MacCulloch's System of' Geology. 367 



of the most elaborate paper in the Geological Transactions as 

 incapable of writing either the elements or a system of geolo- 

 gy. He might give lists of characteristic fossils,— he might 

 teach the mode of observing, collecting, classifying rocks, — he 

 might give the whole substance of Conybeare and Phillips s 

 Geology of England, and yet might prove himself incapable of 

 enunciating a single general law of the science, of drawing 

 just geological conclusions, of assigning causes adequate to ef- 

 fects, or commit errors which the humblest elements of dyna- 

 mics, hydrostatics, or chemistry would have prevented. 



That many important facts depend upon apparently trivial 

 determinations of the geological position of individual strata, 

 we must not be conceived to deny. All we assert is, that such 

 a determination, per se, is of little interest to science, and that 

 much precious time, capable of giving the most important ex- 

 tension to our knowledge of natural laws, has been spent in 

 the determination of matters of fact which, the chances are equal, 

 may never add to the limits of geological science. To well di- 

 rected efforts we can set no limits. The physical geologist 

 must be perpetually indebted to the natural historian for the 

 determination of facts which the knowledge of the latter will 

 enable him to answer much more decisively than any moderate 

 acquisition of the former could be expected to effect. Yet the 

 mechanical philosopher is not a closet geologist. His depart- 

 ment does not, indeed, lead him to map the junction of two 

 strata with the precision of a surveyor, or to decide with ela- 

 borate investigation whether a red sandstone be old or new, 

 or a limestone represent the encrinal series or the coal measures: 

 — but his walk is by the volcano and the torrent : — It is he who 

 can judge how far causes now in action are competent to the 

 production of past events. He watches the silent erosion of 

 the ocean-beaten cliffs ; his skill computes the slow but sure 

 transportation of the glaciers. Trained in the school of lober 

 induction, he passes with philosophic caution from the known 

 to the questionable ; he traces the analogy of present eflccts to 

 past effects, and thence, of preset II causes to past earned; I"' 

 can seize the differences which science teaches should subsist 



between the results of power small in amount prolonged through 



time of indefinite extent, and of power indefinitely grtal acting 



during a short space of time. The mineralogist may compan 



NEW BEBIBS] VOL. V. NO. II. OCTOBER 18:31. A B 



