I Love the Smell of Fossils in the Morning!

He ain’t got no distractions
Can’t hear those buzzers and bells.
Don’t see no lights a flashin’
Plays by sense of smell.

(Pete Townshend, Pinball Wizard)

♦

Earlier this week, Dave Rudkin and I visited quite a number of outcrops in southern Ontario. We were looking for several things, but most of all we sought evidence of the sorts of unusual Ordovician fossils we have found in Manitoba at William Lake and Airport Cove. On the afternoon of the second day, as we crawled over yet another roadcut, I had a flash of intuition and suddenly said to Dave,

“We won’t find the fossils here. These rocks just don’t smell right.”

Because they really didn’t. I had recalled that there is a particular “tang” in the air when we hammer the rocks at William Lake and Airport Cove. Part of this tang may result from the strata at those sites being dolostone rather than limestone, but they also share a subtle aroma that is lacking at many other dolostone fossil sites. What that smell is I really don’t know, but it was entirely absent in the flat scent palette of these Ontario strata.

At William Lake, there is often ample opportunity to smell the rocks. Here, Debbie Thompson and Michael Cuggy work through one of our previous rubble heaps, while in the background I am examining a “new” dolostone bed.

You might think it odd that I would sniff rocks. I don’t  really go around purposefully inhaling these aromas, but doing this sort of paleontological work one really has no choice about it. The fossils are often tiny and obscure, and after you split the rock you have to get your nose right up to it as you peer through a hand lens. If the rock has a dust coating then the surface must be wetted to make the fossils visible, and if you aren’t near to one of the water pails you end up using spit instead. I have to admit that there have been times I have licked the surface of a rock in my hurry to see what a particular small fossil might be. So I know very well what those fossil-bearing strata smell like!

Other fossil sites also have distinctive smells, of course. In my scent memory, it is easy to conjure up the whiff of bitumen in the Eramosa lagerstätte of Ontario, the lime dust of the Tyndall Stone quarries in southern Manitoba, and the sulfurous pong of a pyrite-rich locality on the west coast of Newfoundland. Elsewhere, the rock-smell is obscured and overwhelmed by local factors. In some working quarries the pervasive odour may be the diesel fumes of operating machinery. There are places in the modern intertidal zone where the combination of salt and microbial scum completely masks whatever smell the rocks might have. And woe betide you if you need to work along a shore where purple sulfur bacteria have taken over the decomposition of seaweed mats!

In the field I often appear to have my nose stuck into the geological record. (photo © Dave Rudkin, Royal Ontario Museum)

Could it be at all useful to recognize that rocks bearing particular kinds of scents might also bear particular kinds of fossils? Given the limited olfactory abilities of humans, I doubt that we are ever going to find an unusual fossil site by smell alone. But perhaps the absence of a particular smell might be good negative evidence: it might tell us that a rock lacks the chemical makeup that would make it a likely host for fossils preserved in a particular way. Is it too much to hope that in the future we could train a fossil-sniffing beagle, which would rapidly scour outcrops for the faint spoor of long-passed eurypterids?

© Graham Young, 2012