Connell takes a deep dive into geological time through an examination of the landscape and stratigraphy of the Bowker Creek/Thaywun Valley.
From the Victoria Daily Colonist, October 23rd, 1938-
In and around Victoria there are areas of low ground usually sloping gently towards the sea and never at any great height above it. Before modern streets and drainage systems invaded them some of these were little more than swamps in wet weather. I have a distinct recollection of driving many years ago over a rude trail through one of them where now charming suburban homes stand high and dry at all seasons.
Even today there may be found areas of peat bog in such localities, and on one occasion in late years I went to a house close to the Oak Bay golf links to see the unusual spectacle of a garden on fire. From a heap of burning rubbish the underlying peat, combustible after the summer’s drought, had become ignited to a depth of three or four feet at least. The trenches dug for sewers and even the roadside ditches have again and again revealed former conditions very different from the turf and thicket of today’s surface. By the Pemberton Woods the heaps of recently excavated soil have shown shells whose marine origin is obvious to the most casual passer-by. Across the road from the northwest corner of Ross Bay Cemetery a sewer trench dug a dozen years or more ago showed in a very interesting manner the successive stages by which the present land surface came into existence. The late Dr. Newcombe gave particular attention to the long sewer trench extending through the valley south of the Hillside Avenue ridge, and I once accompanied him along what was then the later portion of it running across the flats on each side of Foul Bay Road.
The part of this area lying in the vicinity of Haultain Street has received a good deal of notice because at times of unusually heavy rains floods have occurred and a good deal of inconvenience has thereby been caused to the house-holders.
The area has a natural drainage system by way of Bowker Creek, a small stream rising in the open country beyond the narrow valley that separates Mount Tolmie from Oak Hill, the rocky eminence rising above the old orchard attached to St. Luke’s Rectory. Very little of the stream remains in its pristine condition. The hand of man has from time to time deepened it and straightened it, but here and there a little bit of the old bed remains, or did until perhaps this very time at which I am writing. Like so many of our streams, it has always been a seasonal water-course, carrying off the superfluity of the winter rains from the open fields. It is a far cry from its present tamed and managed state to what it was when the earliest part of its course ran through the cedar swamps through which ran the trail to the Uplands, which became the Cedar Hill Crossroad. In the far-off days when the Todds and the Irvines settled by its headwaters the howl of the wolf echoed through the forest and the elk came down in winter from the snows of the Sooke and Goldstream hills.
During the past week I received messages from two of those many friends to whom I am from time to time indebted for news of interesting finds. Both directed my attention to the fresh excavation being made to deepen Bowker Creek and relieve the winter flood condition in the area west of Richmond Road. The particular place referred to was where Trent Street meets the stream. There, I was told, a very interesting section of the subsoil of the district was to be seen with shells and diatomaceous earth, and I was not disappointed.
The neighborhood of Trent Street has an old-fashioned look about it, for relics of the past linger in the hedges and clumps of hawthorn that suggest British lanes. It is not the double hawthorn of our boulevards but the single or white thorn, the “may” that takes its name from the month in which, under the old calendar, the scented flowers opened their sweetness. But here we are by the stream, now a straight open cut with almost perpendicular sides. On each bank lie heaped high the materials taken out of its bed and from the extended sides.
Pure White Shells
Looking down the trench we see that the sides are dark grey and brown for the most part, the chief exception being about the middle, where a very obvious light-colored band about eighteen inches thick appears. The bottom of the trench, now covered by a shallow stream of water, is yellowish, and above it in the bank can be seen the pure white of shells. The piles of debris on the banks present a convenient opportunity of examining the material of the trench’s sides. Immediately we notice the shells scattered on the surface, most of them are snowy white, for the chief change which has taken place in them during their long burial is the disappearance of any epidermis or horny covering, and of any coloring they originally possessed. The exceptions are specimens of mussel in which the beautiful pearly iridescence of the shell’s interior is preserved and the exterior still retains much of its original blue and brown color. The species of shell we find in the heaps- in addition to the mussel or Mytilus – include Saxicava arctica, Mya truncata, Macoma inquinata, with what appears to be the variety arnheimi, Paphia staminea (a variety with rather widely spaced radial ribs), Cardium corbis, a fragment of another Cardium, Polynices pallida, and a barnacle in poor condition. The interesting thing about these shells is that they are all species inhabiting our present seas, and with a range from the Arctic southward. The shells are usually perfect, the valves usually in pairs. Some of them have a hole drilled in them, no doubt the work of a Polynices, the only specimen of which has itself been drilled similarly.
