104 GEOLOGY OF LOWER MESOZOIC ROCKS OP QUEENSLAND, 



Fiji, New Hebrides, Solomon, and on to the Admiralty Islands."* 

 This line would then be the eastern boundary of the continental 

 mass of which Australia, New Caledonia, New Zealand, etc., are 

 remnants. Within this continental region there are a number 

 of great deeps, e.g., the two Solomon Island deeps (the northern 

 one named the Planet Deep, the other unnamed) and an unnamed 

 deep between the New Hel>rides and New Caledonia. A discus- 

 sion, which the author had recently with Rev. Father Pigot, of 

 Piverview College, produced some facts which seem directly to 

 concern the question of these deeps. The seismometers at the 

 Riverview College observatory have, within the past few years, 

 recorded a number of earthquake-shocks, and Father Pigot has 

 calculated the positions of origin of these shocks. He kindly 

 informed me that quite a large percentage of the shocks recorded 

 had their origin along a line from Kermadec, through the deep 

 between the New Hebrides and New Caledonia, the Planet Deep, 

 and the Swire Deep (east of the Phillipines). The prevalence of 

 earthquake- shocks emanating from this line of deeps is probably 

 connected with faulting-movements, and it may reasonably be 

 argued that these movements are probably a continuation of 

 those which produced the deeps, and, therefore, that these deeps 

 are of very recent origin. If this is so, we have, in these earth- 

 quake-records, evidence wiiich supports Marshall's contentfon as 

 to the true margin of the south-west Pacific. Marshall's con- 

 clusions in this respect seem reasonable; and Text-fig. 2 (p. 105) 

 indicates the probable limits of the continental mass about the 

 beginning of Mesozoic time; this map has been drawn-up mainly 

 from the works of Marshall and Schuchert, already quoted. 



This continental mass was connected with Asia about tlie 

 begitjning of Mesozoic time, and it may have been continuous 

 witli Gondwanaland. The breaking down of Gondwanaland 

 commenced in early Mesozoic time, and the permanent enlarge- 

 ment of the Pacific basin probably commenced about the same 

 time. There are marine Triassic rocks both in New Caledonia 

 and New Zealand —evidences of epicontinental seas— but there 

 is no marine deposit of Triassic age known on the present Aus- 



* Report Aust. Assoc. Adv. Science, xiii., 1911, p. 99. 



