32 BULLETIN 16 9, UNITED STATES NATIONAL MUSEUM 



material was unusually abundant but so disintegrated as to have 

 little value. Dr. Gidley dug in along the bone stratum until firmer 

 material was found in place, made a good collection from this bed, 

 and thus started the quarrying operations that Silberling and others 

 have continued intermittently ever since. Mr. Silberling's opera- 

 tions for the National Museum, resulting in the bulk of the collection 

 here described, consisted in stripping and working out an area of 

 about 1,400 square feet (a very rough estimate). The other important 

 operation, that of the Third Scarritt Expedition in 1935, extended 

 over an area of about 1,750 square feet (also a rough approximation, 

 as the area was irregular and not all uncovered at once). 



The quarry consists of two cuts, one north and one, of smaller size, 

 south of the coulee and original surface exposure. The material 

 collected by Silberling was carefully labeled as to the cut from which 

 it came, but in this study there was found to be no significant differ- 

 ence between the two parts of the collection, and it is all treated as 

 a unit. The greater part of the worked-out area has been filled in 

 again in later stripping, and the cuts left open weather and fill rapidly, 

 so that the form of the quarry is not apparent in the field. The north 

 section has probably been about worked out, except for a probably 

 very rich corner left under heavy overburden. The south section 

 was still rich along the margin as left in 1935 and probably would 

 produce over an area of at least 1,000 square feet, and possibly 1,500, 

 before the bone layer ran out into the hillside, so that the locality 

 as left in 1935 is, as far as such things are predictable, still capable of 

 producing another collection about as large as either of the two so 

 far made there. The quarry has so far produced about 800 good 

 identifiable mammal specimens and perhaps 1,500 single teeth and 

 other unimportant fragments. 



The areal distribution of the fossils is very erratic and patchy. 

 In places it is possible to work for 1 or 2 days without finding any 

 jaws, and in others one man can collect ten or more jaws in a day. 

 In general, however, the fossils seem to be distributed in an elongated 

 area, about 5 to 20 feet in width, usually nearer the smaller figure, 

 and with a tested length of at least 150 feet, which probably will 

 continue to a much greater distance. The general trend is north- 

 northeast to south-southwest. 



In many places the fossils are concentrated in a single and fairly 

 well defined layer an inch thick or even less in which fragments of 

 bone may be so numerous as nearly to make a bone-bed. This 

 material is, however, very fragmentary, and good jaws are exceptional 

 in it. In other places the bone layer is less definite, and the fossils 

 are scattered more sparsely but generally in better preservation through 

 a thickness of about a foot, or up to about 18 inches at most. Oc- 

 casional fragments are found in the nearly barren material above and 



