As we approached the first emerald thicket, I slowed to a creep. The place seemed conspicuously quiet, and I sensed we were being watched.

"Keep a sharp eye," I said, wrenching a rotten branch to one side. "We're not alone."

The oppressive gloom ahead felt thick, tropical, over-cooked: a hotbed of stakes holding up an evergreen roof. Rodrigo stretched the front of his t-shirt to soak up sweat from his forehead. Our guns handy, we pressed on. After a while, insect noises drowned out the silence.

The first half hour was hard going. Without a machete, forging a route through the brush proved taxing. On some of the taller trees, the buttress roots were so pronounced we had to negotiate an insanely convoluted route just to walk around them. Rodrigo explained how these buttresses provide stability for tropical rainforest trees, whose roots are ordinarily not as deep as those in temperate zones. Apparently, these ridges can reach thirty feet in height before blending fully into the trunk; the highest we came across was closer to fifteen feet.

Rays of intense sunlight extended to the forest floor every now and then, illuminating all manner of insects and dry particles in the air, similar to a cinema projection beam in a darkened theatre. As we stopped to rest, I tried to absorb as much of this humid realm as I could.

"I wonder how much of this is extinct in our own time," I said.

Rodrigo sighed. "We're talking paleobotany come to life, that's for sure. I didn't even realize there was ever a land mass where we're standing, so Christ only knows how far back this is."

"Tell me about it. Dumitrescu said the fabric was from an animal that vanished nine thousand years ago. He never said how long the species was actually around."

"Would it have made a difference?" Rodrigo asked.

"Probably not."

"Well, I have to say, Baz, this is the most reckless time travel I've ever been a part of."

I laughed. "Don't thank me now. We're not even lost yet."

His faced remained deadpan as he shook his head and replied, "English optimism."

A remarkable acoustic effect was created by the dainty chirruping of birds we could only partially glimpse, perched high above us, atop lofty lianas. These adaptive, draping vines either climbed into the tree canopy, reaching for sunlight, or started life already up there and sent roots down to the ground.

Rodrigo took to naming new, strikingly colored species of birds he spotted through these creepers as a means of keeping his spirits up. It proved a helpful distraction for me, also, from the ever-so-elusive rustling sound I swore kept pace on either side. By the time our path opened up into a stunning glade awash in a deluge of sunlight, my friend had named over a dozen fresh, possibly endemic, species: 'Nice With Soya Sauce', 'Robin Under-the-Hood' and 'Luke Vinewalker' are the ones I can recall.