430 
THE GEOLOGIST. 
liosaurian from tlie coal-formation of Nova Scotia, by Mr. O. C. Marsli> 
Eeptilian remains from the coal-measures have hitherto been few in num- 
ber, and have been nearly all regarded as Batrachian or Amphibian. 
The present remains w ere embedded in a stratum of argilla .;eous chocolate- 
coloured shale, which forms part of Group XXVI. of the section made of 
the South Joggins coal-formation, in 1852, by Lyell and Dawson, and is 
about 800 feet above the level of the beds which have furnished the Den- 
derpeton and Hy'^onomus. These remains are those found in 1855 by 
Mr. Marsh, and referred to at page 110 of tliis journal. 
Geeat Ameeicax Deseet. — In their acquisitions from Mexico the 
Americans have acquired not only good, bad, and indifferent lands, but 
they have also acquired the Great Colorado Desert, extending from the 
base of San Bernardino south-westwards, for 180 miles, and having a 
superficial area of 9000 square miles. Excepting the Colorado the 
whole of that district is without river or lake, and the desert stretches 
off to the horizon on all sides without a vestige of vegetation or life. Its 
surface is ashy and parched ; its frame of mountains rise in rugged 
pinnacles of brown rock, bare even of soil. Words are unequal to the 
task of describing its wide expanse, 'the purity of its air, the silence of its 
night, the brilliance of the stars which shine over it, the glare of the mid- 
day sun, and the violence of storms of dust and sand. Parts are even 
destitute of the latter, and present a surface of smooth, compact, sun- 
baked clay. Other parts are covered with heaps of sand, in depths of 
fifty to eighty feet high. Xear the mountains along the Colorado is a 
perfectly flat terrace paved with pebbles, of nearly uniform size, of por- 
phyry, jasper, quartz, carnelian, and agate, all rounded by the action 
of water, and polished till they glisten by the driven sand. The northern 
part of the desert is thought to be the dry bed of an ancient freshwater 
lake, the beach lines of which are strongly marked; and probably, at 
a comparatively recent period, the waters of the Calif ornian Gulf covered 
all the clay portions of the area, which are still below its level ; and if a 
channel were cut through the natural embankment of the Colorado these 
portions, at least, of the desert, woidd be doubtless again covered. It is 
even proposed to effect an outflow of the river for the fertilization of this 
vast arid tract by an artificial irrigation. 
It is possible that the Colorado district may have been elevated within 
historic or immediately prehistoric times, as earthquakes still agitate that 
region ; and in 1852 there were eruptions of mud and hot water in the 
central parts of the valley. 
Fossil Fish in Magnestax Limestone. — There has recently occurred 
in the Magnesian Limestone at Fulwyll Hill some interesting examples of 
fossil fish. The specimens belong to three or probably four species of 
JPalcsoniscus, and to a single species of Acrolepis. Those of the former 
genus are by far more common, and nearly all of them belong to one 
species. Specimens of Acrolepis are exceedingly rare. Three species of 
Palseoniscus have been described by jMr. J. W. Kirby under the names of 
P. varians, P. latus, and P. Ahhsii. They are all small, the largest not 
being more than four inches in length. Along with the fish have been 
found traces of terrestrial plants. Most of these fossils are found in abed 
of slaty and laminated limestone, not more than two feet thick, and only a 
short distance from the base of the " Upper Limestone." The occurrence 
of fish in this subdivision is interesting, as no remains of higher orga- 
nization than mollusca had been previously known to exist in it ; nearly 
all the vertebrata of the Permian series of the district being confined to 
the marl-slate near the bottom of the formation. They are, in fact, the 
