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 (lEOLOaiCAL SECTIONS 
 
 CROSSING NEW HAMPSHIRE AND VERMONT. 
 
 By PROin. C. H. HXrOBiCOCns.. 
 
 CONCORD, N. H.: 
 
 PRINTED MY THE REPUBLICAN PRESS ASSOCIATION. 
 
 1884. 
 
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 DESCRIPTION 
 
 O V 
 
 Geological Sections 
 
 i 
 
 CROSSING NEW HAMPSHIRE AND VERMONT. 
 
 By P>R,Oii\ C. H. HITCHCOCK. 
 
 CONCORD, N. H.: 
 
 PRINTED BY THE REPUBLICAN PRESS ASSOCIATION. 
 
 18 8 4. 
 
y 
 
 T 
 
 1 1 
 
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V 
 
 GEOLOGICAL SECTIONS OF NKW HAMPSHIRE 
 AND VERMOiNT. 
 
 ^ 
 
 »Six years ago the final report \\\i<n\ the Geology of New 
 Hampshire was pnblislied by order of the legislature. Since 
 that time the author of this paper, who held the ofHce of state 
 geologist, has had occasion to revise the general sections de- 
 scribed in his report, and also to extend tlietn through Vermont. 
 Specimens to the number of three thousand illustrate them upon 
 the shelves of the museum of the New Hampshire College of 
 Agriculture and the Mechanic Arts, where colored profiles will 
 also be found upon a liberal scale. The profiles are forty feet 
 long, extending the entire length of the room upon the back 
 side of the case and between the shelves. The different series 
 of strata are represented by colors, and the numbers printed 
 upon the profiles correspond to those pasted upon the specimens 
 directly in front. Thirteen slielves are arranged in order, one 
 over another, from the floor to the ceiling. Care is taken not 
 to impede the view of the colored profiles by braces or railing 
 in the gallery, so that the visitor may examine the whole series 
 either in detail or at a glance. These shelves are a truthful 
 re[)resentation of nature. Three thousand ledges are represent- 
 ed in their proper geographical order, and by proper study any 
 one can classify the several groups without the labor of travel- 
 linsi over the country. More or less of theory is given in the 
 profiles, and the author is desirous of iiaving his views submitted 
 to criticism. The conclusions derived from the study of these 
 sections have been embodied in the reports upon the geology of 
 
both New Hampsliire and Vermont ; l)iit a resiirvev of them has 
 eimbled me to convct doubtful points, to confirm trutliful rep- 
 resentations, to change the published section lines where im- 
 provements were i)ossible, to take advantage of observations 
 made by other observers, ami to present a connected view of 
 what lias l)een learned concernin<>; the <;eological succession in 
 the two states, A knowledge of this territory furnishes the key 
 to unlock the mysteries of New England geology, as well as 
 th.it of the whole of the middle -ection of the Atlantic <>-eo(rrai)h- 
 ical area. In the same room at Hanover may be seen a large 
 colored ge()h)gical relief-map of New Hampshire uiM)n the 
 scale of one mile to the inch horizontally, and one thousand feet 
 to the inch vertically. Portions of Vermont are also shown, 
 and it is our i)urpose to show the whole of that state, as well as 
 a part of Maine, upon the same platform. These relief maps 
 and half of the specimens illustrating the Vermont sections 
 belong to Dartmouth college. 
 
 A similar collection of specimens is on exhibition at the rooms 
 of the American JNIuseum of Natural History in New York, 
 together with the same large relief-map of New Hampshire, 
 colored t<> correspond with the published geological map 
 of New Hampshire. A special description of that has been 
 printed in Bulletin No. 8 of the {)ublications of that institution. 
 At the normal school in Plymouth there is a similar exhii)itiou 
 of the New Hampshire i)art of this collection, but no attempt 
 has l)een made there to grouj) them in order upon shelves ac- 
 companied by the colored illustrative protiles. 
 
 Our object in preparing this ski-tch is to so record the most 
 important facts connected with our explorations, that those who 
 visit Hanover may have the opportunity to verify our conclu- 
 sions for themselves by studying the specimens, both lithologi- 
 cally and stratigraphically. The work of exploration was under- 
 taken with the determination to discover what the rocks them- 
 selves taught, and not in the interest of any theory. Hence 
 students may rely upon the truthfulness of all the representa- 
 tions. The specimens come from ledges in the localities indi- 
 cated, and the positions of the strata are stated according to 
 our best judgment from personal observation. If there is ever 
 any want of symmetry in the folds, if one side of an axis seems 
 
 tu 
 
 1 * 
 
r» 
 
 & 
 
 to possess an fXiiiiSiTutod tliicknt'ss, it is bt'caiiHe all the facts 
 needed for full delineation are not known. I'uin.s are taken not 
 to represent curves and fividts except those whose existence is 
 un(|Ui'stional»le. Ilencu' tiie in(|uii'cr can utilize the ten veais of 
 field and otilee work embodied in tlieho colleetions nearly as well 
 as if he had jjone over tiie <rronnd iiiniself. IU> will also under- 
 stand for iiiniself tin,' localities where supplementary observa- 
 tions are needed. 
 
 About 00,000 feet thickness of strata occur over this territory. 
 As they have not been particularly investi<fated elsewhere, it 
 follows that many <»roups must exist not ^eneniily recognized, 
 and peculiar designations must be employed which will be per- 
 plexing. To assist the incpiirer, I will, at first, present a few 
 general conclusions, based upon a terminology readily under- 
 stood, reserving the fuller details of our scheme of classification 
 and structure for the sequel, to be fully a[)preciated only by a 
 painstaking exanjinution of the larger profiles and specimens in 
 the cases. 
 
 It should also be borne in mind that our various grou|)s or 
 formations are classified according to stratigraphical reasons, 
 and not lithology. liithological names may be used for conven- 
 ience, or so as to avoid the multiplication of local designations. 
 A lithological similarity is useful in tracing a formation from 
 farm to farm, or town to town, throughout a county, or to iden- 
 tify the opposite side of a synclinal basin or :Miticliiial ridge. 
 Furthermore, unlike rocks are never assumed to be identical. If 
 a honihli'iide schist and clay slate dip toward each other, tiiey 
 are assumed to be of different age and separated by ii fault or 
 unconformity. All the igneous rocks of our field are held to be 
 truly eiiiptive. and are devoid of marks of stratilicatioii. If a 
 granitic rock siiows foliation, it is classed among the gneisses. 
 
 Tlie pul)lished sections accompanying this [)aperhave the hor- 
 izontal scale of ,(„,,',, I, II' ''"*! t''*-' vertical of about icoVod- '^'^^^y 
 are arranged geograpiiicaliy correct with reference to each other, 
 and the meridians and longitude are drawn as upon a map. In 
 some cases the extreme east or west ends of tlie sections are not 
 rei)resente(l. Tlu' base line of all the sections is ir).')0 feet 
 below tide-water. Twelve vai'iatioiis of lines, dots, and dashes 
 indicate as many groups of rocks upon wliich our pri'uary con- 
 
cliisions art! based. Tliev .'ifo, — 1 . *Xini!;;irji j^ioiip. -J. I ppor 
 Canibro-SiliiriMii slates uod scliists. M. Camhro-Siliiriuii liino- 
 stoiH's. 4. '!'lic C'omicoticiit Valley mica schists, <|iiartzit('8, 
 ot(!., n-fcrii'd a) llie ('oils <j;r()up in the New Ilaiiipsliire reports, 
 and the ealciferons mica schists of the re|)orts of lioth statea. 
 .0. Potsfhim sandstone. (1. Clay slates an(', arjrillitic and other 
 schists, supposed to lie of Ciimbiian njjc Of these, the "(Jeor- 
 gia slates" of the N'ernioiit report conttiin the (Hoielhis and Jn- 
 gcliiKi ; the ()thers have not yet yielded any (»r<ianiMn. 7. Mica 
 schist of eastern New Hampshire, a part of the *' Hoekiii<j;h!iin 
 group" of the re|)ort. M. Iluronian. inclndinji- the chi(»ritic, 
 ar<;illitic. dioritic schists, (pnirt/ites. -ind protojjenes thinking 
 the (Jreen IMountains. :uid adjoiiiiiiij, the ( onnccticut liver, or 
 the rocks UHiially refern-d to this yroiip l>y authors ; also the 
 '• Merrinnick <>'roiip," •' Ferriiiiiiioiis slates.'" •• Ki-arsar^e u,i()up," 
 and part of the •" Hockin^hain ^roiip " of tlii' New llamiishire 
 report. !>. Montalhan rocks, as delined in the New Hampshire 
 report, iiicludinif the schists holdin<i- the co.'irse <iranite veins 
 carryiiiii' niercliantahle mica. lo. Ordinary <rneiss, inclnding the 
 "(Jreen ."Mountain." '• Lake U'iiiiiipiseo<>-ee. and •• IJethlehem" 
 varieties of the reports. 11. Poiphyrilic <>iieiss. To these 
 may he added another distinction f<»r tiie uiistratilied rocks, ia 
 which are I'luhraced granite, syenite, and [lorphyiy. 
 
 Till: < A>llll{()-S11,11!1AX. 
 
