1866
Helmut Petschler & Company, 1864
Helmut Petschler & Company, 1865
Helmut Petschler & Company, 1866
Helmut Petschler & Company, 1860
![Study of Ferns on the Limestone Rocks. [Derbyshire]](https://media.getty.edu/iiif/image/083e8dd3-0cf4-4e7c-b7a9-1d0f4af21609/full/843,/0/default.jpg)
