129

THE GEOLOGY OF THE APPLEBY DISTRICT, WESTMORELAND.

WITH SPECIAL REFERENCE TO THE AREA TO BE VISITED DURING THE LONG EXCURSION OF 1907

Dv JOHN EDWARD MARR, Sc D, F.R S

(Read July Silt. I907)

CONTENTS PAGE I -Introduction I~9 II -The Lower PalreozOIc Rocks · 131 ] II.-The Old Red Sandstone Penou · 134 TV.-The Carbomferous Penod • • 135 V.-The New Red Sandstone Rocks 136 VI -Intrusive Igneous Rocks 138 VII -Glacial Phenomena 140 YIII -PhysIOgraphy 141 References 147

I -INTRODUCTION HE geologIcal structure of the Appleby Dlstnct IS of par• T tIcular Interest, for It determmes one of the dommant physical features of our Island-namely the Pennme Chain or Backbone of England. The country ImmedIately around Appleby forms compara• tIvely low ground, between the heIghts of the Lake Dlstnct to the west and the Pennme scarp to the east Through thIS low ground runs the nver Eden, and thIS low country has been termed Edenslde by the late Mr GoodchIld. The general pOSltlOn of Edenslde is shown on the accom• panymg map (Plate II) by the stIppled portlOn of New Red Sand• stone extendmg In a N.N. W. dlrectlOn from KIrkby Stephen, past Appleby, to wIthIn a few nl1le~ of the CIty of CarlIsle, where It passes Into the north-Cumbnan plam lymg east of the Solway. The map, Plate II (by the late J. G. GoodchIld), also shows the dIstnbutIon of the pnncIpal geologIcal formatlOns. EdensIde IS geologIcally a synclme between the Lake DI5trict antIclIne to the west and the Penmne antIclIne to the I'ROC. GEOL. Assoc., VOL. XX, PART 3, 1907.J II 13° JOHN EDWARD MARR ON east, but the eastern 11mb of the synclllle IS cut offby the prinCipal Penmne fault, and accordmgly we find, apart from detail, a repetitIOn of the rock-groups which occur to the west of the fault on Ib eastern side, and the general dip IS m an easterly directIOn, save in the case of the highly convoluted Lower PalceozOlc rocks ~.=! Standlllg on a promInent ~ ~ height near Appleby, we 5ee to ~~ the west the Lake DI5tnct " ~ c" c" hlll~ of Lower Palceozolc rocks, "'" " nearer are the hills between "i 0...0..." " "... Shap and l'ennth, formed by the M~ V overlymg Carbomferous strata, "::! " I ~ " and the ground on which we Jzl c- B ~'" ~ 5tand con~lst:; of the yet more Ul § ~~'" Z recent New Red Sand5tone '"<=: ;:: Turl1lng to the ea~t the POSI• ~ tIon of the Important Pennme Ul "'"Ul 0 0 .c" Fault IS shown by the 5udden ~ u " rise of the great Pennll1e ~carp ~ "S With the Lower PalceozOlc hills z t: ~ 0 (fJ of comcal shape III the fOle• [:: " "- U 0 if ground The fault runs between ~ the latter and the New Red If.'" -" OJ bn [f, Sandstone ...:'-' ~ ..-l" " If we cro~sed over the Pen• t) " Z ~ mne Cham we should reach the '" i3 N "E '" 0 '" New Red Sandstone of the tract "I 8 "ou: around the mouth of the TLe~, 0...~~~ _ v '"~ thus traverslllg between the fault .... § ~ '-' ~..c a: and Tees-mouth the same rocks <5 ~ 11) ~ ..... uZ over which we pass when "alk• Illg from the eastern confines of .... N '" the Lake District, past Shap and Appleby, to the Pennme Fault The SectIOn (Fig r 3), III which details are omItted,

~ 5hows the general he of the '"ii rocks to the summIt of the '"''" PennmE' Cham i:! 00" The stratified rocks WIll be :n "" described III the order of their i:! antiqUity, begmnlllg with the most anCient. THE GEOLOG \" OI THE APPLEBY m;:,TRICT, \\ E"nIORELAND I 3 I

THE GEOLO(,IC\L DEPOSITS FOUND IN THE ApPLEBY DISTRICT. r Recent (AlluvIUm peat, etc ). QUATERNAR\ \. Glacial (boulder clay, sand, and gravel) St Bees Sandstone. MESOZOIC J TrIas { Gypseous Sandstones and I Marls MagneSian Llme~tone and Plant Beds. PermIan J Upper Pennth Sandstone. Upper Brockram Lower Pennth Sandstone UPPER.r l Lower Brockram P AL:EOZOIC f Millstone Gnt Carboniferous Limestone Carbomferou~ SerIes. I Sand~tones, shales, and con· ~ glomerate~ Old Red Sandstone (PolygenetIc conglomerate). ~ Brathay Flags. SilurIan 1 Stockdale Shales. AshgIll Shales r Staurocephalus and Kelsley LOWER 0 d D~~:~s~~:l~s. P ALtEOZOIC 1r OHClan f Corona beds lBorrowdale V oleanlc rocks Sklddaw Slate~ with Milburn V oleanlc rocks

II.-THE LOWER PALiEOZOIC ROCKS. The Lower PalreozOlc Rocks occur In an inlIer to the east of Edenslde (see the Map, Plate II, and SectIOn, FIg. 13), extendIng III a directIOn nearly north and south from the neighbourhood of Melmerby to the western flanks of Roman Fell, havll1g an average Width of about a mIle. On the west they are separated from the New Red Sandstone, as already stated, by a great fault, III many respects the most Important III the dlstnct This has generally been spoken of as the Pennllle Fault, but the Geological Surveyor" term It the Outer Penmne Fault, glVll1g the terms Inner Pennll1e Fault and Middle Pennllle Fault to two other faults whIch we Will now notIce The Il1ner fault on the" hole separates the Lower PalreozOlc rocb from the Carbol1lferous roch of the great escarpment, though a few patches of Lower PalreozOlc rocks occur to the east of It III one or two valley bottoms, and the Carbomferous rocks on the top of Roman Fell are on Its western I3 2 JOHN EDWARD MARR ON sIde. Its throw IS not very great. The MIddle Fault along the greater part of ItS course dIvIdes two group" of Lower Pal

w E. FI F2 F3 ~; 4 FIG I+ -SECTION ACROSS THE PENNINE FAULT - Y E Mal r. Length of SectIOn about 2 mIles.

