The BILBY Geotrail
Basic Information for Locating Benchmarks Yourself
CHESTERTOWN ME CHURCH SPIRE
THE GEOTRAIL
The Maryland Society of Surveyors (MSS) welcomes everyone to participate in this statewide trail which showcases the different “Benchmarks” used by surveyors and which geocachers enjoy finding. The BILBY trail will include a total of 20 cache locations with geocoins awarded at different levels of caches found.
To most non-surveyors any brass disk they find is a benchmark, however not all benchmarks are created equal. There are approximately a dozen different types of benchmarks, and this trail will introduce you to 5 of the most common. Azimuth Marks, Triangulation/Horizontal Marks, Reference Marks, Special Marks and Bench Marks also known as Vertical Marks.
One MSS geocoin will be awarded when 3 caches are found from EACH of the five different types of marks (15 total finds). We have a limited amount of National Oceanic and Atmospheric Administration geocoins that will be awarded to anyone finding all 20 BILBY caches. Be sure to record the code word from each cache to qualify for geocoins.
To claim your geocoin(s) use this link to access the decoder. If multiple people share one geocaching username, only single coins will be awarded per user.
First of all, we will refer to all these marks as “Control Stations” since the word benchmark really pertains to just one type of control station. Next, we will use “Bench Mark,” with two words, since that is the way the National Geodetic Survey (NGS) defines it and the NGS is the federal agency that maintains this network of control stations.
While Geocaching.com no longer allows you to find and record these in your geocaching statistics, you can still post your finds on Waymarking.com and the NGS would welcome all finds or DNF’s to be recorded in the Survey Mark Recovery section of their web site. The NGS also has an interactive map located on their Map Page to help you find them.
Here are the five types of Control Stations and locations in the BILBY Geotrail:
HISTORY AND WHY THE NAME BILBY
The first set of Control Stations were placed around 1816 when Thomas Jefferson established the “Survey of the Coast” with the mission to map the eastern coastline of the United States. Since boats were the main method of transportation and how to get goods to the citizens of this new nation, accurate maps were needed to identify rivers, bays, harbors, shoals, light houses and any other navigation aids to keep commerce moving safely.
The only way to make measurements, until GPS was invented over 200 years later, was by direct line of sight. Measuring from hilltop to hilltop was a way to cover large areas quickly, however since the hills and mountains were mostly forested, they needed a way to get above the trees. Lumber was obtained either from the forest itself or purchased at a nearby lumber yard to construct towers. Some towers were constructed over 100 feet tall.
Jasper Bilby (1864-1949), who this trail is named, was a surveyor and geodesist that worked for the U.S. Coast and Geodetic Survey. Jasper (Click Here for more information) saw the enormous amount of manpower and cost to build these towers which were typically left behind, due to the time and manpower to dismantle then transport them to a new location. He noticed the steel windmills used by farmers to pump water and thought he could do something with that. He developed a tower within a tower system, so the survey instrument was on one tower and the operator stood on another. That way as the operator moved around to take readings it did not affect the stability of the instrument. The inner and outer towers were color coordinated and bolting the sections together made assembling and disassembling easier and faster.
THIS STATION
A SPECIAL control station is one that was placed for a unique situation/use. It may or may not also fit into one of the more conventional categories. All stations in the NGS database have a unique two-letter, four-number label known as a permanent identifier or PID as names of stations are frequently repeated. Clicking the link below, after the station name, will take you to the datasheet which has a lot of information about this station.
CHESTERTOWN ME CHURCH SPIRE (PID JV4999) was first observed in 1896 and used as an Intersection mark. The position of this station is determined by sighting the spire from several nearby horizontal marks and the intersection of those sight lines is used to compute the latitude and longitude of the spire. Since the Intersection station can be seen for many miles in all directions it makes a perfect way for determining an accurate azimuth line when sighting it from any horizontal mark within miles of the spire.
THE CACHE
The posted coordinates will take you to the Chestertown ME Church Spire as shown in the picture above and the focus for this BILBY cache.
Please take a picture of the spire with a signature item and post with your log. While this is not required, it shows your appreciation to those many volunteers who helped create the BILBY trail.
To find the information for this cache, go to the waypoint listed and enter the date on that cornerstone into certitude below. There are two cornerstones at the church so make sure you use the date from the cornerstone at the waypoint.
Driving to the final would be recommended but walking is allowed.
You can validate your puzzle solution with
certitude.