Cambrian in age. That means that 

 these animals lived at the beginning of 

 the first of the geologic periods whose 

 rocks enclose more than the merest 

 traces of the presence of life on earth. 

 Such hoary antiquity in itself gave these 

 fossils an added importance. 



But more was to come. As continued 

 field work built up the collections from 

 the Ediacara Hills, geologists reviewed 

 the evidence for assigning an Early 

 Cambrian age to the fossils. Beneath 

 the jellyfish-bearing bed are nearly two 

 thousand feet of Pound quartzite with 

 no fossils aside from a few worm bur- 

 rows down near the base; above it, this 

 formation continues for a hundred feet 

 with no fossils, and is followed by about 

 450 feet of barren Ajax limestone before 

 the next fossil-bearing layers are en- 

 countered. Those higher fossils, how- 

 ever, are brachiopods and spongelike 

 archaeocyathids similar to fossils recog- 

 nized elsewhere as being earliest Cam- 

 brian in age. Therefore, some of the 

 investigators reasoned, Spriggia and its 

 associates must be even older than sup- 

 posed, and thus of pre-Cambrian age. 

 Now throughout the world there are a 

 few occurrences of pre-Cambrian fos- 

 sils, but they reveal very little of the life 

 of those times. If the Ediacara fossils 



$ai 



Like heel-marks in a velvet carpet, impressions of delicate extinct 

 jellyfish dot the surface of this piece of ancient quartzite (silici- 

 fied sandstone) from the Ediacara Fossil Preserve in South Aus- 

 tralia. The undulating surface of the rock reveals the ripple- 

 forming action of gentle waves lapping upon a Cambrian beach. 



are indeed pre-Cambrian, they are in- 

 comparably the best fossils from that 

 ancient time. At present, however, 

 some geologists date the deposit as Early 

 Cambrian, while others date it as pre- 

 Cambrian. 



In May 1958, Sprigg's original local- 

 ity and a patch of the surrounding coun- 

 try were set aside as the Ediacara Fossil 

 Reserve, under the control of the Aus- 

 tralian Minister of Education and of the 



South Australian Museum. With the 

 cooperation of these authorities, the 

 specimen discussed here was secured last 

 year by a Chicago business man, Mr. 

 Victor D. Oakley, while visiting in Aus- 

 tralia, and was recently presented by 

 him to the Museum. Following the 

 usage of both the American (1956) and 

 Russian (1962) Treatises on fossil inver- 

 tebrates, we have catalogued the speci- 

 men as Cambrian. 



AUGUST Page 7 