 Trohahly the whole of this division of tlii' Paleozoic rocks 
 occurs in the Champlain valh'y. Sections I toX'H display amass 
 of green hydro-mica ^(•lli^ts overlying the fossiliferoiis limestones 
 of this series, and ma_\ . perhaps, represent the Loraiiu' slates of 
 Ni'w York. On our section lines the 'I'renton is wanting in 
 immediate contiguity to these schists, so that the (piestion arises 
 whether these schists may not represent i)eds that were laid 
 down in the Trenton age. So far as recognized, the Trenton 
 beds are limc.stones ; hiit there must have been sediments coeval 
 with those limestones in the ancient seas: still it is but a rude 
 conjecture tliat would refer them to this aye. Thev are called 
 Loraiue upon the sections. These beiis were called •• Magnesian 
 
 * Foniicflv ivj.'iir.U'(l as Lower Helc!erberg, 1ml ricmly sliirwti by I'rol'. K. P. Whit- 
 liulil lu bt'Kiiig to tlu' Niiigiiru.— ./»!. AVv'. Jour., Ill, vol xxv, p. ;!0S. 
 
V 
 
 slate" by Prof. Emmons, and constituted the iipi)er member of 
 what he styled " Lower Tuconic." The relations of the lime- 
 stones to the schists are well showTi upon section IV in Mt. Kolus. 
 There aliout 'jOO feet of the schists are isolated fr(»m all connec- 
 tion with the main ran<^e, and rest upon about two thousand feet 
 thicl<nes8 of limestones, almost horizontid except at their base. 
 The same schists reappear in what is cal. 'd tlu; Taconic range 
 of mountains, a few miles west of Mt. Kolus. They universally 
 dip east, and would l>e regarded as older than the limestones 
 except for the section in Mt. Kolus. This fact has led to care- 
 ful search at the junction of the two fornuitions for evidence of 
 a fault. Se(!tion V shows this break very plainly in Tinmouth. 
 Section I affords the most satisfactory evidence of the passage 
 of the limestones beneath the schists of the Taconic range. At 
 North Pownal a fault has broii^iit up the limestones from be- 
 neath the heart of the mountain lango. To llie east, near tlie 
 Massachusetts line, the limestones dij) west toward these schists, 
 contrary to the nearly universal position of these rocks west of 
 the Hoosac Mountains. IJy following the Troy ilt Boston 
 Railn^ad to the north from North Powntd. we tind the limestouea 
 nearly or quite continuous to lloosick Kails, where the charac- 
 teristic fossils of the C'liazy and calciferous sandrock occur in 
 them. This section, therefore, demonstrates the inferior place 
 of the limestones as compared witli the schists. This is in the 
 heart of the classic Taconic grounds, where the late Professor 
 Emmons deduced the conclusions giving rise to the existence of 
 the noted Taconic system. 1 cannot ascertain tiiat he discov- 
 ered this western dip in Pownal, and the consetpieut connection, 
 ledge by ledge, of his Stockbridge limestones with the (,'hazy 
 and calciferous at lloosick. It is just here that the fatal defect 
 to the establishment of the Taconic system, as delined by 
 Emmons, exists. His paleontological arguments were better 
 than the stratigraphical. 
 
 TIIK CAMBRIAN. 
 
 On the west Hank of the Careen Mountains, sometimes rising 
 higher tlian the main raiigi'. is a band of (luart/.ite, which re- 
 ceived from Emmons the appellation of " Granular (piartz," and 
 
It wns iimdo tlio hiise of his Taconic Hystcm. Our Hi'ctions fthow 
 tlmt it iiiiint'«li:itfly iiiidcrlit's the calcifcioiis HiiiKliock. siihI liav- 
 in^^ foHsilh Hliniliir to IIkjsc found clMiswiu'ie in llu- I'otsdam 
 BHiidHtoiK', it is clearly a mcmbj'r of the Camhrian Hcrivs. lii 
 80IIU' (|iiarti'i's the ctTort has been made, iiiisiictH'ssfully, to refer 
 it to the Middle Silurian sandstones. Upon sections III and 
 V'll, besides other localities nieiitioni'd in the I HO I report, the 
 basal beds contain pebbles of blue (piartz, which are reco<i;ni>!ed 
 as havinj^ been derived from t!ie adjacent "gneisses of the (Jreen 
 Mountains. Hence this (pnirtzite has been fortned since the 
 elevation of the Green Mountains above tide water. The cal- 
 ciferous sandrock had its ori}j;in posteriorly to the (puirt/.ite, and 
 likewise the several other members of the limestone }j;roup in 
 their turn, and there is a natural order of succession in time o* 
 the formations from the <2,neiss to the west. 
 
 Three bands of sandstone, therefore, are referred to the Pots- 
 dam in the Cham|)lain valley : — first, the normal j^ray sediment- 
 ary beds at the foot of the Adirondacks, always known under 
 this name since IHIO ; second, the quartzite on the flank of the 
 Green Mountains ; third, a ran<;e of reil s mdstone and dolomite 
 from the Canada line to IJridport, whore it is succeeded by out- 
 crops of a material not distinguisliable from the first-named 
 band. Partly accompaiiyinji; the middle band is a series of 
 slates and hard sandstones, passing into roolinjj; slates, called 
 " Georgi.a (jroup " if the state report, which carri(>s such fossils 
 as Ole.nelliifi iuuX^bii/elina, and is, therefore, tlioutjlit to be some- 
 what older than the typical Potsdam sandstone. These are 
 partly connected with a series of schists gradually increasing in 
 thickness and width of territory from section VI I, east of Mid- 
 dlebury. to the Canada line. The quartzite first named termi- 
 nates lietween sections N'll and \'III, save a«. it may merge 
 into these scliists. The continuation of th'^isc •-■. iiisi-^ into Can- 
 ada is an area partly of Cambrian and partly of Levis age. 
 
 We can now understand the physical histor;.' of western Ver- 
 mont in the early Paleozoic age. The Adirondacks and Green 
 Mountains luid been elevated above the sea, and constituted dry 
 land, connecting on the east witii tiie large Atlantic area — New- 
 fu*;ndland to Alabama — and on the north-west with the gen- 
 era 11 v recognized Laurentian of IJritish America. The waves 
 
 1 
 
 ■> 
 
 U 
 
r 
 
 i 
 
 daHliiti}; nt tho Vermont iind Now York shoro Hmph ncoutniilated 
 the (|iinrt/ (Ifrivi-d from tin (liHintt'<j;ratioii of the ^jtiu-iKMcs into 
 bunks of piirolv silicioiirt siindH, frtMHiciitly tcinu'd •• priiuordiiil 
 seu-lx'iK'hi's." 'I'lic otlicr umtoriiilN, of liner textiiri', were wiiMlied 
 out into tlie deeju'r waters, but remlied Hulllci«'ntl.v ntur the »ur- 
 fuce to allow of the exiMtence of trilobites, annelids, and sea- 
 weedw. Atlenjrth tlu! silii-iouH sediments ceased to aeeunmlute, 
 and 'imestones took their place, fallinj;; iiown upon the slaty 
 foundations. In the Trenton a<jo, the last of the limestones, 
 this sea became disconnectetl with the Atlantic ocean through 
 the present Gulf St. Lawrence, as shown by the distinctively 
 American types of life existinjj throutihout the interior. 'i"he 
 limestones were finally eoverecl by the I'lieii and Loraine slates. 
 Partial elevations of the Champlain country had been in |»rog- 
 ress during the building up of the C'amltrian aiul Cambro-Silu- 
 rian, but there must have been a very important one after the 
 deposition of the Loraine group. The whole Champlain valley 
 seems to have been then raised above the ocean, since no rocks 
 of later ago have been deposited in this basin within the limits 
 of New Kngland. Tho linal results of all the elevatory move- 
 ments have been tlu; crowding towards each other of the prim- 
 itive land-areas ; the faulting of the primal slates ; the raising 
 of the beach beneath Burlington and St. Albans— and changing 
 its color from gray to red — overturning many of tho limestones 
 and sandstones; developing the synunetrical folds in the red 
 sandstone about Monkton and I-'ertisburg ; and the alteration of 
 the calcareous beds into snow-white marbles. 
 
 THE CiKKKN .MOINTAIN AMULINAI. 
 
 ■> 
 
 U 
 
 I 
 
 The existence of the anti linal ridge of the (Iroen Mountains 
 was the most important oontri' -utiou to science made by the late 
 geologictd survey of Vermont, though its value was not then 
 ap|)reciated. Nearly all our sections illustrate the existence of 
 this structural feature. Only No. VI II; purely monoclinal ; and 
 this, like VII and VIII, is to be regarded as an inverted anti- 
 clinal. The elevatory pressure seems to have been greatest 
 along the middle part of the state, so as to have overturned this 
 
10 
 
 main axis. In I a mass of mica schist of uiuictermined age, 
 possibly 3Ioiitalb!in, constitutes the smnmit of the iiisihest rid<^e. 
 continuous from tlie Iloosac mountain over the celebrated tun- 
 nel to No. 11 in Searsburg. where it rests upon the eastern Manic 
 of the elevated country. The gneiss is narrowewt at the tunnel, 
 and widest along section I, where it may readily be seen to be 
 composed of three parallel axes. The more western one may 
 not extend many miles northerly, and ic is more like the typical 
 Laurcntian than any otiier area. Very satisfactory sections are 
 obtained in tl;-3 valleys of the Winooski, La Moille. and Mis- 
 sisco rivers, cut down across this formation more than .'5.000 
 feet, just north of Camel's Hump, Mt. Mauslield, and Jay Peak 
 (compare IX to XIII). Upon the high mountains the strata 
 are ap-t to l)e obscured by extensive deposits of till. Logan's 
 scheme of sti-ucture involved the existence of a synclinal in- 
 stead of anticlinal, while his description of Sutton mountain* 
 showed that the true structure could not be suppressed. Sel- 
 wyn, his successor in oHice, declares that the physical character 
 of the region entirely favors the anticlinal structure for the 
 Green Mountains in Canada. Prof. J. I). Dana has also an- 
 nounced his conviction that these gneisses in southern Vermont 
 are older than the (juartzite, and of Archa'an age.t 
 
 In southern Vermont, wiiere the elevated region is widest, 
 the rocks are usually well-defined gneisses, including protogene. 
 North of VI the feldspar diminishes in amount, and at length is 
 mauifented in scattered crystals, seen chiefly where tiie layers 
 are broken. An inexperienced observer will overlook the feld- 
 spar upon the higher mountains in the northern part of the 
 state. It is pro|>erIy a feidspatliic mica schist. Adams, the 
 first state geologist, suggest(,'d the name of •' Green ^Mountain 
 gneiss" for the whole terraue, in view of this marked litholoo:- 
 ical feature. We (ind, on examination, that this micaceous 
 band is proltably the e(piivalent of a mica schist or mic;iceous 
 gneiss in sev(>ral gneissic terranes of this age in the Connec- 
 ticut iiydrograpiiie basins in both states, and that it is overlaid 
 by hornblende scliist. 
 