I. Sklddaw Slates Fr Outer Fault 2. Upper OrdOVICIan and SIlUrian. Fz MIddle Fault 3 Carbomferous. F3 Inner Fault 4 New Red Sandstone

Above the EllergIIl Beds are graptolIte-bearmg shales WIth Intercalated ashes and lavas, markmg the change from the non-volcamc Skiddaw Slates to the volcamc Borrowdale Rock,;. These were called the MIlburn beds by the late Mr. GoodchIld. Certam volcamc rocks at the north-west corner of Roman Fell may be of the same age as the MIlburn beds (2) The Borrowdale Volcantc Rocks (LlandeIlo )-Near the northern extremIty of the InlIer, and still between the mIddle and mner faults, IS a group of contemporaneous porphyntlc and veSIcular baSIC andeSItes and ashes whIch are undoubtedly the eqUIvalents of the well-known Eycott HIll rocks, north-east of KeswIck, the latter occur some way down m the Borrowdale Senes The hIghest rocks of the BorrO\,dale Senes are found In the block between the mIddle and outer faults, and pass up mto the hIgher OrdovIcIan sedIments They comlst of rhyolites and rhyolItIc ashes, and form several of the conical hIlls of the mlIer, THE GEOLOGY OF THE APPLEBY DISTRICT, WESTMORELAND. 133 mcludmg Knock PIke and Dufton PIke. On these PIkes they are usually very rotten, and the best exposUles are found m the stream-courses, espeCIally m Swmdale Beck, where one of the lavas IS of great Interest. It IS descnbed by Mr. Harker as an "eutaxIttc" rock wIth discontmuous band~ of crystallIne character consisting of clear felspar quartz and decompositIOn product5. It has caught up fragment5 of an earlIer Andesitlc lava, and the flow-lines stream around these fragment5 The highest bed of thIS senes m Swmdale Beck IS an ash whIch IS Immediately succeeded by fos51lIferous depOSits, themselves contalnmg ashy matenal. The rhyolItiC group of the mlIer IS qUite comparable with that which forms the 5ummlt of the Borrowdale Senes m the Lake District The general stnke of these and the succeedmg rocks IS W N.W and ESE, but they are repeated several ttmes owmg to faults which cross from the outer to the middle Penmne faults With a general N.E. and S W. trend. These cross-faults produce five mam blocks of strata, one at the extreme northerly end of the inlier north-east of Melmerhy, the second With Knock Pike and Swmdale Beck, the thud wIth Dufton Pike, Pusgtll, etc, the fourth With Gregory and Kelsley, and the fifth WIth Roman Fell and part of Hilton Beck Each of these blocks dIsplays the rhyolIttc senes. (3) The CorOlla Beds -These conSIst of ashy calcareous shales, and argIllaceous limestones, the latter sometimes largely composed of Beyriclua. The beds are seen m theIr proper posItIOn m Swmdale between the rhyolIttc senes and the over• lymg Dufton Shales, but the most fOSSIliferous localIties are the Alston Moor Road near Melmerby, PU5glll, and the flanks of Roman Fell. In addItIOn to the type fOSSil Trematzs corona, Llllguia temtigralIItiata seems to be confined to thiS group The bed5 are probably of Lower Caradoc age. (4) The Dufton Shales.-Dark grey or black cleaved shales With much calcareous matter, and thm bands of limestone, greatly folded, so that no accurate estimate of thickness can be made, but they are probably not more than 500 ft. thick They are usually very fossllIferou5, With a marked upper Caradoc fauna mcludmg Ca/ymene senana, C),bele verrztc{Jsa, Trtnucltus setlcorms, Orthls testudinaria. The best fOSSIliferous localitIeS are Swmdale, Pusgill, Hurmng Lane, and Billy's Beck. (5) Keirley and Staurocepltalus LImestones -White, grey, and pmk limestone With olive green argillaceous lImestone5 and greemsh 5hales mtercalated. In Swmdale Beck the grey limestones are sparsely fos5Ihferous, though the argillaceous limestones con tam abundant fOSSils. In the Kelsley Block the grey, pmk and white lImestones are often crystallIne and very fOSSIliferous The fauna, which IS of great mterest, has been made the 5ubJect of a paper by Mr. Cowper Reed (see list and I34 JOHN EDWARD MARR ON references at end). The lImestone:; are of Lower Ashgllhan age. Considerable attention Will be paid to the development of the Itmestones m the Kelsley Quarnes (6) Ashgzll ,shales -Leaden grey shales of Upper Ashgillian age succeed the Kelsley Limestone of Swmdale. They contam the charactensttc StropllOlJIena e) stlurtana and Phacops (Dalman• mtes) mucronatus. They form the highest OrdovlClan strata of the area (7) Lower Stockdale Shales ( Ske/gill Beds).- The relatIOnship between the highest OrdOVICian and the lowest Silunan strata IS nowhere sho",n m the mlIer, as a fault always separate'> them. In the adjacent Lake Dlstnct the Skelglll Beds 'iucceed the Ashgill Shale., With perfect conformity. These Skelglll bed" m the mlIer are found m three or four Isolated patches. The most lllterestmg IS a very poor exposure of the lowest zone but one (the Dllllorphograptus confertus• Lone) faulted agamst the Kelsley hmestone of Kelsley, and one of the succeedmg zone (of J}Eonograptus fimbrtatus) m Great Rundale Beck In each case the beds are dark grey to black GraptolIte shales (8) Upper Stockdale Shales (Browgtll Beds) -These are best exhIbited m Swmdale Beck, where they are separated from the Ashgill Shales hy a fault. Two zones occur here, the lower of Monograptus tltrriculatus, the upper of lIIonograptus CrtSpus, but fOSSIls are now difficult to obtam The beds are pnle green and grey mudstone and fine gnts, WIth datker seams contamlllg the Graptohte', The Skelglll beds are of Llandovery age, and the Browglll beds are the equnalent of the Tarannon Shales (9) Brathay Flags -The Brathay Flags are greYIsh shales with a few Graptohtes of Wenlock age. They are seen m Swmdale Beck and near Harbour Flat. These are the highest Sllunan beds near Appleby, though a patch of COlllston Gnt of Lower Ludlow age occurs at the most northerly POlllt of the mlIer III a stream below the Alston Moor Road

II I.-THE OLD RED SANDSTONE PERIOD.

