436 Notices respecting New Books. 



almost wholly belong to terrestrial genera of the natural monoco- 

 tyledonous orders, Filices, Lycopodiacene, and Equisetaceae, and, by 

 their analogy to existing tropical tribes, seem to demonstrate that 

 the climate of these northern regions was then warmer than it is at 

 present. 



" The fossil plants of the middle aera, which accompany the lias 

 and oolitic rocks in Yorkshire and Sutherland, belong chiefly to 

 the natural monocotyledonous orders, Filices, Lycopodiacess, Equi- 

 setaceae, and Cycadeae, but fragments of dicotyledonous plants also 

 occur with them. 



" The least ancient group of fossil plants, which are enclosed in 

 strata above the chalk, are a mingled suite of monocotyledonous 

 and dicotyledonous tribes, both terrestrial and lacustrine, bearing 

 considerable analogy to plants now in existence. The greater number 

 of fossil shells are certainly marine, but those which lie in layers 

 amidst the monocotyledonous plants of the carboniferous formation, 

 belong almost wholly to fresh-water genera, now in existence. 

 Other local aggregations of fresh-water shells occur in the upper 

 part of the oolitic series of rocks ; but a general deposit of this kind 

 occurs among the most recent, and contains species very similar to 

 those that now exist. 



" The greater portion of the most ancient fossil shells, &c. belong 

 to genera now extinct, as the Productae, Spiriferse, Pentameri, Or- 

 thoceratites, Trilobites, and many genera of Crinoideaj and on the 

 other hand, the least ancient of the fossils, though specifically 

 distinct from existing races, are mostly included in the same genera. 



" But the most important results to geology, arising from the 

 contemplation of organic remains, are founded on a minute scrutiny 

 of their specific characters, and a careful register of their localities 

 in the strata. It is not enough for the rigid accuracy of modern 

 inquiry, to say that a given rock contains corals, shells, and bones 

 of fishes; but we must know the particular species, and determine 

 all the circumstances of their occurrence. The more exact and 

 extended our researches on this subject become, the more clear will 

 be our statements on the succession of created beings, the more 

 certain our applications of zoological principles to determine the 

 relative antiquity of rocks, and the more satisfactory our views of 

 the formation of the strata. Works which, like the present, profess 

 to describe the rocks and fossils of a particular district, lose a large 

 portion of their utility if they are composed without reference to 

 general principles. It is in such local catalogues that the man of 

 enlarged views in geology ought to find the best evidence of im- 

 portant truths, and the means of correcting serious errors. For 

 these important ends, it is necessary that every known locality in 

 the strata should be recorded of every fossil. For want of this pre- 

 caution, fossils have been often stated to be characteristic of a par- 

 ticular rock, when in truth they occur in several others; and thus a 

 crowd of errors have been introduced, which have obscured the 

 truths taught by Mr. Smith, and given occasion for denying that a 

 comparison of their imbedded fossils is useful in identifying and 

 discriminating the strata. Deeply impressed with the interest and 



importance 



