A. 
 
 b. 
 
 ■,'iu 
 
 .%. 
 
 
 m 
 
 IMAGE EVALUATION 
 TEST TARGET (MT-3) 
 
 / 
 
 // 
 
 O 
 
 , .<'' C^ 
 
 <? 
 
 
 7, 
 
 1.0 
 
 I.I 
 
 1.25 
 
 
 ||M 
 
 2.2 
 
 1.8 
 
 1.4 111.6 
 
 V] 
 
 <? 
 
 /i 
 
 ^;. 
 
 
 
 
 /A 
 
 '^ 
 
 *v 
 
 V»°^i 
 
 % 
 
 'C^V<> 
 
 '<i>^ 
 
 V 
 
CIHM/ICMH 
 
 Microfiche 
 
 Series. 
 
 CIHM/ICMH 
 Collection de 
 microfiches. 
 
 Canadian Institute for Historical Microreproductions . Institut canadien de microreproductions historiques 
 
 1980 
 
Technical Notes / Notes techniques 
 
 The Institute has attempted to obtain the best 
 original copy available for filming. Physical 
 features of this copy which may alter any of the 
 images in the reproduction are checked below. 
 
 D 
 D 
 D 
 D 
 
 Coloured covers/ 
 Couvertures de couleur 
 
 Coloured maps/ 
 
 Cartes gdographiques en couleur 
 
 Pages discoloured, stained or foxed/ 
 Pages ddcolor^es, tachet^es ou piqu6es 
 
 Tight binding (may cause shadowc or 
 distortion along interior margin)/ 
 Reliure serrd (peut causer de I'ombre ou 
 de la distortion le long de la marge 
 int^rieure) 
 
 L'Institut a microfilm^ le meilleur exemplaire 
 qu'il lui a 6t6 possible de se procurer. Certains 
 ddfauts susceptibles de nuire d la quality de la 
 reproduction sont notds ci-dessous. 
 
 D 
 D 
 
 m 
 
 Coloured pages/ 
 Pages de couleur 
 
 Coloured plates/ 
 Planches en couleur 
 
 Show through/ 
 Transparence 
 
 Pages damaged/ 
 Pages endommag^es 
 
 Tl 
 
 P' 
 o1 
 fi 
 
 Tl 
 
 C( 
 01 
 
 ai 
 
 Tl 
 fi 
 in 
 
 IV 
 ir 
 
 b 
 f( 
 
 n 
 
 Additional comments/ 
 Commentaires suppl6mentaires 
 
 Bibliographic Notes / Notes bibliographiques 
 
 D 
 D 
 
 D 
 
 Only edition available/ 
 Seule Edition disponible 
 
 Bound with other material/ 
 Reli6 avec d'autres documents 
 
 Cover title missing/ 
 
 Le titre de couverture manque 
 
 n 
 
 Pagination incorrect/ 
 Erreurs de pagination 
 
 Pages missing/ 
 Des pages manquent 
 
 Maps missing/ 
 
 Des cartes g^ographiques manquent 
 
 n 
 
 Plates missing/ 
 
 Des planches manquent 
 
 Additional comments/ 
 Commentaires suppldmentaires 
 
The images appearing here are the best quality 
 possible considering the condition and legibility 
 of the original copy and in keeping with the 
 filming contract specifications. 
 
 Les images suivantes ont 6t6 reproduites avec le 
 plus grand soin, compte tenu de la condition et 
 de la nettetd de I'exemplaire filmd, et en 
 conformity avec les conditions du contrat de 
 filmage. 
 
 The last recorded frame on each microfiche shall 
 contain the symbol —»> (meaning CONTINUED"), 
 or the symbol V (meaning "END"), whichever 
 applies. 
 
 Un des symboles suivants apparaitra sur la der- 
 nidre image de cheque microfiche, selon le cas: 
 le symbole — »- signifie "A SUIVRE", le symbole 
 V signifie "FIN". 
 
