A continuation of the volcanics of the early Cascade Range in Washington, accretionary lapilli, like volcanic “hail stones” made of concentric rings of ash around an ash core, are common clasts in the Ohanapecosh Formation.

 

 

Mount Rainier, viewed from the southeast.

This photo is of a long tube pumice lapilli shard from the Wildcat Creek beds, Ohanapecosh Formation. The Ohanapecosh Formation contains early eruptions from the ancient Cascades in Washington State.

Pumice is a highly vesicular rock. The long tube varieties exhibit parallel gas escape structures running longitudinally within the rock, which can be seen in thin section (see below). The blue-green color is from the clay mineral product, clinoptolite, of the alteration of the original volcanic glass.

Rocks provide us with the fossil record, and therefore interpretations of fossils without any discussion of their geological context are misleading. This is especially the case when anti-evolutionists argue that the fossil record is a “weakness” of evolution – either not supporting common descent or descent with modification – as these arguments rarely mention the geological context. Comments and examples will unfold with time.

While the rocks and fossils are raw unbiased data, there certainly are biases in the preservation of fossils and their discovery. These quotes serve as a drive-thru expectations of what the fossil record provides.

“Certainly paleontologists have found samples of an extremely small fraction, only, of the earth’s extinct species, and even for groups that are most readily preserved and found as fossils they can never expect to find more than a fraction.”
George Gaylord Simpson

Simpson, George Gaylord, The Major Features of Evolution, 1953

“The preservation potential of different biomolecules is approximately inversely proportional to their information content.”
-Briggs, D.E.G., Evershed, R.P. & Lockheart, M. J. 2000. The biomolecular paleontology of continental fossils. In Erwin, D. H, and Wing, S. L.,  eds.,
Deep Time,   Paleobiology Suppl. To 26(4): 169-193.