On Land-tracts during the Secondary and Tertiary Periods. 269 



sented by 25 ; or in other words, that eight 'perimeters of the 

 regular inscribed polygon of twenty sides (and by still stronger 

 reason, eight circumferences of the circle itself) exceed twenty- 

 five diameters. 



Observatory, March 7, 1862. 



XXXVIII. On the Form and Distribution of the Land-tracts du- 

 ring the Secondary and Tertiary periods respectively ; and on the 

 effects upon Animal Life which great changes in Geographical 

 Configuration have probably produced. By Searles V. Wood, 

 Jun. 



[Continued from p. 171.] 



Section 3. — The Changes in the Geographical Configuration which 

 resulted from Post-cretaceous Volcanic Action. 



WE have numerous evidences that, since the close of the 

 secondary period, the volcanic energy has, with the 

 exception of the chain of the Cordillera, its continuation in the 

 Rocky Mountains, and the coast ranges of the latter, been exerted 

 in a diametrically opposite direction to that which I have attempted 

 to show prevailed throughout the secondary period, the tertiary 

 bands having been, with these exceptions, from east to west. I 

 have collected below the various tertiary geological systems and 

 anticlinals of which I am cognizant, and also the existing vol- 

 canic bands, omitting the Andes, with the average direction they 

 possess : the strictest accuracy in direction is not pretended, the 

 point of the compass being given which coincides nearest with 

 the general strike or direction of the chain or band. 



The following are the systems or anticlinals whose direction is 

 due to post- cretaceous action. (The figures on the left hand 

 refer to the diagram.) 



1. The Antilles E. to W. 



2. Venezuela and Trinidad E. to W. 



3. The Isles of Portland, Purbeck, and Wight, \ ^ w 



and Weald of Kent / Cl " t0 vv * 



4. The Pyrenees E. to W. 



5. The Balearic Isles W.S.W. to E.N.E. 



6. The Atlas W.S.W. to E.N.E. 



7. Malta and Gozo N.W. to S.E. 



8. The principal Alps, and the Noric Alps E.N.E. to W.S.W. 



9. The Apennines, and the Julian and Dinaric Alps. N.W. to S.E. 



10. Bosnia and Albania N.W. to S.E. 



11. The Carpathians (Northern) W.N.W. to E.S.E. 



12. The Carpathians (Southern) W.S.W. to E.N.E. 



13. The Balkan E. to W. 



14. The Caucasus and Crimea W.N.W. to E.S.E. 



15. Armenia and Ararat W.N.W. to E.S.E. 



16. Galicia and Cappadocia W. by S. to E. bv N. 



17. The Turco-Persian frontier N.W. to S.E. 



18. Crete E. to W. 



