14- The Ohio Journal of Science [Vol. XIX, No. 1, 



and possibly the second stages) : first, the patch plants ; secondly, 

 the Coriaria; thirdly, the Aristotelia, with possibly Fuchsia 

 and Melicytus; fourthly, forest. 



"If the above list of the plants collected be analyzed, 

 it will be seen that of ninety-one species observed on the 

 isolated northwestern face, twenty-four (or 26 per cent.) may 

 be called bird-distributed, fifty-three (or 58 per cent.) wind- 

 distributed, and only fourteen (or 15 per cent) are difficult to 

 account for." 



THE GREAT PUMICE AREA OF NEW ZEALAND. 



Another region, whose revegetation must have been more 

 similar to the Katmai district than any of those yet mentioned, 

 is an extensive area in New Zealand which was covered with a 

 heavy deposit of ash and pumice by some prehistoric eruption. 

 Revegetation has already occurred over this country, which has 

 largely grown up to bushland or even to forest. A study of 

 this area should throw much light on the processes by which 

 the raw mineral ash is converted into soil. Such a study is 

 not yet available, but the difficulties encountered by the 

 colonists in attempting to utilize these lands for grazing throw 

 a very interesting side light on the problem. 



Although the forage plants grown on these pumice soils 

 are normal, so far as reported, they are so seriously deficient as 

 stock feed that cattle and sheep which are pastured on them 

 shortly sicken and die of a curious malady locally known as 

 "bush sickness." I am informed that horses may live for 

 twenty years in perfect health on pastures which are fatal to 

 cattle or sheep in the course of a few months. Sheep are more 

 susceptible to "bush sickness" than cattle, and young animals 

 more so than old. There is thus much borderland country 

 where lambs cannot be raised to maturity, in which cattle 

 suffer but little. The researches of Aston and his associates 15 

 indicate that the trouble is due to a deficiency of available 

 iron in the forage, and considerable progress has been made 

 toward alleviating the condition by applying some iron com- 

 pound such as the sulphate to the soil. The investigation which is 

 still in progress bids fair to throw much light on the general 

 problem of revegetation of volcanic terrains. 



15 Aston, B. C. The Chemistry of Bush Sickness. Jour. N. Z. Dept. Agriculture 

 5: 121-125. 1912. Also Ibid. 3: 394. 1911. 6: 616. 1913. And other articles there 

 mentioned. 



