12 SMITHSONIAN INSTITUTION 



crowns, as in the recent discovery, they are more or less fragile, flattened, or 

 broken. This means that in the former case the bulbs, with the crowns and 

 stems swept away by currents, were left resting in the mud, where they 

 remained but little disturbed during fossilization until the organic soft parts 

 were replaced and the cavities filled by limestone or silica, like those of shells ; 

 while in the latter they were distorted or broken by the weight of the other 

 remains piled upon them before they had time to solidify. 



Upon the evidence of all these new facts, I think it may be considered that 

 our knowledge of the bodies called Camarocrinus is advanced to the extent of 

 proving that they belong to the genus Scyphocrinus, of which they formed the 

 bulbous distal end of the stem, having the functions of a root, and fixing the 

 crinoid habitually to the sea bottom. 



After the first draft of this paper had been read before the Paleonto- 

 logical Society in December, 1912, and the first six plates to illustrate it pre- 

 pared, I learned from Dr. August Foerste that he had found some other crinoid 

 remains associated with the Camarocrinus at one of the Hardin County locali- 

 ties mentioned in his paper of 1903, before referred to/ and he very kindly 

 sent them to me for examination. They proved to be fragmentary specimens 

 of two or three species of Scyphocrinus. As this is the region from which the 

 type of Scyphocrinus pratteni was probably derived, and as the Camarocrini 

 collected by Dr. Foerste were in an unusually fine state of preservation, this 

 occurrence suggested the possibility of further discoveries, and I decided to 

 defer publication until I could have the territory carefully examined, in the 

 hope of obtaining better material for the illustration of the Tennessee species. 

 For this purpose I was so fortunate as to secure the cooperation of Prof. W. F. 

 Pate, of Kentucky, who had in former years made some remarkable collections 

 for me in the Tennessee Silurian ' and whose intimate acquaintance with the 

 Silurian and Helderbergian formations of that region renders his assistance 

 especially valuable. He spent nearly a month during the summer of 1915, and 

 further time in 1916, chiefly in Hardin County, with extraordinary results. 



Mr. Pate readily identified the Camarocrinus horizons mentioned by 

 Foerste" at localities on Horse Creek and at Pyburn's Bluff, and traced the 

 finely preserved specimens to the layer producing them — a great bed filled with 

 Camarocrinus, but no other fossils except a few adhering to the bulbs. This 

 layer is composed of a rather friable, highly siliceous clay, interbedded among 

 a series of white limestones, and is the mud bed in which the bulbous roots once 

 rested on the sea bottom. Here the Camarocrinus occurred in great numbers, 

 firm, rotund, showing the irregularly plated surface of the bulbs in nearly their 



1 Journal of Geology, voL II, p. 683. 



* The Late Niagaran Strata of West Tennessee, Pate and Bassler, Proc U. S. National Museum, 

 vol. 34, p. 407, 1908. 



*Op. cit., pp. 682-685- 



