It is the object of this Guide to afford help to those students of Natural History who desire to make observations in the Cambridgeshire district.

It is our pleasant duty to acknowledge the assistance we have received from many willing helpers in preparing the Guide.

In the first place we wish to tender thanks to the various authorities on the different subjects who have without remuneration written the articles included in the book.

To the Editors and Publishers of the Victoria History of the Counties of England we owe our thanks for the article on the Vertebrate Palæontology of the County which was written by Mr R. Lydekker for the County History of Cambridge, and is here allowed to appear in advance. We are also indebted to them for the use of other materials acknowledged in the body of the work.

The Geological Map of the County was kindly made by Mr H. H. Thomas, M.A., of H.M. Geological Survey. Our thanks are due to him and also to the Controller of H.M. Stationery Office, who has permitted us the use of the topographical details inserted on the map of H.M. Ordnance Surveys (4 miles to the inch), and of the Geological lines which are taken from the maps of H.M. Geological Survey. The map has been prepared at the Office of the Ordnance Surveys, Southampton.