RECORDS. 671 



odon were found, the latter serving as nuclei for large concre- 

 tions. The search for skeletons was no longer confined to the 

 bluffs, but chiefly directed to the level grass lands below. 

 Quarries have been plotted in detail, during this excursion, for 

 exact location of bones hitherto discovered. On the slopes of 

 . the Freeze-out Mountains, fine outcrops of underlying Trias 

 were recognized, in probable substantiation of Professor Marsh's 

 conclusion as to the existence of the Jurassic below. 



He also described the mode of occurrence of the mastodon 

 recently found by a German, while digging in his market garden, 

 three miles back of Newburgh, N. Y. The skull was first 

 found and was injured by the excavator ; afterward the tusks, 

 backbone, scapula and pelvis, but no limb bones. The associa- 

 tion of many stems, gnawed by beavers, indicated the probability 

 of a series of dams, which successively caused a rising of the 

 waters and the deposit of the layers of humus, etc., over these 

 bones. 



Professor Dodge gave a preliminary account of his work 

 at Pueblo Bonito, New Mexico, during the summer. The object 

 of the work was to find evidence concerning the antiquity of 

 the Pueblo ruins in the Chaco Cafion. The evidence to be ob- 

 tained from the deposits on which the ruins are situated, seems 

 to indicate a very long occupation of the country previous to the 

 desertion of the ruins. 



Doctor Julien discussed the common distribution of opal 

 or hyalite ; the exclusively recent character of all existing occur- 

 rences of this mineral, in seams, veins and contact deposits ; its 

 transitional and unstable character and ready passage into more 

 permanent forms of silica; its apparent survival in small propor- 

 tion in the soluble pait of chalcedony and its varieties ; the 

 probability that some of the known geological aggregations of 

 amorphous silica (chert, hornstone, etc.) were not deposited as 

 such, but originally in the form of opaline silica ; and the office 

 of this diffused mineralizer in the silicification of fossils. 



Mr. Kunz described his recent visit to the ancient locality 

 of jade (nephrite) at Jordansmiihl, near Breslau, Germany, 

 with the special object of study of the minerals associated with 



