April 28th, 2021 ~ Vol. 91 No. 17
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Looking Back - John Kinnear
Boulders I Have Met
Looking Back
John Kinnear photo
Conglomerate boulder on hilltop
Just about anywhere you look in the valley bottom of the Crowsnest Pass you will find large errant boulders laying about. They have been left, for the most part, where they first landed but sometimes they get shoved off to the side or used for obstructions to keep red necks off of non-motorized trails. There is a remarkable collection of them scattered about in the bush around here, in some of the most unlikely places and they are often visible on the hillsides above the Crowsnest River.

I grew up playing on a huge displaced boulder that is definitely what one would call an erratic. It is a monstrous conglomerate chunk of rock from the Cadomin formation and it sits on top of the hill near my present home in Coleman. The reason I can say it is an erratic is because it doesn’t belong where it is. It is now confined to the Mountain View Industries compound, surrounded by a chain link fence.

Conglomerate is nature’s version of concrete and like concrete is a composite of smaller round and angular pieces of other rocks fused together with a matrix of sand or silt or clay. The pieces of rock are referred to as clasts. Most conglomerates have hard chert pebbles within them and the cement is usually quartz which makes it an extremely hard, weather resistant rock. This ancient specimen is about a half mile away from its original source formation. It is not a long way for an erratic to travel but nevertheless definitely a boulder displaced by glaciation. Its source, the Cadomin conglomerate, is the basal sandstone of the Kootenay (coal bearing) formation and a bit of its outcrop is clearly visible on the bend in the highway just west of Horace Allen School.
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The ridge that this boulder sits on is part of the Virgelle Formation, a sequence of sandstones, shales and siltstones formed from the beach sands exposed on the shores of the ancient Colorado Sea. It is interesting to note that in several earlier years of Vern Decoux’s scrapbooks there is reference to this boulder by Fire Chief Henry Zak. In articles run some weeks after the Yuletide he invites anyone with old Christmas trees to bring them up to the big boulder on the hill where a giant bonfire was planned. They obviously had a safe plan to conduct such an event on this promontory. Doesn’t that sound like fun? The event undoubtedly was clearly visible from all over town.

Speaking of boulders, the scrap books mention, in 1951, that the Virgelle rock bluff near my home was blasted through to turn the then Fourth Street in Coleman into the main highway route. It created a lot of boulders which were summarily dumped further west to elevate and level the new road past places like the old Catholic Hall (now Rum Runners). A recent excavation into this roadway just west of Rum Runners proved to be a bit of a headache for the contractor repairing deeply buried services alongside the highway. Of course they unexpectedly ran into a lot of the boulders from the Virgelle bluff.

Decoux’s 1957 scrapbook reveals a picture of that cut through the Virgelle that looks pretty dam scary. There was no allowance for sidewalks and the sides of the rock cut were steep. People trying to walk through the tight space alongside the highway there risked getting run over or clobbered by a loose boulder. A later 1959 scrap book clipping talks about the fact that the cut had been finally widened and sidewalks installed. There is also a picture of men working in the Nez Perce Creek bed near the highway lining the creeks edges with some of the rock from the Virgelle cut. A winter works project during the time that many coal mines were shutting town.

As mentioned in my March 24th column (Decoux’s Delicious Dandies) the 1951 conversion of Fourth Street into the main highway also ran into some giant erratic boulders near Nez Perce Creek. Two totally different types, one conglomerate and one from the volcanics were found in 2019 when the town did the sewer and road upgrade near the underpass.
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The boulders of the Crowsnest Volcanics are hardened lava called trachyte and are readily recognizable, on closer examination, because of the pinkish feldspar, greenish pyroxene and black melanite crystals (phenocrysts) within the trachyte. I dug a few crystals out of the volcanics this summer, a rather tricky thing to do as they are quite friable. Black diamonds to me as a kid.Years ago I queried naturalist and explorer David McIntyre about volcanic erratics and was surprised to learn that there is a line of Crowsnest volcanic boulders that were “marched” eastward down the Crowsnest River valley out onto the prairie. David, in fact, indentified a large boulder on a ranch near the Montana border as being a piece of the said volcanic. How’s that for being shoved around 11,000 years ago?
Just east of the volcanic outcrop, below the trailer court above Willow Drive, one can find a dozen or so large volcanic boulders that are a couple hundred yards away from the source bed. They stick out like sore thumbs on the hillside. Curiously enough, most have split in half or develop large cracks in them, something that conglomerate or large sandstone boulders rarely do. Unless of course we help them along the way with a stick of powder or two. One volcanic boulder is large enough that a homemade ladder is still up against it for kids to climb up on it.

While sipping on a schooner at the Rum Runners patio the other day I noticed a magnificent river boulder rock wall on the north side of the highway. It forms the south fence of one of the houses perched on the hill. I got to thinking about early Pass pioneers and their penchant for weaving large river rock into walls and foundations of all types. Everywhere you look you can find rock walls and fences created with boulders and mortar and a bit of fitting creativity. It is a classic hallmark of early Pass constructions. Once you start to look around you realize they are everywhere. Italian immigrants to this boulder country did not hesitate to weave them into their properties.
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Looking further east, across from the Consolidated High School, one can find another enormous boulder sitting like a silent sentinel on a recently landscaped terrace there. It is another volcanic whopper and it isn’t going anywhere anytime soon. Perhaps it will become an integral part of whatever is developed there. Some creative license will be required to make that ten ton boulder part of any construction there. You can be sure the dozer operator that ran into it was not impressed. Cudo’s to him for being able to stand it up the way he did.

For me the grand daddy of all boulders can be found within that 110 million tons of limestone that swept across the valley near Frank exactly 118 years ago. Bill Kovach told me that there is a monolithic monster within the slide that is affectionately referred to as Hotel Rock. The name is not far off the mark. I was stunned when I first approached it.

I took a photograph of Hotel Rock some years ago with my friend Lou Lecerf standing up against it to show its size. I did a little scale calculation using Lou as a height reference. The visible part of the boulder measures 60 feet wide by 30 feet thick by 50 feet long. One cubic foot of limestone weighs about 165 pounds. So what we can see of Hotel Rock weighs an astounding 7,425 tons.
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What is even more interesting about this brobdingnagian is what you see on top. (I have always wanted to use that word somewhere by the way!) There is a very thin layer of dark shale on its topside and remarkably, a tree growing out of it. On the enhanced photo in this column the thick red line shows the contact between the Mount Head Formation (limestone) and the Kootenay Formation (sandstones, shales, coal). The black line on the rock shows the shale/limestone contact point. The Frank Mine travelled along that red line all the way to Hillcrest Mine! I am convinced Hotel Rock comes from this contact point between these two formations, along what is known as the Turtle Mountain fault. So because the shale is on the top side and the limestone forms the lower part of Hotel Rock it appears that this monster chunk of Turtle Mountain landed upside down from whence it came.

It is incredible when you think of it. One humungous boulder, 7,425 tons of rock in one piece, carried down the mountainside to where it lays today. Now that’s a boulder story.

Author’s Note: Check out the on-line version of this column for a lot more interesting boulder shots. Also see Pass Herald Archives June 15th,2010 for a related article entitled, “Boulders From Another Place and Time” to learn more about glacial erratics and the Foothills Erratic Train.
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April 28th, 2021 ~ Vol. 91 No. 17
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