Notice of Professor Steffens’ Geological Writings. 357 
first established in a more imperfect and lower grade at the 
appearance of the calcareous and siliceous series in the forma- 
tion of the crust of the earth. We now know that this can be 
explained in a much simpler and more natural manner, by the 
consideration, that the strata of the siliceous and argillaceous 
series of the newer formations of the earth were always formed 
under circumstances of disturbance, inasmuch as the surface of 
the earlier continents was at such periods broken up and the 
plants stripped off, which latter formed, as they do on the con- 
tinents of the present day, by much the prevailing mass of 
bodies of higher organization. The rocks of the calcareous 
series, on the other hand, were deposited slowly and tran- 
quilly under a great ocean, and it is in the bosom of the deep 
that by much the largest quantity and the most varied kinds 
of animal beings are still produced. It does not, however, 
remain the less an essential and valuable service rendered 
to geology by Steffens, that he was the first to point out with 
exactness, and to illustrate this contrast ; and it is to the ap- 
pearance of this essay in a great measure, that we are to ascribe 
the greatly augmented mere evinced at the time in the pro- 
gress of our science. 
This is the most importing of the works by Steffens devoted 
to Geognosy. He published a continuation of it at Hamburg 
in 1810, entitled, Geognostisch-geologische Aufsdtze, which con- 
tains a variety of important observations. He there gives a 
lively and original account of the phenomena of the coal for- 
mation, in which he explains the innumerable, often a hun- 
dred times recurring, parallel beds of coal, by the probably 
different nature of the climate of the earth at earlier periods, 
regarding them as the products of an alternation of energetic 
summers, and winters abounding in floods. The work likewise 
includes some very curious observations on geognostical pheno- 
mena occurring in the great plain of Northern Germany, on the 
two remarkable projecting gypsum hills of Liineberg and Se- 
geberg, whose age he endeavoured to determine, and which 
were not more minutely investigated until long afterwards.* 
* Steffens published a work on Mineralogy, entitled “ Handbuch der Oryk- 
tognosic,” 3 vols. Halle, 1811-15.—Ep1t. 
