King — Preliminary Notice of a Memoir on Rock-jointing. 327 



There are two systems of the kind — one meridional, and the other 

 equatorial, depending on the maximum frequency of the joints in certain 

 points of the compass. The first, especially, is divisible into two sec- 

 tions — east-of -north, and west-of -north : a third section, not so strongly 

 developed, may be added, which, running north and south, that is, 

 between the others, may be called medio-meridional. The equatorial 

 system, in general imperfectly developed, may also be divided into 

 two or more sections. As the earth's continents have their chief 

 coast-lines running in directions corresponding to the two principal 

 meridional sections, his contention is, that their east coast-line 

 belongs to, and has been aligned, by the east-of-north meridional 

 jointing; also that their west coast-line stands in corresponding rela- 

 tion to the west-of-north section. 



Contending that jointing, slaty cleavage, great lines of faulting, 

 continental coast-lines, and mountain chains are correlative phe- 

 nomena, he feels himself powerfully sustained, not only by the 

 parallelism between the United States coast and the Appalachian 

 ridges, but equally by the corresponding parallelism of enormous 

 faults — some with a down-throw of thousands of feet — which charac- 

 terise this mountain system. One of the faults is known to stretch 

 from Quebec to New Jersey ! 



The disturbances which developed the " great feature-lines " of 

 our globe seem to have been in operation in pre-Cambrian periods. 

 Evidences have been discovered in the Rocky Mountains, by Clarence 

 King, of a mountain, or regional mass, defined in one tract by a 

 nearly vertical cliff, which, with an altitude of 30,000 feet, was 

 presumably in existence before the earliest palaeozoic deposits were 

 formed. 



The agent which gave an east-of-north trend to the west coast of 

 Europe similarly affected much of the north-west coast of Africa ; and 

 seemingly it struck obliquely across the equatorial section of the 

 Atlantic, re-appearing at Cape St. E,oque, and proceeding onward, 

 along the mountainous sea-board of Brazil, to the La Plata. Enor- 

 mous as undoubtedly is this extent of coast-line formation, it is 

 surpassed by what is presented by the west coasts of the two 

 Americas and the east coast of Asia ; obviously the former, with its 

 parallel mountain ranges, being in genetic relation with the west-of- 

 north and median sections of meridional jointing, and the latter with 

 the east-of-north section. 



Attention is next directed to the great inland ranges constituting 

 the Alps and the Himalayas. Both mountain masses have been more 

 or less affected by forces exerted in directions belonging to the two 

 principal sections of meridional jointing; but in both cases the phe- 

 nomenon has been greatly swayed by movements presumably acting 

 under the influence of the equatorial system. 



The disturbances which developed High Asia — a vast continental 

 mass within a continent stretching from India to the tundras of 

 the Taimyr peninsula, in Asiatic Siberia — have ridged it up trans- 