A penod of upheaval followed the depOSitIOn of the Lower PalreozOlC rock., At thiS tIme the older rocks were folded, faulted, and cleaved The great movement of the Middle Pennine fault now occurred, and the cross-faults breaklllg the rocks of the west part of the mher mto blocks were produced, along WIth many others At the same tIme great denudatIOn occurred. Between 20,000 and 30,000 feet of rock must have been removed where the lowest Upper Pal reo ZOIC rocks rest on low members of the Sklddaw Slate Senes '1 HE C,EOLO(, Y' OF THE APPLIcBY DISTRICT, WESTMORELAND. 135

The~e change~ took place while the Old Red Sand5tone was depo~lted in Scotland. Around the borders of the Lake District the basal Carbomferous rock~, as a rule, rest with marked unconformity upon the upturned and eroded edges of the Lower PalreozOlc formatIOns, transgre%mg from the Upper Ludlow Rocks of the Tebay district to the Lower Sklddaw Slates of the Sklddaw regIOn This unconformity in our area IS seen near Melmerby, and 5tlll more clearly on Roman Fell In both of these locahtles, below the rocks which are umversally referred to the Carbomferous, are discontmuous developments of a pol}genetlc conglomerate-a rock consistmg of pebbles of divers character denved from many kmds of rock. I am mclIned to refer thIS to the Upper Old Red Sandstone, .and not to the Carbomferous, and there i~ some eVidence of Important changes havlllg occurred between Its depOSitIOn and the formatIOn of the overlymg Carbomferous rocks It con• S15t~ of a somewhat mcoherent reddl5h sandstone matnx with pebble:, of vanou~ 51",es, denved not only from the local Lower PalreozOlC rocks, but from gl1els~e~ and schIsts of distant regions Much movement ha~ takE'l1 place smce the formatIOn of the conglomerate, and the pebbles are often stnated, mdented, bent and faulted.

IV.-THE CARBONIFEROUS PERIOD.

Our attentIOn WIll be chiefly devoted to the rocks on the t:a~t Side of the Lo" er PalreozOlc mlier, where they are de~eloped m the great scarp of the Cross Fell Cham Above the polygenetlc conglomerate of Roman Fell is a massl~e rock of much greater hardness, consisting of a yellow, grey or red sandstone With ~mall rounded pebbles largely of vem-quartz, and thu~ markedly contrasted With the pebbles of the polygenetlc conglomerate. ThiS forms the great mural scarp of the summit of Roman Fell, and the beds are bent sharply down to a stream on the east Side of the Fell, where they are succeeded by sandstones a~soC1ated With a fossilIferous limestone Above thiS senes comes the most Important limestone of the dlstnct, the Melmerby Scar Limestone, whose white cliffs are on a clear day readIly seen from a distance, runmng along the lower part of the great scarp for many miles. The Mel• merby Scar Llme'itone IS the degenerate eqUivalent of the Lower ~car LImestone of the Yorkshue dales. Above It, other hme- 5tones, WIth some sandstones and shales, occur tier above tier on the face of the scarp, until at last the Millstone Gnt is seen formmg the summit of the highest point of the cham-Cross .Fell (2,929 feet). JOHN E.D\LARD IIL\RR ON

The occurrence of an InIter of MIllstone GrIt close to Appleby, surrounded by rocks of New Red Sand~tone age IS of Interest, as beanng on the sequence of these newer rocks. The paireontoiogical dIvIsIons of the Carbonrferous rocks of the Cross Fell scarp are now beIng worked out In detaIl bv Prof. Garwood, and as we shall not examIne the whole senes further descnptIOn here IS unnecessary.

V.-THE NEW RED SANDSTONE ROCKS.

These rocks belong to the PermIan and TnaSSIC systems, but as they were eVIdently formed under very SImIlar ConditIOD', In thIS area, we may consIder them under the head of New Red Sandstone. TheIr general dIP IS In an easterly dIrectIOn, and accordingly the oldest beds run on the whole to the west of Edenside, the newer on the east, but along part of the Roman Fell tract the oldest rocks are brought up by a sharp bend agaInst the outer PennIne fault (A) PERMIAN ROCKS -It 15 well known that a great penod of elevatIOn and denudatIOn occurred after the deposItIon of the Coal Measures, and before the accumulatIOn of the lowest Permian rocks of the north of England, and that the latter accordIngly rest dIscordantly on the former ThIs unconformIty IS not readIly seen In our dIstnct, OWIng to faultmg and the obscurIng mantle of dnft. Just west of Appleby, however, the PermIan rocks rest on dIfferent members of the Lower Carbonr• ferou5, and thIS appears to be for a short dIstance an unfaulted Junction UnconformIty IS, however, shown by the abundance of MountaIn LImestone pebbles In the basal PermIan rocks, IndIcatIng that the Upper Carbonrferous beds had been at that tIme removed by denudatIon. (I) Penntit Sandstone wztit Brockrams.-In the Pennth dIstnct the lowest PermIan rocks are the well-known Pennth Sandstones. As these are traced southwards towards Appleby, thin bands of breCCIa occur. These breccIa5 are locally known as brockrams, and consIst of angular fragments chIefly compo~ed of Carbonrferom LImestone, In a matrix of sandstone resemblIng the ordmary Pennth Sandstone5 The Itmestone fragments are often more or less dolomitIsed. Around Appleby two Important developments of brockram occur, one at the base and the other near the summIt, and accordIngly the senes IS there subdIVIded into: Upper Penrith Sandstone, Upper Brockram, Lower Pen nth Sandstone (mIddle sandstone), Lower Brockram. \.,~ ...... :..:...~-'f N(.\WR(ld

