392 



SCIENCE 



[N. S. Vol. XXV. No. 636 



GASTBOLITHS 



In a recent article entitled ' Gastroliths ' ' 

 Dr. G. R. Wieland described some highly 

 polished quartz pebbles, that I had shown to 

 him, stating that they had been obtained in 

 Colorado. This is an error. The pebbles 

 came from the same locality as those obtained 

 by him from Mr. Speers.' They were found 

 in the Jurassic or Morrison formation of 

 Montana near the Big Horn Mountains and 

 were near, but not associated with, stegosau- 

 roid dinosaur bones. It is noteworthy that 

 some of these jasper pebbles were dug from 

 the clay in this polished condition, showing 

 conclusively that they had been polished either 

 before or during deposition. Others had been 

 uncovered by erosion. Associated with the 

 polished stones were many of less brilliant 

 colors that were unpolished. 



Mr. R. P. Whitfield informs me that he has 

 seen quartz pebbles as highly polished as these 

 at Spirit or Devil's Lake near Baraboo, Wis., 

 which had been polished by the action of the 

 wind. However, in a collection of wind-pol- 

 ished stones from New Jersey, preserved in 

 the American Museum, all show faces and 

 parallel angles that have been determined by 

 the direction of the wind and position of the 

 pebbles at different times. Some of these 

 specimens are highly polished, but in no case 

 showing the luster of the Montana specimens. 



In the contents of chickens' gizzards I have 

 found that pieces of glass subjected to its 

 action for some time invariably have the edges 

 rounded, while the faces are etched, entirely 

 lacking the former polish. On the other hand, 

 hard quartz pebbles found within the body 

 cavity of a Moa show polish and considerable 

 luster. 



The unusually high polish of the Montana 

 pebbles does not seem satisfactorily explained, 

 either by the action of the wind or pressure 

 of the clays. But, notwithstanding their 

 proximity to scattered bones, there does not 

 seem sufBcient evidence to assume that these 

 stones had been swallowed by dinosaurs as 



• Science, N. S., Vol. XXV., No. 628, pp. 66-67, 

 January 11, 1907. 



"Ibid., N. S., Vol. XXIII., No. 595, pp. 819-821, 

 May 25, 1906. 



were the stomach stones of Plesiosaurs.' 

 There is, however, an example nearly as well 

 established for the herbivorous dinosaur Clao- 

 saurus of the Laramie formation. 



In 1900, while collecting fossils in Weston 

 County, Wyoming, which is a continuation 

 of the Converse County beds, I found a Clao- 

 saur skeleton imbedded in a hard concretion- 

 ary sandstone. In chipping off the surplus 

 stone three rounded well-worn pebbles were 

 found, near the fore legs, embedded in the 

 same matrix. These specimens were preserved 

 and the occurrence made note of at once, for 

 similar stones had not been seen any where, in 

 the deposit. These pebbles are rounded and 

 vary in size, the largest measuring nearly 

 three inches across. They resemble those 

 found with plesiosaur remains and are pol- 

 ished to about the same degree. 



It would be interesting to know what per 

 cent, of acid is contained in the stomach of 

 such birds as the Ostrich and Rhea. 



Barnum Brown 



American Mjuseum of Natural History, 

 February 1, 1907 



SPECIAL ARTICLES 



reconnoisance of a recently discovered 



quaternary cave deposit near auburn, 



california 



It was recently my good fortune to be sent 

 by Professor J. C. Merriam to investigate a 

 cave which had been brought to his notice 

 through Dr. J. C. Hawver, of Auburn, Cali- 

 fornia. Professor Merriam has since visited 

 the cave and has kindly turned his notes over 

 to me. In recognition of Dr. Hawver's vigor- 

 ous prosecution of the work of cave explora- 

 tion in this region we have named the cavern 

 Hawver Cave in his honor. 



Hawver Cave is situated about three miles 

 due east of Auburn, Eldorado County, Cali- 

 fornia. It is in one of several lenses of lime- 

 stone in the Calaveras formation of that re- 

 gion. The trend of the lenses is north and 

 south and the fissures in the limestone extend 

 in the same direction. The entrance of the 

 cave is on the top of the knoll a little south 



'Ibid., N. S., Vol. XIX., No. 501, pp. 184-185, 

 August 5, 1904. 