 It follows, from tlie rehitions of th(> Cambrian quartzites to 
 
 *(ir(.lo^'y (il'Ciuiailil. ISO.'i, pujr,. o,-,i 
 
 t Quar. Jour, ( ;eol. Soc, XXXVIII, 397, 1882. 
 
i 
 
 the giK'U.s, tluit the latter is of pi-e-Cambrian age. The " pri- 
 mordial sea-beach" detined the western limits of this ancient 
 land. If we nse a similar criterion for the determination of the 
 eastern limits of this land, we mnst travel to Hraintree in Mas- 
 sachnsetts, or far down in ^^aine, to find thoin. There are 
 nnfossiliferons (jnartzites and limestones, probably the efpiiva- 
 lent of these western bands, in IMymonth, Vt.. Hhode Island, 
 and near the mouth of lVii()bsc()t bay. The tirst are about ten 
 miles in length. There are also areas of slate of undetermined 
 awe. In later times tiie Conneetieut vallev deepened sufliciently 
 to allow of the <j;rowth of Niagara and lleldcrl)erg coral reefs. 
 
 couur.LATiox OK Tin; (ii!i:i:N mointain and new uami'shire 
 
 GNEISSKS. 
 
 The sections will enable us to i)r()ceed a step fin'ther. and cor- 
 relate the gneisses just descril)ed with those of south-eastern 
 Vermont, the C'onnecti<'ut valley, and both llanks of the high- 
 lands l)etween the Conneetieut and Merrimack rivers in New 
 Hamiishire. First of nil, ujjou Nos. II, III. IW and V the 
 Green Mountain terrane repeats itself in the well-delined range 
 marked on the N'ernionl map as extending from Halifax to Hart- 
 land. Next, passing the small (Juilford, lirattleboro', and 
 Vernon areas, we find the terrane again rising with greater width 
 from Winchester to Fit/.william in 1. Swanzey in II, Surry, (ill- 
 sum, and Stoddard in III. but largely covered by later rocks, 
 Acworth and Lempstei- in l\'.("roydon and Springlield in V, 
 Hanover and C'an:ian in VI. Orford and Weiitworth in VII, 
 Haverhill and Benton in VIll. IJethlehem in IX. .lefferson and 
 Berlin in X. and Milan in XI. This is the noitiiern termination 
 of the ti'rraui'. It next shows itself u|)on the Merrimack sIojjc, 
 viz.. at Peteiborougli in II. Dcering. Weare, and Dunbarton in 
 III, Warner in IN'. Andovei' in N'. in very limited amount. It 
 seems on this Hank of the highlands to lie more in small patches 
 than as a l)road lielt. Tiie next appenrauci' of this gni'iss is in 
 the remarkable range from Mason (1), through 3Iilford and 
 Amherst (II), IManeheslt'r, C'andia in HI, Northwood and Har- 
 rinsiton in IN'. This range is characterizt'd !)y the thoroughly 
 crvstalline saecharoidal aspect of the constituents. No one 
 
12 
 
 HMHhnr with tvpicul Lnurentim, ir,.o,Mi(l will find UuusoU far 
 <n>M. ho,... hotwe,.,. M..,s,>nuM<l DcHMliel.l. Mo,i„ IJ.Hin and 
 m.u ...t L. no,ll...a.st.n. oxt..,„i,, of th. p,.,.vi,...slv .n. - 
 
 tlOIU'd (riiCISSIC W.iVC. 
 
 . •l""' ^■• \l. n.Kl VII is .....odi.M- .•on,s,mMu...s miv... ..Mrllv oo- 
 
 nu-Hl....,, w,.l. „,„ l.v.,n.,n„,i.i,. l.si.. ,.f L,,., Wi.,.,!pis.o.oe 
 
 Ins .n.,, ,s ,.oio,-c.,l ,.,.o,. ll.. u,a,.. suj^^.^ts a ..o.lh-we.t ,ir 
 
 ..•n. a ,..„,„..,,, uvn.l. Co.u,.as.s „l.s..-vations, l.ow.v.r, show 
 
 " "".'\''-"i''^' ♦" '"' t'- -■""'- ''i--tion ; h..K..., th. whole of 
 
 tlu- or,.,,..l an.:, is ,.ot visihl.. hoi..^, conc-ealed hv h,to,- for.na- 
 
 '>"s. 'l"s.sti„.ln-oad.stofalIof,!„te.Ta,u..s;and it comes 
 
 U. h. ^„.„„„s.o.ee laia. expo.u.vs fo.- g,-a,.ite, ■...t the 
 
 ..s o. ,oi,a ,o„ ,.a„ al,..ost always he disce,.,..d. The dillicultv 
 
 >< d,s ,„„„sh,.,o. the two ,.oeks is ...Ue,. i,. the Mai,.e tha,. tl/e 
 
 '="^'' ";':'•""- / !'<• dese,-i,,tio„s i^iven by Selwy., to the oldest 
 
 La.ne,, ,a,. ^„e.ses of Canada will apply well to those in the 
 
 •"- 'i->.u-.. 1 he next fol,, is seen at Nashua an<l Hudson in 
 
 _H-npstead,nII,a,uMVest Kppi,,. i,. ,„. There a.-e still 
 
 .-■•;--<>' sn.all si.e below scn-tion III. espeeiallv in Massa- 
 
 cl.use Us wl,e,.e o,.,- pnMished n,ap shows the no,-th-east ternd- 
 
 m.s ot (he band wl,i..h ha. affonled (he Enzoo. in Ch^hnsfo,.! 
 
 Inns.nueh as (h.se seve,.al ^neissi. ,,,n^es rese.nbie one an- 
 '»<''^'.''- =>"'l '-Nln''it the usual pheuo,,,.,., „f st,atiu,aphieal eon- 
 ;"'^'';:'"- -''*""-• '- '•••I'lin^' lu.ueath supe.-io,. 'fo.Muations or 
 •-<i"-|. ove,- s„!| u,o,va„eieu, .roups, it is but a neeessarv 
 av„e,.ah.a„ou.o,.o,K.l,H,e,ha(.heyeau,e inb. existence in the 
 sMuu. ^eolo^ieal a^e. a,ul 1 hat ( hey a,v all (o b. ranked as the 
 7'"^-'-'>s of (he Cveu Mo„u,ain sc-ies. p,e-Cambnau. -Vr- 
 H.a.u,.o,|.:o/oie. li ma v be ,vn,a,ked (hat th. ,i,st ha> a north- 
 ^^••'>- "vnd ,„ sou(lu,M \enuo,„.ve,.oin,o. „,„,, .,,,t,,,,v j,, ,,,, 
 
 7;l'''- I'-'t <>'• 'he s,a,... :,,ul ,,ot ex(e,,di,,o. in,o the do,.,iuion 
 "'■■'"••"'••' '"•*••'■ "'"' •^^'•'".v u,ile.. Th. othe,- .•anues ,r,,u. 
 -i.ilveou,seu,o,veaste,ly. and lie uea,iy in tl,e „on„al .uu-th- 
 i-'M ninov o( (heroiavspondino (eiTaue> south of N.w Ku.dand 
 - n, the hi,l,la,.d> of N..W Vo,.k. New .le-^sey. and (h; Blue 
 •^•d^v ol \ „.on„a. U .. have. the,vfo,-e. an extensive -n'oup of 
 gueissu. a,vas esseutiallv .o,ui,)nous tYuu, Newfoundland to Vla- 
 '^^""^' *'" the Atlanti. iuude,- of this e.-ntineut. Tuev a,v of 
 
 f 
 
 1 
 
 f. 
 
 I 
 
 4 
 
18 
 
 ir 
 1(1 
 1- 
 
 Eozoic :i2;o, coeval with the formations of the Laurontiiui liish- 
 lands, and developed along a different line of growth. They 
 constituted an Arohieaii Atlantis, now parti; lly submerged, hut 
 playing an important part in the building up of the North Amer- 
 ican continent. 
 
 THE OLDKST OK TIIIC (JNEISSES. 
 
 These common gneisses overlie a peculiar rock, whose largest 
 development follows the water-shed between the Connecticut 
 and jMerrimack svstems of drainage, the tract of iii<;hest eleva- 
 tion in the state south of tlie White Mountains, and tlic group 
 passes beneath the mountains north of the Merrimack basin. 
 This rock is a gneiss, containing distinct crystals of orthoclase, 
 from one lialf to three inches in length, which are usually 
 arranged in lines of sup])osed ])edding. A more conspicuous 
 ledge is rarely seen ; and hence geologists have universally rec- 
 ognized and described the rock. It is the AiKjtnt ijiieiss of 
 Europe, and Logan mentions it as a constituent of the Lauren- 
 tian in Canada. It is not met with in Vermont. 
 
