62 WALKS AND TALKS. 



Jbassalian fauna, and brought up the very prototype of its own 

 mechanism. 



But see ! somebody is here with a lantern. How sleepily 

 the light gleams in the darkness. There is no fire in it. 

 Something it is. An animated lantern. A lantern without 

 a flame. It is another strange fish. It is phosphorescence 

 which gleams mildly from his shiny sides. Still another lan- 

 tern-bearing fish. Here are luminous plates beneath the eyes; 

 behind them, in a cavity, retinal tissue, as if these structures 

 were planned for eyes ; but they are not eyes. Real eyes are 

 present. We discover, then, faint relief from the palpable 

 darkness in which we have groped. 



But our task is done ; our curiosity is gratified ; we have 

 glimpsed the underworld, and have gathered observations on 

 which we shall ponder, many a day. Let us now, like the 

 heroes of epic song, ascend to the light of the upper world. 



XI. BY THE ROCKY 



STRATA AND THEIR CLASSIFICATION. 



LET us walk in front of the precipice which frowns along 

 the hill-side near the village of Panama, on the west. It is 

 no more instructive than a thousand other cliffs, but it may 

 be more convenient to reach. The cliff rises fifty or sixty feet 

 and presents a broken and rugged front. The brown and yel- 

 lowish rock is composed of fine silicious grains, with small im- 

 bedded pebbles, and thus answers the description of a con- 

 glomeritic sandstone. The face of the cliff shows several 

 yawning fissures extending from bottom to top. The winter 

 snow drifts into these in such abundance as to remain, some- 

 times, till midsummer. One of these chasms is known, there- 

 fore, as the " Ice House." You observe that this precipice is 

 composed of layers of sandstone piled one above the other. 

 These are strata, and the whole formation is stratified. [Notice 

 that one of these layers is a stratum not "a strata;" and we 

 must never say " stratas."] You observe, also, that some of 



