412 Mr. D. A. Bannerman : First Impressions [Ibis, 
from Biskra to Touggourt the desert was partially covered 
with plant-life'—heavy rains had fallen, and the result was 
abundantly manifest. The formation of the myriads of tiny 
sand-mounds which dot the plain, through the agency of the 
bushes Limoniastrum , Salsola , etc., has already been ably 
explained by Dr. Hartert, and even from the carriage 
windows it is evident that these little hillocks are the centre 
of the animal life of the desert. The line passes within view 
of the Chott Melrir and Chott Merouan, and the sight of 
these vast sheets of water alone upsets one^s preconceived 
idea of the Sahara. Unfortunately, now that it is no longer 
necessary to spend three or four days over the journey, the 
ornithologist must not expect to get much idea of the bird- 
life ; he will not, for instance, catch a glimpse of Galerida 
thehlce deichleri , the pale Crested Lark which is found on the 
stony patches amidst the sandy desert, nor of Ammomanes 
phoenicura arenicolor, of Eremophila alpestris bilopha , or 
even of Alcemon alaudipes alaudipes, the Bifasciated Lark 
which occurs, we know from past explorers, in the sandy 
parts of the desert and 'even on the bare dunes. To see 
these birds in their home-surroundings the journey must be 
made on camels, as Lord Rothschild and Dr. Hartert have 
always done in the past. The remarkable spectacle of a 
whirlwind of powdered saltpetre was witnessed at one point 
during our journey, when the train was passing over a plain 
glistening white as freshly fallen snow, the surface being 
encrusted with crystallized nitre. This part of the desert lies 
considerably below the level of the sea. Two or three days 
were spent at Touggourt, and from there my wife and I rode 
on mules to Temacin and Zaouia, taking mint tea at the 
hitter village with the renowned Marabout who had enter¬ 
tained Lord Rothschild and his party in 1909. 
Between Touggourt and Temacin the desert is of a very 
different nature from that farther north ; much of the way 
leads through sand-dunes (Plate V. fig. 1), where only 
Galerida cristata arenicola was observed. Large tracts of the 
desert, particularly where the sand is hard, are covered with 
pieces of gypsum, which sparkle in the sunlight like pieces 