 Nearly tiiirty areas of this formation have been delineated on 
 the New Hampshire map. The largest extends continuously 
 from J.ii'frey to Groton, dips beneath mica scliists to rise again 
 in Ellsworth, continues to Franconia, and then underlies the 
 Bethlehem grouj) of gneiss to arise for the last time to the sur- 
 face at the Wing Road railroad junction. The extreme points 
 thus indicated are 10') miles apart. On section I this rock just 
 rises to the surface in Kindge ; on J I. tlu; southern extremity of 
 the main range is touclied in .laftrey ; on III. IV, \', ^'I, and 
 VII, the rock is very conspicuous. Two ranges are seen in VI, 
 VII, and \TI1, and it uncomformably underlies the other gneiss- 
 es in several instances. The api)arent doubling in \l is occa- 
 sioned Iiy the crossing of a crooked range. Other rocks inter- 
 stratified witii and integral parts of the formation are ordinary 
 gneisses, hard mica scliists, ferruginous (pmrtzites. and librolite 
 aggregates. The stratification is often obscure, and entirely 
 obliterated in many localities, or where the crystals of feldspar 
 are irregularly disposed. No tower group than this has been 
 recognized in any sections, or anywhere else in New England. 
 
14 
 
 1 
 
 IIOKNBLENDE SCHIST (JKOUI'. 
 
 Ha vino: asrortainod the stnitigraphical rel.itions of the 
 gneisses, we find the first rock coverin-,. ihem to he a band of 
 hornblende schist, occasionally feldspathie, and not unfrequently 
 1,500 feet thick. It is best understood in the southern parts of 
 our held, partly because better exposed, and partly because it 
 has been less studied in the north. First noticed in the Guil- 
 ford and Hrattleb(,ro', Vt., anticlinals I and 11, it was detected 
 only by exploration to hold the same position on boti, flanks of 
 the Hahfax-IIartland gneiss II. III. and IV. On I it also over- 
 lies the Green Mountain terrane. In New Hampshire it borders 
 a tract of gneiss between II and III in Cheshire county ; flanks 
 the west border of the Hanover gneiss, and covers tl/e Canaan 
 synclinal in VI; and overlies gneiss in Surry, III, and Haver- 
 hill, VIII. There is a continuous range of it close to the Con- 
 necticut river, between Cornish and Haverhill. In fact it is so 
 constant next the older gneisses, that if it be clearly absent, the 
 presence of a fault or of an unconformity may be assumed. In 
 Vernon it encircles an nrea of gneiss, and the structure indicated 
 IS that of an overturned anticlinal. The rocks over the horn- 
 blende are the green schists formerly called talcose. This is 
 proved upon I, III, IV in Vermont and the Connecticut river 
 range about Cornish. Similar beds are associated with the 
 green schists in Marlborough, II, and the Ammonoosuc gold- 
 field. It seems more intimately connected with the green sdiists 
 than with the gneiss, though often only the hornblende band 
 will be present. 
 
 HURONIAN. 
 
 This name is used as a matter of convenience to desi<>-nate all 
 the various schists of chloritic and argillitic aspect o'verlvin^ 
 the gneisses and inferior to the Cambrian, so far as known" 
 The tcrraiies in Vermont and western New Hampshire are the 
 ones that have been st.iciied the v,,ost, and are the most valua- 
 ble for the determination of age, l)ecause more nearly related to 
 the original Canadian exposures called by this name. ' The supe- 
 riority of the main Huronian belt upon the east side of the 
 Green Mountains to the gneiss is obvious upon every section 
 
 1 
 
16 
 
 from I to VIII. This view is confirmefl upon II to V by the 
 inferior position of the Halifax-IIarthind range of gneiss. 
 
 The Connecticut river range is first seen in IV, and from 
 thence lo Maine and Canada upon every section it adjoins the 
 hornblende schist or older gneisses, resting upon them. From 
 VI to XI it is easy to connect the Green Mountain and Connec- 
 ticut river ranges by a synclinal fold. V\)ou XII and XIII the 
 direct connection is interru[)ted by granites and schists that 
 seem to occupy the i)lace of the lialifax-Hartland range, II to V. 
 The apparently overlying position of the Iluronian west of the 
 calciferous in IX and XIII is due to inversion, as proved by the 
 occurrence of the fossiliferous Helderberg in similar position 
 just to the north of XIII in Canada (Lake Memphremagog). 
 West of the Green Mountains the Huronian has its normal 
 development in Canada and in the northernmost counties of 
 Vermont, gradually diminishing in breadth southerly. It is not 
 found south of VII. In southern New Hampshire the argillitiCr 
 quartzose, and micaceous divisions predominate nearly to the 
 exclusion of the chloritic schists, which, with the characteristic 
 dolomite, is seen in Raymond and Derry. Steatite occurs in it 
 at Francestown in the ferruginous slates, and in the mica schists 
 of Derry. All the schists referred to this series invariably 
 overlie the gneisses. 
 
 MONTALBAN. 
 
 So far the assignment of the formations to their proper order 
 has been comparatively easy ; but the introduction of the word 
 Montalhcm immediately suggests discussion. Inasmuch as the 
 typical locality, as shown by the name, lies within our territory, 
 tiie relations of the group must be brielly discussed. The name 
 of '"White Mountain Series" was tirst employed by myself in 
 IrtO'J. as a matter of convenience, in the discrimination of the 
 crystalline rocks of the White Mountain region and their exten- 
 sion into Massachusetts. Previously our geologists had usually 
 reo-arded these ervstalline schists as of Paleozoic age, prol)ably 
 
 * '111 
 
 Devonian. My studies in the Ammonoosuc district enal)lecl me 
 to advocate their pre-Silurian origin, and hence to give them a 
 special ntune. It was not intended to describe them as a .s»/.s?em 
 separate from the Laurentiau. though the conviction had been 
 
If) 
 
 more tlian once stated in puhlic tliat tli 
 prove to belong to a mot 
 
 applied with tlii 
 
 •e recent series. Tlii 
 
 ese rocks would probabl 
 
 IV ♦ 
 
 s name was also 
 
 what si„,N„,. .,,,0. .,f .0 't „ ■i,,,",r,;',';''''«' ">";- 
 
 ciferous mica schists in our reno.t^ r,. «" 'P and cal- 
 
 -■■...10., „„.,.. t„i., ,„»ig,„ui„„ 'r:„f ;;Zt tr' ;; "^ 
 
 a »y.st„„, below, „„„ tl,e „H,o,. „l.„ve, the H ,™ i , ° .T ""' 
 yet given i,s aiiv nioofs of fl„. u,l """."■"'■ "« has uot 
 .■ived from the .t, dv of th . " "«^" "' "'" M"""'"..". de- 
 
 elusions have he 1 Ull *'"""""" '"."."it', hut the con- 
 
 mica »ehi»t g,.o „ la . t,', , • •■"■'" '■"""'™'- •"'"- i» " 
 
 that the feldspathie r.^:!::^ ^^JZ ^^^ ^ 'T'' 
 belong. tOH„ oldc,. .e,.ies, whiehtni^lit t «„ ,"' it;'"""" 
 has named it in North C-i.-oh-nn h. V ^- ^^^'''^' 
 
 examined the .nVel of Ta AV ' ''•'"' '^""•^"^•''^"- ^ "^^ve 
 
 i^.- Hunt, who;i:.::iit^2:;z:r:;:, -rr-^ ---^ 
 
 has been shown above to be Cea 1 e, tt n the if ^""'" 
 and as it constitutes the axis of th; P Vr ^^•"■0'"'^». 
 
 by him to be thus a In^ • , '" ^^lountains, allowed 
 
 series, as defuHHl bv hZ , " '""" '''' '''' ^^^'^"^''^"'- 
 .!» utiiiKd i,\ Hunt, embraces two oroiijis of ,„-,. i» 
 
 ent age. Hence the woid 1ms heen nsed 1,^,^ "'■',""*"- 
 
 "'7'i..l.l.v ernpio, it in its original ig . ti o rr.i '" "" 
 
 New Ha,,.,.:',;;!";: o " 'xii. ':,::'„:';';:;f-"-'- -' '"■"' ^" ''.^ 
 
 position. Theexalnples cited ,i'l;"'.;,:7= ";'" J""^'- 
 eii. part of the st,.te. 'Mwil ...e hom the north- 
 
 -MIC.V SCHISTS, 
 
 thus t.„ described, especially i„ southern New 
 
 *Vol. II,p. (ioG, 
 
17 
 
 V f 
 
 I 
 
 Hampshire, is miqnestionable. No autlinr who has devoted any 
 attention to tiiese groups lias snp;<xested an inferior position for 
 them. They may he called Silurian. C'auihrian, or pre-Cam- 
 brian, according as each author is inclined to regard New Eng- 
 land very ancient, or on the verge of the Paleo>5t)ic. Such of 
 the Rockingiuvm grou|) as is not referred to the Huronian be- 
 longs here, as shown in the Pack Monadnock Mountains (II), 
 Belmont, Gilmanton, and Milton (\'). It constitutes the sub- 
 stance of several interesting nioinitains. like the Pack Monad- 
 nock, 'rem[)le, and Lyndeborongh. west of the [Merrimack, and 
 Catamount. Fort, Xottingham, lUiie Hills. lUue Job, Ilussey, 
 Chesly, and Teneriffe, to the east. This orographic feature is 
 paralleled in Mts. Monadnock, Kearsarge, and Raggetl, of a 
 possible older group carrying andalusite. 
 
