The origin of the entablature is unknown, but could be due to flooding of the lava flow, causing much more rapid cooling, or the interaction of stress fields from the two regions of columnar jointing as they approach one another.
32.
Mathews based this on the age of the underlying till, the existence of pillow lava close to the bottom of some lavas, indicating subaqueous volcanism, the columnar jointing at the edges of the lavas, indicating rapid cooling, and the absence of apparent palaeogeography.
33.
Mathews based this on the age of the underlying glacial till, the existence of pillow lava close to the bottom of some lavas, indicating subaqueous volcanism, the columnar jointing at the edges of the lavas, indicating rapid cooling, and the absence of apparent palaeogeography.
34.
The particular site was chosen because of the presence of several interesting geological features, including the " Organ Pipes ", themselves a pattern of vertical pipe-like rock structures exposed by the erosion of the creek, and a tessellated pavement, where the rock surface has been split into regular " tiles " by joints related to columnar jointing.
