Notices respecting JVezo Books. 319 



that Nature has distributed the Lower Palaeozoic rocks in three 

 nearly equal subsystems ; and the problem awaiting solution is to 

 find a name which shall cover the entire system, and three other 

 names of subordinate value for each member of this remarkable 

 triad. 



The Parallel Roads of Glenroy ; their Origin and Relation to the 

 Glacial Period and the Deluge. By James Macfadzean. 8vo. 

 149 pages, with a map. Menzies and Co. : Edinburgh [1883J. 



This is a thoughtful work, full of the results of the author's read- 

 ing, by w T hich he has collected arguments and facts to elucidate his 

 views of the origin of these " Parallel Roads." He mentions all 

 the hypotheses that have been framed to account for these local 

 terraces : — namely, (1) an artificial origin by human agency ; 

 (2) natural, by a flood, (3) by the sea, by lakes dammed up, (4) 

 by an undetermined obstacle, or (5) by debris, or (6) by ice. The 

 authors and references are carefully mentioned. After describing 

 the " Eoads " and the hillsides on which they are, he states his 

 objections to the glacial theory of their origin ; and ultimately 

 shows that these terraces were formed, not during a gradual emer- 

 gence of the land, but during its subsidence, and that the several 

 levels or stages were connected with the successive tidal conditions 

 obtaining in the several bays (now glens) opening on the two sides 

 of the sinking land. These stages were formed by the tidal waters 

 gradually overstepping the dividing cols, and by the resulting posi- 

 tions of the cotidal lines then existing round the British Isles (p. 31), 

 and modifying the coating of debris on the mountains by average 

 high-tides at certain levels. The play and action of the tides 

 under all the presumed circumstances of the case are carefully 

 described by the author, and dealt with for each of the terraces. 

 It was the rise of the sea of the Glacial Period in the North- 

 Atlantic basin that invaded and terraced these Highlands ; and the 

 author sees his w T ay to account for its retreat without having 

 effaced the terraces (p. 44). 



The evidences of the great rise and fall of the oceanic waters, 

 the author finds in connection with the distribution of the early 

 and the late Tertiary deposits, respectively, in different regions of 

 the earth. In the North- Atlantic and South-Pacific quarters of 

 the globe he finds the land to have been high in the early Tertiary 

 period ; but at the close of that great period the level of the ocean 

 was reversed in the four quarters, the water having retired from 

 the other two quarters to invade the North- Atlantic and South- 

 Pacific areas. Northern Europe became an Archipelago ; and co-rela- 

 tive facts are noticed for New Zealand and Australia (p. 20). The 

 local differences, such as the two meridian lines of maximum 

 change of level and two of no change, are carefully pointed out 

 (p. 107). 



To account for these great oscillations of level, the author treats 



