SECTIONAL TRANSACTIONS.—C. 389 
Some few parts of this metallographic province, like parts of a petrographic 
province, show evidence that appears, if considered in the parochial manner to which 
Prof. Cullis referred, to contradict these general conclusions; but the broader the 
basis, especially when fortified by detailed work over extensive parts of the 
mineralized belt from its northern to its southern limit, the more stable should be 
the theory built upon it. 
Prof. H. Fairrirty Osporn.—Continental Migrations of the Jurassic 
Sauropoda and the Tertiary Mammalia. 
The sauropod-migration theory advanced in this paper is that the Upper Jurassic 
—Lower Cretaceous migrations of the giant reptiles known as Sauropoda paved the 
way for the primary migrations of the primitive Jurassic mammalia, thus giving a 
world-wide distribution to the pro-mammalia, pro-monotremes, pro-marsupials and 
pro-placentals. This sauropod theory would explain the presence of similar-stock 
mammals from which the higher forms adaptively radiated, each centre of radiation 
starting with its distinctive prototypes and ending through adaptive radiation with 
many parallelisms and convergences. The presence at widely scattered points of 
similar multituberculates has been reinforced recently by the discovery of Notostylops 
in South America, Central Asia, and the Rocky Mountain region, 
To present this theory clearly, a new equal-area world map has been prepared to 
display the great migration routes of the sauropods, probably from a Central Asiatic 
stock into all the continents, including Australia and the great island of Madagascar. 
Recent studies of the sauropods by Matthew, von Huene, Longman, and Matley, 
following the earlier researches of Owen, Marsh, Cope, Osborn and Gilmore, all 
showing the world-wide distribution of similar forms of sauropods, tend to confirm 
the central Asiatic theory of origin. 
On this new zoogeographic map are plotted the successive discoveries of great 
mammalian centres of adaptive radiation, namely, (1) Europe, (2) India, (3) Australia, 
(4) South America, (5) Central Asia, which leave two very important centres still to 
be discovered ; (6) northern Asia and (7) western Africa. The radiations from these 
seven great mammalian centres have gradually been traced back into Lower Eocene 
and finally into Upper Cretaceous time, facts consistent with the sauropod migration 
theory. 
Mr. V.S. Swaminataan.—T'he Materials obtained by Dredging and Drilling 
in the Tuticorin Area, South India. 
The paper embodies the results of the examination of materials obtained by 
borings connected with the improvement of the Tuticorin Harbour. Recent changes 
in the coastal outline—during geological and historic times—are discussed and the 
source of the materials touched upon. This is followed by a detailed description of 
the strata penetrated along :— 
1. The Reclamation Line and Shore Turning Basin ; 
2. The Canal Line ; 
3. The Devil Pass Channel ; 
4. The Turning Basin and 
5. The Berth Borings. 
Some six charts and diagrams illustrate the paper. 
Dr. C. A. Martey.—The Harlech Dome. 
This communication deals with the stratigraphy of the mountainous Cambrian 
country of Merionethshire between the Vale of Festiniog and the Barmouth estuary, 
and is founded on the field-work of the late Prof. Charles Lapworth and Dr. T. Stacey 
Wilson, whose survey of the region on 6-inch and 25-inch scales was left unfinished 
and unpublished, except for a brief statement of the stratigraphical succession which 
appeared in a paper on the Dolgelley Gold Belt by A. R. Andrew, who described the 
south-eastern part of the area in 1910. 
