DENDROID GRAPTOLITES OF HAMILTON, ONTARIO. 3 



of the various collections of Hamilton, Ontario, graptolites was 

 necessary. This restudy resulted in the suppression of a number of 

 Gurley's manuscript names and descriptions, which in themselves 

 gave evidence that they did not represent the author's final judgment. 



But few of the specimens in the national collection were labeled 

 so that they could be assigned to their proper species without further 

 study. Fortunately, in many instances the illustrated specimens 

 were numbered and mentioned by number in the manuscript. Speci- 

 mens in the collections of the New York State Museum and the Walker 

 Museum of Chicago University, kindly loaned by the authorities of 

 these respective institutions, proved to be better supplied with labels, 

 and the study of them helped greatly in the identification of the 

 species. 



A few words in connection with the preparation of the accom- 

 panying illustrations may be of some interest. Doctor Gurley's 

 drawings were prepared by first inking in the graptolite as seen on 

 ordinary blueprint photographs of tlie specimens, and then bleaching 

 out the background. This method, although satisfactory in many 

 cases, did not give good results with poorly defined specimens, so in 

 the additional illustrations which Avere made the following method 

 of procedure was used : The objects were first treated to a thin coat 

 of French retouching varnish, which brought out the details of even 

 the poorest material fairly well. Specimens so coated are in ex- 

 cellent shape for study, but on account of the reflection of light from 

 the slightly polished surfaces, do not lend themselves well to pho- 

 tography. This difficulty Avas overcome by photographing the speci- 

 men immersed in water. 



The wonderful fauna of dendroid graptolites at Hamilton, Ontario, 

 has been collected with untiring enthusiasm by Col. C. C. Grant, 

 to whom science is indebted for the discovery of many new species. 

 Colonel Grant has published interesting popular accounts of the 

 geologic features at Hamilton in the Journal and Proceedings of 

 the Hamilton Association, and has likewise figured, without descrip- 

 tion, some of the more interesting graptolites. Up to the present 

 time the description of these forms has been mainly from the pen of 

 Prof. J. W. Spencer, whose articles upon the subject are noted in the 

 bibliography of the species beyond. More recently Doctor Ruede- 

 mann has described the Xiagaran forms occurring in New York. 



In the present article I have endeavored to carry out Doctor Gur- 

 ley's plan of publishing complete descriptions of these dendroid grap- 

 tolites. For this reason the original descriptions of Spencer and 

 others are inserted whenever they have been thought to add to the 

 completeness of the work. Likewise all of the species have been illus- 

 trated, either by copies of the original figures or by additional draw- 

 ings and photographs, and in some cases by both. 



