The Devonian rocks of western Ontario yield new fossil discoveries. This work by Henry Alleyne Nicholson details newly identified fossil specimens found within the Devonian geological strata of western Ontario. It focuses on the classification and description of these paleontological finds, contributing to the understanding of ancient life forms present in the region during that geological period. The text likely presents detailed anatomical descriptions and comparative analyses with previously known species.

This specialized monograph likely serves as a foundational text for paleontologists and geologists focusing on the Devonian period and the fossil record of North America. Its detailed descriptions and classifications would be essential for researchers in the field, providing critical data for further study and comparative analysis. The work's value lies in its specific contribution to the scientific understanding of ancient ecosystems and evolutionary history.