 The original copy was borrowed from, and 
 filmed with, the kind consent of the following 
 institution: 
 
 National Library of Canada 
 
 L'exemplaire filmd fut reproduit grdce d la 
 g6ndrosit6 de I'dtabiissement prdteur 
 suivant : 
 
 Bibliothdque nationale du Candda 
 
 Maps or plates too large to be entirely included 
 in one exposure are filmed beginning in the 
 upper \e>H hand corner, left to right and top to 
 bottom, as many frames as required. The 
 following diagrams illustrate the method: 
 
 Les cartes ou les planches trop grandes pour dtre 
 reproduites en un seu! cliche sont film^es d 
 partir de Tangle sup^rieure gauche, de gauche h 
 droite et de haut en bas, en prenant le nombre 
 d'images ndcessaire. Le diagramme suivant 
 illustre la mdthode : 
 
 1 
 
 2 
 
 3 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
^WB 
 
 [From the Quautkulv Journal of tfte Geological Hocivay for 
 
 August IbTO.J 
 
 NoxK on the Puosphaxes of the Laurentian and Cambrian Rocks 
 of Canada. By J. W. Dawson, LL.D., F.R.S., F.G.S. 
 
 The extent and distribution of the deposits of apatite contained in 
 the Laurentian of Canada and in the succeeding Pala;ozoic forma- 
 tions, have not escaped the notice of our Geological Survey, and 
 have been refeiTed to in some detail in Reports of Mr. Vennor, 
 Mr. Richardson, and others, as well as in the Geneml Report 
 prepared by Sir W. E. Logan in ISiiS. Some attention 1ms also 
 been given, more especially by Dr. Sterry Hunt, to the question of 
 the probable origin of these deposits*. My own attention has been 
 directed to the subject by its close connexion with the discussions 
 oonceraing Eozoou ; and I have therefore embraced such opportunities 
 as oiferctl to visit the localities in which phosphates occur, and to 
 examine their relations and structure. I would now present some 
 facts and conclusions respecting these minerals, more especially in 
 their relation to the life of the Laurentian period, but which may 
 also be of interest to British geologists in connexion with the facts 
 recently published in the ' Journal ' of this Society in relation to 
 the similar deposits found in the Cambrian and Silurian of Wales t. 
 
 In the Lower Silurian and Cambrian rocks of Canada phoaphatie 
 deposits occur in many localities, though apparently not of sufticiont 
 extent to compete successfully for commercial purposes wiili tluj 
 rich Laurentian beds and veins of crystalline apatite. 
 
 In the Chazy formation, at Alumctte Island, and also at Gren- 
 ville, Hawkesbury, and Lochiel, dark-coloured phosphatic nodules 
 abound. They hold fragments of Lingukf, which also occur in the 
 containing lieds. They also contain grains of sand, and, when 
 heated, emit an ammoiiiacal odour. They are regarded by Sir "\V. 
 Logan and Dr. Hunt as coprolitic, and are said to consist of *■' a paste 
 of comminuted fragments of Linr/ida;, evidently the food of the 
 animals from which the coprolites w^ere derived" J. It has also 
 been suggested that these animals may have been some of the larger 
 species of Trilobitos. In the same formation, at some of the above 
 places, phosphatic matter is seen to fill the moulds of shells of 
 Phurotomaria and Holopea. 
 
 In the Graptolite shales of the Quebec group, at Point Levis, 
 similar nodules occur ; and they are found at Rivitre Ouelle, 
 Kamoiu'aska, and elsewhere on the Lower St. Lawrence, in lime- 
 stones and limestone conglomerates of the Lower Potsdam grouj) 
 which is probably only a little above the horizon of the TSlenevian 
 or Acadian series. In these beds there are also small phosphiitit^, 
 tubes with thick wails, which have been compared to tlie snpjto'^^'d 
 worm-tubes of the genus Srr2)('lit(s^. 
 
 * Geology of Canada, 1S()3 ; Clieiuiool and Qeologicd! Essays, 1 '^7;» 
 
 !■ Davies & Ilicks in Quart. Joiirn. Oeol, Soe. Auguat ISTf).' 
 
 { Geology of Canada, p, lif). 
 
 § Geology of Canada, ^j. 2r)9 ; Kichard'<0'»'d Kepoi't, 180!». 
 
