ix, 399­ 406; 1851 • 17-DEWALQUIl, G., Notice sur Ie systsme eifelien dans Ie bassin anthraxilere du Condroz. Bull. Acad, Ruy. Belg., xi, 64.83; 1861. 18---Notice sur 1e systerne eifelien dans Ie bassin de Narnur, iu«, xiii, 140-155; 1862. 19---0bservations sur Ie terrain silurien de l'Ardenne, IUd., x xv, 413-427 ; 1868. 2o--Prodrome d'une Description geologique de la Belgique. 8vo., Brussels, 1868. (Re-issue, Pl" 50 I, 1880.) 21---0n the Devonian System in England and in Belgium. Rep. Brit. Assoc. for 1877, Sections, 69-7°; 1878. 22-DuMoNT, A., Mernoire sur les Terrains Ardennais et Rhenan de l' Ardenne, du Rhin, du Brabant et du Condroz. Mem, Acad. Roy. Belg., xx (pp 613); 1848. 23---Memoires sur les terrains cretaces et tertiaires. Cret. (pp, 556), 1878 ; Tert., Part I (Pl" 449), 1878; Part II (Pl" 459), 1879. (All Edited by M. Mo cm.os, and published by MusePhilippeville, BIlIl. Mus. Roy. d'/Jist. Nat., i, 89; 1882. 28----Sur I'origine des Calcaires devoniens de 1a Belgique. Bull. Acad, Ray. Belg.,ser. 3. ii, 264; 1882. 29--- Les origines du Calcaire Carbonifere de la Belgique. INd., ser, 3, V, 21 I; 188.i. 30---and M. MOURLON, Explication de la Feuille de Cilley (Carte Geot, Belg.}, 8vo., Brussels, 1882. 284 APPENDIX II.

31------Explication de la Feuill e de Dinant (eU"te osa. B elg.) ; , 883 , .12------and J. C. PURVES, Ex plication de la Feui lle de Clavier ( Carte os«. Belg.), , 88 3. 33·------Explication de la Feu ille de Natoye (Carte Geol. Belg.), 1883. 34------Explication de la Feuille de Modave (Carte Creal. Btlg.), 1884. 35-ETH ERIDGE, R., On the Physical Structure of \ Vest Somerset a nd No rth Devon, a nd on th e Pal reontologica l Va lue of the Devonia n Fossils . Quart. :Jour n. Geol. Soc., xxiii, 568 -698; 1877. 36 - --Ann iversary Address to th e Geological Society. I bid., xxxvii, Devonia n and Carboniferous, pp. 152- 200 ; 188 1. 37-GEIKIE, A., Text Book of Geology, znd Ed., 1885. Belgia n Rocks and their Correlation with those of England. Silurian , p. 689; D evonian, p. 7°1 ; Carb oniferous, p. 743. 38-GoOW IN-AusTEN, R., On the Possible Extension of th e Coal-measures benea th the South-Ea stern Part of England. Quart. J oum. Geol, Soc., xii, 38 '73; 1856. 39-Go OWIN-AuSTEN, R., On the Proba bility of Finding Coal under the Per­ mian, New Red Sa nds lone, an d other Super incumbe nt St rat a . Report of Royal Coal Comm ission, ii, 424-4 34 ; 18 7" 40---0n some furt her evidence a s to the Ra nge of the Pala-ozoic Rocks beneat h th e South Ea st of England. R ep . Br it. A ssoc. for 1879, pp. 227 - 229, 1879. 4,- GOSSELET, J., Mernoires sur les terrains primaires de la Belgique, des environs d'Av esnes et d u Boul on na is. 8vo ., Pa ris, 1860. 4 z---Coupe geolog ique de la Vallee de Ja Meuse, de Mezieres a Givet. B ull. Soc, Geol, France, ser. 2, xx i, 304-309 ; 1864. 43-- ·-Etudes sur Ie Gisem ent de la Houille dans le Nord de la France. B ull . Soc. In dust. N ord. de la France, No. 6, pp. 24; 1874. 44---Ca rte Geolog ique de la bande meridionale des Ca lcaires Devoniens de l' Entre-Samb re-et Meuse. B ull . Ac. R o!!. Belg ., ser. 2, xxxvii, (pp 36) ; 18 74. Map , I: 8 0.000. 4S---Com pt rerulu de I' Exc ursion dans les Ardenne s. Ann. Soc. Geol. Nord, iv, 210-23 1 ; 18 76. 46---Le Ca lcaire de Givet, Ann. Soc. Ghi. N ord, iii, 36-75 . 1876; vi, 2' 46, 1878. 47 - - -Notes sur Ie Farnenn ien. Alii,. Soc. Giol. No rd, iv, 303-32°; vi, 389 -.W9; vii, 195-201, 206-2 U. 18 76-80. 48---Esquisse geo logique du dep artem ent du Nord et des con trees voisin es j 1880. 49.---Les Schistes de Furnay, AlIn. Soc. Geol. Nord, x, 63.86; ,88.3. 50---Note sur I'Ar kose d' Haybes et d u Fra nc.Bois de Willerzies. ibid" x, 194, 2°7; 188.3· 51----Sur la faillie de Ra ma g ne et sur Ie metamorph isme qu'elle a prod uit l bul ., xi, ' 76-19°; , 884. APPENDIX II. 285

