McCoys Ferry, Four Locks, Dam 5… » Dam 5 Potomac River



3 responses to this post.

  1. Posted by HikerBiker on April 30, 2012 at 8:45 pm

    On the rock wall just upstream from the dam is a block engraved with the following:
    B M
    U S C S
    Can anyone tell me what entities the BCM and the USCS represent? Im guessing the wall was built in 1878.


  2. Posted by LevelWalker on April 30, 2012 at 9:51 pm


    I’m running your question past someone who has really good knowledge of canal structures, but I do have a guess. The best answer for USCS seems to be Unified Soil Classification System, and C is the symbol for clay, while M is the symbol for silt. CM used together makes pretty good sense as a possible soil breakdown for a river bank. Hopefully I can confirm or deny this with a little help from a friend.


  3. Posted by LevelWalker on April 30, 2012 at 10:24 pm

    A more likely possibility (per Steve Dean of the C&O Canal Association) is that abutment work was done in 1878 due to a significant flood in 1877. The initials could refer to individual stone masons, etc. He stated that different groups use various plaques, etc. as a means of conveying their information. Can you describe the lettering? For example, was the it on a brass plate or carved directly into the concrete or stone? This is a very compelling question that you ask, and finding an answer can add greatly to a historians knowledge of the park. I’m not a historian per se, but I’ll keep digging (no pun intended).


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