The debris stream fed into a larger creek that cut a channel into the canyon side.
The canyon steepened.
Waterfalls muscled down over boulders.
The trail veered close to the tumbling creek and I thought, easy to lose your footing.
Shelburne nimbly navigated the trail like he’d done it a thousand times before.
We dropped until our trail bottomed out onto an oak-studded ledge overlooking a wide rocky river.
The river ran like a boulevard through a high-rise canyon.
I looked downriver, to the west, and then upriver, to the east. We were in the southern district of the Shelburne neighborhood.
Walter said, “Which way would Henry have gone?”
Shelburne said, “I’m sure he’s been all over this river canyon but which way now? I don’t know. From here, the trail goes east and west. From here, we follow the river. At least according to my grandfather’s letters, as interpreted by my father. The trail meets the waterway, at the southern grapes.”
“Grapes?”
“Early explorers found wild grapes growing along the banks and named the river for them. They spoke Spanish. Grapes in Spanish is uvas. My grandfather spoke Spanish. My father got a Spanish-English dictionary. Voila, the Yuba River. South fork.”
“So from here,” I said, “Henry might go either direction.”
Shelburne nodded. “Which way would you go?”
We had studied the geologic maps back at the lab.
Out in the field, it was show time.
The Shelburne family blue lead offshoot splintered at the river. There were mapped outcrops west, and east. So the question became, in which direction lay the contact metamorphic zone with the chiastolite hornfels aureole? Because that was the landmark Henry Shelburne would have sought.
Walter spread his hands, east and west. “In either direction we have a pluton invading metamorphic rock. A pluton, if you’ll recall Mr. Shelburne, is a large body of igneous rock that can cook the country rock to hornfels.”
“Good, fine.” Shelburne looked ready to bolt. “Which way?”
I jerked a thumb downriver. “South Yuba Rivers Pluton is thataway.”
Walter jerked a thumb upriver. “Bowman Lake Pluton is up yonder.”
“Although,” I said, “we’re not necessarily looking for a large mapped pluton.”
Walter nodded. “Could be a small and unmapped igneous dike.”
“Which way do you like?” I asked my partner.
Walter scratched his ear, considering. “I like the mapped rock unit up yonder.”
As did I. The rock unit up yonder was known to have been intruded by numerous small igneous dikes. I said, “I tend to agree.”
“Then let’s go.” Shelburne turned. “Upriver.”
More like, above the river. The river was a good sixty feet below us.
I paused to read a wooden interpretive sign staked into the ground. Once, the river had been level with the ground we now stood upon. And then debris had washed down from the mining pit above, elevating the river bed. And then, over time, the flowing water carved out its bed anew, leaving behind compacted-gravel benches like the one beneath our feet.
As soon as possible we’d need access to the river.
Meanwhile, we were at the mercy of the trail.
Save for Shelburne occasionally shouting his brother’s name, we hiked in silence. It was a rollercoaster trail that took our breath away. The trail paralleled the river but the rugged rock of the canyon walls forced the route to climb, traversing the descending ridges and knife-gullied canyons. Now and again the trail dipped down steep rock benches to skirt the river but there was no way down to the gravel banks, save a dicey scramble.
We pushed on.
Finally we got lucky. The trail jacked hard right and switchbacked down to the river’s rocky bench.
“What do you think?” Walter asked me.
I took in the lay of the land. “I think it’s prime.”
“I think,” Shelburne said, “we should keep moving.”
Walter turned to Shelburne. “We need to establish a baseline. This appears to be a natural catch-basin for anything coming downriver. Sediment, debris, minerals. Including, perhaps, float from a metamorphic contact upriver.”
Shelburne gave a brusque nod.
I thought, something here doesn’t sit right with him. I wondered, what’s here?
Nothing out of the ordinary, as far as I could see. The river bank was paved in cobbles and pebbles, armored with boulders. A gravelly sandbar extended halfway across the water.
Shelburne sat on a boulder and folded his arms.
Walter and I turned to our work. We shed backpacks and took out field kits. Walter claimed the rocky bank and I headed out on the gravel bar to sample the geology mid-river.
I found a promising spot, a submerged bedrock hump that bridged the water and slowed its flow. A group of boulders gathered, forming deep crevices, a natural hydraulic trap on the river bottom where material coming downstream was likely to get lodged.
I knelt to sample.
The water was low. I wondered how much of a rainstorm was needed to saturate the watershed feeding this river. Right now, shafts of late afternoon sunlight glassed the surface. Where clouds shadowed, the river turned inky. A rainbow trout nosed the bottom, the fish multicolored as the gravel. I scanned the riverbed, noting how the rocks and sand acted as riffles, thinking geologically speaking this was an eminently likely site to find grains of gold. Gold is heavy. Water needs a brute-force flow to suspend gold and move it along, and the moment the water slows, the heaviest grains bail out and settle into pockets and crevices. I peered into a large crack. Looking, I abruptly realized, for the telltale metallic flash. I shifted position and did see a flash but it was silver — muscovite mica. Still, my mouth had gone a little dry. I moved on to the next crevice, the next little hollow. The gravel here was mostly buried under silt and sand that had settled out of the river flow. I bent lower and plunged my hands into the water, wetting my sleeves, running my fingers through the sandy bed, unearthing grains of quartz and chert and mica and every other freaking mineral that lived in this micro-niche but no gold.
Hold on. What are you looking for again, lady? You’re looking for float. Diorite. Hornfels. That’s what should make your mouth go dry.
Not gold.
I glanced at Walter, who was examining a specimen under his hand lens, and then I glanced at Shelburne, who was still in that strange funk on his boulder, staring into the distance.
They were paying me no attention.
I recovered my dignity and paid heed to the little pool and riffle pocket where, in my professional opinion, something worth examination might be lodged. Upon closer examination I noticed a ledge. It was recessed, in shadow, and the riffling water was silty, but nevertheless I could make out the shape of a cobble in there. Hard to tell the texture and color but it was worth a closer look.
I reached.
My fingers closed on the cobble.
I yelped.
I’m not afraid of snakes but for a moment I thought this must be the hump of a coiled water snake, clammy and cold. But if it were a snake it would have moved, would have recoiled from my touch, would have slunk out from the crevice and skedaddled or, worse, and wrapped itself onto my hand and given me a bite. This was no snake. This did not recoil. It simply pushed my fingers aside.
Walter was suddenly beside me. “Cassie?”
I let go of the thing and sat back on my haunches. Heart pounding.
Shelburne sprinted across the gravel bar to flank me on the other side. “What is it?”