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1 July 2022

Friday fold: lithified python

A quick Friday fold that I observed last month in a boulder of riprap at Chippokes State Park in Surry, Virginia. I have absolutely no idea where this rock was quarried; but it doesn’t look like anything I’m familiar with in Virginia, so maybe the Baltimore Mafic Complex??? Anyhow, it’s not native to the Coastal Plain, but it shows a pleasing fold train of green and gray amid the black …


26 October 2018

Friday folds: Mather Gorge Formation

It’s been a very Billy-Goaty week for me. Three times since Sunday afternoon, I’ve taken people to the Billy Goat Trail’s “A” loop in C&O Canal National Historical Park. On Tuesday and Thursday, it was my NOVA Physical Geology students. On Sunday, though, it was just my son and me. Good news! He helped me discover a new fold by exploring some new rock outcrops and climbing on them. He …


27 August 2018

Beautiful Swimmers, by William Warner

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 and calm, paced very similarly to John McPhee’s writing, rich in quotes from the watermen …


16 June 2017

Friday fold: toothpasty Tomstown

I spent last weekend at the National Association of Geoscience Teachers’ Eastern Section meeting, based out of the Community College of Baltimore County in Catonsville, Maryland. One of the two field trips I took headed out to the western Piedmont, Blue Ridge and Valley & Ridge provinces of western Maryland. On that trip, we took a tour of Crystal Grottoes, a commercial cave south of Boonsboro. I was impressed at …


9 February 2017


Do you remember the blog post four years ago about documenting the doomed outcrops at Scientists’ Cliffs, Maryland? It was the site of gorgeous Miocene fossil exposures in the Calvert Formation. Here’s what the site looks like now: Photo by Peter Vogt   That ugly thing at the base of the cliff is a gabion, protecting the houses on the clifftop and making fossil access impossible. I’m glad we got …


27 January 2017

Friday fold: the Bradshaw Layered Amphibolite

The Friday fold can be found along the Fall Zone, where crystalline metaigneous rocks of the Piedmont meet the gently sloping strata of the Atlantic Coastal Plain. Contemplate their high metamorphic grade and their tight folding, and imagine the mighty mountains that once rose on this spot.


12 September 2015

New GigaPans from Team M.A.G.I.C.

Hampshire Formation outcrops on Corridor H, West Virginia: [gigapan id=”178008″] link (Marissa Dudek) [gigapan id=”177198″] link (Callan Bentley) Faults in the Tonoloway Formation, Corridor H, West Virginia: [gigapan id=”176602″] link (Marissa Dudek) Conococheague Formation, showing stromatolites and cross-bedding: [gigapan id=”177155″] link (Callan Bentley) [gigapan id=”177355″] link (Jeffrey Rollins) Tiny folds and faults, from a sample I collected somewhere, sometime… oh well, it’s cool regardless: [gigapan id=”178807″] link (Robin Rohrback) Fern …


3 August 2015

The Sykesville Formation, in 6 new GigaPans

As part of my work on the GEODE project, I’m always looking for good imagery to teach key concepts in geoscience. One important concept that I’ve been thinking about lately is the principle of relative dating on the basis of inclusions. Just as you can’t bake a loaf of raisin bread without already having raisins in your kitchen, rock units that are included in another rock unit must be older …


5 March 2013

Documenting doomed outcrops: Scientists’ Cliffs, Maryland

The community of Scientists’ Cliffs in Maryland is a private community that happens to sit on some of the most amazing fossil exposures in the Coastal Plain. The strata in question are part of the Miocene-aged (~14 Ma) Calvert Formation. The Scientists’ Cliffs outcrops are better than the more famous outcrops at Calvert Cliffs State Park, mainly because of easier access. At the park, you have to hike in a …


10 November 2012

New GigaPans from the M.A.G.I.C. project

My students Chris Johnson and Robin Rohrback have been busy adding to the Mid-Atlantic Geo-Image Collection. Check out a few of these new GigaPan images: [gigapan id=”117788″] link [gigapan id=”117786″] link [gigapan id=”117390″] link [gigapan id=”117346″] link [gigapan id=”116919″] link


26 August 2012

Paw Paw Tunnel GigaPans

A weekend expedition to GigaPan the C&O Canal’s singular Paw Paw Tunnel results in an exposition on Devonian sedimentation, Alleghanian mountain-building, structural geology, and the incision of the Potomac River to produce entrenched meanders.


10 May 2011

Four new gigapans from the Billy Goat Trail

Yesterday afternoon, I spent some time in the field with a colleague, a student, and a gigapan. I took four gigapan images, which are of varying quality due to the partly cloudy day, but still you ought to find them interesting to explore. You can see any of them full-screen by clicking on the word “GigaPan” in the lower right corner: Antiform in Mather Gorge Formation, C&O Canal: [gigapan id=”77023″] …