INTRODUCTION. 3 



travertine or calcareous deposit, -which is often compact and of 

 crystalline hardness, but does not permeate the structure of 

 the enclosed substances ; such are the so-called petrified eggs, 

 skulls, nests, branches, &c., formed by immersion in the in- 

 crusting springs of Derbyshire and other localities. 1 



These preliminary remarks will suffice for our present pur- 

 pose, and prepare the observer to find many of the fossil shells, 

 corals, bones, &c. in the collection, presenting but little differ- 

 ence in appearance from similar objects collected on the sea- 

 shore, or from the beds of streams and rivers ; while others will 

 be seen to resemble masses of rock, having only the forms of 

 organic bodies. Certain peculiar conditions in which animal 

 and vegetable remains occur will be explained in the course 

 of our investigations, as well as those indications of former 

 beings observable on the surfaces of rocks and slabs of stone, 

 though all vestiges of the original structures have perished. 



And here it will be necessary to remind the reader that the 

 objects we are about to examine possess a twofold interest; for 

 they are to be regarded not merely as relics of extraordinary 

 types of animals and vegetables which nourished in the earlier 

 ages of our globe, and have long since become extinct, but also 

 as natural records of the condition of the earth and its inha- 

 bitants, affording indications of the extent and duration of 

 the lands and seas, and of climatorial temperature, &c., 

 through vast periods of time, in ages long antecedent to the 

 creation of the existing species and genera, and the establish- 

 ment of the present order of animated nature. 



In contemplating the principal objects that will come under 

 our examination, it will, therefore, be requisite occasionally to 

 refer to the geological characters of the strata in which they 

 were imbedded, and describe the particular locality whence 

 certain fossils were obtained ; these digressions will, I trust, 

 increase the interest of our survey, and prove alike attractive 

 and instructive. 



The reader who is wholly unacquainted with the principles 

 of Geology should refer to some elementary work on the 

 science, if he would fully comprehend and enjoy the marvellous 

 histories of the past which will be placed before him in the 



1 See "Medals of Creation ;" or, "Wonders of Geology," vol. i. p. 75. 

 (6th edit.) for details. Impressions of leaves on travertine are figured 

 in Pict. Atlas, pi. iii. fig. 2. 



