This is the revised version of the fossil specimens image dataset.
Previous version: 1550 image files in 5 folders. 
Total: 6.41GB
See: Xu, H.-H.: High-resolution images of 1550 Ordovician to Silurian graptolite specimens for global correlation and shale gas exploration. https://doi.org/10.5281/zenodo.5205216. 2021.

In this revision:
There are 2951 fossil specimen images. Every specimen has two photos, one is original, another shows specimen with a scale bar. Occasionally in some large image the scale bar is embedded and beside the fossil specimen. 
All in JPG format. Single JPG file ranges from 822 KB to 7.055 MB. 
Total :10.4 GB.
All specimens were collected in 1958-2020 

Example: 
The file name: ‘9721Cardiograptus_amplus_S.jpg’, ‘9721’ is the specimens number, ‘Cardiograptus_amplus’ means species name is ‘Cardiograptus amplus’, with ‘_S’ means it is a photo with scale bar. In all scale bar, the minimum unit is millimeter. 


Author and contact: 
Hong-He Xu
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
39 East Beijing Road, Nanjing, 210008
China
E-mail: hhxu@nigpas.ac.cn