GOL 135: Field Studies in Geology - Geology of the Billy Goat Trail

Callan Bentley
Northern Virginia Community College


One-day field trip course with pre-trip reading and post-trip essay. This field trip will examine the geology of Maryland's Bear Island, considering the metamorphic and igneous rocks exposed by the river, sedimentary deposits, and the cutting of Mather Gorge and Great Falls by the Potomac River. Note: This trip involves strenuous hiking over very rough terrain.

Course URL: http://www.nvcc.edu/home/cbentley/gol_135/billy_goat/index.htm
Course Size:
less than 15

Course Format:
Lecture and lab

Institution Type:
Two Year College

Course Context:

This is an introductory course with no pre-requisites and does not serve as a prerequisite for other courses. It is a 1-credit class. Typically, half of the students take the course are doing so for transfer credit to educational programs at George Mason University or Marymount University or to a business program at Averett University. The remainder are taking it for NOVA credit (general education req., perhaps ~40%) or for personal fulfillment (~10%).

Course Content:

Students use the remarkable exposures of rocks along Mather Gorge (Potomac River downstream of Great Falls, Maryland) to learn rock identification and interpretation. The course emphasizes distinguishing observations from interpretations, and how to chronologically reconstruct a particular area's geologic history. Geomorphology is a minor theme.

Course Goals:

I want students to be able to develop a sense of how geologic information is gathered and processed. I want students to gain perspective on how deep geologic histories may be accessed by those with the cognitive tools to do so: we are constantly surrounded by clues about our past, clues of which most people are ignorant.

Course Features:

Students in this 1-credit class (1) read up on the geological ideas that will be expressed on the field trip via a course website, (2) participate in a day-long field trip, hiking along the Billy Goat Trail, and stopping to discuss key outcrops. A mix of student-focused exploration and instructor-focused explanation are employed. (3) A summarizing activity is typically employed at the end of the trip (time dependent); students are handed a mixed-up series of geologic events (interpretations) and rocks/structures (physical evidence), and challenged to work together as a team to put them in the proper chronological sequence from oldest to most recent. For a video of this process, see this YouTube clip:
Finally, (4) after the trip, the student works independently to author a comprehensive paper which synthesizes the information they gathered on the trip with the pre-trip readings and instructor-led discussions. This paper is submitted via e-mail either as a final draft (due 2 weeks after the trip) or as a rough draft (due within a week of the trip, commented on by the instructor, and returned to the students for polishing up before submission as a final draft on the usual due date).

Course Philosophy:

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Students submit a ~5-page essay summarizing the geological history of the Billy Goat Trail region. The paper is to be written in chronological order, and pair any interpretive statement about past events with physical evidence observed on the trip. These papers are submitted within 2 weeks of the trip date, and rough drafts are encouraged.


Teaching Materials:

Rubric for the grading of field trip papers (Acrobat (PDF) 20kB Jun25 10)

References and Notes:

Online pre-trip readings at: