Mélange

Mélange: A mixture; a medley; odds and ends; a motley assortment of things, . . .

“In geology, a mélange is a large-scale breccia, a mappable body of rock characterized by a lack of continuous bedding and the inclusion of fragments of rock of all sizes, contained in a fine-grained deformed matrix.”

However you look at it, St. James Church in Lower Jemseg, New Brunswick, is a mélange. Its architecture is a mixture of features and influences that somehow combine to make a charming and coherent building. Geologically, it can also be considered a mixture, though of course it is one produced by human agents rather than the immense forces that generate a mélange under natural conditions.

Even visitors with no knowledge of geology will immediately recognize that materials in the sturdy outer walls were derived from a variety of sources. Below and beside the windows, large blocks of dark purple sandstone contrast with various paler shades in the smaller blocks. The buttresses are armoured with wedge-split granitic rock, while rounded granite fieldstone can be seen in places in the walls. And then there is that soft, pale carved stone around the windows and the doorway. What are all these stones, and how did they get here?

The stones were pulled together through human expediency and opportunity. Jemseg, on the low-lying east bank of the lower Saint John River valley, is not a place endowed with wonderful bedrock, but the local geology is varied. Some of the stone came from nearby sources, but a bit of it travelled what might be called an unreasonable distance.

Constructed in New Brunswick’s great burst Anglican church construction in the latter part of the 19th century, St. James Church dates from 1887 and was consecrated in 1889 (general information about the church can be found here). This stone building is quite different from most of the churches built in this phase, which are wooden and “gothic”. Its form is also crudely gothic, but leavened with a dose of what might well be Scandinavian influence, particularly in the shape of the tower.

Although this church may seem like an old structure to those of us who live in western Canada, it is relatively recent in the history of Jemseg, a place that was first settled by Europeans in 1659 and that served as the capital of Acadia in 1690-91, some 325 years ago. Settlement occurred so early here because the junction of the Jemseg and Saint John Rivers was desirable as a trading post location. Both waterways are readily navigated, and Jemseg is higher than the marshy islands and moose pasture immediately adjacent to the rivers.

The tower beautifully illustrates how Hampstead Granite was used to armour exposed corners of the building.

And although 1659 seems like the dawn of time in terms of European settlement in Canada, the stones that form the church are of course far older; the oldest stone is literally as old as the hills that form the west side of the valley some 20 kilometres below Jemseg. This stone is the remarkably tough and beautiful granite that forms the edges of the buttresses and corners of the church. It shows remarkably little wear from its long exposure to the elements there.

The granite quarried in the Hampstead area from the 1830s up to the mid 20th century is commonly referred to as Hampstead Granite or Spoon Island Granite. It was used most commonly for monuments and grindstones, but this church demonstrates that it could also be incorporated into structures (though I suspect that it was rather difficult to work with in this role). Geologically, the Hampstead Granite is part of the Early Devonian Evandale Granodiorite (roughly 400 million years old), an intrusion of 20 square kilometres that consists of “light grey to pink, medium-grained, equigranular, hornblende-biotite granodiorite varying to monzogranite” (Government of New Brunswick industrial minerals summary).

A detail of the Hampstead Granite showing the dark biotite and hornblende, and lighter quartz and feldspars (coin diameter is 26.5 mm).

Granitic intrusions are bodies of rock that cooled slowly from the molten state,  often associated with the melting of crust that occurred as the Earth’s crust was deformed near plate boundaries. In this particular case the granite was formed near the meeting of two tectonic zones, the Gander and Avalon zones, during the growth of the Appalachian Mountains. The Early Devonian in this region is associated with closure of an ocean during the Acadian Orogeny, one of the several intervals of intense deformation, plutonic (deep) igneous activity, and metamorphism that resulted in the development of the Appalachians (see here for a substantial discussion of the Acadian Orogeny in this region, a topic far too complex to be explained using my meagre knowledge of structural geology and tectonics).

Following a mountain-building interval, the new steep slopes and high elevations are subject to greatly increased rates of erosion and sediment transport. In this region, the Devonian orogenic deformation was followed by a major interval of sediment deposition during the Carboniferous, roughly 360 to 300 million years ago. Carboniferous sedimentary rocks, many of them formed in rivers, swamps, and floodplains, cover eastern New Brunswick and the rest of the Carboniferous Maritimes Basin.

In this wall, varied sandstones, some of them showing cross bedding or cross stratification, are adjacent to a corner of Hampstead Granite.

Most stone in the walls of the Jemseg church is clearly Carboniferous clastic rock: broadly speaking it is “sandstone”, though much of it is “dirty sandstone” that could be more properly called arkose or even greywacke. I am not sure what formation was its source, though from its very mixed quality it is likely the most local of the stones incorporated into this structure. The bedrock underlying the village would be of this sort, so some of the stone could have even been quarried here, or perhaps across the river where the land is a bit higher. The variety of stone, however, suggests that much of it was collected as loose pieces. Since the pieces are angular they were not transported by water or ice; they are regolith that had been frost-wedged from the bedrock beneath.

A very “dirty sandstone” containing abundant rock fragments and a mixture of minerals.

