Vll 



PROLOGUE 



The day was calm. The waves that lapped the shore were small, 

 almost lazy; they were the waves of shallow waters, not of the open 

 ocean. A ruddy sun shone in the hazy sky. The slow stream that 

 came down to the foreshore rippled a little in the light wind, and the 

 pebbles tumbled here and there without much energy. Drama was 

 not wholly absent, for along the skyline all but lost in the distance 

 were two or three volcanic cones. They were quiet just now, but a 

 walk along the beach would soon bring a traveler to a stretch of all 

 but impassable lava, where once, not so long back, the molten rock 

 had oozed and hissed into the waters from an inland fissure. It would 

 happen again, but no one could foresee just where and when the 

 encounter would take place. 



The day was calm and the scene was lonely. The beach was 

 devoid of shells. No flies buzzed; nothing at all hopped or crawled 

 along the water's edge. No birds flew; no fish swam in the sea; 

 no clawed creatures scuttled below the tidal waters. The rocky 

 lands inward from the sea were utterly barren of life. Neither lizards 

 nor mice could be found, and neither a tree nor a blade of grass 

 spread green blades to the sunshine. Yet life was present, even 

 abundant, in the scene. It grew everywhere that the shallow waters 

 brimmed out to dry land: dense knobs and sheets of algae and bac- 

 teria covered all the shallows, out into the bay and up the stream 

 toward the higher lands. That life was never out of touch with 

 water; it never survives higher than a matter of inches from moisture. 

 Inland, here and there, a few dry old knobs could be found, quite 

 whitened, rocklike — a growing mat of the only life in this quiet 

 land, stranded forever by some shift in the watercourse. 



Modem structures formed by microbial mats found in 

 Australia are analogous to structures formed by ancient 

 microbial mats billions of years ago in a similar environment. 



Photo courtesy of J. W. Schopf 