 In the Connecticut valley there are 10,000 or 12,000 feet of 
 mica schists and associated rocks. Many of them are charac- 
 terized by the presence of staurolite and garnet, and by this fea- 
 ture are distinguished from a contiguous band of Cambrian clay 
 slate. Its basal member is a quartzite. 1.000 feet thick in 
 Cheshire and Grafton counties, and frecjuently occurring in im- 
 mense masses, as in Croydon, Grantliam, Moose, Cuba, and 
 Piermont mountains. This rock resembles the Potsdam at the 
 west base of the Green Mountains. In Washington county, 
 Vermont, it may be replaced by a quartz schist, often micaceous. 
 The calcareous member occupies a great many square miles in 
 Vermont, amounting to more than one fourth of the entire area 
 of that state. Logan regards the Canadian extension of this 
 band as of Niagara, or upper Silurian, age. Dana supposes the 
 fossils at Hernardston, Mass., to be so connected with this ter- 
 rane that they determine its age — being upper Silurian or De- 
 vonian. There are many ditlicnlties involved in readily refer- 
 ring this entire series to the upper Silurian ; but if any collector 
 will Ijring in fossils from characteristic localities proving its Ni- 
 agara age, there will be uoJiing in our interpretation of its strat- 
 igraphy inconsistent with such a discovery. The rocks are evi- 
 dently the newest of any of the great systems of strata described 
 in our reports. To elevate them to the upper Silurian would 
 not carry any higher the chloritic, silicious, or feldsi)athic schists 
 already enumerated. 
 
IS 
 
 A brief disfii»si(m of llu- stratiiirapliy of the Coos and ealcif- 
 eroiis mica schist croups will show wiiy they take their hifih 
 place ill .)iir NVsteni, and illustrate the nature of the dillietilties 
 encountered in undersfaiidino- the various dips and overturns of 
 the strata in our Held. These groups are not separated in our 
 sections, as they are supposed to he essentially the same series, 
 and their litholoiiical differences sueh as result from loeal (-auses. 
 The ealeareous division lies chietly in Vermont, and on XI. XII, 
 XIII, west of a orniiitic area. The most eastern of the mic.a- 
 ceouJ iireas upon XIII. and a part of the same in V. are ealca- 
 reous ; all the other schists of this ajiv in New Ilami)shire lack 
 tlie limestone. There is no foundation for the statement some- 
 times made, that the staurolite and andalusite crystals have 
 been produced l.y the proximity of oranite or other iirneous 
 rocks when erupted. On the contrary, these ii-neous rocks are 
 common in the calcareous areas where silicates art' rare, and 
 are absent where these cruciform minerals are abundant. 
 "^ The natural relations of the micaceous group and the neigh- 
 boring series are displayed upon VI, VII. VIII. Four series 
 of rodvs are disposed in a synclinal form : the micaceous group 
 is at the summit, underlaid fust by clay slate, second by the 
 Huronian, and third by gneiss. The synclinal is complex, as is 
 to be expected where elevating forces have l)een so active. 
 Upon VI there are nine, and upon \'II there are seven, axes in 
 the mica schist west of the Connecticut. So many groups in 
 synclinal attitude must represent the natural order, and hence 
 afford a basis for exi)laiiiing apparent exceptions by overturns, 
 faults, and unconformities. Upon the other sections some one 
 cr more of these four groups are wanting, but those present in- 
 variably sustain the same relations to one another. 
 
 The calcareous divisicn is widest where the natural relations 
 of the four groups are manifested. To the south of VI it has 
 narrowed very nuich, and lies further east than the axis of the 
 area northwards. This deHection has been oc-asioned by the 
 elevation of the Ilalifax-Hartlaud range of gneiss, since it occu- 
 pies the line of the central axis, and has its northern end en- 
 vironed by the mica schists, as shown on V. Repetitious of 
 this gneiss, with the accompanying hornblende schist, are seeu 
 upon^I and II, and there are others in Massachusetts. It would 
 
 y 
 
Ill 
 
 seem !vs if tlic clay slato and i\w Iluroiiian were less constant 
 than the mica schists and y;neiss, since Ihcy do not afjpear along 
 this range. The eastern bund of the llnronian does not appear 
 at all south of III, and its place ovit the gneiss may he takeu 
 by the hornblendic group. The absence of the "'ay slate alone 
 is sutlicient to enalde us to assume the existence of an uncon- 
 formity of the mica schist over the hornblende group. If tlie 
 slates and Iluronian were ever deposited over the Ilalifax-Ilart- 
 land gneiss, they have been sul)se(iuently removed by elevatiou 
 and denudation before the deposition of the mica schists. 
 
 An exiimiiiatiou of the more nortiieru sections shows that 
 older or eruptive rocks take tiie placi' of the Ilalifax-Ilartland 
 gneiss of IX, XII. and XIII. Upon IX tlie granite has uplifted 
 the adjoining strata, so that if our order of the groups were 
 determined by their succession on this lint', we would call the 
 micaceous rocks older than the slates, and the Iluronian newer 
 than the slates. The intrusion of this immense mass of gi-anite 
 gave an unusual dip to the mica schists, and being of unyielding 
 composition, the more tiexiltle slates and chhn'itic schists were 
 overturned upon both sides. The fundamental gneisses upon 
 bot'.i sides seem to have been unaffected, except that they stand 
 more nearly erect than before. Ui)on XII and XIII, the gran- 
 ite is larger in amount, and accompanied by gneiss and Huro- 
 nian, — though scarcely shown ni)on the profiles, — and the over- 
 turns are less conspicuous. Just to the north of XIII the over- 
 turning of the Huronian is made more obvious by the presence | 
 of Ilelderberg fossils in strata dipping beneath it The eruptive ] 
 granites have [lenetrated fissures in the mica schists, so that | 
 the latter nnist be the oldest. Logan and the Vermont report 
 regarded the granites as of Devonian age, because the disturbed 
 rocks were thought to be upper Silurian. 
 
 It seems likely that these granites npon IX, XII. XTII, were 
 connected with the uprising of the Halifax-IIartland gneiss in 
 southern Vermont. If granite is derived from the fusion of 
 schists, these bosses might have originated from the melting of 
 rocks connected with that range deep down in the earth. Small 
 areas of gneiss are connected with these granites u|)on the same 
 axial line in the middle of the calciferous groups, and Selwyn 
 finds them near the United States border in Canada, saving 
 
 r 
 
 1 ' 
 
20 
 
 these " aro appuictitly repetitions of the crystalline schists of 
 the unKM Sutton mountiiin iintidinal to the north-west."* C;ran- 
 ite-also occurs there. Tiio end of the .^niciss ranj^e is connected 
 with the granites upon IX, XII, and X 111 by an anticlinal line, 
 seen upon every inlrrniediate section. I'pon VIII, X, and XI 
 this line is developed into a mountainous range, and the strata 
 have very low dips. Thus the normal structure of this great 
 basin is that of a synclinal, with an anticlinal in the middh- more 
 highly elevated than the sides, and sometimes bringuig up the 
 uiuleilying gneiss. This feature is not conlined to the calcifer- 
 ous gri)UiK " Dozens of similar folds can readily be seen upon 
 our chart; and the discovery of this type of structure aids nia- 
 teriallv in the understanding of the New England folds. Au- 
 thors "have pointed out a similar type of basin in the Apptda- 
 chian regie, n of Pennsylvania and Virginia, as instanced in Tay- 
 lor's sec^tiou across the coal measures near Nesquehoning, Penn. 
 'Jliere is great significance to be attached to the subordinate 
 foldings of the calciferous group apart from this central line, 
 lu the" middle of the area upon I, the underlying hornblende 
 rock is brought up twice, and tiiere are as many as live folds. 
 Upon III the"strata are entirely monoclinal, and separated by a 
 band of clav slate and a fault from the non-calcareous division. 
 Along White River, upon VII, but not delineated in our figure, 
 we have discovered a horizontal fault in this group, and there 
 must have been an extensive shoving westward of part of the 
 series. The effects of the dislocation have not been observed 
 outside of the formation, nor for a distance of more than r,00 
 feet. 
 
 THE OUKUX or GUANrrK. 
 
 One of the subjects elucidated l)y the study of the New Hamp- 
 shire rocks is the origin of granite. Owing to false theories, 
 our predecessors have supposed it to have been derived from 
 the semi-fusion of stratified rocks. Careful studies in the field, 
 and the new methods of investigation with the microscope, are 
 leading in the direction of purely igneous eruption. Two ex- 
 cellent" illustrations are at hand, the one from Mt. Willard, and 
 the other from :Mt. Ascutney. 
 
 ♦ Geoloyy of Cumida ; n port of progri!:?s for I87'.t-Sn, piige 5. 
 
21 
 
 MT. WIl.l.Altl). 
 
 'I'liis iiioiintuin in uciiily ."5. ()(»(» feet al)()ve the sen. and nearly 
 1,000 feet above the Notch at the Crawford Mouse. Most of it 
 is composed of a hard mica schist or jj;neiss ltelon<>;inij; to the 
 Montali>an series, and is the end of this rock as developed in 
 the Presidential ran<j;e. Tho mountains to the west of the Saco 
 rivor consist of eruptive liianites, whicli have Iteen extruded and 
 l)oured over tliis i\Ioii(all»an i^roup. Two separate eruptions 
 are noted at jNIt. Willard. The first and oldest is tcrnjod Conway 
 granite, or a coarse-<;rained rock with l)iotite foi' its mica. It 
 once lilled tiie whole valley of the .Saco in the White .Mountain 
 rei^ion. and continues north-westei'ly throu<i,ii Mt. Willard and 
 the Mts. Tom and l{osel)i'ook ran<j;es. The other is tei-med Al- 
 bany granite, both these geo<>i'apliical names being derived from 
 the adjacent towns, where they are admirably develojied. This 
 Albany granite seems to have l)een a i)urelv iiineons mass, com- 
 
 ». t5 1.1- 
 
 ing u|) between the Conway on one side and a compact andalii- 
 site mica schist upon the other, termed the Ivearstirge group, 
 from its occurrence upon ^It. Kearsaige. The mica schist haa 
 been alYected by the contact of a melted ni.'iss in such a way as 
 to clearly prove that the Albany gi'anite was eruptive. The 
 peculiar effects of this intrusion are called" contact phenomena," 
 and they have been produced only by the presence of a hot liq- 
 uid adjacent to an earthy rock capable of alteration. 
 
