Callan Bentley The subtitle of this wonderful book is “Watermen, Crabs, and the Chesapeake Bay.” It’s an excellent account of crab ecology in the Chesapeake Bay as it stood in the mid-1970s, and simultaneously a sympathetic portrait of the lives of the locals who capture those crabs for sale to the seafood market. The writing is thoughtful … Read more
It’s Friday, and I have another guest Friday fold to share: This one is from my Denver friend Greg Willis, who tells me it’s from near Arapaho Pass, near where we rain-hiked. Ahhhh, yes – a singularly soggy hike up in the Colorado Rockies. I remember it well, and it looks like Greg had better … Read more
A reader asks: “What is foliation and what makes it so important to the structure of rock?”
Callan answers with a lot of images of beautifully foliated rocks.
I’ve got a few books to catch up on from my summer reading. The first is Under a Green Sky (2007), by University of Washington geoscientist Peter Ward. I picked this up because it was referenced in another book I’d read recently: Peter Brannen’s The Ends of the World (2017). (I’ve got a review of … Read more
Break out your paddle and sunhat. We’re going kayaking on Lake Moomaw, in search of Friday folds…
In the Landisville Quarry, Lancaster, Pennsylvania, there is a quarry that cuts into Cambrian limestones. (The exact identity of these limestones is apparently a matter of some dispute, but that’s not going to stop us!) I visited the quarry in June on a field trip offered through the NAGT’s Eastern Section annual meeting. We witnessed … Read more
The Friday fold is an outcrop of folded chert from the Franciscan mélange in Mendocino County, California. (It should look familiar to anyone who’s ever visited Marin Headlands near San Francisco.)
This is an interesting book – simultaneously about Enlightenment science, energy flows driving human history, and the boundary-less conception of politics, religion, and science that was embraced by Benjamin Franklin, Thomas Jefferson, and the book’s principal protagonist, Joseph Priestley (and to a lesser, or at least less-well-documented, degree by John Adams). The discussion begins in … Read more
Today we feature a famous recumbent, chevron anticline near Hill City, South Dakota has been featured as a Friday Fold or not, but thought I would give it a go. The rocks are Proterozoic metagreywacke turbidites with 70 complete or partial Bouma sequences. This is believed to be a late (D4) fold in the Black … Read more
Hiking Siyeh Pass in Glacier in Glacier National Park on Tuesday with my Montana State University field course, we spotted a few new folds in the Empire Formation (a transitional unit between Helena Formation and Grinnell Formation). Here is one of the students serving as a sense of scale, with interesting features on either side … Read more