8 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1921. 



surface there were 285 feet (86 meters) of a yellowish weathering 

 magnesian limestone, named the Ghost River formation, which 

 represents the great interval between the Cambrian below and the 

 Devonian above. Sixty miles to the west, over 4 miles in thickness 

 of limestone, shales and sandstones occur in the break in sedimenta- 

 tion of Ghost River cliffs. 



Returning to Bow Valley, the party left the Canadian Pacific 

 Railroad at Lake Louise and went north over Pipestone Pass to the 

 Siffleur River, which is tributary to the Saskatchewan. In the north- 

 ward facing cliffs, 25 miles (40 kilometers) east of the Glacier Lake 

 section of 1919, and 40 miles (64 kilometers) north of Lake Louise, 

 a geological section was studied that tied in the base of the Glacier 

 Lake section of 1919 with the Middle and Lower Cambrian forma- 

 tions. Returning up the canyon valley of the Siffleur River to the 

 wide upper valley of the Clearwater River, a most perfectly exposed 

 series of limestones, shales, and sandstones of Upper Cambrian and 

 later formations was found, which cleared up the relations of the 

 upper portion of the Glacier Lake section to the Ordovician above. 



The work was considerably handicapped by forest fires in July 

 and August and by unusually stormy weather in September. 



PALEONTOLOGICAL FIELD-WORK. 



Dr. R. S. Bassler, curator of paleontology, National Museum, suc- 

 ceeded during the year in securing for the Museum's collections two 

 much-desired specimens, one a large well-preserved fossil elephant 

 skull formerly exhibited in Cincinnati, the other a highly fossilifer- 

 ous limestone slab of Silurian age quarried out by him near Oxford, 

 Ohio. Such a slab has long been desired to show the advancement 

 in life from the primitive Cambrian forms, represented in the large 

 Cambrian sea-beach sandstone exhibit, to the higher and more com- 

 plex species of succeeding geological periods. Notwithstanding the 

 numerous occurrences of fossiliferous limestone of Ordovician and 

 Silurian age, it was not until the past year that a layer affording 

 slabs of suitable size and sufficient perfection of preservation was 

 brought to the attention of the Museum. Numerous large blocks of 

 stone had to be removed before the real task of quarrying the de- 

 sired slab was begun. The work was successfully accomplished with 

 the generous assistance of Dr. W. H. Shideler, professor of geology 

 at Miami University, Oxford, Ohio, who first located the specimen, 

 and before the close of the year this valuable educational exhibit was 

 installed in the hall of invertebrate paleontology. 



At the conclusion of this work Doctor Bassler proceeded to Chicago 

 for the purpose of securing casts of type specimens of fossils in the 



