INDIAN STONE IMPLEMENTS. 483 
produced by land plants, as yet altogether unknown to us. 
If the Palzeozoic was the age of Acrogens, the Eozoic may 
have been that of Anophytes and Thallophytes. Its plants 
may have consisted of gigantie mosses and lichens, present- 
ing us with a phase of vegetable existence bearing the same 
relation to that of the Palæozoic which the latter bears to 
that of more modern periods. But there is another and a 
more startling possibility, that the Laurentian may have been 
the period when vegetable life culminated on our planet, and 
existed in its highest and grandest forms, before it was 
brought into subordination to the higher life of the animal. 
The solution of these questions belongs to the future of 
geology, and opens up avenues not merely for speculation, 
but also for practical work. 
The above must be regarded as merely a Ne of the 
present aspect of the subject to which it relates. Details 
must be sought elsewhere. — Nature. 
INDIAN STONE IMPLEMENTS.* 
BY J. J. H. GREGORY. 
THE stone selected for arrowheads and tomahawk points, 
was, as a rule, very hard in its nature, compact in structure, 
and fine grained, presenting a conchoidal fracture when bro- 
ken. In the valley of the Connecticut these conditions were 
satisfied by a variety of hornstone, along the sea coast in 
the porphyry. In each of these localities I have found some 
arrowheads made of jasper, some of white granular quartz, 
and occasionally one from slate, but the greater propor- 
tion of these are collectively small, though it is evident 
Mii ptr deir qn on the Stone used by the Indians within the limits s Eee er 
in the manufacture of their a with some remarks on the ess of man 
facture, Se at the Troy meeting of the American Association for the signum 
of Science, 