 The Montalban njcks were terribly shattered before the pro- 
 trusion (" the Conway rock, and tiie fragments cemented by a 
 fine-grai d granite, which never passes into the former. The 
 breccia thus formed is finely shown at the railroad house, a 
 mile south from tiie Crawford House. A few hundred feet 
 farther south, the Conway granite is well shown, luit the con- 
 tact l)otween this and the Albany cannot be seen along the rail- 
 road, rt is necessary to climb the stoei) south side of Mt. Wil- 
 lard to find the various series of rock altered by contact. The 
 Conway granite, having once passed through the fire, is not al- 
 tered, and therefore tln> changes to be described are altogether 
 in the schists. 
 
 The AUiany granite is char.acterizi'd 1)y tiie presence of crys- 
 tals of feldspar so numerously scattered through the mass as to 
 
 I 
 
22 
 
 ! ',1 
 
 give it u (Spotted apiK'iirunce, while llu; matrix is a jjivy, lliic- 
 graimliir aji<rr('<;ato of iiraiiitit! minerals, somowluit io«i'ml'!iiig 
 the mixture (tf peitper ami salt. In om early reports this gran- 
 ite had Iteen called " spotted," and also '' trachytic," on aeoount 
 of these features. 
 
 Wlieii t'xamined mieroscopieally, the line-grained mass shows 
 qnartz in formless grains, with tliiidal inelusions. hornhlende, 
 liiotite, magnetite, and apatite. Angito and rtnor-spar are also 
 freqnent constitnents. Hut the marked individuality is given 
 by the uniform presenee of well-crystalli/ed. scpiaro prisms of zir- 
 con. Kvery sample of this rock from Mt. Willey. examined hy 
 Dr. Ilawes. showed an abundance of zircons, which arc white, 
 clear, glassy, and sonietimos yellowish. The large orthoclase 
 feldspar crystals are known to mineralogists as Carlsbad twins. 
 This descrii)tion represents the normal character of the gran- 
 ite ; but both to the right and the left of the centre prominent 
 differences manifest themselves, which are thus described by 
 Dr. Ilawes: '^Vt a distance of one hundred feet from the con- 
 tact, the crystals that form the granite have become smaller, with 
 the exception of the large feldspar crystals, which are in conse- 
 quence more conspicuous. At a distance of sixty feet a ten- 
 dency in the (piartz to assume crystalline forms is noticed, and 
 the rock Itegins to appear porphyritic. At fifteen feet from the 
 contact with the schists, the quartz is found in well delined 
 dihexagonal pyramids as large as peas, and these with the 
 Carlsbad twins of orthoclase are imbedded in a ground mass no 
 lon<rer resolvable bv the unaided eve or lens. I'ijou the con- 
 tact the ground moss is nearly black in color. Hinty in texture, 
 and apparently homogeneous. The Albany granite has become 
 a ([uartz porphyry. 
 
 ''The accomi)anying microscopic changes are as striking. 
 Api)roaching the contact there is a continual diminution in the 
 amount of the hornblende and the size of its crystals. There is 
 a corresponding increase in the amount of the biotite, which 
 finallv entirely rei)laces the hornblende. These biotite crys- 
 tals are at lirst (juite large, l»ut they diminish rapidly in size 
 near the contact, and u[Hjn the contact are reduced to a dust. 
 The ground mass which makes its appearance between the 
 quartz and orthoclase crystals grows firm, but upon the contact, 
 
thouiili of extiviiu' flin-ness, it is .still entirely cryHtiillinc. In 
 tliiH mouiKl iiiii»!s iill tilt! minerals «)f the <iiiinite fcnind in speci- 
 raens (liwtsint from the eontaet are re(.;oji;iii/al»le, l»nt near the 
 contact no imlivi.liml erystals ean be determined. In this 
 sorieH of ehan<;eH all the minerals have taken part except tho 
 twin feldspars and the zircons. 
 
 "These moiliiications, \vhi(,'li are repeated in a less conspic- 
 nons manner npon approachin<j; the contact witii the granite 
 npontlie opposite side of the nniss. are sncli as mi<j;ht l»e induced 
 in a molten eruptive mass, which like modern lavas contained 
 some crystals already found at the time of eruption by the etTect 
 of contact with cold walls, the hydrous nature of one and the 
 anhydrous nature of the other being factins modifying the 
 extent of the effect." 
 
 The sciiists of the Kearsargc group consist of (piartz, mnseo- 
 vite and chlorite, with many layers tilled with l)eantifnl pencils 
 of andalusite. Unimportant accessories are biotite, titanic iron 
 partially decomposed into lencoxene, magnetite, and tourmaline. 
 No marked change is visible in it at tiie (Ustance of lifty feet 
 from the line of conta-t. At twenty-five feet the schists are 
 more delinitely and coarsely crystalline, biotite becomes more 
 prominent, and tourmaline crystals have i)ecome very common. 
 At fifteen feet the rocks are still schistose, but much fractured, 
 and full of shining dots that indicate a new crystallization. 
 Here the rock is a mica schist. The chlorite decreases, and 
 biotite and tourmaline increase, lietwecn this point and the 
 contact the schist loses t-ntirely its structure, and is alteri'd into 
 a black hornstone. l)r('aking into smaller angular fragments. 
 Ten feet from the schists a (pnditative reaction for lioric acid 
 can be obtained. 
 
 Last of all is a well defined zone, or a dark gray mass lilled 
 with reticulated black veins. Scarcely noticeable at the toj) of 
 the mountain, it lK'conie> wide and proiiiinciit Itelow. Tlie veins 
 divide and siilulivide. giviim' to the whoK' a fused, slaggy ap- 
 pearance. Microscopically it is found to l>e a iieaily pure mix- 
 ture of tourni.'iliue and (piarlz. 
 
 Just l)etweeu the tourmaline veinstone 'And AUniny granite is 
 a breccia, called the -'mixed zone" by Dr. Ilawes, varying 
 from one to twenty feet wide upon Mt. Willard, but known to 
 
u 
 
 be much widor olscwlicre, as upon iMt. Tcni, It coKsists of 
 
 fr 
 
 agnients ot various schists, pieces ot a roreigu (juaitz poi- 
 phyry. :!!1 connected by the granitic material. The fehlspar 
 crvstiils iire aii Itroken to fragments and the whoh' mass is im- 
 pregnated witli tourmaline. 
 
 Summarized, tliese zones may be thus stated : 1. Zone of the 
 argillitic mica chloritic schist, containing by actunl nnalysis 
 from ;ir> to .■)ll pel' cent, of (piartz. II to ID per cent, of miisco- 
 vite. no biotite, -S to !;> percent, of clilorite. "i i)i'r cent, each 
 of titanic and magiu'tic iron, and no tourmabne. 2. Zone of 
 the biotitic mica sciiist. ccjutaiuing \'> per cent, of quartz, 4:5 of 
 botli mi-'as, (> of chlorite, and :> of the iron oxyds. ;>. Zone of the 
 toui'maline hornstone. containing .')() per cent, of ((Uartz, 21) of 
 the micMs. no ciilorile. 1 of tiie iron oxyds, 1.") of toui'maline. 
 4. Zone of the tounnaliiu' veinstone, containing .")0 per cent, of 
 quartz, no mica or chlorite, ."i per cent, of iron oxyds, and 4() of 
 tourmaline. .">. Zone of the mixed sciiists and granite, (i. Zone 
 of the granite por[ihyry, biotitic. 7. Zone of the Albany liorn- 
 blendic graniti'. 
 
 There seems to be a systematic and progressive series of 
 changes in the schists. First, water lasbeen removed ; second, 
 boric acid and silica have been added : tliird, alkalies have been 
 added directly upon the contact. These additions and changes 
 are such as would come from igneous eriqitions. and theri-fore 
 the inference is nuthorized that the Albany granite was eruptive 
 like lava. The inclusion of varied products in the mixed zone 
 indicates the movement of a lluid mass no inconsiderable dis- 
 tance through lissures. Very hot vapors must have accomi)a- 
 nied the eriqttion. 
 
 Such is a brief sunnnary of the paper of the late Dr. Ilawes, 
 formerly assistant upon the (ieological Survey of New Hamp- 
 shire, published in the .!///''/'/>«?( Jourmil of iScioux' ldkI ^Irts, 
 in Januarv, bSMl . 
 
 JIT. ASCL'TNKY GW.VXrrK. 
 
 rpon V we have delineated two peaks of granite or syenite 
 known as :Mt. Asciilney and Little Asciitney. The igneous rock 
 seems to have been erui)ted from below through one or more 
 
 I 
 
' '■ t 
 
 ven<-s and siM-eaO. over the rock adjiieent, very much in the man- 
 ner of modern lava. 
 
