518 Reviews — International Geological Congress, 



is now issued as a supplement to the volume before us. This 

 Table is printed on coloured papers, the colours for each geological 

 system corresponding with those adopted on the Geological Map 

 of Europe in course of publication by the Congress. The Table 

 is an elaborate and comprehensive one. In it are indicated the 

 prominent biological zones in each stage, and also the various 

 types of deposit, organic and detrital, and the conditions under 

 which they were accumulated, from the Abyssal to the Aerial, 

 in the principal localities where they have been recognized. The 

 author has received help from many geologists, especially from 

 Karpinsky in reference to Carboniferous, from Kayser in reference 

 to Devonian, and from Lapworth with regard to Silurian. The 

 Table is not put forward as the authoritative scheme of the 

 Congress ; it is essentially an independent work ; but the author's 

 hope is, that it will serve as a basis for an international Table of 

 Formations constructed essentially on chronological grounds. In 

 his explanatory remarks he gives much information on the history 

 and usages of various terms, and adds a " Repertoire Strati- 

 graphique " or glossary of terms applied to different divisions 

 of strata in various parts of the globe. On these matters he invites 

 criticism and correction, and without doubt he will have no reason 

 to complain that they are wanting. 



In treating of the geology of the globe where peat and blown 

 sand have been formed in one area while radiolarian ooze was being 

 slowly accumulated in another, we certainly require other terms 

 than those of Norwich Crag, Kimeridge Clay, or May Hill Sand- 

 stone. The general biological and physical history of the globe 

 must in the main be an indoor study to the individuals who attempt 

 to deal with so vast a subject, for they must gather the materials 

 from the detailed observations of the many local workers. The 

 question is, how far can the local workers adopt the general terms 

 now proposed, and at the same time make known the results of 

 their labours in terms that would be locally applicable and intelli- 

 gible. Formations are restricted to certain areas, and their time- 

 limits vary not only in different countries but within varying 

 geographical limits in one region. Without local names, of course, 

 the stratigraphy of a district can never be clearly explained. Were 

 the terms adopted by Renevier to come into use, the Middle and 

 part of our Lower Lias would be Pliensbachian, our New Red Marl 

 would be Juvavian, the Spilsby Sandstone would be Berriasian, the 

 Atherfield Clay Barremian, the Bracklesham Beds Lutetian, and the 

 Coralline Crag Plaisancian. In some cases our formations would 

 fairly correspond with the time-limits implied by the general tenns; 

 in other cases our formations would represent but a portion of an 

 age, or belong to more than one age. Such difficulties in the way 

 of general correlation are well understood and recognized by all 

 geologists; and if a universal scheme be adopted, then the local 

 formations of each country can perhaps be referred to as Tremadoo 

 Beds (Potsdamian), Magnesian Limestone (Thuringian), or Inferior 

 Oolite (Bajocian), without implying more than an approximate 

 correlation. It must be borne in mind that serious differences exist 



