10 Mantellian Museum at Lewes. 
discoveries of Mr. Mantell were made in the beds of Weald-clay, 
sand, and sandstone below the chalk and green sand formation. 
He observed, that though the latter strata, as is well known, 
contain exclusively the remains of marine animals, such as Nau- 
tilites, Ammonites, and Belemnites, with other shells of marine 
genera, the strata of the former contain almost exclusively 
the remains of terrestrial plants, and shells analogous to fresh- 
water shells, or the bones of vertebrated animals, some of 
which were of enormous magnitude, and were evidently formed 
for walking on solid ground. The strata in which these remains 
are found must have been deposited in a fresh-water lake or 
estuary, or in the bed of a mighty river, on the sides of which 
lived and flourished plants and animals analogous to those 
of tropical climates ; these strata compose a great fresh-water 
formation below the chalk.* 
The labours of Mr. Mantell did not in the first instance re- 
ceive the attention that they justly merited. ‘There is a certain 
prejudice more or less prevalent among the members of scientific 
societies in large cities, such as London or Paris, which makes 
them unwilling to believe that persons residing in provincial 
towns or in the country (des esprits campagnards, as they are 
called) can do any thing important for science; and it is 
strangely imagined, that a city geologist, who runs over a 
district in a few days, can make greater discoveries than 
any one residing in it, who is in the habit of daily and 
repeated observation. It is true, indeed, that the local 
geologist may sometimes be liable to draw erroneous in- 
ferences which more extended researches might have cor- 
rected; but his record of facts, if faithfully given, will always 
possess the highest value, and contribute to remove geology 
from the dominion of theory to the empire of truth and to 
place it on a solid basis. 
It was fortunate that the ardent and intelligent mind of Mr. 
Mantell, enlightened by anatomical and physiological science 
connected with his professional pursuits, perceived the true 
value of his discoveries; but, to make them properly appreciated 
by his own countrymen, the testimony of Baron Cuvier was 
wanting. This illustrious anatomist pronounced the Iguénodon, 
discovered by Mr. Mantell, to be a reptile more extraordinary 
than all those which have been hitherto known (encore plus 
* Some geologists would restrict the term fresh-water formations to beds 
deposited in lakes, but this appears taking a hypothesis for a fact ; we 
know too little of the ancient surface of the earth, to decide whether what 
are. called fresh-water basins were originally lakes, or estuaries, or the beds 
of immense rivers. From the occasional occurrence of oyster shells in the 
Sussex-beds, it is highly probable they were deposited in an estuary. 