GhOLOGICAL MAP OF CUMBERLAND AND WESTMORELAND -J G. GOODCHILD. THE GEOLOGY OF THE APPLEBY DI'oTRICT, WESTMORE.LAND 137

The brockrams \[,r) much In character) m some ca~es there IS much matrIx, whIle 111 others the fragment~ are ~o numerou!> that the rock mIght at first be taken for actual Carbomferou!> LImestone The Lower Brockram IS well !>een in Burrells Quarry, south of Appleby, where the fragments are large and numerous The rock here IS remarkably evenly JOinted The same rock I!> brought to the surface by a fault to the east of Appleby, and I~ seen on the road to Dufton The Lower Pennth Sandstone IS "ell seen on the road at Appleby, east of the Eden, Just south of the Court House, where it exhlblt~ very marked fal5e bedding, 1I1clmed on the whole from east to west, and 5uggestmg a \\ e!>terly travel of the matenals The Pennth sandstone IS mually of a bnck red colour. the grains consl~t chIefly of quartz. wIth a certam amount of decomposed felspar The grams are frequently markedly rounded, present1l1g a "mlllet-!>eed" appearance, though 111 many cases they have receIved a !>econdary depOSIt of sIlIca, glvmg rIse to the well-known cry!>tallme ~andstones The absence of the detntal mIca IS slgmficant, and affords a ready means of dlstlllgUlshmg the Pen nth and Sl Bees' Sand~tones The Upper Brockram IS 111 general respect5 51mIlar to the lower breCCIa. It I~ seen, among other places, 111 HIlton Beck. Prof P F. Kendall has 5hown that, although the fragments, lIke those of the Lower Brockram, are largely denved from the Carbomferous Luuestones, there IS al~o a faIr proportIOn of older rocks, such as conglomerate, vem-quartL and rhyolIte He argues that the basal Carbomferous beds whIch were covered dur1l1g the formatIOn of the Lower Brockram, had now become exposed by denudatIOn, and sugge!>t;, that movement occurred along the Pennlne fault between the formatIon of the two brockrams ) If the thIckness of the Pen nth Sandstones group be taken at 1,000 ft. (the thIckness I'> very dIfficult to estImate) he argues for a movement along the fault to that amount. The Upper Pennth Sandstones on the "hole re~emble the ~andstones between the brockrams They may be seen on the road to Dufton, and al~o In HIlton Beck (2) Ntlton Shales, MagneSIan Limestone, G~C -Above the Pennth Sandstone group come!> a vanable group of grey and yellow sandy shales, gypseous shale;" and Impure magnesIan lImestones and sandstone", known as the HIlton Shale~, bemg well expo!>ed In the beck of that name The group IS of mtere!>t on account of the occurrence of planb, first dIscovered by Prof. Harkness The followmg have been recorded• Alethoptens goepperti, CardlOWrpU11l tnangulare, Odontopterzs sp. Splle?lOpteris dichotoma, S. Naumalllll, Ullmantlla selagtnotdes and U Bronlli, a flora known In the German Kupferschlefel JOHN EDW.\RD 1\L\RR ON

It IS very dIfficult at the pre 'lent day to secure good specImens from the HIlton exposure. (B) TRL\<;SIC RocKs.-The plant bed5 are succeeded by a 'iene~ of gypseous red shales, whIch are taken as the basal depOSIts of the Tnas"ic roch. Mr. GoodchIld gIVe5 a figure m the Survey ~Iell1Olr of these shales restmg unconformably upon the plant beds near Newblggm, 50me way north of Appleby. They appear to pass up mto the St Bees' Sandstone, of whIch mdeed they may be regarded as the base. The St Bee5' Sandstone IS well bedded, of a more purple red than the Pennth Sandstone, It con tams thm mcon5tant " wayboard~ ., of red shale, often shows dl5colouratlOn patche~, 15 rarely crystallme, and above all contams a faIr amount of detntal mIca. Many good exposures of the rocks of thI'> dIVIsion are seen, as It IS extensIVely quarned for bUlldmg purposes Thele are large quarnes jU'it west of the VIllage of Dufton, and others by the SIde of HIlton Beck, a~ one approaches the vIllage of HIlton Mr. W. Brockbank records plant'> at two honzons at HIlton Beck See II'it of References, pp. 147, 148. There are no newel rocks near Appleby, though the St Bee5' Sandstone around CaIlisle l'i ~ucceeded by hIgher Tnasslc rock5, and ultimately by LIaSSIC rock5 'itIll preserved Il1 an outlier

n -INTRUSIVE IGNEOUS ROCKS. Many Igneous d) kes and small bo'>ses are found among the Lower PalreozOlC rocks, belongmg prmClpally to the groups of the quartz-porphynes and lamprophyres '1 he most mterestmg are the ma'>s of quartz porphyry on the western flank of Dufton PIke, often termed the" Dufton gralllte," whIch IS remarkable for the large plates of mIca, and the lamprophyres of Swmdale Beck. One of these contams rare phenocrysts of orthocla,>e resemblmg the well known porphyntlc crystal,> of the Shap gralllte :Mr. Harker and I have gIVen reasons for supposmg that thIS group of dyke,> are apophyses of that gralllte, m whIch case they are of Devolllan age A later mtruslOn IS the well-known \Vhm SIll, whIch runs for mlle5, at 5lightly dIfferent honzons, among the lower Carbom• ferous rocks of the great Pennme 5carp. It \\lll be seen around HIgh Cup GIll. The rock IS a dIabase, conslstmg of plagIoclase felspar, augIte, and an Iron ore In the Appleby Dlstnct, where It IS thm a5 compared With the development on the east SIde of the Pennmes, It 15 a fine-gramed rock, and the amount of meta· morphIsm whIch It produces on the roch \\Ith whIch It is m contact IS less than that produced to the east m the well-known sectIOn at Falcon Clmts, m Upper Teesdale. THE (;E.OT Ot.Y OF THE \PPLE.IlY DISTRICT, WE-,T\IOREL.\ND 139

