NO. 12 



SMITHSONIAN EXPLORATIONS, I917 



the round white spots), six broad ribs, and a large tail. Branchiae 

 or gills shine through the thin shell as well as traces of the leg's. 

 Another curiotis form, figure 5, is a soft-bodied holothurian with 

 many flexible podia or false legs. A small, roimd shell hai)pened to 

 rest on the sea bottom just where the head part of the animal was 

 later pressed down upon it. Another soft-bodied form is Portalia 

 uiira (figs. 6 and 7), wdiich is related to the sea cucumber or Holo- 

 thurian which may be seen growing on the sea bed at Catalina Island, 

 California. The shale bed at the cjuarry suggests that the waters 

 of the acient Cambrian sea above it swarmed with life just as the 

 ocean does to-day at Catalina Island. But this was long before the 



Fig. 10. — Granny, the mountain squirrel. Frequently showers of hroken 

 rock and dirt were thrown by the blasting all about the place where Granny 

 was sitting, but she invariably dodged under protecting slal)s and appeared 

 soon after as unconcerned as though nothing had happened. Photograph by 

 Walcott, 1917. 



advent of fishes on the earth so there were no fish, and no traces 

 of them occur in the fossil bed. The superb preservation of the 

 fossils at the quarry is all the more remarkable when we consider 

 that they have been buried for twenty million years or more and 

 subject to all the vicissitudes that rock materials experience from the 

 time that they are simply hardened mud buried beneath thousands 

 of feet in thickness of layers of mud, sand, and pebbles. Then all 

 were changed by pressure and chemicalization into solid beds of 

 sandstone, slaty shale, and limestone. These were later compressed 

 and elevated into motmtain ranges and more or less worn away by 



