198 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



The most serious difficulty in the proper study of the type-specimens 

 was due to their hick of preparation. It is hoped, however, that in 

 the text and figures presented here a little has been added to our 

 conception of a form long neglected. 



I take this opportunity to express my appreciation of the assist- 

 ance given me during the preparation of this paper. To Dr. George 

 P. Merrill, head curator of the department of geology, U. S. National 

 Museum, I am first of all indebted for making possible the arrange- 

 ments for the preparation and study of this material, and I gratefully 

 acknowledge the many privileges extended ; to Prof. Charles Schu- 

 chert, of the Yale University Museum, I am under obligations for 

 the generous manner in which he placed at my disposal the types and 

 all other camptosaurian material contained in the collections under 

 his charge. I also wish to thank Prof. E. 8. Lull, of the same insti-, 

 tution, for courtesies extended during my visit to New Haven. For 

 the privilege of studying material and assistance rendered, I am 

 grateful to Dr. W. D. Matthew and Mr. Barnum Brown, of the 

 American Museum of Natural History, New York. I am also in- 

 debted to Mr. Norman Boss, of the U. S. National Museum, for effi- 

 cient assistance in the preparation of material, and to Miss M. W. 

 Moodey in the final preparation of the manuscript. 



HISTORY OF THE DISCOVERY OF QUARRY NO. 13. 



With the specimens upon which the present paper is based were 

 found many of the original field labels, on which the locality is given 

 as " Quarry No. 13 or No. 13^, 8 miles east of Como, Wyoming." A 

 brief history of the discovery and methods employed in working this 

 important deposit of fossil remains is here given on account of the 

 perfection of many of the specimens found in the quarry. It has 

 furnislied the holotypes of Camjjfosavrufi dispar, C. nanus, and the 

 allied forms, Dryosaunis alius, besides a vast quantity of other 

 material, chiefly pertaining to the Stegosaurida?, among which are 

 the holotypes of Stegosaurus sideatus and Dimcodon latieeps.^ In 

 response to an inquiry made of Mr. W. H. Reed, of Laramie, Wyom- 

 ing (the original discoverer), as to the history of the discovery of 

 this deposit of fossils, he Avrites: 



In August, 1871). I t'ouUl see the end of quarry No. 10, where the type of 

 Brontosdirnis crcclxiis Marsli was found, so I took one of my men, Mr. E. G. 

 Ashley, and we started out east from the niahi bluff (or Como-bluff). On the 

 fourth day of our search, in the afternoon, being in the lowest of the .Jura bone 

 horizon, we found some hollow bones in the wash and soon after discov- 

 ered the quarry. The first bones to be taken u]) was a nearly complete skeleton 

 of AUosauru>!. After this skeleton had been taken out, we found large quan- 



« Prof. R. S. Lull informs me that the holotypes of Coelurus fragilis and 

 Morosaiu-iis lent us also came from this quarry. 