A day has been ~et apart for "Isltlng the Shap gramte, for, a<; already mentioned, the gramte 1<; connec.ted \\ Ith the Appleby DI5trJC't, as Its apophyses extend mto the rocks of the mller. The VISIt to Shap wIll enable us to see the" e<;tern hmb of the great earth-wave whose trough IS m Edemlde The gral1lte Itself IS mtru~lve Jl1 rocks of the Borrowdale Volcamc Group It forms a mass about I~ mIles along Its greatest dIameter, bemg a rough elhpse appro,\lmatmg to the CIrcular form. The gral1lte, save \\ hen ~tamed red, has a grey matnx of orthoclase and some plagIOclase felspar, quartz and bIotIte A notIceable pOInt I'> that the quartz c.rystalhsed before the orthoclase In thl'> matnx are embedded large pmk orthoclase crysta]<; sometlme~ tIl 0 mche<; m length. The abundance of dark mcluSlOns IS of mterest, some are fragments of other rock whIch have been caught up m the gramte, but many are more baSIC v:metIes of the rock Itself, marked by the pos~ ess lOn of bIotIte, plagIOclase and sphene These baSIC patches con tam the large orthocla<;e phenocrysts, \\ hlcn are usually corroded, and have an altered margm of plagIoclase and quartz They are dosely related In character to the lamprophync apophyses The apophy"es occur as dykes and SIlls, chIefly r.ldlatmg from the gral1lte, and extendmg to dIstances of over 12 Imle,> from the ma>s, though they are most abundant near that mass, where they frequently con tam orthoclase phenocrysts. The dyke rocks are of two kInds, lamprophyres and quartz porphynes, the fonner belllg more baSIc and the latter more aCId than the gramte Itself. The phenocrys ts ll1 the lamprophyres are rounded and corroded, WIth plagIOclase margms lIke those of the baSIC patches m the gramte. The aureole of metamorphIsm e:octend" to a dIstance of ahout three-fourth<; of a mIle from the gramte margm. A great \anety of rocks has undergone m eta morphI~m, mcludmg baSIC, lllter• medIate and aod lavas and ashe<;, Impure hme<;tone<;, .,hales and gnts, and also a metallIferous vell1. The lavas and ashes had undergone weathenng before metamorphIsm The alteratIOn of the mtennedJate and baSIC rocks presents pomts of mterest Near the gral11te margm the rocks are completely re-crystalh<;ed, With formatIOn of water-clear felspar and a purple-brown mICa. The veSIcles of the lava were filled \\,Ith amygdalOldal sub"tance before alteratIOn ThIS has been converted mto crystalhne calcite, fibrous amphibole, epIdote, garnet and other mmerals. SimIlar changes have taken place m the metalliferous vem. The Impure hme<;tones are changed mto hme-sillcate rock, WIth development of vanou~ mmerals such as hme-garnet and plaglOc1a<;e The other rocks have undergone vanous changes accordmg JOHN EDWARD MARR ON to their cOmpOSitiOn, but as the time will be too limited to examme these m detail, It 15 unnecessary to partlculanse them here.

VII -GLACIAL PHENOMENA.

In the lImited tract of ground which we 5hall traverse, It 15 not probable that we shall come across any glacIal 5true, and the directIOn of travel of the Ice IS mdlcated mam!y by the dls• tnbutlOn of the boulder::., and to some extent by the conforma• tIOn of the ground The stme which ha've been ob5erved m the dlstnct, and the distributIOn of the pnnclpal boulders IS shown 111 the map by the late J. G. Goodchild, here reproduced on Plate III The pnnClpal glacial accumuiatlOn5 are ull, with some II1tercalated sand~ and graveb, and local morame~ The till IS widely »pread over the lowland::. of Edenslde Its surface IS not level, but presents whale-backed ndge5 01 drumlms with mtervemng hollow::. These drumlll15 have a general dIrectIOn of S 30° E, a5 noted by 1\1r. Tlddeman OtherwI::,e the till 15 of an ordmary character An mterestmg sectIOn 15 seen m a quarry of St Bees' Sandstone near Hilton Beck, where m one place the till has been forced for a dl'>tance of about 6 feet below a proJectmg hard bell of the sand5tone The sand5 and gravels assocIated with the tIll were probably formed m more than one way Mr Tlddeman record5 the findmg of a tooth of ox, probably bl~on, mclean 5and and gra.\"el below the boulder-clay at Appleby Local morames occur at the ends of some of the valley~ entenng Edemlde from the Penn me Cham. The most promi• nent are at the end of the High Cup, alley, and at Cosca, near the mouth of Great Rundale Beck The most 1I1terestmg boulder5 are tho::,e of GallO\\ay, wIth which mU5t be cla~sed the Carrock Fell gabbro~, and the Enner• dale granophyre which have come from the north-west , and of the Shap gral11te whIch have come from the west and south-west. Both sets of boulders ultImately pa5s over Stammoor Pass, on the east of the upper end of the Edenslde lowland5 The passage of the boulder,> over thl5 pas'> 15 of great intere5t The Shap gramte boulders are not found pa55mg over the lowe5t part of the pass where the hIgh road and r::ulway crosses the Pennme \\atershed There are, 111 fact, three belt~ of dlstnbu• tlon of boulders among the low ground 111 the \ICll1lty of the actual pass. These be\t5 run approximately ea')t and west The most southerly occupies the lowest ground of the pass, and contams boulder~ which have probably been brought from the high ground surroundmg the head of the Eden valley. The THE GEOLOGY OF THE APPLEBY DISIRICl, Wlc'oDlOR~_LAND. 141 middle belt con tams boulden, of Shap gramte, but none of the (;alloway rocks, while the northernmost belt has a mixture of boulders of Shap and Galloway rocks. The Shap houlders are found m places at a slightly higher elevatlOn than I~ attamed by any of the parent rock In addltlOn to these boulders, fragment~ of Brockram have abo been carned o"er Stammoor. The highest pOint where these rocks occur ZII sitl; IS nearly 700 ft. below the pomt where they cross the watershed. The~e boulders, therefore, have travelled up hill to the e,tent of 700 ft vertical, \\Ithm a distance of four or five nales A full account of the travel of boulders in thl~ district will be found 111 the late l\f r. Goodchild's well-known paper on the "Glaclal Phenomena of the Eden Valley," for which a reference IS given m the li"t of works at the end of thiS paper

