West Point, PA

Upper Gwynedd lies along the southern edge of, and just within, the extensive but simple and monotonous formation called by geologists the Mesozoic, or Red Sandstone, belt. This belt varies from 10 to 30 miles wide and is over 500 miles long. It is the bed of a great river which ran from North Carolina to above New York City, and which has been compressed by geological forces over millions of years into stone.

This bedrock belt is composed of Triassic and Jurassic Age sandstone, siltstone and shale deposited over 260 million years ago in a rift basin. There are two main formations in Upper Gwynedd, the Lockatong Formation and the Brunswick Group. The Lockatong Formation consists of a hard, dark colored and fine grain shale, while the Brunswick Group is made of a soft red shale interbedded with sandstone and siltstone.

The two formations interfinger with each other at various places, one of the locations being directly under West Point.

This map, from a 1983 US Geological Survey, shows the boundary between the Brunswick Group and the Lockatong Formation going through West Point at 2nd Street. (line going through the word "Point" at lower left) Below the line is the hard Lockatong Formation, above it is the softer Brunswick Group. Beginning in 1881, the West Point brick yard quarried the shale in the Brunswick Group, until it closed in 1923.

"The underlying rocks of the township are mostly red or reddish and range from sandstone to shale. No region can be more barren of general geological interest." - Historical Collections Relating to Gwynedd by Howard M. Jenkins.

What does this mean for West Point? If you dig a hole deep enough here you'll find shale! A plentiful supply of building material for....

Foundations ... (these are three different buildings) ...
.... and entire houses!

The people of West Point and surrounding areas didn't have to dig up their own rocks. The West Point Shale Brick Company was doing such a booming business that in July of 1915 they had a private telephone line installed!

West Point Brick Shale Company made bricks of shale, clay, and mixtures of clay and shale. They produced 18,000 bricks and tiles a day, and orders for 50,000 to 100,000 bricks were not uncommon. The location of the brick yard was east of Jones Avenue on land now occupied by Merck Sharp & Dohme.

This excavation for a house in Upper Gwynedd is about five feet deep.
The bottom is solid shale. (and a little mud from the rain)
A pile of shale from a hole dug on Garfield Avenue near Broad Street.
Mixed in with the rocks, the red "dirt" is just pulverized shale, so the pile almost 100% shale.

In this photo taken on Garfield Avenue, red shale bricks have been reused as a border for a garden. The bricks are about 18" long. The shale formation has been problematic in modern times, requiring special heavy-duty equipment to excavate it when laying pipelines or other utilities.