But the heaps have still further revelations. The pale bands we saw in the sides of the excavation are lying about in pieces of various sizes. If we take up one we are surprised by the lightness of it, and to the knowing this disparity between size and weight suggests at once diatomaceous earth. Such it is, and the diatoms of which it is composed are not confined to the white material but extend into the darker deposits, only in the latter the diatoms are mixed with peaty matter while in the white they are extremely free from any foreign admixture. Here, of course, we have to do with plants instead of animals, but with extremely curious plants because, unlike our familiar green things, they occupy shells which they builds themselves, they move about freely in the water, and their discarded houses are among the most beautiful and the most durable things in the world. When alive these little plants are not green, but of a beautiful golden brown color, the chlorophyll works just as effectively and assiduously as the green and to the same purpose. So that in the life of the innumerable grades of sea animals all are found to depend ultimately on the microscopic diatom.
Of course, the diatoms being individually invisible to the naked eye, the pale-colored earth requires examination under the compound microscope, and a magnification of about 300 diameters is necessary. The variety of form thus perceived in the Bowker Creek valley earth is fascinating, I found on my return home. Some of the diatoms are of comparatively large size and there seems to be a larger proportion of these than in samples of the earth from other places on the Island. No one who has not looked through the microscopist’s instrument can conceive how exquisitely beautiful these objects of clearest silica are, how charmingly shaped and how exquisitely ornamented.
Of course much of their remains are fragmentary, but every particle retains its share of the beauty of the whole. Essentially the diatom’s case consists if two parts, the one fitting over the other, and enclosed by a hoop. Naturally these are liable to become separated, and thus individual valves are usually seen in these fossil collections.
We are now in a position to put our fossil shells and diatoms and the deposits in which they are found together in a mental picture of their history. I say “fossil”, for such these remains are, although their species may be those of the sea that washes our shores today and the ponds that brighten our valleys. “By a fossil is meant”, according to a classic definition not to be improved on, “any body or the traces of the existence of any body, whether animal or vegetable, which has been buried in the earth by natural causes.” We find, then, in our section shown in the Bowker Creek trench three distinct stages based upon the inter-glacial clay deposits which underlie our lowlands. The first and lowest is a marine stage during which all these valleys were submerged below the sea and the life of the sea went on as it does today. This stage followed the close of the last glaciation by which the inter-glacial deposits were stripped down to the clay. And thus the marine deposits are really those of a raised sea-bottom. According to the only topographical map I have at hand, the Trent Street land surface is about thirty feet above the sea, but if we go back to the land above the Mount Tolmie-Oak Hill valley we find there also marine shells just below the surface and, of course, at a much higher level.
Where Plants Grew
Then followed the fresh-water stage. The land rose sufficiently to lose its covering of salt water and in due course a lake or swamp filled the basin where green plants grew – their obscure remains can still be seen – and diatoms abounded, and where pond snails moved slowly among the under-water vegetation. Gradually, as the land rose higher, approaching its present position, the drainage of the swamps took place and Bowker Creek took the waters to the sea at Oak Bay as another shorter stream drained the northern end into Cordova Bay just below Mount Douglas. The last stage was thus the accumulation of the upper soil and the growth of a dry land vegetation.
Today as we stand on the bank of the deepened and broadened creek and look northward we see in the distance the bold mass of Mount Douglas; nearer on the right the precipitous west face of Mount Tolmie; and the tree-crowned top of Oak Hill opposite.
But between us and these prominent features of the landscape stretches the broad, gradually sloping plain, rising to meet the oak glades between the Normal School and the golf links, running up the narrow valley into the distance between the rocky hills, and spreading to the right towards the sea from which it has risen; on the left, passing out of sight towards the gap between Spring Ridge and the Hillside Avenue ridge. Does it require a great effort of the imagination to recover mentally this scene? Today the skylark nests and sings its mounting song; then the waves washed the sides of the distant hills and the water lay deep and still many fathoms beneath, where now we stand.