■rn 
 
 286 
 
 J. W. DAWSON ON THE PIIOSPHATKH OK CANAIIA. 
 
 Tlio Acadian or Monevian group, as developed near St.. John, 
 New ]^rnns\vi('k, contains layers of calcareous sandstone blackened 
 with pliosphatic matter, which can be seen, under the lens, to consist 
 entirely of shells of Lhu/nhv, often entire, and lying close together 
 in the jjlane of the deposit, of which in some thin layers they apjjcar 
 to constitute the principal part**. Mr. Matthew informs mo that 
 these layers belong to the upper ~iart of the formfition, and that the 
 layers crowded with Liitf/uht' are thin, none of them exceeding two 
 inches in thickness ; but he thinks that the dark colour of some of 
 the associated sandstones and shales is due to comminuted LitKjuJce. 
 
 At Kamouraska, where I have studied these deposits, the ordinary 
 phosphatic nodules are of a black colour, appearing brown •\vitli blue 
 spots when examined in thin slices with transmitted light. They 
 arc of rounded forms, having a glazed but somewhat pitted surface — 
 and are very hard and compact, breaking with glistening surfaces. 
 They occur in thin bands of compact or brecciated limestone, which 
 arc very sparingly fossiliferous, holding only a few shells of ni/olithcs 
 and certain Scolithttfi-liko cylindrical markings. In some of these 
 beds siliceous pebbles occur Avith the nodules, rendering it possible 
 that the latter may have been derived from the disintegration of 
 older beds ; but their forms show that they arc not themselves 
 pebbles, riiosphatic nodules also occur sparingly in the thick beds 
 of limestone conglomerate which are characteristic of tliis formation ; 
 they are found both in the included fragments of limestone and in the 
 paste. The conglomerates contain large 8lal)s and boulders of lime- 
 stone rich in Trilobites and HyolithiS ; but in these I have not 
 observed phosphatic nodules. 
 
 In some of the limestones the phosphatic bodies presen'^ a very 
 different a])pearance, first noticed by llichardson at lliviere Ouelle, 
 and of which I have found numerous examples at Kamouraska. A 
 specimen now before me is a portion of a band of grey limestone, 
 about four inches in thickness, and imbedded in dark red or purple 
 shale. It is filled with irregular, black, thick-walled, cylindrical 
 tubes, and fragments of such tubes, along with phosphatic nodules 
 ■ — the whole crushed together confusedly, and constituting half of 
 the mass of the rock. The tubes are of various diameters, from a 
 (juarter of an inch downward ; and the colour and texture of their 
 walls are similar to those of the ordinary phosphatic nodules. 
 
 Under tlie microscope the nodules and the walls of the tubes show 
 no organic structure or lamination, but appear to consist of a finely 
 granular paste holding a few grains of sand, a few small fragments 
 of shells without apparent structure, and some small spicular bodies 
 or minute setae. The general colour by transmitted light is brown ; 
 but irregular spots show a bright blue colour, due probably to the 
 presence of phosphate of iron (vivianite). The enclosing limestone 
 and the filling of the tubes present n coarser texture, and appear 
 made up of fiagments of limestone and broken shells, with some 
 dark-coloured fibres, probably portions of Zoophytes. Scattered 
 
 * Bailoy mid Matthew, " GeolDgy of New Brunswick," Geol. Survey Reports. 
 
J, W. DAWsoM OX TJIK rilU.srilATKS 01' CANADA. 
 
 28; 
 
 through tlie matrix there arc also amall fragmenta, invisible to the 
 naked eyo, of brown and blue [ihosphatic matter. 
 
 One of the nodules t'rom Alumette gave to Dr. Hunt .'i()*38 of 
 calcic phosphate ; one from Hawkesbury 44-70 ; another from 
 lUvit-re Quelle 40-34 ; and a tube from the same place GT'oU*. A 
 specimen from Kamouraska, analyzed by Dr. Harrington, gave 
 55't)5 per cent. One of the richest pieces of the linguliforous sand- 
 stone from St. John yielded to tlie same chemist 30'S2 of calcic phos- 
 phate and 32'44 of insoluble siliceous saud, the remainder being 
 chiefly carbonate of lime. 
 
