INTRODUCTORY REMARKS. iii 



Dr. Fr. Maurer, Mrs. Robert Gray, and Mr. R. Etheridge, junr. To Professor 

 Schliiter, in particular, my best thanks are due for the help which he so freely 

 accorded to me in studying the original types of Goldfuss and Bargatzky, and in 

 collecting Stromatoporoids from the Devonian deposits of Germany. I am, 

 further, deeply indebted to the kindness of my friend, Magister Friedrich Schmidt, 

 who conducted me over the Silurian districts of Esthonia and Oesel, which his 

 own researches have rendered classical ground, and who assisted me in examining 

 in the University of Dorpat the originals of the Stromatoporoids described by 

 Baron von Rosen in his well-known treatise on this group of organisms. 



With regard to the general plan of the Monograph, it is sufficient to say that 

 the first portion will be devoted to a general survey of the entire group of the 

 Stromatoporoids, as far as such a survey seems to be at present possible ; while the 

 second and concluding portions will deal solely with the descriptions of the British 

 species. I may add that I have made no attempt to deal in any way with any 

 but the Palasozoic forms of the Stromatoporoids. There are certain Mesozoic and 

 Kainozoic fossils which will, in all probability, ultimately find a place in this 

 group, but no sufficient material has been available to me for the investigation of 

 these. 



The plates and wood engravings of this, the first instalment of the work, have 

 been drawn from the specimens and slides by myself ; and I take this opportunity 

 of expressing my sense of the accuracy and beauty of Mr. Hollick's reproductions 

 of my drawings upon the stone. In preparing the figures illustrative of micro- 

 scopic structure, I have been in many cases greatly assisted by an excellent series 

 of micro-photographs ; and I am much indebted to Mr. George Gellie, of Aberdeen, 

 for the care and intelligence with which these have been executed by him. 



