PREFACE. 



When looking over the descriptions of the stratigraphic sections of the 

 Paleozoic formations of China by Baron Ferdinand von Richthofen [China, 

 1882, vol. 2] and their contained Cambrian fossils described by Dr. W. 

 Dames [China, 1883, vol. 4, pp. 1-33] from Liau-tung, and Dr. Emanuel 

 Kayser [pp. 34-36], I was impressed with the necessity of having the strati- 

 graphic sections studied in detail, and extensive collections of fossils made, 

 in order that comparisons of value might be instituted between the Cambrian 

 sections and faunas of the western portion of North America and the Paleo- 

 zoic sections and their contained faunas in eastern Asia. This project was 

 held in abeyance for eighteen years, and had it not been for the support of 

 the Carnegie Institution of Washington it might not have been consummated. 



Dr. Bailey Willis has given, in the preface of volume i, part i, of "Re- 

 search in China," 1907, a brief statement of the events that led to the sending 

 of an expedition in his charge and the securing of data and collections by him 

 and his associate geologist, Mr. Eliot Blackwelder. 



On the return of Messrs. Willis and Blackwelder, I made a preliminary 

 study of the Cambrian fossils and submitted to them the results of the study 

 bearing on the interpretation of the various geological sections in which the 

 fossils occurred. These were included in their description and discussion of 

 the stratigraphy of Shan-tung, Shan-si, and Shen-si. Mr. Blackwelder also 

 made a rapid reconnaissance of the southwestern portion of the province of 

 Liau-tung, Manchuria, and identified certain Cambrian formations, but did 

 not find any fossils. 



From the collections made by Baron von Richthofen, it was evident that 

 a considerable Cambrian fauna existed in the western part of Liau-tung, so 

 I delayed final publication of the description and discussion of the Cambrian 

 collections made by Messrs. Willis and Blackwelder, in the hope that material 

 could be secured from that region. Learning in the spring of 1909 that Prof. 

 Joseph P. Iddings, of the University of Chicago, was about to visit Japan 

 and China in connection with his study of eruptive rocks, I induced him to 

 visit Manchuria and make a collection of Cambrian fossils for the Smith- 

 sonian Institution from the island of Tschang-hsing-tau, east of Niang-niang- 

 kung, in the province of Liau-tung. He was so fortunate as to secure the 

 services of Li San, Dr. Bailey Willis's interpreter, who was also a good 

 collector, and they obtained a large number of specimens, representing over 

 fifty species of invertebrate fossils. 



Wishing to have better illustrations of the species described by Messrs. 

 Dames and Kayser for Baron von Richthofen, I wrote to Prof. W. Branco, 



