-i>28 Reviews, and Notices respecting Ne'v Books. 



vesicular and cavernous structure assumed by masses during their 

 refrigeration from a state of fusion, must necessarily have occasioned 

 in the crust thus cooling down and consolidated. He assigns the 

 weight of the materials, and the eruption of elastic vapours, as the 

 concurrent causes of these disruptions. He adds that these disrup- 

 tions of the crust, must, from the disturbances communicated to the 

 incumbent waters, have been necessarily attended with diluvial ac- 

 tion on the largest scale. When these waters had subsequently, in 

 the intervals of quiescence between these convulsions, deposited the 

 materials first acquired by their force of attrition, these sediments 

 formed, by their consolidation, various stony and earthy strata. 

 Thus, he observes, we may recognise a double origin of the rocky 

 masses, the one by refrigeration from igneous fusion, the other by 

 concretion from aqueous solution. " We have here distinctly stated," 

 Mr. Conybeare remarks, " the great basis of every scientific classi- 

 fication of rock formations." By the repetition of similar causes 

 frequent alternations of new strata were produced, until at length, 

 these causes having been reduced to a condition of quiescent equi- 

 librium, a more permanent state of things emerged. In concluding 

 his sketch of this portion of the geological anticipations of Leibnitz. 

 Mr. Conybeare particularly invites to the following clause the at- 

 tention of those writers of the present day, who appear to assume it 

 as an essentia! condition of their theories, that the same physical 

 causes can never, under any former circumstances, have acted with 

 more intense energy than they actually exert : " Donee quiescentibus 

 causis, atque sequilibratis, consistentior emergeret rerum status." 



The contributions to geology of Hooke, Lehman, Fuchsel, Saussure 

 and Werner, are next briefly reviewed ; the first general announce- 

 ment that the various species of organic remains grouped together in 

 the rock formations bear a constant relation to the age of those for- 

 mations, being shown to have been made by the illustrious professor 

 ot Freiberg. The progress of geology, from the period at which it had 

 in his hands begun to assume the systematic character of a regularly 

 digested science, may be considered, Mr. Conybeare remarks, as 

 having presented three marked stages, distinguished by three succes- 

 sive schools. Each of these schools has selected for the more especial 

 object of its attention a single member of the three great geological 

 divisions in the series of formations, i. e. the primitive, secondary, and 

 tertiary; and the succession of these schools has, by a singular coin- 

 cidence, followed the same order with that of the formations to which 

 they were devoted : it may also be observed that the leaders of each 

 school have been distinguished geologists of three different nations, — 

 Germany, England, and France. The first, or German school, is that 

 of Werner himself. The second, or English school, generally recog- 

 nises the masterly observations of Smith, first made public in 179!), 

 as those which have principally contributed to its establishment. The 

 third school, or that of Tertiary Geology, owes its foundation to the 

 admirable memoir on the Basin of Paris, published by Cuvier and 

 Brongniart in 1811. The labours of these schools of geology, and the 

 effect upon the progress of the science produced by the establishment 



