Poor health continued to plague Wachsmuth. His doctor recommended outdoor exercise and suggested fossil hunting as a pleasant and healthy pastime. Wachsmuth soon found that the local
limestone formations held an extensive array of the Paleozoic fossil animals known as
crinoids. Eventually, the region would be recognized as one of the world's richest sources of these fossils. By 1865, the grocery business had made Wachsmuth financially independent. He and his wife traveled first to Cambridge, Massachusetts, to visit Agassiz and the
Museum of Comparative Zoology. Next, the Wachsmuths continued on to Europe where they examined museum collections and collected fossils to take home. His last stop was the British Museum in London where he was pleased to learn that the reputation of his collection in Burlington had preceded him. In 1872, Agassiz visited Burlington again and was impressed by the growth of the collection and the quality of the fossils. He purchased the collection for $6,000 and hired Wachsmuth to take charge of the entire crinoid assemblage at Harvard's Museum of Comparative Zoology. Agassiz encouraged Wachsmuth to study the literature on crinoids and publish his own findings. Wachsmuth held this position until Agassiz's death in December, 1873. Wachsmuth traveled to Europe and Asia in 1874, bringing with him a small collection of crinoid fossils which he sold to the British Museum for £80. He returned to Burlington the same year and set out to build another, even larger collection of fossils. With the help of his wife and Frank Springer, the new collection of crinoids soon rivaled any in the world. Because of his health, Wachsmuth spent winters collecting fossils in the warmer climate of the American South. Springer traveled to Europe and brought back an extensive selection of fossils from England, France, Russia, and Bohemia. Other fossils from around the world were purchased or acquired in trade. Wachsmuth built a special, fireproof museum behind his home to store the fossils. In addition a comprehensive library of crinoid literature was gathered. Wachsmuth and Springer published their findings in a variety of scientific journals. They were not interested in naming and describing new species but instead concentrated on issues of morphology and classification. The culmination of their work was the two-volume "Monograph of the North American Crinoidea Camerata" (1897), published by the Museum of Comparative Zoology after Wachsmuth’s death. This work fundamentally revised contemporary crinoid taxonomy. ==Works==