 Various opinions may bo entertained as to the origin of these phos- 
 pliatic bodies ; but the weight of evidence inclines to the view origin- 
 ally put forward by Dr. Hunt t, that the nodules are coprolitic ; and 
 I would extend this conclusion with some lit+^le modification to the 
 tubes as well. The forms, both of the tubes and nodules, and the 
 nature of the matrix, seem to exclude the idea that they aie simply 
 concretionary, though they maj- in some cases have been modified 
 by concretionary action. There arc in the same beds little })iles of 
 worm-castings of much smaller diameter than the tubes, and less 
 phosphatie ; and there are also >SVo/«77t«s-like burrows penetrating 
 some of the limestones, and lined with thin coatings of phosphLtio 
 matter similar to that of the tubes. Further, the association of 
 similar nodules in the Chazy limestone with comminuted IJwjuhe, 
 as already stated, is a strongly confirmatory fact. 
 
 The tubes are of unusual form when regarded as coprolitic ; but 
 they may have been moulded on the sides of the burrows of marine 
 worms ; or these creatures may have constructed their tubes of this 
 mfiterial, either consisting of their own excreta or of that of other 
 animals lying on the sea-bottom. In any case, the food of the 
 animals producing such excreta must have been very rich in solid 
 phosphates, and these animals must have abounded on the sea- 
 bottoms on which the remains have accumulated. It is also 
 evident that such phosphatie dejections might either retain their 
 original forms, or be aggregated into nodular masses, or shaped 
 into tubes or burrows of Annelids, or, if accumulated in nmss, 
 might form more or less continuous beds. 
 
 The food of the animals producing such coprolites can scarcely 
 have teen vegetable; for though marine plants collect and contain 
 phosphates, the quantity in these is very minute, and iisually not 
 more than that required by the animals feeding on them. 
 
 We must therefore look to the animal kingdom for such highly 
 phosphatie food. Here we find that a large proportion of the 
 animals inhabiting the primordial seas employed calcic phosphate in 
 the construction of their hard parts. Dr. Hunt has shown that the 
 shells of Lingula and some of its allies are composed of calcic 
 phosphate ; and he has found the same to be the en ic with certain 
 Pteropods, as ConitJaria, and with the supposed worm-tvbes called 
 SerpuHtes, which, however, are very different in structure from th.- 
 tubes above referred to. 
 
 * Goologj of Canadn, p. 461. t Tbul 
 
288 
 
 J. \V. OAWfiON ON Tin; l'U08PUATE8 OF CANADA. 
 
 It has long been known that the crusts of modern Crustaceans 
 contain a notable percentage of calcic phosphate ; and Hicks and 
 lludloston have shown that this is the ease also with the Cambrian 
 Trilobites. Dr. Harrington has kindly verified this for mo by 
 aualyidng a specimen of liighly trilobitic limestone from the Lower 
 Potsdam formation at St. Simon, in which the crusts of these 
 animals are so well preserved that they show their minutely tubu- 
 lated structure in great perfeetiou imder the microscope. He finda 
 the percentage of calcic phosphate duo to these crusts to be 1'49 
 per cent, of the whole mass. It is to be observed, however, that 
 the crusta of Trilobites must have consisted very largely of chitinous 
 matter, which, in some cases, still exists in them in a carbonized 
 state. A ci-ust of the modern Lhnuhis, or King Crab, which I had 
 supposed might resemble in this respect that of the Trilobites, was 
 analyzed also by Dr. Harrington. It belonged to a half-grown 
 individual, measuring 5-25 irehes across, and was found to contain 
 only 1'845 per cent, of ashes, and of tliis only \''A per cent, of 
 calcic phosphate. The crusts of some Trilnbites may have contained 
 as large a proportion of organic matter ; but they would seem to 
 have been richer in phosphates. Xext to Limjalce and Trilo- 
 bites, the most abundant fossils in the formations containing the 
 phosphatic nodules are the shells of the genus H>iolkhes, of Avhich 
 several species have been described by Mr, Billings*. Dr. Har- 
 rington has ascertained that these shells also contain calcic phosphate 
 in considei'able proportion. The proportion of this substance in a 
 shell not quite freed from matrix was 2*09 per cent. These shells 
 have usually been regarded as Pteropods ; but I find that the 
 Canadian primordial species show a structure very different from 
 that of this group. They are much thicker than the shells of proper 
 Pteropods ; and the outer layer of shell is perforated with round 
 pores, which in one species are arranged in vertical rows. The 
 inner layer, which is usually very thin, is imperforate. In one 
 species (I believe, the H. mnerimnus of Billings) the perforations 
 resemble in size and appearance those in the shells of Terehmtuhv. 
 In another species (//. micans probably) they are very fine find close 
 together, as in some shells of tubicolous worms. I am therefore 
 disposed to regard the claim of these shells to the rank of Pteropods 
 as very doubtful. They may bo tubicolous worms, or even some 
 peculiar and abnormal type of Brachiopod. In connexion with 
 this last view, it may be I'omarked that the operculum of some of 
 the species much resembles a valve of a Brachiopod, and that the 
 conical tube is in some of them not a much greater exaggera- 
 tion of the ventral valve of one of these shells than the pecidiar 
 