 The summit of Aseiitiiey lies near the south-east corner of 
 "Windsor, })ut i)ortions of the mass are situated in the towns of 
 West Windsor and Weathersfield. If the two mountains were 
 just alike, the granitic area, when i)rotracted upon a m:ip, would 
 resemble a pair of spectacles ;— as it is, the eastern higher area 
 is four and a half miles long, two and one eighth wide, and the 
 sunnnit ;5,1'S() feet above sea level, while the base of the cone is 
 1,200 feet above the sea. The western area is nearly circular, 
 a mile and one fourth in diameter, and 1,700 feet above the sea. 
 The rock is often a hornblende granite — mica not being exclud- 
 ed—and the variety called ijranitdl by Dr. llawes, eontaining 
 neitluM- of the accessory minerals, is abundant in irregidar 
 patches in every part of the cones. IJrecciated masses conqiosed 
 of the underlying stratitied rocks are plentiful upon the west 
 side of the larger mass and upon the smaller mountaiu. inso- 
 much that one can easily lielieve i)(,>rtions of the granite have 
 been made from the melting ilown of the fragments. The major 
 axis of the '• spectacles is six and one half miles long, at right 
 auoles to the course of the strata. Two stratilied groups under- 
 lie the unstratitied area. :Most of the eastern cone is located 
 upon the calcitVrous mica schist. The rest of it. and the smaller 
 cone, rests upon gueiss. The gneiss underlies the mica, schist at 
 the same angle of dip, and we do not yet discover any strati- 
 graiihical axes in the latter. The relations of all these rocks 
 ai)pear upon section \ . This granite seems to occupy a posi- 
 tion similar to that of the gui'issic antit'lii\als in (ruilford, 1, and 
 Brattleboro', II, or lUack ^Mountain in Duunnerston. 
 
 There is no evidence of elevation of th" schists, in conse(pience 
 of a disturbiuice, when tlie igneous mass cann' up. The same 
 local variations api)ear upon the south that are visible at the 
 north sides of the mountains. The mica schists nnmifest the 
 presence of heat for a ilistauce of ;"iOO feet or more from the 
 oranite. The slates have lieeu indurated so that thev ring like 
 iron when struck l>y a hauiiner. The liuiestones are sometimes 
 calcined, and even gia/.ed. \'eins enter both the rocks from the 
 granite for several yards distance. The gneiss is not altered at 
 the contact line. It would seem, therefore, as if we had here 
 
 I 
 
2$ 
 
 examples of contact-phenomena, and only the later strata are 
 aft'ected, because the iineiss had already lieen made crystalline 
 before the eruption of the granite. 
 
 The adjacent hill-tops of the mica schist country are approxi- 
 mately 1.200 feet above the sea. which corresponds with the 
 elevation of the base of the granite. On entering the valleys of 
 erosion at the base of the granite, where small streams have re- 
 mov(>d considerable rock, it is discovered that the schists run under 
 the igneous rock, certainly for -'^00 feet. Were a tunnel driven 
 through the mountain, as through the celebrated Kammorburg 
 of Hohemia, similar phenomena would be found ; — below a cer- 
 tain horizon— say 1,200 feet— only the schists would be cut 
 through, excepting the central plug of granite. The cone of 
 granite has its base upon the floor of schists, while its height is 
 about 2.000 feet. It is to be regarded as an overflow of igneous 
 matter upon the common rock of tlie neig!il)orhood, and where 
 .0 comes in contact with clayey layers they were baked ; and 
 where limestones were heated, the result was calcination, indu- 
 ration, and glazing. Ui)on this view it is easy to understand 
 why there should be an indurated belt about AOO feet in width 
 enveloping the cone. Tiie heated mass covered the surround- 
 ing country just so far, anil Miat outer shell has since been 
 removed by denudation. 
 
 :My father, in the (Geological Keport of Vermont, advocated 
 the doctrine of the derivation of the granite from below, l)ut 
 supi)Osed the cone continued to I'ularge below the surface, and, 
 as he conceived of it as a liquid, suggested its enclosure by walls 
 of schist which have subsequently been rtunoved by erosion. 
 The prevailing modern view of tlu' origin of granite is like this, 
 except that it demands a greater degree of erosion. Says Prof. 
 J. W. Judd, in his work on volcanoes. 1S,S1, p. 2r)2,— '• The 
 plutonic rucks, as we luu-e already seen, exiiibit sullieient proofs 
 in tlieir liighly crystalline character, and in their cavities con- 
 taining water, litiueiled car! ionic acid, and other volatile sul)- 
 stances, that they nuist iiave been formed by tiie very slow con- 
 solidation of igneous materials under enormous pressure. Great 
 pressures, it is evident, could only exist at great depths beneath 
 the earth's surface. ]\[r. Sorl>y and others have endeavored to 
 calculate what was the actual thickness of rock under which 
 
 ^ iV 
 
27 
 
 A- 
 
 certain granites must have boon formed, by nieasurino; the 
 amount of contraction intlie liquids which liavo boon imprisoned 
 in tlio crystals of these rocks. The conclusions arrived at are 
 of a sutilciently startlinn; ciiMracter. It is inferred that the 
 o-runites which have boon thus examined nuist have consolidated 
 at depths varying from 00,000 to 80,000 feet beneath the earth's 
 
 surface," etc. 
 
 If Ascutney were the only granite mountain in New England, 
 it might be easy to imagine an erosion of from 20. 000 to 70,(»<»0 
 feet from around it ; but what is true of this mountain must 
 have been true of all New England and of the whole crystalline 
 area of the Atlantic coast. A tract of country, say 1 ,000 miles 
 long and ;^00 miles wide, according to this view, has been cov- 
 ered bv rock from fotn- to fourteen miles in thickness, which 
 has been transitorted by streams of water oceanward. If that 
 were true, t)<en our Atlantic coast line would have been several ,^y- ^' 
 hundred miles nearer the old world than it is now. 
 
 Such extreme views are entirely unnecessary. Two other 
 agencies may be called upon, besides the weight of overlying 
 rock— lateral pressure and elastic vapor held ii confinement. 
 Or, if it be necessary to believe that the liiiuids condensed so 
 far below the surface, the igneous mass may have Howod through 
 fissures witiiout losing its inclusions, and kept thom intact till 
 within a few hundred^ feet of the light. If slides prepared for 
 the microsooi.o can iiold drops of liriuid carbonic acid restrained 
 by the twentieth part of an incii of rock-wall, why could not 
 several hundred feet of pasty cooling lava bo eciually eftectual? 
 At the surface the inclusions nnist have escaped into the atmos- 
 phere just as. upon stream sof niodorn lava, steam and vapors 
 boil aiid disappear. After solidification, all those imprisoned 
 vapors are tinnly enclosed wiiother within ten feet or ten miles 
 of rock. The original -urface, i\ow deiuidod, may have been a 
 genuine lava. Some modern lavas, like granites, contain inclu- 
 sions of condensed gasos. and present many of the phenomena 
 characteristic of the oldor rock; yet no one supposes that five 
 or ton miles of rock has boon romovcd from above them. The 
 conditions of niodorn aipioo-igneous lava fusion are not very 
 different from those invoked for the origin of granite. 
 
 It is easy to name other mountains of granite and i)ori)hyry, 
 
 ,» 
 
 .V 
 
28 
 
 
 which so resemble Ascutuey as to make one believe the}' will 
 present evidences of a similar origin. Such may be found upon 
 our sections, — as Moose Mountain near the east end of V ; 
 Green Mountain, Kdingluim, and the Ossipee Mountains in V' I ; 
 Pequawket in YlII ; and Star King, near Jefferson, in IX. 
 There are many others in tlie Wliite Mountains. 
 
 Another class of volcanic ejections, probably older than the 
 granites of the White Mountains, are largely developed upon 
 sections XI to XIII in Vermont. Tiie rocks are referred to the 
 Huronian in our descriptions, and consist of stratitied diabsises, 
 protogenes, epidotic and chloritic scliists, fine-grained quartzites, 
 etc. It is su|)posed they may have been metamorphosed from 
 volcanic ashes and scoritt. Some of the mountains exhibit 
 dome-shaped features, and thei^fore resemble volcanic piles 
 much degraded. Selwyn calls the extension of these rocks into 
 Canada the "Volcanic group." and was the first person to call 
 attention to their reseml)Iance to rocks of igneous origin in 
 Great Britain and Australia. These views will commend tliem- 
 selves to those who are familiar with the lithological character 
 of igneous rocks. 
 
 EARLY HISTOIiY OF TiIK CONTINENT. 
 
 In the geology of New Hampshire I have shown how the dry 
 land of the state has been gradually reclaimed from the primi- 
 tive ocean, and that the earliest islands can now be recognized in 
 the several porfihyritic gneiss areas. I have lately gone further, 
 and argued tliat tliese same areas, with others like them, re|)re- 
 sented liie lirst dry land of the whole American continent. It 
 is claimed tliat they were of eruptive origin, very much like sub- 
 marine volcanoes, and that they gradually gathered sediment 
 from the wash of the hills, and increased in size on account of 
 general continental elevation. Some of the conclusions were 
 suggested by a personal study of the Hawaiian islands. A few 
 of the considerations favoring our theory will now be presented. 
 
