The Snake and Red & White Roadcuts
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
Between Canton and Dekalb Junction, there are two roadcuts on NYS Rt 11, exposing several rounded "gneiss knuckles". Easy access, and you can drive close. Use caution when parking beside the road, there is no need to go on private property. Do not climb the rocks,as there may loose footing or ice in the winter.
Between Canton and Dekalb Junction on Route 11, there are seveal smoothly rounded "gneiss knuckles" that are characteristic of the Lowlands Adirondacks landscape. Really elongate low ridges that trend northeast-southwest, these hard rock barriers have exerted strong control over drainage trends. Major rivers, like the Oswegatchie, that drain across this region from the highlands, are forced to zig and zag between the ridges on their way to the St. Lawrence; tributaries to them are channeled in a similar manner. Many of the intervening valleys are underlain by marble, which is less resistant than the gneisses and is therefore poorly exposed. In addition to drainage control, this northeast structural "grain" has influenced human development; US 11, for example, runs parallel to it because it is easier and cheaper to build a road that way. The route is part of the Old Military Turnpike.
There are many excellent roadcuts south of Canton. The large "Snake" roadcut, is whitish marble 4.2 miles from Canton, shows, on the southeast side, a thin interlayer of feldspathic rock that has been sinuously infolded with the marble, so that it looks like its namesake. The Snake probably originated as a flat-lying layer of volcanic ash deposited with the parent limesotne of the marble, in a marine environment that existed perhaps 2-3 billion years ago. Subsequent Grenville metamorphism, 1.1 billion years ago, converted the rocks to their present crystalline state and caused the intense deformation shown here. The Snake effectiely delineates the folding style of the marbles, which is decidedly plastic as opposed to brittle. Adirondack marbles like this often contain bands of thinly interlayered silicate rocks that illustrate just how complex deformation can be. The silicate layers weather in relief and are usually rusty, or they contrast sharply with the whitish, recessively-weathered marble in between.
Several more excellent roadcuts are between Dekalb Junction and Richville (9 miles). One of the most dramatic is the Red and White cut 4 miles south of DeKalb Junction. Really comprising several cuts on both sides of the road on a long, gradual hill, the white is Precambrian marble, and the red is iron-stained conglomerate and sandstone, all assigned to the basal Potsdam sandstone. Contacts between the marbles and the sedimentary materials are irregular, the sediments have a dumped appearance, and there are blocks of marble in them. These and other features leave little doubt that the sandstone is one of the sinkhole fillings so common in the marbles of the Lowlands Adirondacks. Apparently most of the Precambrian bedrock of the Adirondack region was eventually blanketed with sandy and conglomeratic sediments during its immersion in the Potsdam Sea; thick pockets occur wherever a solutional topography of sinkholes and caves had previously developed in marbles. Doming of the Adirondacks has since stripped the sandstone cover, except in pockets like this near the St. Lawrence Lowlands.
Roadcuts at the south end of the Richville bypass, 10 miles south of Dekalb Junction display similar features, with brick red conglomeratic rocks on the west and marbles on the east. These and other cuts a short distance south of the bypass also contain reddish conglomeratic dikes, where the orginal, water-saturated sedimants filled narrow fractures in marble.
To log his Earthcach you must post a picture of you with your GPS with the Roac cut in the background and email the answer to the following questions: 1. Are there shrubs, small trees or grass growing from the cut on either side of "The Snake"? 2. I On which side of the road is "The Snake" most conspicous? (send a Photo with your GPS and your choice) 3. What other colors are found in cut at "The Snake"? 4. What could be a better description of the "Red & White" cut?
Between Richville and Gouverneur, the gneiss ridge-marble valley topography is especially well-developed. In Gouverneur, note the several buildings constructed of gray, rough-hewn Gouverneur marble, an extremely popular stone and architectural style throughout the North Country during the 19th century. In some buildings, Potsdam sandstone is used as decorative trim, giving a striking gray-red pattern to the stonework.
In Gouverneur, you pass over the Oswegatchie River, which follows a remarkable course downstream, its path involving a series of hairpins controlled by the distribution of hard and soft rock. The river has been forced to follow a tortuous 27-mile course to advance just 4 miles northwest toward the St. Lawrence River.
Additional Hints
(No hints available.)