Wednesday, August 29, 2012

The Stuff of Agatized Whale Brain Dreams

Somehow this past Winter I missed this story in the local newspaper. Only in the past week or so did this discovery finally come my attention when I found it on a local blog. My then-girlfriend back in 2008 or thereabouts discovered a fossilized whale brain cavity along the Gaviota Coast of Santa Barbara County and a good many years before that local rockhound par-excellence Ralph Bishop found a similar specimen of a bit lesser quality also in Santa Barbara County. However, both were casts comprised of mudstone filling in an empty whale skull brain cavity. What I did not heretofore fathom (and apparently neither did scientists until quite recently) was the ability of the natural world to actually fossilize actual whale brains and not just fossilize them with some ugly leaverite material but with blue chalcedony or rust-colored druzy quartz. The aforementioned fossilized whale brain cavity specimens are both quite cool but are not beautiful per se. However, these silicated whale brains (below) are out of this world cool and have captured my rockhounding passion and imagination like nothing has for some time now.

Agatized whale brain in partial fossilized whale skull.  Photo courtesy of David Middlecamp - San Luis Obispo Tribune
While reading the aforementioned blog posting about the south San Luis Obispo County agatized whale brain discovery (I'm guessing it was on the Nipomo Mesa) there was mention made of an earlier discovery of a similar specimen elsewhere on the Central Coast. I found out quite a bit more about this earlier discovery from this older post on The New Unschooler. As it turns out it was found near Los Olivos, in Santa Barbara County sometime in the first half of the 20th century. The New Unschooler blog post features the three photos of it (below) taken by the discoverer's grandson, Bob MacGillivray. I now have a new rockhounding holy grail: agatized (or otherwise silicated) whale brain! Prior to this my two rockhounding holy grails had been a large piece of agatized (better yet with variation carnelian) whale bone (I have found really small pieces at Agate Beach near Bolinas, CA, and still hope to find a largish transparent agate chunk of petrified whale bone someday). I also have long lusted for locating the legendary fossilized marine shells replaced by myrakite (cinnabar in chalcedony) that have been found in the Santa Lucia Range at the Oceanic Mine as well as by the aforementioned Ralph Bishop out in the Bryson area.
Fossilized whale skull with brain-cavity filled with the original payload. Photo by Bob MacGillivray of Los Olivos, CA.
Great brain structure with an apparent iron oxide staining. Photo by Bob MacGillivray of Los Olivos, CA.
Inside one brain lobe (at right) is a druzy quartz-lined cavity. Photo by Bob MacGillivray of Los Olivos, CA.


  1. Makes one wonder on how quickly silicification has to occur in order to preserve the original soft tissue. Certainly not a process of thousands or even hundreds of years.