Large granite boulder positioned on a leafy forest floor. Moss is growing on one side and there is a series of small dots/markings on the boulder surface in a grid pattern
No, I’m not testing #MichiganErratics for allergies. Dots are #SchmidtHammer measurements that reveal the relative hardness of #rock surfaces. Strong rock ➡️ short exposure; weak rock ➡️ long exposure. #geomorphology #geology #geochronology #GreatLakes