 Calceola of the Upper Silurian and Devonian, which has been 
 regarded by some palaeontologists as a true Brachiopod. I have not, 
 however, had any opportunity of comparing the intimate structure 
 
 * Calceola with that of these shells. Shells of HyolUhes occur in 
 
 tho Lower Potsdam in the same beds with the phosphatic nodules ; 
 
 and in one of these Mr. Weston has found a series of conical shells 
 
 * Canadian Naturalist, Dor. 1871. 
 
J, W, DAWSON ON THE PnosPHAXES OF CANADA. 
 
 289 
 
 Crustaceans 
 
 Hicks and 
 
 ) Cambrian 
 
 for me by 
 
 the Lower 
 
 .8 of those 
 
 itely tubu- 
 
 He tindft 
 
 to be J -49 
 
 iVcver, that 
 
 >f chitinous 
 
 carboni/ed 
 
 hich I had 
 
 )bites, was 
 
 lali'-grown 
 
 to contain 
 
 er cent, of 
 
 ! contained 
 
 lid secra to 
 
 Lud Trilo- 
 
 aining the 
 
 !, of which 
 
 Dr. Har- 
 
 phosphato 
 
 ;tancc in a 
 
 hcse shells 
 
 that tho 
 
 rent from 
 
 ) of proper 
 
 ith round 
 
 )ws. Tho 
 
 In one 
 
 rforations 
 
 rehratuhv, 
 
 i iind close 
 
 therefore 
 
 Pteropods 
 
 !von some 
 
 xion with 
 
 )f some of 
 
 that the 
 
 cxaggera- 
 
 > peculiar 
 
 has been 
 
 have not, 
 
 structure 
 
 occur in 
 
 nodules ; 
 
 ical shells 
 
 of HyoJlthes pressed one within another, as if they had passed in an 
 entire state through the intestine of the animal which produced the 
 coprolite. 
 
 Iiiii.-<rauch, then, as some of the most common invertebrates of 
 the Cambrian seas secreted phosphatic shells, it is not more incredible 
 th;it carnivorous animals feeding on them should produce phosphatic 
 cop'olites than that this sliould occur in Ae case of more modern 
 aiiimals feeding on fishes and other vertebrates. 
 
 We may now turn to the question as to the source of the abun- 
 dant apatite of the Laurentian rocks. Were this diffused uniformly 
 through the beds of this great system, or collected merely in fissure 
 or segregation veins, it might bo regarded as having no connexion 
 with other than merely mineral causes of deposit. It appears, 
 however, from the careful stratigraphical explorations of the Cana- 
 dian Survey, in the districts of Eurgess and Elmsley, which are 
 especially rich in apatite, that the mineral occurs largely in beds 
 interstratified with tho other members of tho series, though deposits 
 of the nature of veins likewise occur. It also appears that the 
 principal beds are confined to certain horizons in the upper part of 
 the Lower Laurentian, above the limestones containing Eozoon, 
 though some less important deposits occur in lower positions*. 
 