VIII -PHYSIOGRAPHY

The lowland tract of Edenslde IS clearly "tectomc" as regards Orlgm, due to the lettmg down by the Penmne fault of the softer New Red Sandstone strata bet" een the Pal~oz01c rocks of Lakeland to the west and of the PenmnE's to the east The present features, however, are no doubt directly due to denudatIOn As the general trend of the strata, and of the stnp of Lower Pal~oz01c rocks IS on the whole a little east of south, the trend of the major features 15 111 the same directIOn The most prom111ent of the~e features IS undoubtedly the great Pennme scarp, determmed 1l11tlally by the appositIOn of soft rocks to hard produced by the outer Penmne fault. Comlderable modlficatlOn has taken place m detaIls. To the east of the 111ner Pennme fault, the scarp run~ fairly regularly, save where mdented by consequent streams flowmg \\e~tward from the Penmne watershed The scarp It~elf 15 diversified by gentler slopes, due to shales, and steep slopes and scars caused by the ba~al conglomerate~ and sandstones of the Carbol1lferous, the hlghel hme"tones and sandstones, and by the Whm Sill The mner PE'nl1lne fault IS Jt~elf sometime" marked by a depreSSIOn, as, for Instance, the col between -Brownber and the Carboniferous range to the east, and a sImIlar col between Murton Pike and the same ndge The Lower Pal~oz01c rocks form hIgh ground, though ne"er nsmg to the height of the mam elevatlOn of the Pennmc watershed The Sklddaw slates between the mIddle and ll1ner faults are u"ually marked by fairly steep vegetatlOn-clad ~lopes, though where gnts, ashes, and dom111ant quartz vems eXist, they form hills, such as Burney, Brownber, and Murton Pike The latter I~ bounded by faults 1.-1-2 JOHX ED\\-ARD ]\IARR ON

on four :,Ides, and so pre5enb the form of a pyramid on a quadrangular base. The mIddle Pennme fault IS marked by a depres510n along the greater part of Its length This IS well seen between Dufton Pike and Brownber The Lo\\ er PalxozOic rock~ between the middle and outer Penmne faults, also nse 1I1to plke& m many places, ~uch as Knock Pike, Dufton Pike, Gregory and Kelsley Bank The~e are compo:,ed eIther enurely of rh)ohte, or, m the case of the last named, of rhyolite and hmestone These pikes also are, 111 most cases, bounded by faults The pikes sometime:, 5how the conca, e cun e of water eroSIOn, as Murton Pike and Dufton Pike, "hlle the ~ummlb frequently have the convex curve of weathering beneath vegeta• tIOn, well :;hown on Knock PIke The Importance of boundmg dlVlslOnal planes as opposed to rock structure IS well exemplified 111 the case of Dufton and Murton Pikes, of remarkably SImilar appearance, though the former IS composed of rhyolite and the latter of Sklddaw Slates Roman Fell exhibits two types of scenery. It lies between the mner and outer Penn me faults The lower part IS Lower Pal::eozOic rock, and has slopes Similar to that of M urton PIke. But though the Carbomferous rocks which once overlay the sum• Imt of Murton Pike have been removed, they still occur on Roman Fell, and gIVe nse to the great mural 5carp of con• glomerate which ha::. already been noticed as cappmg that fell The middle Penn me fault here passes beneath thiS 5carp, without dlsplacmg ItS rocks, showmg ItS pre-Carbomferous age along thiS part of ItS course, though It would seem that sub• sequent mOvement has occurred m post-Carbol11ferous time along a more northerly part of It::. course, to the south of Melmerby Commg now to the New Red Sandstone rocks of Edemlde, "e have already remarked that they produce lowland a::. contrasted WIth the elevated ground to the east and west, but there l'> conSIderable diverSity of character 111 thiS lowland The Brockrams and Pen nth Sandstones form on the "hole com• paratively elevated ground for thiS lowland, WIth the escarpment facmg W. and the dIp ~lope E. The softer plant beds and accom• panymg dep051ts form a depres::'lOn, to the east of whIch IS the scarp-slope of the St. Bees' Sandstone, usually nsmg to the hIgher ground on the "est Side of the outer Pennme fault The character of the SUI face of Edenslde IS, a:. before observed, considerably modified by the drumlins \Ve:.t of Eden:'lde the Carbomferous type of country IS agam developed, though the ground IS generally lower than that of the Penn1l1c scarp This Carbomferous country ends to the west WIth a promment scarp at Shap fac111g the Lower PalxozOic country of Lakeland. THE GEOLOGY OF THE APPLEB\ DI"TRICT, W£~ll\IORlcL\XD. 143

Another interesting physlOgraphlcal study IS connected wIth the rIver courses The main drainage of the dlstnct IS conducted by streams whIch were Il11tlated on the aXIS of uplIft of the Penl11ne Chain whIch produced the pnmary watershed of the area They flowed In the dIrectIon of the dIp, to the east and \~est respectIvely. The westerly flowing streams became tnbutanes of the Eden il11tlated In the trough of the syncl1l1e, and accord1l1gly flo\\ 1!lg as a strIke-stream In the dIrectIOn of the aXIS of that synclIne. Fe" of the dlp-stream5, however, now flow dIrectly trom the water5hed to the Eden, OWing to capture of the headwater5 of the les~ Important dIp-streams by the tnbutarIes of the more Important, worklllg along lmes of weaknes~, whethe: fault~ or 50ft depOSIts The pnnclpal captures ha\ e been brought about along the lme of the MIddle Pennine fault, e.g, Great Rundale, flowmg behmd Dufton PIke to S" mdale, or along the lme of the Outer Penl11ne fault, e g, SWIndaie Beck mto MIll Beck, or agam along the strIke of the Permran plant beds and theu a~soclated 50ft rocks, e g, Murton Beck by Fnth Beck Into MIll Beck The5e are but a few example~ of many dIverSIOns, some of whIch \\ ere probably helped by glaCIal mterference The next feature of Interest IS due to the asymmetrIcal natule of the uplIft The area may be regarded as exhlbltmg an asymmetncal earth-fold, haVing a gentle trough lImb to the \\est, slopmg eastward, a steep 5eptum or mIddle lImb slopmg west• ward, and a gentle arch lImb 510pmg eastward from the 5ummlt of the Penl11ne Chain Thl~ was complIcated by the Pennme faults, but, nevertheless, the geological centre of the fold whIch Il11tlated the dramage from the top of the Penl11ne Chain IS marked by the posltIon at the 5urface of the Lower PaheozOlc rocks. The" law of uneven slopes" has cau~ed a modIficatIOn of the mItral dramage. As the \\ estern slope IS much ~teeper than the eastern, denudatIOn ha5 proceeded more rapidly on the" est SIde of the Pennmes than on the ea~t Side ThIS IS, firstl), the case WIth the general weatherIng and transport of the weathered matenals by mconstant runnels, and hence the mam lme of water5hed, though parallel WIth the one of uplIft beneath the Lower PalreozOlc rocks, now lIes to the east of It Secondly, the law of unequal slopes ha5 caused stIll greater dIfference between the erOSIOn of the westerly and easterly flowmg streams, and the former are engaged In cuttmg notches through the watershed towards the east. The most Interestmg example of thIS IS presented by HIgh Cup GIll, of \\ hlch the head 15 now some dIstance east of the mam lme of watershed ThIS gIll 15 at pre5ent engaged m captunng for Its trIbutanes the small streams whIch once dramed Into the Tees by a tflbutary runl11ng In the actual line of HIgh Cup GIll, but m the contrary dIrectIOn Part of thIS tnbutary 144 JOHN EDWARD lIIARR ON

