THE OLD RED SANDSTONE. 257 
be covered, two seasons hence, with flowers and fruit. That 
strangely formed organism presents no existing type among 
all the numerous families of the vegetable kingdom.* There 
is an amazing luxuriance of growth all around us. Scarce 
can the current make way through the thickets of aquatic 
plants that rise thick from the muddy bottom ; and though 
the sunshine falls bright on the upper boughs of the tangled 
forest beyond, not a ray penetrates the more than twilight 
gloom that broods over the marshy platform below. The 
rank steam of decaying vegetation forms a thick blue haze, 
that partially obscures the underwood ; deadly lakes of car- 
bonic acid gas have accumulated in the hollows; there is 
silence all around, uninterrupted save by the sudden splash 
of some reptile fish that has risen to the surface in pursuit of 
its prey, or when a sudden breeze stirs the hot air, and shakes 
the fronds of the giant ferns or the catkins of the reeds. 
The wide continent before us is a continent devoid of animal 
life, save that its pools and rivers abound in fish and mollus- 
ca, and that millions and tens of millions of the infusory 
tribes swarm in the bogs and marshes. Here and there, too, 
an insect of strange form flutters among the leaves. It is 
more than probable that no creature furnished with lungs of 
the more perfect construction could have breathed the at- 
mosphere of this early period, and have lived. 
Doubts have been entertained whether the limestone of 
Burdie House belongs to the Upper Old Red Sandstone or to 
the inferior Coal Measures. And the fact may yet come to 
be quoted as a very direct proof of the ignorance which ob- 
tained regarding the fossils of the older formation, at a time 
when the organisms of most of the other formatioas, both 
above and below it, had been carefully explored. The Lime- 
stone of Burdie House is unequivocally and most character- 
isticaily a Coal Measure limestone. It abounds in vegetable 
* See Note O. 