 The principal apatite -bearing band of the Laurentian consists of 
 beds of gneiss, limestone, and pyroxene-rock, and has a thickness of 
 from 2600 to 3600 feet. It has been traced over a great extent of 
 country west of the Ottawa river, and has also been recognized on 
 the east side of that river as well. The mineral often forms compact 
 beds with little foreign intermixture ; and these sometimes attain a 
 thickness of several feet, though it has been observed that their 
 thickness is variable in tracing them along their outcrops. Several 
 beds often lie near to each other in the same member of the series. 
 Thin layers of apatite also occur in the lines of bedding of the 
 pyroxene-rock. In other cases disseminated crystals are found 
 throughout thick beds of limestone, sometimes, according to Dr. 
 Hunt, amounting to two or three per cent, of the whole mass. 
 Disseminated crystals also occur in some of the beds of magnetite, a 
 mode of occurrence which, according to Dr. Hunt, has also been 
 observed in Sweden and in New York in tho Laurentian magnetites 
 of those regions. 
 
 The veins of apatite fill narrow and usually irregular fissures ; 
 and the mineral is associated in these veins with calcite and with 
 large crystals of mica. In one instance, at Ticonderoga, in New 
 York, the apatite, instead of its usual crystalline condition, assumes 
 the form of radiating and botryoidal masses, constituting the Eupyr- 
 chroite of Emmons. Since these veins are found principally in the 
 same members of the series in which the beds occur, it is a fair 
 inference that the former are a secondary formation, dependent on 
 the original deposition of apatite in the latter, which must belong 
 to the time when the gneisses and limestones were laid down as 
 sediments and organic accumulations. 
 
 * Vennor's Beports, 1872-73 A 1873-74. 
 
 I 
 
290 
 
 J. W. 1»AW80N ON THK l'U()Sl>lIATK8 OK CANADA. 
 
 In all the loculitics in wliieh I have been able to examine tlie 
 Laurentian apatite, it presents a perfectly crystnllino texture, while 
 the containing strata are highly metamorphosed ; and this appears 
 to bo its general condition wherever it has been excniined. Nume- 
 rous slices of the more compact apatite of the beds have been 
 prepared by Mr. Weston, of the (Joologicul Survey ; but, as might 
 bo expected, they show no trace of organic structure. All direct 
 evidence for the organic origin of this substance is therefore still 
 wanting. There are, however, certain considerations, based on its 
 mode of occurrence, which may be considered to afford some indirect 
 testimony. 
 
 If, with Hunt, avc regard the iron ores of the Laurentian as 
 organic in origin, the apatite which occurs in them may reasonably 
 be supppsed to be of the same character with the i)hosphatic matter 
 which contaminates the fossiliferous iron ores of the Silurian and 
 Devonian, and which is manifestly derived from the included 
 organic remains. 
 
 If wo consider the evidence of Eozoon sufficient to establish the 
 organic origin, in part at least, of the Laurentian limestones, wo 
 may suppose the disseminated crystals of apatite to represent copro- 
 litic m-.sscs or the debris of phosphatic shells and crusts, the structure 
 of which may have been obliterated by concretionary action and 
 metamorphism. 
 
 Such Silurian beds of compact and concretionary apatite (without 
 structure, yet manifestly of organic origin) as that described by 
 Mr. Davies in the ' Journal ' of this Society, may be taken as fair 
 representatives of the bedded apatite of the Laurentian. Further, 
 the presence of graphite in association with the apatite in both cases 
 may not be an accidental circumstance, but may depend in both on 
 the association of carbonaceous organisms, whether vegetable or 
 animal. 
 
 Again, the linguliferous sandstone of the Acadian group is a 
 material which, by metamorphism, might readily afford a pyroxenite 
 with layers of apatite like those which occur in the Laurentian. 
 
 The probability of the animal origin of the Laurentian apatite is 
 perhaps further strengthened by the prevalence of animals with 
 phosphatic crusts and skeletons in the Primordial age, giving a 
 presumption that in the still earlier Laurentian a similar preference 
 for phosphatic matter may have existed, and, perhaps, may have 
 extended to still lower forms of life, just as I he appropriation in 
 more modern times of phosphate of lime by the higher animals for 
 their bones eeems to have been accompanied by a diminution of its 
 use in animals of lower grade. 
 
