REPORT OF THE CHIEF ASTRONOMER 65 



SESSIONAL PAPER No. 25a 



necessary condition and recalls the observation of McGee, who describes parts 

 of the Gulf of California as being 1 floored with quartz and fresh feldspar sand 

 -washed into the Gulf, during the cloud-burst seasons, from the adjacent arid 

 land* 



In no ca:e is there any evidence of pronounced metamorphism of the sedi- 

 ment. The tendency of metamorphism would be rapidly to increase the grain 

 •of the rock and to obliterate the delicate structure of bedding. The persistence 

 of the extremely fine grain and of thin bedding seems to show that we have 

 "the sediment scarcely more changed from its original state than was necessi- 

 tated in the act of consolidation. 



Fossils. — Very abundant chitinous or calcareo-chitinous plates or films of 

 highly irregular forms were found at a horizon about 975 feet below the top 

 of the Altyn formation. These were seen at only one locality, namely, on the 

 back of the ridge south of Oil City, at a level barometrically determined to be 

 6,875 feet above sea. In the well exposed ledges at that point thousands of the 

 fragments can be readily laid bare by splitting the thin-bedded, silicious dolo- 

 mite in which they occur. At least 200 feet of the series is, at intervals, 

 -characterized by the fragments. In spite of the formless nature of the frag- 

 ments they were at once suspected to be of organic origin and to belong to the 

 pre-Cambrian genus, Beltina, described by Walcott as occurring in the Greyson 

 shales of the Belt mountains in Montana.! A collection of the fragments 

 was sent to Dr. Walcott, who kindly determined them to have the essential 

 features of Beltina danai. The resemblance of the material to that collected 

 at Deep creek in the Belt mountains extended even to the character of the 

 rock. ISTo other species were discovered among the fragments nor did the 

 formation prove fossiliferous elsewhere. At several horizons but particularly 

 in the lowest member of the Altyn, large concentric concretions suggesting 

 Cryptozoon were found but no evidence of their being of organic origin has 

 been forthcoming. 



The Beltina horizon at Oil City must be close to that which had been 

 found by Weller at Appekunny mountain, near Altyn. Reporting on his col- 

 lection Dr. Walcott wrote: — 



' The mode of occurrence of the material is similar to that found in the 

 Greyson shales of the Algonkian in the Belt mountains, Montana. Hun- 

 dreds of broken fragments of the carapace of the crustaceans are distributed 

 unevenly through the rock. Occasionally a segment or fragment of what 

 appears to be one of the appendages is sufficiently well preserved to identify 

 it.'t 



The repeated occurrence of the Beltina bed at three widely separated locali- 

 ties shows their very considerable importance as a horizon-marker in this little 

 known part of the Cordillera. The fossils themselves have intrinsic interest 

 in representing one of the oldest species yet described. 



* W. J. McGee, Science, Vol. 4, 1896, p. 962. 



t C. D. Walcott, Bull. Geol. Soc. America, Vol. 10, 1899, pp. 201 and 235. 

 ? Bull. Geol. Soc. America, Vol. 13, 1902. r>. 317. 

 25a— 5 