of the Tee'3 '3tIIl exI'3ts unmodIfied due east of the head of HIgh Cup (HIgh Cup NIck) and flm\'3 over the Tyne Bottom LIme stone, and the rehc of the floor of thIS tnbutary 1'3 clearly traceable on eIther sIde of the upper portIOn of the HIgh Cup valley, "hlch now termInates In a very typIcal cIrque, of whIch the semIcIrcular clIff IS formed by the WhIn SIll and Tyne Bottom LImestone whIch here rest~ upon It The Eden has by no meall'3 establI'3hed ItS base level along the upper parts of It'3 course, and has been In geologIcally recent

FIG IS -SKETCH MAP OF A PORTION OF THE COURSE OF THE RIVER EDEN. -:1 E. Marr Scale 6 Inches = I mile. A IS the town of Appleby The tracts of AllUVIUm are marked with the usual Sign. The rest IS rock chiefly dnft-covered.

tunes rejuvenated, as shown by the IncIsed meanders along a portion of ItS course. One of these IS responsIble for the eXIstence of Appleby. A loop of the river causes a tongue of hIgh ground, on the hIgh narrow neck of whIch the Ca~tle 15 bUIlt, whIle the houses of the cltrzens extend down the slope from the castle towards and on to the allUVIal tract of the river. (See FIg. 15) In addItIon to the inCIsed meanders, there are hangIng valleys connected WIth the trIbutanes flOWIng Into the Eden from the east Most of these, It IS true, are more or less graded 'IRE GEOLOGY OF lRE APPLEBY DISTRICT, WE"nWRELAND. 145 on those parts of theIr cour~es whIch traverse the New Red Sandstone Rocks, and only "hang" above the outer Penmne fault, but one valley, that of Croglm 'Yater, some mIles north of Appleby, plunges down cascades and waterfalls ImmedIately above It~ JunctIon WIth the Eden, glvmg rIse to the pIcturesque features of Nunnery Walks The pO~ItlOn of the hangmg valley IS here determmed by a faIrly hard mass of Pen nth Sandstone. Smce the penod of rejuvenescence, a sufficIent penod has dapsed fOl temporary base-Ievellmg of the Eden at Appleby, and accordmgly, owmg to lateral eroSIOn, tongues of allUVIUm have been formed alternately on eIther sIde of the ~tream, as shown m the figure. The encroachment of HIgh Cup GIll on the Tees drainage has been notIced as an exemplIficatIOn of the law of unequal slopes. But there IS a yet more Important cause of modIficatIOns of the orIgmal Eden dramage whIch may now be consIdered. The soft New Red Sandstone rock, over whIch the Eden runs for the greater part of Its course, allowed the flver rapIdly to corrode after Its InItIatIOn, and accordmgly we find that the town of KIrkby Stephen, where the southern termmatlOn of the New Red depo~lts IS sItuated, but seven mIles from the river-head, I~ less than 600 ft above sea-level 'Ye must go many mIles farther down the adJommg RIvers Tees, Swale, Ure, and Lune before we cross the 600-ft. contour-lme, for these nvers run for long dlstal1ces over rocks of a harder nature than that of the New Red Sandstone. Accordmgly the tnbutanes of the hIgher parts of the Eden have a steeper grade than those of the rIvers mentIOned, and therefore tend to e~tend theIr heads backwards and so to capture the headwaters of the tnbutanes of the above• mentIOned rIvers. In the case of the Swale the capture has proceeded to a slIght extent only, but It IS more marked m the ca'>e of the Tees, Ure, and Lune One effect of capture IS the productIOn of what may be termed "fish-hooks" A trIbutary, say, of an easterly flowmg nver, has Itself a general easterly trend. When captured by a westerly flowmg nver the water bends round III a fish-hook curve Thus the Balder, a trIbutary of the Tees, appears once to have ansen on 'Yarton Fell, about five mIles WNW of ItS present source. It has been captured by two streams, Swmdale Beck (one of many SWll1dales m thl5 dlstnct) and Auglll Beck, flowmg past Brough mto the Eden, WIth the fonnatlOn of a fish-hook at each pomt of capture A SImIlar feature occurs at the head of the Eden, where Hell GIll Beck flows west of south for about three mIle'> as though to Jom the Ure. The upper part IS of the nature of a hangmg valley, and descends by Hell GIll Bndge to Jom the northerly• flowmg Eden, agam formmg a fish-hook. But the most mterestmg case of capture IS seen m the case of the head waters of the Lune at Ravenstonedale. It IS proposed PROC GEOL Assoc., VOL. XX, PART 3, 1907.] I2 JOHN EDW.\RD ;,[ARR ON

to devote a day to thIs tract, and a somewhat fuller descrIptIOn l~ necessary Ravenstonedale is a horseshoe·~haped depressIon among the mountams to the south·we~t of KIrkby Stephen, apparently the head of a valley whIch e~tend~ west to Tebay, where the ,\ater~ turn south to flow through the gorge of the HowgIll Fells, a~ the RIver Lune Standmg on an emmence near the vIllage of

To Eden

f-B S .... st ...... To Lune "" ...... ~.~ .... >.,: ...... : ...... : ....

