This is the dataset used in a research paper "Extraction of stratigraphic exposures on visible images using a supervised machine learning technique". The content is Augmented images used in the U-Net training (aug_images.zip) train/*.png: augmented original images (14,219 files) train_masks/*.png: augmented hand-masked images (14,219 files). Note that original images include images obtained using google-image-download, a Python script published on GitHub (https://github.com/Joeclinton1/google-images-download/tree/patch-1, Copyright © 2015-2019 Hardik Vasa). The whole images we obtained by google-image-download were labeled as noncommercial reuse with modification. For more details, please refer to a research paper "Extraction of stratigraphic exposures on visible images using a supervised machine learning technique". Correspondence: Rina Noguchi (r-noguchi@env.sc.niigata-u.ac.jp)