« EelmineJätka »
rule, that a deposit of calcareous tufa or shell-marl will be found under the vegetable mould around the margins of almost all our smaller lakes, these having occupied at one period a larger extent of surface than that included within their present areas. As a mineral manure, this calcareous deposit ought to possess considerable value, but I did not find any particular importance attached to it either at Belleville or Trenton, and it seemed to be very little used.
The limestone surface immediately under the Drift appears throughout the entire district to have been polished and grooved by glacial action; but it is only here and there, and more especially where a recent removal of the Drift deposit has taken place, that the results of this action are now visible. At the period of my visit to Belleville (June 1859) a beautiful example of polished and striated rock had just been laid bare in some drain excavations on the south side of Bridge Street, west of the Moira ; and I observed the same effects on the exposed faces of limestone at “The Plains,” between the Moira and the Shannon; and, still more distinctly, opposite the Shannonville Station, on the north side of the Grand Trunk Railway. At the latter locality, large slabs of rock exhibited a polished surface equal to that of plate-glass, with fine striæ running across it in a general N.W. and S. E. direction. By the effect of weathering, however, these results of ancient glacial action become more or less rapidly obliterated.
The Trenton limestone of the district in question is lithologically divisable into two distinct sets of beds. Of these, the upper are thinbedded (passing indeed into shales,) and are exceedingly fossiliferous; whilst the lower are thick-bedded and almost destitute of fossils. These lower beds are well displayed at the quarries on Ox Point, and at other places eastward along the Bay of Quinté They form a most excellent building stone. The upper or thin.bedded limestones
crop out extensively along the banks of the Trent, Moira, and Salmon rivers, and are exposed in most of the road cuttings of the district, and along the line of the Grand Trunk Railway. They literally teem with the more common fossils of the Trenton group. A list of those actually collected, is given below. These beds lie apparently in horizontal layers, but at Ox Point and other places some low anticlinals or undulations are visible, and a careful examination of the district shows a slight but general dip towards the south-west. A road cutting near the west bank of the Moira exposes a bed of calcareous clay about a foot in thickness interstratified with the shaly limestones of the upper
part of the Trenton series. This bed, pointed out to me, by Campbell Wallbridge, Esq., of Belleville, contains numerous impressions of strophomena alternata and other Trenton forms, and is thus (as shown moreover by its position amongst the shaly limestones) a true member of the group. It is the first example of this kind of association that I have met with in the Trenton series, but a similar interstratification of clay and limestone beds has been seen, I believe, in other places,
About Belleville, the most prolific fossil localities are the river banks, and an old cutting for a mill-race on the east bank of the river, a little north of the Railway Station. The banks of the river (the Salmon) at Shannonville, and a cutting on the Railway at that place, about half a mile west of the Station, are also good localities; whilst around Trenton village many excavations and small quarries will be found exceedingly rich in fossils. On the steep side also of the high land at Rednersville in Prince Edward's County, some good specimens may be procured. This is the highest position occupied by the Trenton Limestone immediately around Belleville. I was led to understand by persons residing in Belleville, that the rock was not limestone ; but it consists simply of the same shaly limestone as that seen on the banks of the Moira, as shewn in the following section (lettered as in figure 1), from which moreover, an idea may be gleaned of the vast amount of denudation which must have taken place in that neighbourhood, both before and after the deposition of the Drift.
Bay of Quinte
At some of the above mentioned localities, and especially in the old mill-race near the Railway Station at Bellevile, I found Columnaria alveolata, until recently considered typical of the Black River Limestone, associated with ordinary Trenton fossils; and near the Episcopalian Church at Shannonville, I found the same coral with Stromatocerium rugosum, also accompanying Trenton species. These types therefore, (as already shewn by Sir William Logan and others,
from the examination of other localities) although highly characteristic of the Black River Limestone, are not absolutely peculiar to that formation (or sub-formation) as was formerly thought to be the case. The subjoined Table gives an enumeration of the fossils collected, during my visit, at Belleville and in the surrounding district.
PLANTS : Indistinct fucoids, and at Rednersville an undescribed form presenting a thick primary stem-mass, with numerous dichotomous branchings.
CORALS and CRINOIDS : Stromatocerium rugosum (Shannonville). Stenopora fibrosa (the Chætetes lycoperdon of Hall, &c.): Variety 1, ramosa, the branched form, most abundant on the surfaces of the flat layers along the banks of the Moira ; Variety 2, concava, the flattened or salver-shaped form concave above, abundant everywhere, more especially at the Railway cutting near Shannonville ; Variety 3, globosa, the true “puff-ball” form, rather uncommon.
Columnaria alveolata (Belleville, Shannonville). Petraia (Streptelasma) cornicula. Glyptocrinus ramulosus ? (stem fragments only.
BRYOZOONS: Ptilodictya (Stictopora) acuta, common at most of the fossiliferous localities, with a few other (indeterminable) forms.
