OSTEOLOGY OF THE ARMOKED DINOSAURIA. 



An inclosure in the above letter shows the quarry to have been located in the 

 northeast quarter of section 5, township 22 north, of range 76 west, Albany County, 

 Wyoming. 



Under the supervision of Mr. Reed, at that time employed by Prof. O. C. 

 Marsh, Quarry No. 13 was worked for the remainder of the season of 1879 and 

 during the summers of 1880, 1881, and 1882. In 1883 further excavations were 

 made under the direction of Mr. J. L. Kenney, and in 1884, Mr. Fred Brown as- 

 sumed charge of the explorations, which were continued uninterruptedly imtil the 

 autunm of 1887, when the quarry was abandoned as exhausted. 



The fossils in Quarry 13 were found in a stratum of sandy clay, as I have de- 

 termined from the matrix still adhering to the bones, and as indicated in the sec- 

 tion (fig. 1) made by Brown. This layer is intercalated between bands of marl 

 or clay, green below and brownish above, all three lying between layers of sand- 

 stone. All are tilted at a considerable angle from the horizontal. The correla- 

 tion of this layer with other fossil horizons in this region of Wyoming is discussed 

 in a previous arti- 

 cle on the Osteol- 

 ogy of Campto- 

 saurus, etc' 



Plan of tvork. — 

 The fossils collect- 

 ed from Quarry 

 No. 13 prior to 

 1882 are now pre- 

 served in the col- 

 lection of the Yale ^'°' 1~^'^<^^'°'* °^ quarry is. made by Mk. Fred brown m 1884. 



University Museum, while the specimens resulting from the later excavations (the 

 expense of collecting having been defrayed by the United States Geological 

 Survey) are in the paleontological collections of the United States National Museum. 

 Rough sketch maps of the quarry were made by Reed, on which he indicated 

 the relative positions of all of the important bones found. Unfortunately only a 

 few of these are now available. Later Brown formulated a more detailed plan of 

 recording the relative positions of the specimens uncovered. The quarry was 

 divided (see fig. 2) into what he designated diagrams, beginning with No. 1 and 

 ending with No. 13. In some cases it is found that one diagram represented a 

 season's work, while in other instances several diagrams were worked out in one 

 year, probably due to the varying number of fossils found in the different sections. 

 The diagrams were subdivided into 2-foot squares and, the maps being platted on 

 the scale of 2 feet to the inch, bones as found could be accurately located on them. 

 Each bone or group of bones (when taken up in one block) was given a quarry 

 number, the bones found in each diagram beginning with number 1 (except 

 diagrams 2 and 3) and continuing serially for all of the specimens in that section. 

 The number being placed on a label with the specimens as well as on the map, the 

 precise position of a bone in relation to those found near it could be quickly and 

 accurately determined when the specimens reached the laboratory. A compilation 



1 C. W. Gilmore, Proc. U. S. Nat. Mus., vol. 36, 1909, pp. 297-301. 



