A number of vSpecies included in Chapter 11. have never 

 been described in print, but have simply been illustrated in 

 the "Illustrations of Devonian Fossils/' published in the 

 Palaeontology of New York series. In the case of these species, 

 the descriptions here given w^ere made up from the illustra- 

 tions and explanations of the plates of the above book. 



The localities given for the fossils are those described in 

 Part I. Fossils quoted from West Hamburgh and Ham- 

 burgh-on-the-Lake probably come from Averv's Creek. 



Chapter III. deals with the problems of the distribution 

 and migi'ation of marine invertebrates, and in Chapter IV. 

 a glossary of Palgeontological terms is given. The list of 

 reference works of both general and special character is 

 added in the hope, that it may meet the demand of manv 

 who wish to extend their stucU' be^'ond what is given in the 

 succeeding pages. 



I wish in this place to acknowledge my indebtedness to 

 numerous friends for aid received in the preparation of this 

 guide. In the field-work, I have had the constant and able 

 assistance of my brother, Mr. P. L. Grabau. For special 

 courtesies received in the field I am under obligation, among 

 others, to Mr. A.J. Hutchinson and famih^ of North Evans, 

 to Dr. F. W. Hinckel of Athol Springs, and to Mr. Truman 

 G. Avery of Hamburgh-on-the-Lake. In the preparation of 

 the drawings for Part II., I have received the verv able 

 assistance of Mr. John A. Hutchinson, who made pen and 

 ink copies of all the gastropods and cephalopods, besides 

 numerous other forms. Acknowledgements for assistance in 

 this part of the work are also due Mr. I. C. Hanscom, Miss 

 A. D. Savage and Miss K. B. Wentworth. Unless otherwise 

 stated, the figures of Part II. are reproduced, either directlv 

 or by drawings from the volumes of the Palaeontologv of 

 New York, through the courtesy of the officers of that 

 survey. The use of the plates for the figures in the intro- 

 duction of Part I. was courteously granted by the Massa- 

 chusetts Institute of Technolosfv. 



