When walking through a field on our property the morning of Sunday, September 7, 2014. The circles appeared sometime between 6:30 p.m. Friday, September 5, 2014 and 10:30 a.m. on Sunday, September 7, 2014.There are 8 8ft circles in circumference and 7 13ft circles in circumference. There are also several half circles, that would be of the same size. Many of the circles intersect. The circles were in the lower of two fields close to a creek. (There are two fields near each other. The field that was at a higher elevation and had power lines overhead was not touched.)The vegetation does not appear to be damaged. It wasn't crushed or uprooted. The circles appear as dark very fine powder like material. There isn't a noticeable odor associated with the substance. The substance can be brushed off the vegetation. Samples of vegetation with the substance were collected along with vegetation without the substance. We checked the area again on Wednesday, September 10, 2014. There doesn't appear to be any change in the circles with the exception that they did not appear as dark and pronounced. (Could be due to growth of vegetation.)Digital photos, taken on Wednesday, September 10, 2014 is attached. We also have digital photos and digital videos taken shortly after the circles were found however we have not uploaded the first photos yet. We spoke to a few people with history in the area and no one has seen or heard anything like this previously.