224 Reviews — TJiC New Madrid Earthquake, U.S.A. 



penetrated the borderiug rocks. Subsequent denudation has led to 

 the production of the present physical features. 



The limestone is characterized by its crystalline structure, and 

 although sometimes banded with black layers it is usually a beautiful 

 white saccharoidal marble. The prominent limestone hills before 

 mentioned are regarded by the author as "large blocks of the crust 

 that sank on to the granite magma, relatively less than the surrounding 

 rocks when the Main llange anticline broke up ". l^o palaeontological 

 evidence has been obtained to prove the age of the limestone in the 

 Kinta valley, but in Pahaug the same limestone, less altered, contains 

 Carbonifez'ous fossils. It is the oldest known rock in situ in the 

 Federated Malay States, there being no justification for the statements 

 that have been published concerning the presence of Ai'chaean rocks. 



In describing the Gondwana rocks the author discusses the 

 evidence which leads him to regard the basal clays with boulders as 

 of glacial origin. The clays all contain a certain amount of sand 

 which yields tin-ore and other minerals. In the western part of the 

 area the boulders are mostly tourmaline-corundum rocks ; in the 

 eastern part (Gopeng, etc.) pure corundum boulders occur, as well as 

 a greater variety of other rocks. Referring to the Gopeng clays the 

 author considers that their constitution and the field evidence clearly 

 point to the tin-ore having been derived, with the other minerals, or 

 the bulk of them, from some mass of tin-bearing granite and associated 

 altered rocks, distinct from and older than the Main llange (Mesozoic) 

 granite. At Tekka there are sections showing that the clays arc 

 altered by this granite and invaded by veins of it. It is noteworthy, 

 however, that no clear evidence has been seen of striations or of 

 polished rock-surfaces. The overlying Gondwana rocks comprise 

 chiefly phyllites and quartzites, with also mica-schists, tourmaline- 

 schists, and shales. These newer rocks contain cassiterite, which 

 the author believes to be an original detrital constituent. 



The latest accumulations are those of the lignite and Alluvium ; 

 indeed, the lignites and associated sands appear to form part of the 

 Alluvial deposits, and their thickness in some places " may indicate 

 a long period of deposition in pools or lakes over an area where rapid 

 solution of the limestone bed-rock below led to a steady subsidence of 

 the surface of the ground". 



The concluding portions of the memoir contain particulars of the 

 principal tin-mines and notes on other minerals found in the district. 

 The numerous plates illustrate by excellent photographs some of the 

 physical features of the country, faulted tracts, rock-formations, 

 boulders, mine-works, ore-deposits, and micro-sections of rocks. 



V. — United States Geological Survei'. 



BULLETIN" 494 (1912) is on " The New Madrid Earthquake", by 

 Mr. Myron L. Fuller. This somewhat ancient earthquake, 

 named after New Madrid in Missouri, comprised a succession of 

 shocks, beginning on December 16, 1811, and lasting more than 

 a year. At that time the region was almost devoid of settlers, and 

 the published accounts were few ; nevertheless, the results of the 