 The Laurentian ajjatite pretty constantly contains a small jjcr- 
 centago of calcium fluoride ; and this salt also occurs in bones, more 
 especially in certain fossil bones. This may in both cases be a 
 chemical accident ; but it supplies an additional coincidence. 
 
 In the lowest portions of the Lower Laurentian no organic remains 
 have yet been detected ; and those beds are also poor in phosphates. 
 The liorizon of special prevalence of Eozoon is the GrenviUc band of 
 
J. \\. DAWSON ON TIIK I'llO.Sl'UATKS 01' CANADA. 
 
 2i>l 
 
 ixnniinc the 
 cturo, while 
 his ajjiieurs 
 !(!. Nume- 
 
 have been 
 t, as miglit 
 
 All direct 
 Dieforo still 
 ased OH its 
 me indirect 
 
 ircntian as 
 reasonably 
 atic matter 
 ilurian and 
 e included 
 
 ■itablish (ho 
 estones, wo 
 sent copro- 
 le structure 
 action and 
 
 te (without 
 sscribed by 
 ien as fair 
 Further, 
 botb cases 
 in both on 
 (getablc or 
 
 5roup is a 
 pyroxenite 
 entian. 
 1 apatite is 
 imals with 
 , giving a 
 preference 
 may have 
 [)riation in 
 mimals for 
 tion of its 
 
 3mall por- 
 
 ones, more 
 
 !ases be a 
 
 ice. 
 
 ic remains 
 
 hosphates. 
 
 :le band of 
 
 limoslono, which, according to 8ir William Logan's sections, is about 
 1 1 ,000 feet above the fundamental gneiss. It appears, from recent 
 observations of IMr. Yen nor and Mr. W. T. Morris, that the bed 
 holding the Hurgeas Eozonn is on the same horizon with the Hmo- 
 stone of Greiiville. The phonphates are most abundant in the beds 
 overlying this band. This gives a further presumption that the 
 collection and separation of the apatite is duo to some organic 
 agency, and may indicate that animals having phos])hatic skeletons 
 Krst became abundant after the sea-bottom had been largely occupied 
 by Eozoon. 
 
 I would not attach too groat value to the above considerations ; 
 but, taken together, and in connexion with the occurrence of apatite 
 in the Cambrian and Silurian, they seem to attbrd at least a 
 probability that the se])aration of the Laurentian phosphate from 
 the sea-water, and its accumulalion in particular beds, may have 
 been due to the agency of marine life. Positive proof of this can 
 be obtained only by the recognition of organic form and structure ; 
 and for this we can scarcely hope, unless we shoidd be so fortunate 
 as to find some i)ortion of the Lower Laurentian series in a less 
 altered condition than that in which it occurs in the apatite districts 
 of Canada. Should such structures be found, however, it is not 
 improbable that they may belong to forms of life almost as much 
 lower than th^ Limjuhe and Trilobites of the Cambrian as these are 
 inferior to the fishes and reptiles of the Mesozoic. 
 
 Discussion. 
 
 Mr. Hicks said that the author had traced the existence of these 
 phosphatic nodules considerably lower in America than had been 
 done in England. He was inclined to accept the view of their 
 organic origin, seeing that in England certainly the abundance of 
 phosphates depends on that of organic life. The phosphate was due 
 chiefly to the shell and to the decomposition of the substance of the 
 body of the animals. 
 
 Mr. Keeping remarked that the presence of graphite in these rocks 
 had been ascribed to plants ; if so, the deposit was formed not far 
 from shore, and consequently we should not get that freedom from 
 sediment which is necessary for the production of an extensive de- 
 posit of animal origin. It seemed to him that attributing to these 
 deposits an animal origin was like going round to the back door when 
 the front door was open ; for there was plenty of apatite in the 
 igneous rocks. He believed that even in later ages, when life was 
 more abundant, no workable deposits of coprolite nodules had been 
 formed where now found, but they had been sifted out by the action 
 of water from older deposits ; for example, those of Cambridge from 
 the Gault, and those of the Red Crag from the London Clay.