984 The American Naturalist. [November, 
land, Sweden, Wales and Bohemia. But they have likewise 
been collected in Massachusetts, Georgia, Alabama and Tenne- 
ssee on the Atlantic side of North America, and from British 
America, Utah, Nevada and California on the Pacific side. 
They have also been found in France, in Sardinia,and in Russia, 
while fossils of the immediately succeeding middle and upper 
zones occur in all these places and in India, China, Australia 
and South America. It would thus appear that at a very 
early period in the history of the earth, the faunas then living 
had an almost world-wide distribution. There is, however, 
little to be wondered at in this, since it is probable that the 
conditions of existence at that early day were very uniform. 
Fig. 12. A group of Lower Cambrian Trilobites (much reduced). 
3 What these conditions were in other countries besides 
-= Europe and North America can not be stated, since the rocks 
_ in the more remote places have not been studied with the 
