Plants, Rock.

Oh boy, I’ve been slacking off a lot lately. To compensate for my inactivity on this blog I’m going to try and post a lot over this next week.

A couple years ago I was at my parent’s house for a couple days during the summer. In their kitchen sat a light colored rock. After closer inspection, I determined it was obviously a fossil. It looked like a ridged cylindrical limestone. Remembering back to my morphology and evolution of vascular plants class, I thought this fossil closely resembled an extinct genus Calamites, essentially a giant horsetail. The end of the fossil was broken and showed what looked like a cross-section of radial vascular tissue. A couple months later I took the fossil, which turned out to be my cousin’s, to college to confirm or deny my suspicion. I was so excited about the potential of this rock being Calamites because it was found near my cousin’s house on the Helderberg Plateau of NY, whose rock dates back to before the known fossil record for Calamites.

Despite a botany professor agreeing with my identification, a geology professor promptly dismissed the fossil as the fairly common rugose coral…not even a plant. Oh well, no reevaluation of plant evolutionary time-scale for me. I knew the Helderberg Plateau was a sea floor at one time, but was hoping it was also adjacent to a terrestrial environment, which would increase the probability of Calamites fossilization.

Since then my interest in fossils has remained peripheral, probably because of their scarcity. Luckily, there is a fossil forest south of the Helderbergs. In fact, it was featured in a recent article of Nature. Gilboa, NY is home to a quarry where loads of plant fossils have been found. In the study, Stein et al (2012) identified three types of arborescent trees within their 1,200m2 study site. The pseudosporochnalean genus Eospermatopteris is the predominate fossil of the study site and is characterized by a bulbous root mounds short-lived leaves. The aneurophytalean Tetraxylopteris was identified through analysis of vascular tissue and “orthostichous knobs.” Additional aneurophytalean rhizomes where found terminating at the base of Eospermatopteris possibly indicating using a climbing habit. The third tree-like plant that was found at the site was identified as an ancient club moss, which extended the known range of these plants.

Archaeopteridalean plants found close by, but not in the research plot, indicate a fourth type of ancient tree. These plants are the first to show bifacial cambium growth and were thought to have marked a new type of forest distinct from Eospermatopteris. However, this study refutes that notion because of the proximity and lithologies of both types of fossils. These ancient forests also have implications for understanding ancient atmospheric oxygen and carbon dioxide levels and temperatures.

I think I may try to find of these fossils. Don’t worry, I’m leaving my dynamite and rock hammers at home...

…I don’t actually have dynamite…yet.

Stein, W.E., Berry, C.M., Hernick, L.V., and Mannolini, F. 2012. Surprisingly complex community discovered in the mid-Devonian fossil forest at Gilboa. Nature, 7387: 78-81.