5z---Note sur quelques affleurements des Poudingues devoniens et liasiques, et sur I'existencede depots Siluriens dans l'Ardenne. Ibid., xi, 24-5-253; 1884. 53---Note sur les Schistes de Bastogne. Ibid., xii, [73-194; 1885. 53a~Sur Ie Structure geologique de l'Ardenue d'apres M. Von Lasaulx, lbid., xii, pp. 195-202, 228; 1885. 54---and C. MALAISE, Observations sur le terrain Silurien de l'Ardenne. Bull. Acad. Roy. Bele., xxvi, 61,"8; 1868. 55-HENNRQUIN, E., Expose summaire de la geologie de la Belgique. Bvo., pp. 72 ; 1876. 56-HULL, E., On the Geological Relations of the Rocks of the South of Ireland to those of North Devon and other British and Continental Districts. Quart. Joun,. Geo!. Soc., xxxvi, 255-276; 1880. 57 ---On a Proposed Devono-Silurian Formation. Ibid., xxxviii, ZOO-210I 1882. 58-JOLV, V., Les Ardennes. Fol., Brussels, pp. 284, 30 plates, cuts, &c.; 1854. 59-MALAISE, C., La Belgique agricole dans ses rapports avec la Belgique minerale, 4to., Brussels, pp. 41; 1871 (with Agricultural Map, I: 800,000, znd Ed. of Map in 1873). 60 ----Descriptions de gites fossiliferes devoniens et d'affleurements du terrain cretace. (Com. de la Carte Geol, de la Belgique- Ministere de l'Interieur}, 4to., pp. 69, map, I: 160.000; 1879. 60a-MoRToN, G. H., Notes on the Carboniferous Limestone of Belgium, made during a recent visit to that country. Proc. Liverpool Geol. Soc., Vol. iv, pp. 50-52; 188.~. 61-MoURLON, M., [Notes on the] .. Psammites du Condroz." Bull. Ac. Roy. Belg., xxxix, 602-659, 1875; xlii,845-884, 1876; ser, 3, iv, 504-525, 1882. 6z-MouRLON, M., Geologie de la Belgique. Svo., Brussels, Vol. i, pp_ 316, 188o; Vol. ii, pp. 39z, 188J. 63-MuRCHISON. R, I., Siluria, Ed. 4, Chap. xvi, .. Palseozoic Rocks of the Harz, the Rhenish Provinces of Prussia, and Belgium," pp. 39°-4°5; 1867. 64-D'OMALIUS D'HALLOY, J. B. J., Mernoires pour servir a la description geologique des Pays-Bas, de la France et de quelques contrees voisines, 8vo., Namur, pp. 307 ; 1828. 6S---Coup d'ceil surla geologie dela Belgique. 8vo., Brussels, pp. 1.~2; IS.p. 66-PRESTWICH, J., Report on the probabilities of finding Coal in the South of England. Report of Royal Coal (Jommission, i, 146-165; 1871. 67---0n the Probable Existence of Coal-measures in the South.east of England. Pop. Sci. Rev. xi, 225-z43; 1872. 68-RENARD, A., Some Results of a Microscopical Study of the Belgian Plutonic Rocks. Microscop. Journ. xv, 212-Z18; 1876. 69---Memoire sur la structure et la composition mineralogique du Coticule, et sur ses rapports avec Ie phyllade oligistifere. Mem, Acad. Roy. Belg., xli, 44; 1877. 70 ---Les Roches grenatiferes et amphiboliques de la Region de Bastogne, Bull. Mus. Roy. eni«. Nat. i, 1-47; 1882. 7J---Recherches sur la composition et la structure des phyllades Ardennais. Ibui.. i, 215-25°; ii, JZ7-J52; iii, Z31~268. 1882-84. 286 APPENDIX II.

72-SAUVAGE, C., and A. BUVIGNIER, Statistique mineralogique et geologique du departement des Ardennes. Svo., Mezieres j 1842. 73-SEDGWJCK, A., and R. I. MURCHISON, On the Classification and Distribu­ tion of the Older or Palreozoic Rocks of the North of Germany and of Belgium, as compared with formations of the same age in the British Isles. Trails. Ceol. Soc., ser. 2', vi, 22 ('3°2; 1840. 73a-SHARPE, D., Review of the Classification of the Paleeozoic Formations adopted by M. Dumont. See the Geological Map of Belgium with Reference to its Applicability to this Country. Quart. yourn. Geol, Soc. ix, 18-29; 1853. 74-VALLEE POUSSIN, CH. DE LA, l'Excavation de la Vallee dela Meuse. Ann. Soc. Ceol. Belg, iii, 55-59 j 1876. 75---and A. RENARD, Mernoire sur les caracteres mineralogiques et stratigraphiques des Roches dites Plutoniennes de la Belgique et de l'Ardenne Francaise, Mem. Acael. Roy. Belg. xl (pp. x, 264); 9 pl. 1876. 76---Note sur le mode d'origine des roches cristallines de l'Ardenne Francaise. Ann. Soc. Geol, Belg., xii (Memoire), II-20; 1885. 77-V)N LASAULX, A., Ueber die Tektonik und die Eruptivgesteine der franzcsis­ chen Ardennen. Verh, Nat. Rheinlande und Wes/falens, 40; 1884. (See also Vortriige und Mittheiiungen ] Bonn, 1884.) SKETCH-MAP OF THE PAL,EOZOIC DISTRICTS OF BELGIUM.

t"> ':n (1) m o -\ o '> o ("\ o ~ o o Co ~ V' I.F.. ~ '"~-'\ '> ""'....

Dark shading-Coal Measures, D' Carboniferous Limestones. B Silurian. C~ Upper Devonian. A Cambrian. C2 Miri