In 1892, Cope (then 52 years old) was granted expense money for field work from the Texas Geological Survey. With his finances improved, he was able to publish a massive work on the "Batrachians of North America", which was the most detailed work on the continent's frogs and amphibians ever done, and the 1,115-page "The Crocodilians, Lizards and Snakes of North America".