GSW field trip postponed

Due to the recent rainy weather and a poor forecast this weekend, the GSW field trip to Catoctin Mountain has been postponed until next Saturday, June 9. Please pass the information along, and visit the field trip post (below) for further details and updates.

Draft minutes from the 1531st meeting

Relive the drama of the 1531st meeting with this draft copy of the minutes. If you spot any errors, email them to meeting secretary Victor Zabielski at to be approved at the next meeting.

UPDATE: GSW Spring Field Trip



Due to poor weather forecast this weekend, the GSW Spring Field Trip to Catoctin Mountain has been POSTPONED  until Saturday, June 9, 2018.  Ann Wylie of the University of Maryland will lead the trip.

We will meet at 4810 Middlepoint Road, Myersville, MD at 10:00am. If there is no more parking space, please use the Sand Flats parking area, about 1 mile south off Gambrill Road, for overflow parking.

The field trip will extend from the Pre Cambrian Catoctin metabasalt, through the full section of the Loudon and Weverton Formations on Catoctin Mountain, MD. Here is a good overview of the rock units we’ll see on the trip.

The log house is located on the northwest corner of the intersection of Middlepoint and Tower Roads. (Some GPS devices place the house west of the intersection and on the wrong side of the street.) Here we will see the Loudon conglomerate, and the topographic expressions of the metabasalt-Loudon contact and the Loudon-Lower Weverton contact. The second stop is to a boulder field that marks the contact between the Lower and middle Weverton. At the third stop, we will park cars and walk about a mile along the crest of the easternmost ridge of Catoctin Mountain, where we will visit an old magnetite mine and observe an overturned fold revealing the synclinal structure of this ridge. Upper Weverton forms this ridge. We will return to the cars, and visit an overlook of the Frederick Valley close to the border fault. This is a great place to have a late lunch. A geologic map (draft) of the Catoctins which I have constructed will be provided for discussion. We expect the trip to conclude by early afternoon. There is a lot of walking, but the trail on the east ridge is fairly level after an initial gentle incline. The mine is only accessible by hiking. The boulder field is also a short walk along a trail.
Explore in advance using LiDAR and Google Earth (download the KMZ file from the link below, then just open it in Google Earth): (98 MB)

A direct link to the PDF of the Catoctin Furnace geologic quad is here:

Or, view a color version of the MD lidar in 3D just using a browser here (it’s the “MD elevations” layer near the bottom of the layer list), along with other layers, though the 1968 geologic map is not always geographically correct due to scale and other factors. (Thanks to Martin Schmidt for the link).

Meeting Number 1531, May 2, 2018

The 1531st meeting of the Society will be on
Wednesday, May 2, 2018

Hélène Le Mével, Carnegie Institution – Volcanic unrest in the Southern Andes of Chile

Richard Ortt, Maryland Geological Survey – Title TBA (projects of the MD Geological Survey)

Anne Thompson, NASA – Environmental Success Stories – The View from Space

Meeting flyer to print out and post at your institution – Help spread the word!

Beverages and socializing commence at 7:30pm.
The formal program starts at 8:00pm.
Meetings are open to the public; please join us!

We meet in the John Wesley Powell Auditorium of the Cosmos Club,
2170 Florida Avenue NW, Washington DC 20008.

Entrance is through the club gate, the first right-hand entrance on Florida Avenue north of the intersection with Massachusetts Avenue NW. The auditorium entrance is to the left of the gate. The Powell Auditorium is within walking distance of the DuPont Circle Metro stop (Q Street exit), the Connecticut Avenue bus routes (L2, L4), and the Massachusetts Avenue bus routes (N2, N4).