BRACHIOPODS : Lingula quadrata. Rhynconella increbescens (not common). Strophomena alternata and S. filitesta (both exceedingly abundant). Leptæna sericea. Orthis testudinaria (also very abundant); O. tricenaria (beautifully preserved); O. pectinella ; 0. lynx (only observed by me at Trenton).
GASTEROPODS : Pleurotomaria lenticularis, Murchisonia gracilis; M. bellicincta ; M. sub-fusiformis (?) Subulites elongata.
PTEROPODS (?): Conularia Trentonensis (not very common).
CEPHALOPODS : Orthoceras (Endoceras) proteiforme ; 0. bilineatum; 0. (undetermined species); 0. tenuifilum, or a related species with beaded siphuncle.
TriloBITES : Asaphus platycephalus (= Isotelus gigas, exceedingly common in a fragmentary state); A. megistos (rare). Ceraurus pleurexanthemus (very abundant). Calymene Blumenbachű (tolerably common, and well preserved). Trinucleus concentricus (two fragments only, found at Shannonville)
In the above list it will be seen that I have placed the coral commonly known as Chætetes lycoperdon, under the genus Stenopora, of Lonsdale. D'Orbigny's Monticulipora, to which genus the branched form has been referred, appears to agree in all essential respects with Stenopora, and to be thus an unnecessary addition to the list of Favositian genera. , Calamopora of Goldfuss (including amongst others, Favosites, Stenopora and Chætetes) can scarcely be employed without risk of misconception, and is therefore now almost universally abandoned. Favosites differs essentially from Stenopora and Chætetes in possessing perforated cell-walls. The imperforate favositoidean corals fall into two series: the one exhibiting fissiparous and the other gemmiparous reproduction. The former show in the fracture the interior of the tubes, and constitute the genus Chætetes. The latter show the outside of the cell-walls (reproduction taking place by the lateral interpolation of new tubes) and they form the genus Stenopora. To this genus, if the above definition as given by McCoy and others, hold good, our so called Chætetes undoubtedly belong. This admitted, our common forms, the Calamopora fibrosa of Goldfuss, may be legitimately placed under McCoy's Stenopora fibrosa, and conveniently sub-divided into three varieties : the branching form (variety ramosa); the flat, cup-shaped or salver-shaped hemispherical form (variety concava); and the globular or true “puff-ball” form (variety globosa or lycoperdon). It often happens that whilst one variety is exceedingly abundant at a special locality, the other two are altogether absent. McCoy ("British Palæozoic Fossils," p. 24,) makes but two varieties : lycopodites and regularis, the latter including the branched and polymorphous forms; but those given above, so far as regards Canadian examples, will be found I think of more convenient adoption.
The “petites saillies coniques," the distinguishing character of d'Orbigny's Monticulipora, appear to be a necessary consequence of the mode of reproduction exhibited by Stenopora.*
On proceeding north of Belleville, the thin-bedded limestone gives place to the lower or thick beds, and these in turn merge into a silicious limestone, the probable equivalent of the Black River subdivision ; although the country is so thickly covered by Drift, that sections are only observable here and there. At the village of Hungerford, in the township of that name, the grey silicious limestone is seen to overlie a series of thin flat layers of a reddish calcareous sandstone with pale green spots distributed irregularly through its mass. This rock is apparently an abnormal form of the Potsdam sandstone, or, perhaps a bed of passage between the Potsdam sandstone and the Calcareous sand rock, as it contains from 40 to 50 per cent. of dolomitic carbonate of lime. I found no traces of organic remains in it. I should be inclined to look upon it as the calcareous sand rock, were it not for its agreement, in certain of its physical characters, with the Potsdam sandstone as recognised elsewhere. From this part of the country however, westward to Georgian Bay, the beds between the base of the Trenton and the outcrop of the Laurentian series, are more or less obscure-thinning out altogether, or merging, as it were, one into the
About three miles north of Hungerford village (or perhaps less, the intermediate space being greatly obscured by Drift) the Laurentian or Gneissoid rocks begin to crop out, dipping at a high angle to the north-east, or in a contrary direction to the slight dip of the Silurian strata. Close to the southern limit of the Laurentian outcrop a fine band of crystalline limestone occurs, interstratified with dark grey and reddish beds of gneiss. This may be conveniently examined at the village of Bridgewater in Elzevir Township on the property of Billa Flint, Esq., to whose enterprising spirit, that part of the country owes so much. The specimens of crystalline limestone obtained at this spot, form a marble of excellent quality. I have to regret that from want of time I was unable to examine the run of the band, and its quality at other points. A few fragments of galena and some impure steatite were shown to me, as having been met with near at hand.
These remarks were written several months ago. In the last number of the Canadian Naturalist, we were gratified to find the identity of the so-called Chætetes lycoperdon with Stenopora fibrosa also adopted by Mr. Billings,