Abstract
Many millions of geological specimens are contained in geological museums throughout the world. These collections, some of which date back to the sixteenth century, constitute a rich resource for historians of the geological sciences. The utilization of this resource has been uneven, due to a number of factors, including the background of the researcher, and the state of the collections. In the past two decades major strides have been made in the documentation of collections held in British museums, and compendia, including those for collections in other countries, are now available. Geological collections provide quality primary source material, and can shed light on a range of interesting topics including the nature and scope of geological travels, the often complex relationships between geologists and collectors, and the rationale behind the formulation of geological theories by earlier geologists.