24 The Queensland Naturalist May, 1942 
opportunity offered. Appended is diary of the Outings 
mentioned above for record purposes. 
GEO. II. BARKER, 
lion. Excursion Secretary. 
TIME TABLE 
March Saturday afternoon .Camp Mt. 
April Easter Running Creek 
May Week-end Tamborine Mt. 
June . . . .Week-end Caloundra 
July Saturday afternoon .Mt. Gravatt Cave 
August . . . .Saturday afternoon .Sunnybank 
September . . .Week-end Ft. Lookout 
October . . . .Saturday afternoon .Sandgate 
November . . .Saturday afternoon .Sherwood Arboretum 
December . . .Week Tamborine Mt. 
DESERTS 
(Presidential Address by S. T. Blake, M.Sc., 
16th February, 1942) 
The choice of the subject for this address was in- 
fluenced partly perhaps by the prominence of deserts in 
the daily news, but very largely because the subject of 
deserts has given me much food for thought since I visited 
the very arid parts of Queensland in 1936. What is a 
desert? I have consulted various dictionaries, encyclo- 
paedias, and standard works on geography, botany, 
zoology, and geology without meeting with a really satis- 
factory definition, however freely certain features of the 
desert may be discussed. An accurate definition may be 
impracticable, and in many cases the term seems only to 
have a relative significance, but when we call a place a 
desert, we usually understand it to be a very barren, very 
arid piece of country, usually with very little vegetation, 
quite incapable of supporting large herds of cattle or 
flocks of sheep, and incapable of producing crops. The 
aridity may be due to very low rainfall — less than 1 inch 
per year in some places — usually accompanied by high 
day-temperatures and high evaporation, or the aridity may 
be physiological because the ground is frozen so that the 
