8 ANNUAL. REPORT SMITHSONIAN INSTITUTION, 1923 



Tennessee State survey. In 1921 the study and mapping of the 

 Franklin quadrangle, an area of about 250 square miles just south 

 of Nashville, was well advanced, and this year it was brought to com- 

 pletion and data secured for the preparation of a geological report 

 upon the area, to be published by the State. Stratigraphic studies 

 were then undertaken in contiguous areas, in which Doctor Bassler 

 was joined by Doctors Ulrich and Mesler. The classic section at 

 Nashville, in which the proper delimitation of the formations has 

 long been in dispute, was studied with especial care, and large col- 

 lections of fossils were secured to verify the stratigraphic results. 

 Regarding this section, Doctor Bassler says: 



The deep-sea origin of all limestones has long been taught in spite of the 

 trend of evidence that many limestone formations were laid down in shallow 

 seas. The shallow-water origin of limestone is well illustrated in the sec- 

 tion of Ordovician strata exposed near the blind asylum at Nashville, which 

 has been studied by several generations of geologists. At the base of this 

 section is the Hermitage formation, which was evidently formed along ancient 

 shore lines because it is composed of beach-worn fragments of shells and other 

 fossils. Above this comes the Bigby limestone, the source of much of the 

 Tennessee brown phosphate, and which also is made up almost entirely of the 

 comminuted remains of fossils. Next is the Dove limestone, an almost pure, 

 dove-colored, lithographic-like limestone which shows its shallow-water origin 

 in the worm tubes penetrating it and its sun-cracked upper surface. A slab 

 of this limestone a foot thick, now on exhibition in the National Museum, 

 well illustrates the polygonal upper surface and the penetrating worm tubes, 

 both features indicative of the origin of the rock on old mud flats which were 

 periodically above water and thus became sun cracked. The succeeding Ward 

 limestone is of the more typical blue variety, but here the rock is filled with 

 millions of fossil shells which, under the influence of weathering, are changed 

 to silica and are left free in great numbers in the soil. This section is only 

 a portion of the entire geological sequence at Nashville, but it well illustrates 

 the various types of limestone outcropping throughout the central basin. 



EXPEDITION TO EXAMINE THE NORTH PACIFIC FUR SEAL ISLANDS 



Dr. Leonhard Stejneger, head curator of biology in the United 

 States National Museum, was detailed at the request of the Depart- 

 ment of Commerce, to accompany an expedition to Alaska and 

 adjacent regions during the summer of 1922 to ascertain the status 

 of the fur seal herds in the North Pacific Ocean since their protection 

 through the treaty of 1911 between the United States, Russia, Japan, 

 and Great Britain. The first seal rookeries visited were those of the 

 Pribilofs, where the increase in number of seals on the beaches is 

 very remarkable, and Doctor Stejneger predicts a complete resti- 

 tution of the fur seal herd to its former maximum for the not dis- 

 tant future. A new method of stripping the skin from the dead seal 

 and subsequent cleaning of the skin was being adopted on an ex- 

 tensive scale and was found to be a great improvement over the old 

 method. 