Scandale FIG. 16 -SKETCH MAP OF A PORTION OF THE RIVER DRAINAGE IN RAVENSTONEDALE-Y. E Malr Scale I mch = I mIle. C Coldbeck. F. "FIsh-hook" F B Fnar Bottom. G Gorge. N Newblggm. R Ravenstonedale \'Illage St Ravenstoned.lle StatIOn S Sandwath Beck The broken lme IS the 700 ft contour, the dotted lme the 800 ft. contour. The other contour hnes are not shown

Ravenstonedale the horseshoe seems to be surrounded by hIlls. To the south are the HowgIll Fell~ and \VIld Boar Fell; to the east the rIdge from WIld Boar Fell to Ash Fell, and to the north Crosby Garret Fell and Grange Scar So obVIOusly does the tract wlthm thIS horseshoe seem to belong to the Lune dramage that It is almost wIth a shock that we find the dramage of a con- THE GEOLOGY OF THE APPLEBY DISTRICT, WESTMORELAND. 147 siderable tract of country west of WIld Boar Fell and Its northerly lldge, whIch collects to form Scan dale Beck, flowing through a calion-lIke gorge, through whIch runs the raIlway between Raven- 5tonedale and Smardale statIOns to fall Into the Eden near Soulby, at a heIght of nearly 500 ft above sea-level. Now, the 5oo-ft. contour-lme IS not crossed on the Lune untIl we reach HIgh Borrow BrIdge, many mIles away, and It seems clear that the Scan dale 5tream once starting from the top of the ndge .around the horseshoe near the present Smardale statIOn has cut backwards and captured the former source of the Lune In connectIOn WIth thIS a very lllterestlllg physiographlcal feature near Newblgglll (a VIllage close to Ravenstonedale statIon) may now be notIced (See FIg 16) South of Ravenstonedale statIOn a small stream, Sandwath Beck, flows westward to Jom the Lune, through an allUVIal flat, at a heIght of a lIttle under 800 ft To the east of thiS a meanderIng depre5slOn WIll be seen on the ordnance map wIth ItS bottom always below 800 ft. Let us follow thiS. Walking at fir~t from Newblggm to the N E, we find .a lIttle runnel whIch rIses near the Farm of Fnar Bottom, flOWing on a well-graded bed to JOin the Lune. At Fnar Bottom we find to our surprIse that though m thIS meanderIng valley" e are on the water5hed between the Lune and Eden. from here the wmdmg valley goes to the south-east, and soon a stream nse~ from a "keld" and flows over a faIrly steep but well-graded bed to Jom Scan dale Beck (the trIbutary of the Eden) north of Coldbeck, where It forms a "fish-hook." One explanatIOn IS that thiS meandenng valley was the route taken by the former headwater~ of Scandale to Jom the nver Lune, but that on the capture of Scan dale Beck by the Eden trIbutary, a wmd-gap was formed If the water whIch n5es at the keld extends backward, Sandwath Beck \\111 be SImIlarly captured In the future Unfortunately there is much drIft about here, and although the northern bank of the meandenng valley 1<; formed of lImestone, the southern bank IS occupIed by glacIal materIals, and It may perhaps be claImed by giaclalI5ts that we have a case of a glaclal• lake overflow. However thIS may be, the actual capture and formatIOn of the Smardale gorge seems to me to be entirely unconnected WIth glaCIatIOn. (See FIg 16)

REFERENCES GEOLOGICAl SURVEY PUBLICATIONS

GeologIcal Survey Index Map, Sheets 2 and 5 4 mlle, to I lUch. Pnce 2S 6d e.tch GeologIcal Survey Maps (I-lUCh scale), Quarter-Sheets 102 N W , 102 S W , 102 S E, 98 N E, 97 N W In the New Senes the abo\e quarter-sheets are numbered 24, 30, 31, 39,40 respectIvely. MemOIr on Quarter-Sheet 102 S \V "The Geology of the Country between Appleby and Ulleswater," etc. Pnce IS 6d (48 THE GEOLOGY OF THE APPLEBY DISTRICT.

GENERAL. 1889. GOODCHILD, J G -" An OutlIne of the Geological History of the Eden Valley or Edenslde" Proc Ceo! Assoc, vel XI, p 258 1891 MARR, J. E -"Chapter V., Geology," In a GUIde Book to Appleby In Westmoreland, by the Rev Canon Matthews (Out of prml. There tS a coPy tn the L tbrary 0/ the Ceo!ogzca! Soctety ) LOWER P ALiEOZOIC ROCKS 1891 NICHOLSON, H A, and J E MARR -" The Cross Fell Inher" Quart yourn Ceo! Soc, vol XIVIl, P 500 1896 REED, F R. C.-" The Fauna of the Kelsley Limestone." Quart. Journ. Ceo! Soc., vol Ill, p 407 REED, F. R C.-" The Fauna of the Kelsley Limestone" Part II. Quart Yourn Ceo! Soc, vol 1m, p 67 1906. MARR, J E -" The Stratigraphical RelatiOns of the Dufton Shales and Kelsley Limestone of the Cross Fell Inher." Ceo!. Mag, Dec. v, vol. lll, p. 4~1

NEW RED SANDSTONE. 1862. HARKNESS, R -" Sandstones and Assoclf

IGNEOUS ROCKS. 1877. TOPLEY, W, and G A LEBOUR -" On the Intrusive Character of the Whm Sill of Northumberland" Quart yourn. Ceo!. Soc, vol XXXIIl, p 406. 1891 HARKER, A, and J E. MARR -" The Shap Gramte and the Associated Igneous and MetamorphiC Rocks" Quart. yourn Ceo! Soc, vol XIVll, P 266 1891 HARKER, A -" Petrological Notes on Rocks from the Cross Fell I nher" Bemg an Appendix to a Pa per by HAN Icholson and J E Marr Quart Journ. Ceo! Soc, vol X1VIl, P 512 1893 HARKER, A, and J E MARR -" Supplementary Notes on the MetamorphiC Rocks around the Shap Gramte" Quart yourn. Ceo! Soc, vol xhx, p. 359

GLACIAL. r875. GOODCHILD, J G.-'· Glacial Phenomena of the Eden Valley," etc Quart yourn Ceo! Soc, vol XXXI, p 55. 1887 "Ice 'Vork In Edeuolde." Trans. Cumberland and Westmoreland Assoc , No XI, P II 1.

PHYSIOGRAPHY. MARR, J E -" The vVaterways of Enghsh Lakeland" Ceogr. Journ , vol. VB, p 602 MARR, J E -" Presidential Address to the Geological SOCiety-The I nfluence of the Geological Structure of EnglIsh Lakeland upon ItS present Features" Quart. Yourn. Ceo! Soc, vol lXIl, p. lxvi. CONTOURED MAP TO ILLUSTRATE THE GLACIATION OF EDENSIDE.-J. G GOODCHILD.