It is unfortunate that the builders of the church did not cast slightly farther afield for sandstone: the Rainsford Sandstone (Minto Formation) used in the walls of Christ Church Cathedral in Fredericton has excellent colour and consistency, and the remarkably tough Grindstone Island Sandstone (Boss Point Formation) used in the cathedral’s buttresses is among the best sandstones anywhere. The former was quarried on what is now the Fredericton Golf Club, while the latter is from the upper end of the Bay of Fundy; clearly both of these stones would have been a bit dear for the builders of this parish church.

On a buttress of the Jemseg Church, the facing of local sandstone and armouring with Hampstead Granite (above) can be contrasted with the Rainsford Sandstone with Grindstone Island Sandstone armouring on Christ Church Cathedral in Fredericton (below).

What the sandstone in St. James Church lacks in construction quality, it makes up in geological interest and variety. Walking around the building on a sunny day, you can pick out a great range of features in the buff, golden, chocolate brown, brick-coloured, or rust-red stone: angled crossbeds from the interior of a river sandbar, rusty ironstones that might be associated with overbank flooding on an ancient floodplain, microfaults that cut across the stratification, and a dirty sandstone with admixture of angular and rounded rock fragments from those older granites.

This cross-stratified sandstone also apparently shows small-scale faulting (coin diameter is 26.5 mm).

Although the church’s builders were content with local sandstones, the fine stone that makes the window arches and other carved features has come from very far away, and travelled here by a circuitous route. This is Caen stone, a yellowish limestone of Jurassic age (about 167 million years old) that formed on ancient seafloors in what is now northern France. Caen stone is fine-grained, oolitic, and of very consistent texture. As it is readily carved, it has been used in French buildings for many centuries, and also can be seen in major structures elsewhere such as the Tower of London, Canterbury Cathedral, and the Old South Church in Boston.

The end window illustrates the fine carving qualities of Caen stone. Note the great variety of other stone in this wall!

In St. James Church, why does such an elite material appear directly adjacent to the lowly local sandstone? Certainly it would have cost a substantial amount to ship this stone from France to New Brunswick near the end of the age of sail, but that cost was not borne by the builders of this church. Rather, the stone window frames and door arch here are “remnants”: this Caen stone was part of a large batch shipped to Fredericton several decades earlier for the construction of the cathedral, and presumably the leftover stone had been in storage waiting for just this sort of use. So it was shipped downriver the 50 kilometres from Fredericton, for a fraction of the cost of receiving stone from the other side of the Atlantic Ocean.

As is the case for some other wonderful carving stones, Caen stone’s softness limits its ability to stand up to long-term weather exposure in tough climates. In Jemseg this stone has clearly suffered badly over the years, to the extent that some of it has been patched and much of it has been painted.

Some of the Caen stone has been severely weathered. Note the fine and even grain (coin diameter is 26.5 mm).

For the final piece of the geological story, a close examination of the church’s walls reveals a few interlopers: between the angular blocks of sandstone are occasional pieces of rounded sandstone and cobbles of grey or pinkish granite. These materials are similar to the other sandstone and granite in the walls, but geologically they have travelled through yet another process. They have been to “finishing school”, in the form of erosion, transport, and redeposition.

Some time in the relatively recent past these cobbles and small boulders were picked up from the bedrock where they had resided for several hundred million years. Perhaps they were transported by glacial ice, or maybe bounced around in a river system for a while, before being deposited in a place where people would gather them, such as in a gravel pit or in one of New Brunswick’s famously stony fields (the old story is that farmers often complained about “growing rocks”, as each spring the snow melt revealed a new crop of stones that had been elevated to the surface by the frost).

A piece of granitic fieldstone is incorporated into a wall.

This blog post started out as a simple set of photos of the stone in this lovely church, but like the rocks in the fields it also grew. That is the fascinating thing, when you start to look into the geology and history of many old stone buildings: the linkages radiate outward in every direction, in ever-expanding circles. It is remarkable that a small church can store so much of the past, but all stone buildings, whatever their size, hold within them many stories – the history of the people who built them, the history of the people who quarried and transported the stones, and the geological pasts of the stones themselves.

In addition to the variety of sources linked in the text above, I also consulted print publications including:

Gregg Finley and Lynn Wigginton, 1995, On Earth as it is in Heaven: Gothic Revival Churches of Victorian New Brunswick, Goose Lane Editions.

William A. Parks, 1914, Report on the Building and Ornamental Stones of Canada, Volume II, Maritime Provinces, Canada Department of Mines.

If you wish to find it, St. James Church is located along NB Route 715, at  45°47’9.29″N, 66° 5’42.37″W.

If you ever have the chance to visit, the interior of St. James Church is also worth a look. The board and batten construction is clear evidence of the very high level of carpentry in 19th century New Brunswick, and not surprisingly it is evocative of shipbuilding work (wooden ships were launched at Jemseg). My recollection is that the boards and battens are butternut and oak, respectively.

Just up the road stands this lovely overgrown Baptist church . . .

. . . and just down the road, Jerusalem artichokes wave beside the river.

© Graham Young, 2015