They had heads back then

1913. 100 years ago. BC was still new, still half empty. White Rock was a railway station and a narrow strip of summer cottages along the beach and straggling up the slopes. On the Semiahmoo Reserve lands to the east of the station, some 40 Semiahmoo natives remained on their ancestral grounds around the mouth of the Little Campbell River.

In 1908, the Blaine border crossing, a mile to the east, had been opened. The next year, 1909, the Great Northern Railway line was rerouted to follow the coastline around Semiahmoo Bay, as it does to this day. The trains ran on steam; diesel came much later.

By 1913, developers had already seen the potential of the beach, the railway, and the proximity to the US border, but growth was slow.

Indeed, officials were so keen to develop White Rock that for a brief period in 1912, property lots could be had for free with the purchase of a subscription to a British Columbia travel magazine. (Super. Natural. British Columbia)

1913 changed all that. The Campbell River Lumber Company began construction of a large shingle mill on part of the Reserve lands. By 1918, . . .

The company, with its allied shingle mills and lumber camps, has a pay roll of over 300 men, running into some $35,000 per month. The big lumber mill is fitted with the latest and most up–to–date machinery and labor–saving devices, all run by electric motive power, with steam auxiliary, and turns out timber, flooring, siding, ceiling, shiplap, mouldings and other dressed lumber with an average cut of 100,000 feet per day. This lumber is shipped in carload lots to the prairies and other eastern Canadian points, as well as to a number of places in the United States.
Three shingle mills are operated by the Campbell River Lumber Company, . . . Each of these mills turn out some thirty thousand shingles per day, averaging about 560,000 for the week, the bulk of which is shipped to Pennsylvania. (Surreyhistory.ca)

 This is where the beach walkers came in. They had heads back then.

Row of footings and boards wander along the old breakwater, heading out to deep water.

The Campbell River mill was built on the slope below the present-day Semiahmoo townsite, and on pilings over the last curves of the Little Campbell River, on the inland side of the railway line. Beyond the line, the river was dredged and bordered with a stony breakwater, creating a straight, deep channel for boats.

The river still stays within these banks, though the tide covers them twice daily.

Logs were brought in from near Cloverdale to the east, by a temporary (removed in 1929) railway line, and from Hernando Island, in Georgia Strait; these were boomed down by tug boats, and moored in the bay. A few years later, logs cut near Cultus Lake in the Fraser Valley were hauled down to Bellingham by rail, then dumped into the bay, boomed up, and tug-boated back up to Canada. (A long way around, but transportation wasn't as easy then as it is now.)

The finished product, shingles, shiplap, siding, etc., was shipped out partly by rail, from the siding directly behind the mill, and partly from the scow berth at the end of the pier.

Layout of the mill, ca. 1923. From Surreyhistory.ca.

Most of the mill site was built on piles. Only at high tide was there enough water in the river to store logs. Continuous dredging was required, and piles placed every 12 feet in the river to hold back the sand and silt. Eventually, the dam was built to hold water, and store logs to keep the supply constant. ... The 1800 foot company pier was built in 1921.

And here are today's remains of that old mill:

Old cement footings, and the pilings holding the river in place. Taken from the path beside the rail line.

I have often wondered what those blocks were, down on the flats in the mud and silt. I'm glad I thought to look up my mysterious dog walkers.

This picture was taken from the top of the hill in front of the White Rock Hotel, on Dolfin Steet, looking east. ... The picture, taken in the 1920's, shows the Campbell River Saw Mill pier. At this time buildings were allowed on the beach. (Surreyhistory.ca)

There is an excellent, clear photo of the bay, showing the pier and the river channel, here, on Flickr. (Copyrighted, so you'll have to go there to see it.)

Here's a Google maps photo taken from the Dolfin Street corner, last year:

The current pier is behind us, to the right. The old mill pier is gone, except for the barnacled bits poking out of the sand. Seen full size, the border crossing at Blaine is marked by a white spot (the Peace Arch) near the centre, at the end of the bay.

The mill closed in 1927; many of the workers moved out, leaving empty housing in the community. The mill pier was dismantled. The buildings and machinery were removed. All that remains are the pilings, and those rusting walkers out on the tide flats.

Another Google view, slightly cleaned up. This is from the Reserve, looking over the mouth of the river, where the old mill was. Some of the pilings still stand, gently rotting away.

Google again. The railroad bridge, the mouth of the river, and the flats where the log booms were moored. If you look at it full size, (click) you can see, faintly, the crowds of metal and barnacle ghosts from the old booming grounds.