 1. Considering the igneous origin of tlie earth, volcanic ener- 
 gies would naturally continue their action as soon as there was 
 a crust to be broken through, and immense piles of melted rock 
 would ooze from the numerous fissures. Up to Laurentiau 
 times all admit the universalitv of igneous outflow, while but few 
 
 I { 
 
29 
 
 h 
 
 V 
 
 have ventured to speak of anything like volcfvnic action, except 
 as it has been manifested in the formation of dikes in these 
 early periods. There lias been a tendency to class tlie ancient 
 granites and porphyries with rocks of sedimentary origin, and 
 conse(piently to restrict the action of igneous agencies to phe- 
 nomena of sligiit importance. Several English writers, and, in 
 our country, Dr. Selwyn, of Canada, have been calling our at- 
 tention to the existence of a volcanic group in later Huronian 
 or early Cambrian times. These are the rocks so largely devel- 
 oped about Lake Superior, New England, and the Province of 
 Quebec, consisting of stratified schists, diorites, diabases, 
 araygdaloids, and felsites, identical in composition with true 
 eruptive masses of the same name. Investigation shows that 
 oftentimes tliese schists are disposed like the lavas ejected from 
 one series of volcanic vents. Suppose, for exami)le, that Etna 
 or Vesuvius should become extinct : in the course of ages the 
 rains would obliterate the craters, and reduce the lavas to a 
 rounded dome of greater or less regularity. We should recog- 
 nize the volcanic origin of the mountain in the absence of cra- 
 ters, from the lithological similarity of tlie rocks to those known 
 to have been melted and ejected from vents, while the disposal 
 of the material in a conical attitude shows us that it might once 
 have been protruded from below. So we find in our Eastern 
 country many domes of diabasic or protogenic schists, whose 
 volcanic origin may be predicated, both from their lithological 
 character and physical aspect. 
 
 Now this volcanic group of Huronian times indicates the ex- 
 istence of a greater degree of igneous activity than has been 
 described for the palezoic ages, even in Great Britain ; and con- 
 sequently this is an indication pointing significantly towards the 
 predominance of thermal influences in the still earlier periods. 
 In the Laurentian age the fires sliould have been yet more vigor- 
 ous, because the time of universal igneous fluidity was less re- 
 mote. 
 
 2. A careful study of the crystalline rocks of the Atlantic 
 slope indicates the presence of scattered ovoidal areas of Lau- 
 rentian gneisses. Those best known have been descril)ed in the 
 Geology of New Hami)shire. Instead of a few large synclinal 
 troughs filled to great depths with sediments, the okbst group 
 
80 
 
 
 is disposed in no less tlian twenty-two sirens of small size, scat- 
 tered like the islands in an arcliipelago. In a chapter upon the 
 physical history of tlie slate, I have proposed llie tlieory that 
 the earliest land within its limits consisted of this series of 
 islands, not packed together as closely as now, in an area of per- 
 haps three thousand live lumdred scptare miles, hut as much 
 more widely separated as would be determined by smoothing 
 out the various antielinals and vrelinals that were formed later. 
 Bv reference to <tur maps in Ma'?; ', ]Massachusetts, New Jersey, 
 Pennsylvania, N'irginia, North Carolina, and (ieorgia, many sim- 
 ilar ovoidal Laurentian ai'eas may be specified, usually larger 
 than tiiose of New Hampshire. This may bo due partly to a 
 less thorougli knowledge of the exact areas occu[)ied l)y this 
 older gneiss, and partly to the existence of a greater number of 
 volcanic vents, giving rise to a more widely si)read and thicker 
 mass of ejected material. Over the Atlantic slope and Canadian 
 highlands these primeval islands hnve, in later periods, been 
 cemented together by a subse(iuent dei)osition of material ; but 
 in Missouri, Arkansas, and Texas we recognize, even now, these 
 early islands. 
 
 3. The lithoU)gy of the Laurentian and other crystalline rocks 
 is very like that of igneous ejections. We now divide the Lau- 
 rentian into three parts. First and lowest is the porphyritic gneiss 
 of New ILunpshire corresi)onding to Selwyn's proposed restric 
 tion of the whole series to " all those clearly lower, vuiconform 
 able, granitoid, or syenitic gneisses in which we never lind inter- 
 stratitied bands of calcareous, argillaceous, arenaceous, and 
 conglomeratic rocks." Next will follow the Hastings and 
 Grenville series, and all the schists containing the Eozoon, 
 as well as the Bethlehem, Lake Winnipiseogee, and Mont- 
 alban groups of the Atlantic slope. Tiiird, will follow the 
 Montalban ; while the Labrador or Norian series, sometimes 
 called Upper Laurentian, is rejected since it is an igneous 
 rock, not stratified. The lower Laurentian is azoic, the other 
 wroups eozoic ; and unless newer distinctions are to be made 
 hereafter, it looks as if we might claim these various azoic 
 Laurentian islands as the first-formed dry land, as they cer- 
 tainly are the nuclei of the existing continents. 
 
 There are no minerals in these Laurentian islands that do not 
 
31 
 
 •I 
 
 occur ill eruptive siratiite ; and the scliistose structure is often so 
 fiiint that the field geoloi>;ist need not 1)0 blamed if he acknowl- 
 ed<>es his inability to detect it. Likewise we discover the same 
 fluidiil inclusions and the vacuoles that pertain to granite. If we 
 should follow Sorbv and Clifton Ward in saying that granite has 
 been formed beneath a pressure equivalent to a weight of forty 
 thousand feet of strata, the same must bo said of the early 
 gn-'isses. With this general assertion of the identity of gneiss 
 and eruptive granite we must be satisfied at present, without 
 entering into detail. 
 
 4. The tvualogy of the origin of oceanic islands at the present 
 day suggests the igneous derivation of the I^aurentian areas. 
 Most of the high islands of the Pacilic are com|)osed of lava, 
 with the volcanoes frequently in action. 
 
 The so-called lowlands are likewise of volcanic t>rigin, — since 
 coral polyps have l)uilt up roofs upon the igneous area after the 
 disappearance of the fire, and the Hawaiian areas are encircled 
 by roefs. After the volcanoes have l)ecome cold, loose material 
 would be worked in between them, coral roefs would grow, and 
 in various ways the land area would lio cnlai'ged, and finally an 
 archipelago may become a large island. It needs only time and 
 a rei)etition of these constructive agencies to make a continent 
 out of a series of archipelagoes. 
 
 5. The oceanic volcanic islands are not inferioi in size to the 
 crystalline Laurentian areas upon the present continents. 
 Hawaii, of the Hawaiian group, may illustrate their position and 
 shape. Its area above the water-line is 4,210 square miles, and 
 its cubical contents above the sea-level are about the same 
 with those of New IIanii)shiro. It rises from a plateau over 
 1(5,000 feet deep, thus forming a cone 30.000 f-jt high, whose 
 cubical contents must be twenty times greater than the [jortion 
 making dry land. The length of the entire series of islands, all 
 of similar character, is 350 miles, and the area of the base of the 
 lava must be about 100,000 s(iuare miles. These cones have 
 been built up by the accumulation of lava ejected from the in- 
 terior of the earth, and thoy are entirely isolated, the nearest 
 land being one thousand miles distant. The ground-plan of 
 this volcanic mass is that of two elliptical areas, either of which 
 is l.ke some of our Laurentian islands, and is certainly as large 
 
82 
 
 as any of those tiiiclont lands south of the St. Lawrence. The 
 hind !uva of the Hawaiian ishinds is less than that of Massachu- 
 setts. l)nt their base must l)e etiual to the whole of New Kn<;jland 
 and New York conihined. Surely it cannot be avowed that vol- 
 canic areas a e too small to be compared with the space occu- 
 pied by our oldest formation 
 
 TIITCKNESS OF THE FORMATIONS. 
 
 For a thousand furtiier details the reader is referred to the 
 published and manuscrii)t sections and catalogue, accessible to 
 all in([uirer3 at the Museum. I will close by adding a list of the 
 several formations of New Hampshire and Vermont in their sup- 
 posed natural order, with their estimated thickness : 
 
 FEET. 
 
 Devonian Helderberg, near Memphremagog lake, . . 200 
 Niagara group, at Littleton, etc., .... 500 
 
 CHAMPLAIN VALLEY. 
 
 Loraine slate, ..... 
 Hydro-mica schist (Tacouic range), 
 Trenton limestone, .... 
 Black river and Birdseye limestone, 
 Chazy limestone, .... 
 
 Levis limestone, ..... 
 Upper calciferous sandroek. 
 Lower " '^ . . . 
 
 Fucoidal layer, ..... 
 Potsdam sandstone, red, 
 
 " '' gray, . 
 
 " " quartzite, 
 
 Georgia slates, ..... 
 Cambrian slates and schists, 
 
 Total of Champlain Valley, 
 
 CRYSTALLINE GROUPS. 
 
 Calciferous mica schist and Coos group, . 
 Ivearsarge group, ..... 
 Uockingham mica schist, 
 
 
 . 2,000 
 
 
 400 to GOO 
 
 
 40 
 
 
 400 
 
 
 000 
 
 
 200 
 
 
 400 
 
 
 200 
 
 
 500 
 
 
 . 310 
 
 
 . 1,200 1,200 
 
 
 . 3,000 
 
 
 . 4,000 
 
 13,740 
 
 12,000 
 
 i,3or 
 
 6,000 
 
88 
 
 400 
 
 2,000 
 
 o GOO 
 
 40 
 
 400 
 
 000 
 
 200 
 
 400 
 
 200 
 
 Merrimack group, .... 
 i !iironiiiii, ..... 
 n()riil)lcn(U' schist, .... 
 I'ppcr Liuirentiaii, MoiiL-ilhan, 
 Middle Laurentian, Lake VVimiipiseogee 
 
 Mountain) gneiss, 
 Middle Laurentian, licthlehem gneiss, 
 Lower Laurentian, I'orpliyritic gneiss. 
 
 Total crystalline, 
 
 Grand total. 
 
 • • • 
 
 4,;ioo 
 
 • • • 
 
 12.000 
 
 • • • 
 
 l.ftOO 
 
 • • 
 
 10,000 
 
 ((ireen 
 
 • • • 
 
 is.noo 
 
 • • • 
 
 t;,;5oo 
 
 • • ■ 
 
 5,000 
 
 • t • 
 
 77,000 
 
 • • • 
 
 !)0,740 
 
I